Add HTTP API server, Android app, and CI build/publish pipeline

- docker-compose.yml + tooling-container/src/server.py: serve
  preprocess/OCR/extract over an async job API (POST /jobs, GET
  /jobs/{id}) instead of manual host-script runs per receipt
- android/: Kotlin/Compose app - capture a receipt photo, poll job
  progress, review/edit extracted fields, save locally (Room), export
  to CSV/ODS
- .gitea/workflows/build.yml: build the debug APK and publish it to
  dl.ladkau.de on push
- build-image.sh: also pull ollama/ollama so all pipeline images are
  ready after one script
- add project logo (also used for the app's launcher icon/splash)

.gitea/workflows/build.yml

@@ -0,0 +1,95 @@
+name: build
+
+# Builds the Android app (android/) debug APK on every push/PR, plus
+# on-demand via the Gitea "Run workflow" button. Runs inside a public,
+# prebuilt Android CI image (JDK + Android SDK/cmdline-tools bundled -
+# fuelish's app has no native/NDK code, so it doesn't need a custom
+# builder image the way a project with native components would).
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    # Runner defaults `run:` steps to `sh`, which doesn't understand
+    # `set -o pipefail` used below - force bash explicitly.
+    defaults:
+      run:
+        shell: bash
+    # Must match a label your act_runner is registered with.
+    runs-on: ubuntu-latest
+
+    container:
+      # JDK + Android SDK cmdline-tools, no platform/build-tools installed -
+      # the "Install SDK components" step below fetches exactly what
+      # compileSdk in android/app/build.gradle.kts needs. Much smaller than
+      # kitchen-sink alternatives (~0.7GB vs. several GB), which matters
+      # since every job pulls it fresh.
+      image: thyrlian/android-sdk:10.0
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          # APK naming below uses `git rev-parse --short HEAD` - harmless
+          # with the default shallow clone, but fetch-depth: 0 keeps this
+          # consistent if that ever switches to `git describe --tags`.
+          fetch-depth: 0
+
+      - name: Preflight
+        run: |
+          set -euo pipefail
+          command -v java >/dev/null 2>&1 || { echo "PREFLIGHT FAIL: java not in PATH" >&2; exit 1; }
+          [ -n "${ANDROID_HOME:-}" ] || { echo "PREFLIGHT FAIL: ANDROID_HOME not set" >&2; exit 1; }
+          [ -x android/gradlew ] || { echo "PREFLIGHT FAIL: android/gradlew missing or not executable" >&2; exit 1; }
+
+      - name: Install SDK components
+        run: |
+          set -euo pipefail
+          # python3-pil: android/scripts/gen_app_icons.py's Pillow dependency
+          # (see android/app/build.gradle.kts's generateAppIcons preBuild task)
+          # - not bundled in this image.
+          apt-get update -qq
+          apt-get install -y --no-install-recommends python3-pil
+          yes | sdkmanager --licenses >/dev/null 2>&1 || true
+          # Keep in sync with android/app/build.gradle.kts's compileSdk.
+          sdkmanager "platforms;android-36" "build-tools;36.0.0"
+
+      - name: Build
+        working-directory: android
+        run: ./gradlew :app:assembleDebug --console=plain
+
+      - name: Package
+        # Renames the debug APK with the commit it was built from, so
+        # multiple builds in dist/ (and on dl.ladkau.de) don't collide.
+        run: |
+          set -euo pipefail
+          mkdir -p dist
+          sha="$(git rev-parse --short HEAD)"
+          cp android/app/build/outputs/apk/debug/app-debug.apk "dist/fuelish-$sha.apk"
+
+      - name: Upload build artifact
+        # v4 uses the newer @actions/artifact backend, which this Gitea
+        # instance's artifact storage doesn't support (GHESNotSupportedError) — v3 works.
+        uses: actions/upload-artifact@v3
+        with:
+          name: fuelish-android
+          path: dist/fuelish-*.apk
+
+      - name: Publish to dl.ladkau.de
+        # Uploads the APK over SFTP instead of using actions/upload-artifact
+        # (whose zip wrapping can't be disabled). Only runs on push so PR
+        # builds don't publish.
+        if: gitea.event_name == 'push'
+        run: |
+          set -euo pipefail
+          APK="$(ls dist/fuelish-*.apk)"
+          mkdir -p ~/.ssh
+          echo "${{ secrets.DL_SFTP_KEY }}" > ~/.ssh/dl_sftp_key
+          chmod 600 ~/.ssh/dl_sftp_key
+          sftp -i ~/.ssh/dl_sftp_key -P 2223 \
+            -o StrictHostKeyChecking=accept-new \
+            uploader@dl.ladkau.de <<EOF
+          -mkdir files/fuelish
+          put $APK files/fuelish/$(basename "$APK")
+          EOF

.gitignore

@@ -17,3 +17,18 @@
 # instead of run through the container)
 __pycache__/
 *.pyc
+
+# Android app build output/local config and generated resources (launcher
+# icon + splash art - see android/app/build.gradle.kts's
+# generateAppIcons task and android/scripts/gen_app_icons.py's own
+# doc comment).
+/android/local.properties
+/android/.gradle
+/android/build
+/android/app/build
+/android/app/src/main/res/drawable-nodpi
+/android/app/src/main/res/mipmap-mdpi
+/android/app/src/main/res/mipmap-hdpi
+/android/app/src/main/res/mipmap-xhdpi
+/android/app/src/main/res/mipmap-xxhdpi
+/android/app/src/main/res/mipmap-xxxhdpi

android/app/build.gradle.kts

@@ -0,0 +1,79 @@
+plugins {
+    alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.serialization)
+    alias(libs.plugins.kotlin.compose)
+    alias(libs.plugins.ksp)
+}
+
+android {
+    namespace = "de.ladkau.fuelish"
+    compileSdk = 36
+
+    defaultConfig {
+        applicationId = "de.ladkau.fuelish"
+        minSdk = 24
+        targetSdk = 36
+        versionCode = 1
+        versionName = "0.0.0-dev"
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    buildFeatures {
+        compose = true
+    }
+}
+
+// Compiles with an actual JDK 17 toolchain (auto-provisioned - see
+// settings.gradle.kts's foojay-resolver plugin) rather than whatever JDK
+// launched Gradle, so it stays in sync with android.compileOptions above
+// regardless of which JDK's on PATH.
+kotlin {
+    jvmToolchain(17)
+}
+
+// Regenerates app/src/main/res/{mipmap-*,drawable-nodpi}/* from ../../logo.png
+// (see scripts/gen_app_icons.py) - gitignored generated output, so a fresh
+// checkout needs it produced before any resource-merge/asset-packaging task
+// runs.
+val generateAppIcons = tasks.register<Exec>("generateAppIcons") {
+    workingDir = rootDir
+    commandLine("python3", "scripts/gen_app_icons.py")
+}
+
+tasks.named("preBuild") {
+    dependsOn(generateAppIcons)
+}
+
+dependencies {
+    implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.lifecycle.runtime.ktx)
+    implementation(libs.androidx.lifecycle.viewmodel.compose)
+    implementation(libs.androidx.activity.compose)
+    implementation(platform(libs.androidx.compose.bom))
+    implementation(libs.androidx.ui)
+    implementation(libs.androidx.ui.graphics)
+    implementation(libs.androidx.ui.tooling.preview)
+    implementation(libs.androidx.material3)
+    implementation(libs.androidx.material.icons.core)
+    implementation(libs.androidx.navigation.compose)
+    implementation(libs.androidx.datastore.preferences)
+    implementation(libs.androidx.core.splashscreen)
+    implementation(libs.androidx.room.runtime)
+    implementation(libs.androidx.room.ktx)
+    ksp(libs.androidx.room.compiler)
+    implementation(libs.kotlinx.serialization.json)
+    implementation(libs.kotlinx.coroutines.android)
+    implementation(libs.okhttp)
+    debugImplementation(libs.androidx.ui.tooling)
+}

android/app/proguard-rules.pro

@@ -0,0 +1,9 @@
+# kotlinx.serialization needs its generated serializer classes kept.
+-keepattributes *Annotation*, InnerClasses
+-dontnote kotlinx.serialization.AnnotationsKt
+-keepclasseswithmembers class de.ladkau.fuelish.data.** {
+    *** Companion;
+}
+-keepclasseswithmembers class de.ladkau.fuelish.data.** {
+    kotlinx.serialization.KSerializer serializer(...);
+}

android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.CAMERA" />
+    <uses-feature android:name="android.hardware.camera" android:required="false" />
+
+    <application
+        android:name=".FuelishApplication"
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:networkSecurityConfig="@xml/network_security_config"
+        android:theme="@style/Theme.Fuelish.Splash">
+
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:theme="@style/Theme.Fuelish.Splash">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_paths" />
+        </provider>
+    </application>
+
+</manifest>

android/app/src/main/java/de/ladkau/fuelish/FuelishApplication.kt

@@ -0,0 +1,5 @@
+package de.ladkau.fuelish
+
+import android.app.Application
+
+class FuelishApplication : Application()

android/app/src/main/java/de/ladkau/fuelish/MainActivity.kt

@@ -0,0 +1,22 @@
+package de.ladkau.fuelish
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.enableEdgeToEdge
+import androidx.core.splashscreen.SplashScreen.Companion.installSplashScreen
+import de.ladkau.fuelish.ui.FuelishApp
+import de.ladkau.fuelish.ui.theme.FuelishTheme
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        installSplashScreen()
+        super.onCreate(savedInstanceState)
+        enableEdgeToEdge()
+        setContent {
+            FuelishTheme {
+                FuelishApp()
+            }
+        }
+    }
+}

android/app/src/main/java/de/ladkau/fuelish/data/ApiClient.kt

@@ -0,0 +1,47 @@
+package de.ladkau.fuelish.data
+
+import java.io.File
+import java.io.IOException
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonNamingStrategy
+import okhttp3.MediaType.Companion.toMediaType
+import okhttp3.MultipartBody
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okhttp3.RequestBody.Companion.asRequestBody
+
+/** Talks to tooling-container/src/server.py's two endpoints. Every call
+ * takes the server's base URL explicitly (from [ConfigRepository]) rather
+ * than storing it, since the user can change it from Settings mid-session. */
+class ApiClient(private val client: OkHttpClient = OkHttpClient()) {
+    @OptIn(ExperimentalSerializationApi::class)
+    private val json = Json {
+        ignoreUnknownKeys = true
+        namingStrategy = JsonNamingStrategy.SnakeCase
+    }
+
+    suspend fun submitImage(baseUrl: String, imageFile: File): String = withContext(Dispatchers.IO) {
+        val body = MultipartBody.Builder()
+            .setType(MultipartBody.FORM)
+            .addFormDataPart("image", imageFile.name, imageFile.asRequestBody("image/jpeg".toMediaType()))
+            .build()
+        val request = Request.Builder().url("${baseUrl.trimEnd('/')}/jobs").post(body).build()
+        client.newCall(request).execute().use { response ->
+            if (!response.isSuccessful) throw IOException("upload failed: HTTP ${response.code}")
+            val text = response.body?.string().orEmpty()
+            json.decodeFromString(CreateJobResponse.serializer(), text).jobId
+        }
+    }
+
+    suspend fun getJobStatus(baseUrl: String, jobId: String): JobStatusResponse = withContext(Dispatchers.IO) {
+        val request = Request.Builder().url("${baseUrl.trimEnd('/')}/jobs/$jobId").get().build()
+        client.newCall(request).execute().use { response ->
+            if (!response.isSuccessful) throw IOException("status check failed: HTTP ${response.code}")
+            val text = response.body?.string().orEmpty()
+            json.decodeFromString(JobStatusResponse.serializer(), text)
+        }
+    }
+}

android/app/src/main/java/de/ladkau/fuelish/data/AppConfig.kt

@@ -0,0 +1,10 @@
+package de.ladkau.fuelish.data
+
+/**
+ * Everything the app needs that isn't a saved receipt: just the fuelish
+ * server's base URL (e.g. "http://192.168.1.10:8080") right now.
+ * Persisted via Preferences DataStore, see [ConfigRepository].
+ */
+data class AppConfig(
+    val serverUrl: String = "",
+)

android/app/src/main/java/de/ladkau/fuelish/data/ConfigRepository.kt

@@ -0,0 +1,29 @@
+package de.ladkau.fuelish.data
+
+import android.content.Context
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.stringPreferencesKey
+import androidx.datastore.preferences.preferencesDataStore
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+
+private val Context.configDataStore: DataStore<Preferences> by preferencesDataStore(name = "fuelish_config")
+
+/** Preferences DataStore-backed persistence for [AppConfig]. */
+class ConfigRepository(private val context: Context) {
+    private object Keys {
+        val SERVER_URL = stringPreferencesKey("server_url")
+    }
+
+    val config: Flow<AppConfig> = context.configDataStore.data.map { prefs ->
+        AppConfig(serverUrl = prefs[Keys.SERVER_URL] ?: "")
+    }
+
+    suspend fun save(config: AppConfig) {
+        context.configDataStore.edit { prefs ->
+            prefs[Keys.SERVER_URL] = config.serverUrl
+        }
+    }
+}

android/app/src/main/java/de/ladkau/fuelish/data/FuelishDatabase.kt

@@ -0,0 +1,25 @@
+package de.ladkau.fuelish.data
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+
+@Database(entities = [Receipt::class], version = 1, exportSchema = false)
+abstract class FuelishDatabase : RoomDatabase() {
+    abstract fun receiptDao(): ReceiptDao
+
+    companion object {
+        @Volatile
+        private var instance: FuelishDatabase? = null
+
+        fun get(context: Context): FuelishDatabase =
+            instance ?: synchronized(this) {
+                instance ?: Room.databaseBuilder(
+                    context.applicationContext,
+                    FuelishDatabase::class.java,
+                    "fuelish.db",
+                ).build().also { instance = it }
+            }
+    }
+}

android/app/src/main/java/de/ladkau/fuelish/data/JobDto.kt

@@ -0,0 +1,37 @@
+package de.ladkau.fuelish.data
+
+import kotlinx.serialization.Serializable
+
+/** Mirrors tooling-container/src/server.py's POST /jobs response. */
+@Serializable
+data class CreateJobResponse(val jobId: String)
+
+/** Mirrors tooling-container/src/server.py's GET /jobs/{id} response. */
+@Serializable
+data class JobStatusResponse(
+    val status: String,
+    val result: ExtractedReceiptDto? = null,
+    val error: String? = null,
+) {
+    companion object {
+        const val STATUS_QUEUED = "queued"
+        const val STATUS_PREPROCESSING = "preprocessing"
+        const val STATUS_OCR = "ocr"
+        const val STATUS_EXTRACTING = "extracting"
+        const val STATUS_DONE = "done"
+        const val STATUS_ERROR = "error"
+    }
+}
+
+/** Mirrors tooling-container/src/extract.py's SCHEMA. */
+@Serializable
+data class ExtractedReceiptDto(
+    val petrolStation: String? = null,
+    val transactionNumber: String? = null,
+    val date: String? = null,
+    val time: String? = null,
+    val pricePerLitre: Double? = null,
+    val litres: Double? = null,
+    val discount: Double? = null,
+    val totalPrice: Double? = null,
+)

android/app/src/main/java/de/ladkau/fuelish/data/Receipt.kt

@@ -0,0 +1,27 @@
+package de.ladkau.fuelish.data
+
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+/**
+ * A confirmed receipt, as the user saved it after reviewing the server's
+ * extraction. This app is the system of record - the server is
+ * stateless processing only (see docker-compose.yml / server.py).
+ */
+@Entity(tableName = "receipts")
+data class Receipt(
+    @PrimaryKey(autoGenerate = true) val id: Long = 0,
+    val petrolStation: String?,
+    val transactionNumber: String?,
+    /** DD.MM.YYYY, matching testdata/.../benzin_kosten.ods's ground-truth format. */
+    val date: String?,
+    /** HH:MM:SS. */
+    val time: String?,
+    val pricePerLitre: Double?,
+    val litres: Double?,
+    val discount: Double?,
+    val totalPrice: Double?,
+    /** content:// or file:// URI of the captured photo, kept for reference - null if unavailable. */
+    val imageUri: String?,
+    val createdAtEpochMillis: Long,
+)

android/app/src/main/java/de/ladkau/fuelish/data/ReceiptDao.kt

@@ -0,0 +1,26 @@
+package de.ladkau.fuelish.data
+
+import androidx.room.Dao
+import androidx.room.Delete
+import androidx.room.Insert
+import androidx.room.Query
+import androidx.room.Update
+import kotlinx.coroutines.flow.Flow
+
+@Dao
+interface ReceiptDao {
+    @Query("SELECT * FROM receipts ORDER BY date DESC, createdAtEpochMillis DESC")
+    fun observeAll(): Flow<List<Receipt>>
+
+    @Query("SELECT * FROM receipts WHERE id = :id")
+    suspend fun getById(id: Long): Receipt?
+
+    @Insert
+    suspend fun insert(receipt: Receipt): Long
+
+    @Update
+    suspend fun update(receipt: Receipt)
+
+    @Delete
+    suspend fun delete(receipt: Receipt)
+}

android/app/src/main/java/de/ladkau/fuelish/data/ReceiptRepository.kt

@@ -0,0 +1,25 @@
+package de.ladkau.fuelish.data
+
+import android.content.Context
+import java.io.File
+import kotlinx.coroutines.flow.Flow
+
+/** Wraps the local Room store (the system of record for confirmed
+ * receipts) and the [ApiClient] (stateless per-receipt processing) behind
+ * one entry point for the ui layer. */
+class ReceiptRepository(context: Context) {
+    private val dao = FuelishDatabase.get(context).receiptDao()
+    private val api = ApiClient()
+
+    val receipts: Flow<List<Receipt>> = dao.observeAll()
+
+    suspend fun submitImage(baseUrl: String, imageFile: File): String = api.submitImage(baseUrl, imageFile)
+
+    suspend fun pollJob(baseUrl: String, jobId: String): JobStatusResponse = api.getJobStatus(baseUrl, jobId)
+
+    suspend fun save(receipt: Receipt): Long = dao.insert(receipt)
+
+    suspend fun update(receipt: Receipt) = dao.update(receipt)
+
+    suspend fun delete(receipt: Receipt) = dao.delete(receipt)
+}

android/app/src/main/java/de/ladkau/fuelish/export/CsvExporter.kt

@@ -0,0 +1,28 @@
+package de.ladkau.fuelish.export
+
+import de.ladkau.fuelish.data.Receipt
+import java.io.OutputStream
+
+/** ";"-delimited, not ",": our cells use a German decimal comma (see
+ * [toExportRow]), which would otherwise collide with a comma delimiter -
+ * ";" is also what German-locale Excel/LibreOffice expect by default. */
+private const val DELIMITER = ";"
+private val UTF8_BOM = byteArrayOf(0xEF.toByte(), 0xBB.toByte(), 0xBF.toByte())
+
+fun exportCsv(receipts: List<Receipt>, out: OutputStream) {
+    out.write(UTF8_BOM)
+    out.write(csvLine(EXPORT_HEADERS).toByteArray(Charsets.UTF_8))
+    for (receipt in receipts) {
+        out.write(csvLine(receipt.toExportRow()).toByteArray(Charsets.UTF_8))
+    }
+}
+
+private fun csvLine(fields: List<String>): String =
+    fields.joinToString(DELIMITER) { escapeCsvField(it) } + "\r\n"
+
+private fun escapeCsvField(field: String): String =
+    if (field.contains(DELIMITER) || field.contains('"') || field.contains('\n')) {
+        "\"" + field.replace("\"", "\"\"") + "\""
+    } else {
+        field
+    }

android/app/src/main/java/de/ladkau/fuelish/export/OdsExporter.kt

@@ -0,0 +1,92 @@
+package de.ladkau.fuelish.export
+
+import de.ladkau.fuelish.data.Receipt
+import java.io.OutputStream
+import java.util.zip.CRC32
+import java.util.zip.ZipEntry
+import java.util.zip.ZipOutputStream
+
+private const val MIMETYPE = "application/vnd.oasis.opendocument.spreadsheet"
+
+/**
+ * A minimal hand-rolled ODF spreadsheet writer - no dependency needed,
+ * since an .ods is just a zip of a few fixed XML files. Writes only what
+ * testdata/.../benzin_kosten.ods's own reader (compare_ground_truth.py,
+ * via odfpy) needs: one table, string-typed cells (matching how that
+ * ground-truth sheet itself stores formatted values - see
+ * [toExportRow]'s doc comment), no styles/formulas.
+ */
+fun exportOds(receipts: List<Receipt>, out: OutputStream) {
+    ZipOutputStream(out).use { zip ->
+        // Must be the first entry, stored uncompressed with no extra
+        // fields, so ODF-aware tools can sniff the file type without
+        // inflating - the format spec requires this.
+        val mimetypeBytes = MIMETYPE.toByteArray(Charsets.US_ASCII)
+        val mimetypeEntry = ZipEntry("mimetype").apply {
+            method = ZipEntry.STORED
+            size = mimetypeBytes.size.toLong()
+            compressedSize = mimetypeBytes.size.toLong()
+            crc = CRC32().apply { update(mimetypeBytes) }.value
+        }
+        zip.putNextEntry(mimetypeEntry)
+        zip.write(mimetypeBytes)
+        zip.closeEntry()
+
+        zip.putNextEntry(ZipEntry("META-INF/manifest.xml"))
+        zip.write(manifestXml().toByteArray(Charsets.UTF_8))
+        zip.closeEntry()
+
+        zip.putNextEntry(ZipEntry("content.xml"))
+        zip.write(contentXml(receipts).toByteArray(Charsets.UTF_8))
+        zip.closeEntry()
+    }
+}
+
+private fun manifestXml(): String = """
+    <?xml version="1.0" encoding="UTF-8"?>
+    <manifest:manifest xmlns:manifest="urn:oasis:names:tc:opendocument:xmlns:manifest:1.0" manifest:version="1.2">
+      <manifest:file-entry manifest:full-path="/" manifest:version="1.2" manifest:media-type="$MIMETYPE"/>
+      <manifest:file-entry manifest:full-path="content.xml" manifest:media-type="text/xml"/>
+    </manifest:manifest>
+""".trimIndent()
+
+private fun contentXml(receipts: List<Receipt>): String {
+    val rows = buildString {
+        append(tableRow(EXPORT_HEADERS))
+        for (receipt in receipts) {
+            append(tableRow(receipt.toExportRow()))
+        }
+    }
+    return """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <office:document-content
+            xmlns:office="urn:oasis:names:tc:opendocument:xmlns:office:1.0"
+            xmlns:table="urn:oasis:names:tc:opendocument:xmlns:table:1.0"
+            xmlns:text="urn:oasis:names:tc:opendocument:xmlns:text:1.0"
+            office:version="1.2">
+          <office:body>
+            <office:spreadsheet>
+              <table:table table:name="Receipts">
+                $rows
+              </table:table>
+            </office:spreadsheet>
+          </office:body>
+        </office:document-content>
+    """.trimIndent()
+}
+
+private fun tableRow(cells: List<String>): String = buildString {
+    append("<table:table-row>")
+    for (cell in cells) {
+        append("<table:table-cell office:value-type=\"string\"><text:p>")
+        append(escapeXml(cell))
+        append("</text:p></table:table-cell>")
+    }
+    append("</table:table-row>")
+}
+
+private fun escapeXml(text: String): String = text
+    .replace("&", "&amp;")
+    .replace("<", "&lt;")
+    .replace(">", "&gt;")
+    .replace("\"", "&quot;")

android/app/src/main/java/de/ladkau/fuelish/export/ReceiptRow.kt

@@ -0,0 +1,29 @@
+package de.ladkau.fuelish.export
+
+import de.ladkau.fuelish.data.Receipt
+import java.util.Locale
+
+/**
+ * The first 6 columns mirror testdata/.../benzin_kosten.ods's layout
+ * exactly (date, time, price_per_litre, litres, discount, total_price -
+ * see tooling-container/src/compare_ground_truth.py's column order and
+ * its German-locale decimal-comma / "€"-suffix parsing, which this
+ * reproduces on the way out). petrol_station/transaction_number are
+ * appended as extra trailing columns - present in this app's data but
+ * not in the original ground-truth sheet.
+ */
+val EXPORT_HEADERS = listOf(
+    "Datum", "Uhrzeit", "Preis/Liter", "Liter", "Rabatt", "Gesamtpreis",
+    "Tankstelle", "Transaktionsnummer",
+)
+
+fun Receipt.toExportRow(): List<String> = listOf(
+    date.orEmpty(),
+    time.orEmpty(),
+    pricePerLitre?.let { String.format(Locale.GERMANY, "%.3f", it) }.orEmpty(),
+    litres?.let { String.format(Locale.GERMANY, "%.2f", it) }.orEmpty(),
+    discount?.let { String.format(Locale.GERMANY, "%.2f €", it) }.orEmpty(),
+    totalPrice?.let { String.format(Locale.GERMANY, "%.2f €", it) }.orEmpty(),
+    petrolStation.orEmpty(),
+    transactionNumber.orEmpty(),
+)

android/app/src/main/java/de/ladkau/fuelish/ui/FuelishApp.kt

@@ -0,0 +1,105 @@
+package de.ladkau.fuelish.ui
+
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Menu
+import androidx.compose.material3.DrawerValue
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.ModalDrawerSheet
+import androidx.compose.material3.ModalNavigationDrawer
+import androidx.compose.material3.NavigationDrawerItem
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.rememberDrawerState
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.navigation.NavHostController
+import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.composable
+import androidx.navigation.compose.currentBackStackEntryAsState
+import androidx.navigation.compose.rememberNavController
+import de.ladkau.fuelish.R
+import de.ladkau.fuelish.ui.capture.CaptureScreen
+import de.ladkau.fuelish.ui.overview.OverviewScreen
+import de.ladkau.fuelish.ui.settings.ConfigScreen
+import kotlinx.coroutines.launch
+
+private object Destinations {
+    const val CAPTURE = "capture"
+    const val OVERVIEW = "overview"
+    const val SETTINGS = "settings"
+}
+
+/** Burger menu = ModalNavigationDrawer, leading to Scan/Receipts/Settings -
+ * the app's single navigation host. */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun FuelishApp() {
+    val navController = rememberNavController()
+    val drawerState = rememberDrawerState(initialValue = DrawerValue.Closed)
+    val scope = rememberCoroutineScope()
+    val currentRoute = navController.currentBackStackEntryAsState().value?.destination?.route
+
+    ModalNavigationDrawer(
+        drawerState = drawerState,
+        drawerContent = {
+            ModalDrawerSheet {
+                NavigationDrawerItem(
+                    label = { Text(stringResource(R.string.nav_capture)) },
+                    selected = currentRoute == Destinations.CAPTURE,
+                    onClick = { navigateTo(navController, Destinations.CAPTURE); scope.launch { drawerState.close() } },
+                    modifier = Modifier.padding(horizontal = 12.dp),
+                )
+                NavigationDrawerItem(
+                    label = { Text(stringResource(R.string.nav_overview)) },
+                    selected = currentRoute == Destinations.OVERVIEW,
+                    onClick = { navigateTo(navController, Destinations.OVERVIEW); scope.launch { drawerState.close() } },
+                    modifier = Modifier.padding(horizontal = 12.dp),
+                )
+                NavigationDrawerItem(
+                    label = { Text(stringResource(R.string.nav_settings)) },
+                    selected = currentRoute == Destinations.SETTINGS,
+                    onClick = { navigateTo(navController, Destinations.SETTINGS); scope.launch { drawerState.close() } },
+                    modifier = Modifier.padding(horizontal = 12.dp),
+                )
+            }
+        },
+    ) {
+        Scaffold(
+            topBar = {
+                TopAppBar(
+                    title = { Text(stringResource(R.string.app_name)) },
+                    navigationIcon = {
+                        IconButton(onClick = { scope.launch { drawerState.open() } }) {
+                            Icon(Icons.Filled.Menu, contentDescription = stringResource(R.string.nav_settings))
+                        }
+                    },
+                )
+            },
+        ) { innerPadding ->
+            NavHost(
+                navController = navController,
+                startDestination = Destinations.CAPTURE,
+                modifier = Modifier.padding(innerPadding),
+            ) {
+                composable(Destinations.CAPTURE) { CaptureScreen() }
+                composable(Destinations.OVERVIEW) { OverviewScreen() }
+                composable(Destinations.SETTINGS) { ConfigScreen() }
+            }
+        }
+    }
+}
+
+private fun navigateTo(navController: NavHostController, route: String) {
+    navController.navigate(route) {
+        popUpTo(navController.graph.startDestinationId) { saveState = true }
+        launchSingleTop = true
+        restoreState = true
+    }
+}

android/app/src/main/java/de/ladkau/fuelish/ui/capture/CaptureScreen.kt

@@ -0,0 +1,170 @@
+package de.ladkau.fuelish.ui.capture
+
+import android.Manifest
+import android.content.pm.PackageManager
+import android.net.Uri
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.Button
+import androidx.compose.material3.LinearProgressIndicator
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.core.content.ContextCompat
+import androidx.core.content.FileProvider
+import androidx.lifecycle.viewmodel.compose.viewModel
+import de.ladkau.fuelish.R
+import de.ladkau.fuelish.data.ExtractedReceiptDto
+import de.ladkau.fuelish.data.JobStatusResponse
+import java.io.File
+
+@Composable
+fun CaptureScreen(viewModel: CaptureViewModel = viewModel()) {
+    val uiState by viewModel.uiState.collectAsState()
+    val context = LocalContext.current
+
+    var pendingFile by remember { mutableStateOf<File?>(null) }
+    var pendingUri by remember { mutableStateOf<Uri?>(null) }
+
+    val takePictureLauncher = rememberLauncherForActivityResult(ActivityResultContracts.TakePicture()) { success ->
+        val file = pendingFile
+        val uri = pendingUri
+        if (success && file != null && uri != null) {
+            viewModel.submit(file, uri)
+        }
+    }
+
+    fun launchCamera() {
+        val dir = File(context.cacheDir, "captures").apply { mkdirs() }
+        val file = File(dir, "capture-${System.currentTimeMillis()}.jpg")
+        val uri = FileProvider.getUriForFile(context, "${context.packageName}.fileprovider", file)
+        pendingFile = file
+        pendingUri = uri
+        takePictureLauncher.launch(uri)
+    }
+
+    val cameraPermissionLauncher = rememberLauncherForActivityResult(ActivityResultContracts.RequestPermission()) { granted ->
+        if (granted) launchCamera()
+    }
+
+    Box(modifier = Modifier.fillMaxSize().padding(16.dp)) {
+        when (val state = uiState) {
+            is CaptureUiState.Idle -> Button(
+                onClick = {
+                    val hasPermission = ContextCompat.checkSelfPermission(context, Manifest.permission.CAMERA) ==
+                        PackageManager.PERMISSION_GRANTED
+                    if (hasPermission) launchCamera() else cameraPermissionLauncher.launch(Manifest.permission.CAMERA)
+                },
+            ) {
+                Text(stringResource(R.string.capture_take_photo))
+            }
+
+            is CaptureUiState.Uploading -> ProgressStage(stringResource(R.string.capture_stage_uploading), 0.2f)
+
+            is CaptureUiState.Processing -> {
+                val (labelRes, progress) = when (state.stage) {
+                    JobStatusResponse.STATUS_PREPROCESSING -> R.string.capture_stage_preprocessing to 0.45f
+                    JobStatusResponse.STATUS_OCR -> R.string.capture_stage_ocr to 0.7f
+                    JobStatusResponse.STATUS_EXTRACTING -> R.string.capture_stage_extracting to 0.9f
+                    else -> R.string.capture_stage_uploading to 0.2f
+                }
+                ProgressStage(stringResource(labelRes), progress)
+            }
+
+            is CaptureUiState.Editing -> EditForm(draft = state.draft, onSave = { viewModel.save(it) })
+
+            is CaptureUiState.Error -> Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
+                Text(stringResource(R.string.capture_stage_error, state.message))
+                Button(onClick = { viewModel.reset() }) { Text(stringResource(R.string.capture_retry)) }
+            }
+        }
+    }
+}
+
+@Composable
+private fun ProgressStage(label: String, progress: Float) {
+    Column(
+        modifier = Modifier.fillMaxWidth(),
+        verticalArrangement = Arrangement.spacedBy(12.dp),
+    ) {
+        Text(label)
+        LinearProgressIndicator(progress = { progress }, modifier = Modifier.fillMaxWidth())
+    }
+}
+
+@Composable
+private fun EditForm(draft: ExtractedReceiptDto, onSave: (ExtractedReceiptDto) -> Unit) {
+    var petrolStation by remember { mutableStateOf(draft.petrolStation.orEmpty()) }
+    var transactionNumber by remember { mutableStateOf(draft.transactionNumber.orEmpty()) }
+    var date by remember { mutableStateOf(draft.date.orEmpty()) }
+    var time by remember { mutableStateOf(draft.time.orEmpty()) }
+    var pricePerLitre by remember { mutableStateOf(draft.pricePerLitre?.toString().orEmpty()) }
+    var litres by remember { mutableStateOf(draft.litres?.toString().orEmpty()) }
+    var discount by remember { mutableStateOf(draft.discount?.toString().orEmpty()) }
+    var totalPrice by remember { mutableStateOf(draft.totalPrice?.toString().orEmpty()) }
+
+    Column(
+        modifier = Modifier
+            .fillMaxSize()
+            .verticalScroll(rememberScrollState()),
+        verticalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        LabeledField(R.string.capture_field_petrol_station, petrolStation) { petrolStation = it }
+        LabeledField(R.string.capture_field_transaction_number, transactionNumber) { transactionNumber = it }
+        LabeledField(R.string.capture_field_date, date) { date = it }
+        LabeledField(R.string.capture_field_time, time) { time = it }
+        LabeledField(R.string.capture_field_price_per_litre, pricePerLitre) { pricePerLitre = it }
+        LabeledField(R.string.capture_field_litres, litres) { litres = it }
+        LabeledField(R.string.capture_field_discount, discount) { discount = it }
+        LabeledField(R.string.capture_field_total_price, totalPrice) { totalPrice = it }
+
+        Button(
+            onClick = {
+                onSave(
+                    ExtractedReceiptDto(
+                        petrolStation = petrolStation.ifBlank { null },
+                        transactionNumber = transactionNumber.ifBlank { null },
+                        date = date.ifBlank { null },
+                        time = time.ifBlank { null },
+                        pricePerLitre = pricePerLitre.toDoubleOrNull(),
+                        litres = litres.toDoubleOrNull(),
+                        discount = discount.toDoubleOrNull(),
+                        totalPrice = totalPrice.toDoubleOrNull(),
+                    ),
+                )
+            },
+            modifier = Modifier.align(Alignment.End),
+        ) {
+            Text(stringResource(R.string.capture_save))
+        }
+    }
+}
+
+@Composable
+private fun LabeledField(labelRes: Int, value: String, onValueChange: (String) -> Unit) {
+    OutlinedTextField(
+        value = value,
+        onValueChange = onValueChange,
+        label = { Text(stringResource(labelRes)) },
+        singleLine = true,
+        modifier = Modifier.fillMaxWidth(),
+    )
+}

android/app/src/main/java/de/ladkau/fuelish/ui/capture/CaptureUiState.kt

@@ -0,0 +1,14 @@
+package de.ladkau.fuelish.ui.capture
+
+import de.ladkau.fuelish.data.ExtractedReceiptDto
+
+sealed interface CaptureUiState {
+    data object Idle : CaptureUiState
+    data object Uploading : CaptureUiState
+
+    /** [stage] is one of JobStatusResponse's STATUS_* constants (preprocessing/ocr/extracting). */
+    data class Processing(val stage: String) : CaptureUiState
+
+    data class Editing(val draft: ExtractedReceiptDto) : CaptureUiState
+    data class Error(val message: String) : CaptureUiState
+}

android/app/src/main/java/de/ladkau/fuelish/ui/capture/CaptureViewModel.kt

@@ -0,0 +1,96 @@
+package de.ladkau.fuelish.ui.capture
+
+import android.app.Application
+import android.net.Uri
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
+import de.ladkau.fuelish.data.ConfigRepository
+import de.ladkau.fuelish.data.ExtractedReceiptDto
+import de.ladkau.fuelish.data.JobStatusResponse
+import de.ladkau.fuelish.data.Receipt
+import de.ladkau.fuelish.data.ReceiptRepository
+import java.io.File
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.launch
+
+private const val POLL_INTERVAL_MILLIS = 1_500L
+
+class CaptureViewModel(application: Application) : AndroidViewModel(application) {
+    private val repository = ReceiptRepository(application)
+    private val configRepository = ConfigRepository(application)
+
+    private val _uiState = MutableStateFlow<CaptureUiState>(CaptureUiState.Idle)
+    val uiState: StateFlow<CaptureUiState> = _uiState.asStateFlow()
+
+    // The captured photo's local URI, kept alongside the receipt once saved
+    // (see Receipt.imageUri) - set right before submit(), cleared on save()/reset().
+    private var pendingImageUri: Uri? = null
+
+    fun submit(imageFile: File, imageUri: Uri) {
+        pendingImageUri = imageUri
+        viewModelScope.launch {
+            _uiState.value = CaptureUiState.Uploading
+            try {
+                val baseUrl = configRepository.config.first().serverUrl
+                if (baseUrl.isBlank()) {
+                    _uiState.value = CaptureUiState.Error("Set the server URL in Settings first")
+                    return@launch
+                }
+                val jobId = repository.submitImage(baseUrl, imageFile)
+                pollUntilDone(baseUrl, jobId)
+            } catch (e: Exception) {
+                _uiState.value = CaptureUiState.Error(e.message ?: "unknown error")
+            }
+        }
+    }
+
+    private suspend fun pollUntilDone(baseUrl: String, jobId: String) {
+        while (true) {
+            val status = repository.pollJob(baseUrl, jobId)
+            when (status.status) {
+                JobStatusResponse.STATUS_DONE -> {
+                    _uiState.value = CaptureUiState.Editing(status.result ?: ExtractedReceiptDto())
+                    return
+                }
+                JobStatusResponse.STATUS_ERROR -> {
+                    _uiState.value = CaptureUiState.Error(status.error ?: "processing failed")
+                    return
+                }
+                else -> {
+                    _uiState.value = CaptureUiState.Processing(status.status)
+                    delay(POLL_INTERVAL_MILLIS)
+                }
+            }
+        }
+    }
+
+    fun save(draft: ExtractedReceiptDto) {
+        viewModelScope.launch {
+            repository.save(
+                Receipt(
+                    petrolStation = draft.petrolStation,
+                    transactionNumber = draft.transactionNumber,
+                    date = draft.date,
+                    time = draft.time,
+                    pricePerLitre = draft.pricePerLitre,
+                    litres = draft.litres,
+                    discount = draft.discount,
+                    totalPrice = draft.totalPrice,
+                    imageUri = pendingImageUri?.toString(),
+                    createdAtEpochMillis = System.currentTimeMillis(),
+                ),
+            )
+            pendingImageUri = null
+            _uiState.value = CaptureUiState.Idle
+        }
+    }
+
+    fun reset() {
+        pendingImageUri = null
+        _uiState.value = CaptureUiState.Idle
+    }
+}

android/app/src/main/java/de/ladkau/fuelish/ui/overview/OverviewScreen.kt

@@ -0,0 +1,93 @@
+package de.ladkau.fuelish.ui.overview
+
+import android.content.Intent
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material3.Button
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.viewmodel.compose.viewModel
+import de.ladkau.fuelish.R
+import de.ladkau.fuelish.data.Receipt
+
+@Composable
+fun OverviewScreen(viewModel: OverviewViewModel = viewModel()) {
+    val receipts by viewModel.receipts.collectAsState()
+    val context = LocalContext.current
+
+    Column(modifier = Modifier.fillMaxSize()) {
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(16.dp),
+            horizontalArrangement = Arrangement.spacedBy(12.dp),
+        ) {
+            Button(onClick = { viewModel.exportCsv { uri -> shareFile(context, uri, "text/csv") } }) {
+                Text(stringResource(R.string.overview_export_csv))
+            }
+            Button(onClick = { viewModel.exportOds { uri -> shareFile(context, uri, "application/vnd.oasis.opendocument.spreadsheet") } }) {
+                Text(stringResource(R.string.overview_export_ods))
+            }
+        }
+
+        if (receipts.isEmpty()) {
+            Text(
+                text = stringResource(R.string.overview_empty),
+                modifier = Modifier.padding(16.dp),
+            )
+        } else {
+            LazyColumn(modifier = Modifier.fillMaxSize()) {
+                items(receipts, key = { it.id }) { receipt ->
+                    ReceiptRow(receipt = receipt, onDelete = { viewModel.delete(receipt) })
+                    HorizontalDivider()
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun ReceiptRow(receipt: Receipt, onDelete: () -> Unit) {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(horizontal = 16.dp, vertical = 8.dp),
+        horizontalArrangement = Arrangement.SpaceBetween,
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Column {
+            Text(text = receipt.date.orEmpty())
+            Text(text = listOfNotNull(receipt.petrolStation, receipt.totalPrice?.let { "%.2f €".format(it) }).joinToString(" · "))
+        }
+        IconButton(onClick = onDelete) {
+            Icon(Icons.Filled.Delete, contentDescription = null)
+        }
+    }
+}
+
+private fun shareFile(context: android.content.Context, uri: android.net.Uri, mimeType: String) {
+    val intent = Intent(Intent.ACTION_SEND).apply {
+        type = mimeType
+        putExtra(Intent.EXTRA_STREAM, uri)
+        addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+    }
+    context.startActivity(Intent.createChooser(intent, null))
+}

android/app/src/main/java/de/ladkau/fuelish/ui/overview/OverviewViewModel.kt

@@ -0,0 +1,46 @@
+package de.ladkau.fuelish.ui.overview
+
+import android.app.Application
+import android.net.Uri
+import androidx.core.content.FileProvider
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
+import de.ladkau.fuelish.data.Receipt
+import de.ladkau.fuelish.data.ReceiptRepository
+import de.ladkau.fuelish.export.exportCsv as writeCsvRows
+import de.ladkau.fuelish.export.exportOds as writeOdsRows
+import java.io.File
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+
+class OverviewViewModel(application: Application) : AndroidViewModel(application) {
+    private val repository = ReceiptRepository(application)
+
+    val receipts: StateFlow<List<Receipt>> = repository.receipts
+        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), emptyList())
+
+    fun delete(receipt: Receipt) {
+        viewModelScope.launch { repository.delete(receipt) }
+    }
+
+    fun exportCsv(onReady: (Uri) -> Unit) = export("fuelish-receipts.csv", ::writeCsvRows, onReady)
+
+    fun exportOds(onReady: (Uri) -> Unit) = export("fuelish-receipts.ods", ::writeOdsRows, onReady)
+
+    private fun export(fileName: String, write: (List<Receipt>, java.io.OutputStream) -> Unit, onReady: (Uri) -> Unit) {
+        val app = getApplication<Application>()
+        viewModelScope.launch {
+            val uri = withContext(Dispatchers.IO) {
+                val dir = File(app.cacheDir, "exports").apply { mkdirs() }
+                val file = File(dir, fileName)
+                file.outputStream().use { write(receipts.value, it) }
+                FileProvider.getUriForFile(app, "${app.packageName}.fileprovider", file)
+            }
+            onReady(uri)
+        }
+    }
+}

android/app/src/main/java/de/ladkau/fuelish/ui/settings/ConfigScreen.kt

@@ -0,0 +1,42 @@
+package de.ladkau.fuelish.ui.settings
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.viewmodel.compose.viewModel
+import de.ladkau.fuelish.R
+
+@Composable
+fun ConfigScreen(viewModel: ConfigViewModel = viewModel()) {
+    val config by viewModel.config.collectAsState()
+    val isDirty by viewModel.isDirty.collectAsState()
+
+    Column(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(16.dp),
+        verticalArrangement = Arrangement.spacedBy(12.dp),
+    ) {
+        OutlinedTextField(
+            value = config.serverUrl,
+            onValueChange = { viewModel.update { c -> c.copy(serverUrl = it) } },
+            label = { Text(stringResource(R.string.settings_server_url)) },
+            placeholder = { Text(stringResource(R.string.settings_server_url_hint)) },
+            singleLine = true,
+            modifier = Modifier.fillMaxWidth(),
+        )
+        Button(onClick = { viewModel.save() }, enabled = isDirty) {
+            Text(stringResource(R.string.capture_save))
+        }
+    }
+}

android/app/src/main/java/de/ladkau/fuelish/ui/settings/ConfigViewModel.kt

@@ -0,0 +1,51 @@
+package de.ladkau.fuelish.ui.settings
+
+import android.app.Application
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
+import de.ladkau.fuelish.data.AppConfig
+import de.ladkau.fuelish.data.ConfigRepository
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+
+class ConfigViewModel(application: Application) : AndroidViewModel(application) {
+    private val configRepository = ConfigRepository(application)
+
+    // A local editable draft, seeded once from the persisted config below -
+    // deliberately not a live collection of configRepository.config, so
+    // in-progress edits aren't clobbered by DataStore's own emission of the
+    // write this same screen is about to make on save().
+    private val _config = MutableStateFlow(AppConfig())
+    val config: StateFlow<AppConfig> = _config.asStateFlow()
+
+    private val _savedConfig = MutableStateFlow(AppConfig())
+
+    val isDirty: StateFlow<Boolean> = combine(_config, _savedConfig) { draft, saved -> draft != saved }
+        .stateIn(viewModelScope, SharingStarted.Eagerly, false)
+
+    init {
+        viewModelScope.launch {
+            val loaded = configRepository.config.first()
+            _config.value = loaded
+            _savedConfig.value = loaded
+        }
+    }
+
+    fun update(transform: (AppConfig) -> AppConfig) {
+        _config.value = transform(_config.value)
+    }
+
+    fun save() {
+        viewModelScope.launch {
+            val toSave = _config.value
+            configRepository.save(toSave)
+            _savedConfig.value = toSave
+        }
+    }
+}

android/app/src/main/java/de/ladkau/fuelish/ui/theme/Theme.kt

@@ -0,0 +1,30 @@
+package de.ladkau.fuelish.ui.theme
+
+import android.os.Build
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.darkColorScheme
+import androidx.compose.material3.dynamicDarkColorScheme
+import androidx.compose.material3.dynamicLightColorScheme
+import androidx.compose.material3.lightColorScheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.platform.LocalContext
+
+private val LightColors = lightColorScheme()
+private val DarkColors = darkColorScheme()
+
+@Composable
+fun FuelishTheme(
+    darkTheme: Boolean = isSystemInDarkTheme(),
+    dynamicColor: Boolean = true,
+    content: @Composable () -> Unit,
+) {
+    val context = LocalContext.current
+    val colorScheme = when {
+        dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S ->
+            if (darkTheme) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context)
+        darkTheme -> DarkColors
+        else -> LightColors
+    }
+    MaterialTheme(colorScheme = colorScheme, content = content)
+}

android/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@color/ic_launcher_background" />
+    <foreground android:drawable="@mipmap/ic_launcher_foreground" />
+</adaptive-icon>

android/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@color/ic_launcher_background" />
+    <foreground android:drawable="@mipmap/ic_launcher_foreground" />
+</adaptive-icon>

android/app/src/main/res/values/colors.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- Matches the white background baked into logo.png, so the
+         generated launcher icon / splash screen sit on the same
+         background the source art was designed against. -->
+    <color name="ic_launcher_background">#FFFFFF</color>
+    <color name="splash_background">#FFFFFF</color>
+</resources>

android/app/src/main/res/values/strings.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">fuelish</string>
+
+    <string name="nav_capture">Scan receipt</string>
+    <string name="nav_overview">Receipts</string>
+    <string name="nav_settings">Settings</string>
+
+    <string name="capture_take_photo">Take photo</string>
+    <string name="capture_stage_uploading">Uploading…</string>
+    <string name="capture_stage_preprocessing">Preprocessing image…</string>
+    <string name="capture_stage_ocr">Reading text (OCR)…</string>
+    <string name="capture_stage_extracting">Extracting fields…</string>
+    <string name="capture_stage_error">Something went wrong: %1$s</string>
+    <string name="capture_retry">Retry</string>
+    <string name="capture_save">Save</string>
+    <string name="capture_field_petrol_station">Petrol station</string>
+    <string name="capture_field_transaction_number">Transaction number</string>
+    <string name="capture_field_date">Date (DD.MM.YYYY)</string>
+    <string name="capture_field_time">Time (HH:MM:SS)</string>
+    <string name="capture_field_price_per_litre">Price per litre</string>
+    <string name="capture_field_litres">Litres</string>
+    <string name="capture_field_discount">Discount</string>
+    <string name="capture_field_total_price">Total price</string>
+
+    <string name="overview_empty">No receipts saved yet</string>
+    <string name="overview_export_csv">Export CSV</string>
+    <string name="overview_export_ods">Export ODS</string>
+    <string name="overview_export_done">Exported to %1$s</string>
+
+    <string name="settings_server_url">Server URL</string>
+    <string name="settings_server_url_hint">http://192.168.1.10:8080</string>
+</resources>

android/app/src/main/res/values/themes.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <style name="Theme.Fuelish" parent="android:Theme.Material.Light.NoActionBar" />
+
+    <style name="Theme.Fuelish.Splash" parent="Theme.SplashScreen">
+        <item name="windowSplashScreenBackground">@color/splash_background</item>
+        <item name="windowSplashScreenAnimatedIcon">@drawable/splash_icon</item>
+        <item name="postSplashScreenTheme">@style/Theme.Fuelish</item>
+    </style>
+</resources>

android/app/src/main/res/xml/file_paths.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Where the FileProvider (see AndroidManifest.xml) is allowed to serve
+     content:// URIs from. Captured receipt photos are written to the
+     cache dir by CaptureScreen before being handed to the camera intent
+     and then uploaded - see ui/capture/CaptureViewModel.kt. -->
+<paths>
+    <cache-path name="captures" path="captures/" />
+    <!-- Exported CSV/ODS files (see export/CsvExporter.kt, OdsExporter.kt),
+         shared out via an ACTION_SEND intent - see
+         ui/overview/OverviewViewModel.kt. -->
+    <cache-path name="exports" path="exports/" />
+</paths>

android/app/src/main/res/xml/network_security_config.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- fuelish talks to a self-hosted, LAN-only server with no TLS (see
+     AGENT.md / the server plan - auth and TLS are an explicit v1
+     non-goal for a personal LAN tool). Android's network security config
+     has no CIDR-range matcher, only literal domains/IPs, so rather than
+     enumerate private-range addresses we allow cleartext globally; the
+     app never talks to anything but the server URL the user enters in
+     Settings. -->
+<network-security-config>
+    <base-config cleartextTrafficPermitted="true">
+        <trust-anchors>
+            <certificates src="system" />
+        </trust-anchors>
+    </base-config>
+</network-security-config>

android/build.gradle.kts

@@ -0,0 +1,6 @@
+plugins {
+    alias(libs.plugins.android.application) apply false
+    alias(libs.plugins.kotlin.serialization) apply false
+    alias(libs.plugins.kotlin.compose) apply false
+    alias(libs.plugins.ksp) apply false
+}

android/gradle.properties

@@ -0,0 +1,11 @@
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+android.useAndroidX=true
+kotlin.code.style=official
+ksp.useKSP2=true
+
+# AGP 9's built-in Kotlin support rejects KSP's use of the kotlin.sourceSets
+# DSL to register generated-source dirs (Room's annotation processor, via
+# KSP) - this is AGP/KSP's own suggested suppression, not a workaround for
+# anything we did. See https://developer.android.com/r/tools/built-in-kotlin
+android.disallowKotlinSourceSets=false
+

android/gradle/libs.versions.toml

@@ -0,0 +1,56 @@
+[versions]
+# Version-lookup tools (WebFetch/registry browsing) were unavailable while
+# this file was written, so these are last-known-good pins rather than a
+# freshly verified "latest stable" snapshot - if Gradle can't resolve one,
+# bump it to whatever's current on Google's Maven / Maven Central.
+#
+# kotlin/ksp are pinned to 2.3.x rather than 2.2.20: androidx.room:
+# room-common-jvm:2.8.5 declares a `{strictly 2.3.20}` constraint on
+# kotlin-stdlib, which would otherwise silently resolve above what a
+# 2.2.20 compiler/KSP understands. Keep these two in sync if Room is ever
+# bumped further.
+agp = "9.2.1"
+kotlin = "2.3.20"
+# KSP's versioning stopped mirroring Kotlin's exact patch after the 2.3.0
+# line (no "2.3.20" KSP release exists) - 2.3.12 is the latest in the same
+# 2.3.x line as kotlin above.
+ksp = "2.3.12"
+coreKtx = "1.17.0"
+lifecycleRuntimeKtx = "2.9.4"
+activityCompose = "1.13.0"
+composeBom = "2026.06.01"
+navigationCompose = "2.9.8"
+datastorePreferences = "1.2.1"
+kotlinxSerializationJson = "1.11.0"
+kotlinxCoroutines = "1.11.0"
+room = "2.8.5"
+splashscreen = "1.0.1"
+okhttp = "4.12.0"
+
+[libraries]
+androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
+androidx-lifecycle-runtime-ktx = { group = "androidx.lifecycle", name = "lifecycle-runtime-ktx", version.ref = "lifecycleRuntimeKtx" }
+androidx-lifecycle-viewmodel-compose = { group = "androidx.lifecycle", name = "lifecycle-viewmodel-compose", version.ref = "lifecycleRuntimeKtx" }
+androidx-activity-compose = { group = "androidx.activity", name = "activity-compose", version.ref = "activityCompose" }
+androidx-compose-bom = { group = "androidx.compose", name = "compose-bom", version.ref = "composeBom" }
+androidx-ui = { group = "androidx.compose.ui", name = "ui" }
+androidx-ui-graphics = { group = "androidx.compose.ui", name = "ui-graphics" }
+androidx-ui-tooling = { group = "androidx.compose.ui", name = "ui-tooling" }
+androidx-ui-tooling-preview = { group = "androidx.compose.ui", name = "ui-tooling-preview" }
+androidx-material3 = { group = "androidx.compose.material3", name = "material3" }
+androidx-material-icons-core = { group = "androidx.compose.material", name = "material-icons-core" }
+androidx-navigation-compose = { group = "androidx.navigation", name = "navigation-compose", version.ref = "navigationCompose" }
+androidx-datastore-preferences = { group = "androidx.datastore", name = "datastore-preferences", version.ref = "datastorePreferences" }
+androidx-room-runtime = { group = "androidx.room", name = "room-runtime", version.ref = "room" }
+androidx-room-ktx = { group = "androidx.room", name = "room-ktx", version.ref = "room" }
+androidx-room-compiler = { group = "androidx.room", name = "room-compiler", version.ref = "room" }
+androidx-core-splashscreen = { group = "androidx.core", name = "core-splashscreen", version.ref = "splashscreen" }
+kotlinx-serialization-json = { group = "org.jetbrains.kotlinx", name = "kotlinx-serialization-json", version.ref = "kotlinxSerializationJson" }
+kotlinx-coroutines-android = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-android", version.ref = "kotlinxCoroutines" }
+okhttp = { group = "com.squareup.okhttp3", name = "okhttp", version.ref = "okhttp" }
+
+[plugins]
+android-application = { id = "com.android.application", version.ref = "agp" }
+kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
+kotlin-compose = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlin" }
+ksp = { id = "com.google.devtools.ksp", version.ref = "ksp" }

android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,9 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.6.1-bin.zip
+networkTimeout=10000
+retries=0
+retryBackOffMs=500
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

android/gradlew

@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   gradlew start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh gradlew
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/3d91ce3b8caaf77ad09f381f43615b715b53f72c/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

android/gradlew.bat

@@ -0,0 +1,82 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  gradlew startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables, and ensure extensions are enabled
+setlocal EnableExtensions
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+"%COMSPEC%" /c exit 1
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+"%COMSPEC%" /c exit 1
+
+:execute
+@rem Setup the command line
+
+
+
+@rem Execute gradlew
+@rem endlocal doesn't take effect until after the line is parsed and variables are expanded
+@rem which allows us to clear the local environment before executing the java command
+endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel
+
+:exitWithErrorLevel
+@rem Use "%COMSPEC%" /c exit to allow operators to work properly in scripts
+"%COMSPEC%" /c exit %ERRORLEVEL%

android/scripts/gen_app_icons.py

@@ -0,0 +1,115 @@
+#!/usr/bin/env python3
+"""Generates the Android launcher icon and splash screen art from
+../../logo.png (the repo's brand mark + "fuelish" wordmark).
+
+Only the graphic mark (not the wordmark) works as a launcher/splash icon,
+so this first isolates it: crop the upper portion of the source image
+(where the mark lives) and auto-crop that to its actual non-transparent
+bounding box, rather than relying on any hardcoded pixel offsets that
+would break if logo.png is ever redrawn at a different resolution.
+
+Produces:
+- mipmap-<density>/ic_launcher_foreground.png - the mark centered, scaled
+  to the adaptive-icon safe zone (66% of a 108dp canvas), transparent
+  background - paired at runtime with @color/ic_launcher_background (see
+  mipmap-anydpi-v26/ic_launcher.xml, committed - a static reference, not
+  generated) for API 26+.
+- mipmap-<density>/ic_launcher.png / ic_launcher_round.png - the same
+  mark flattened onto ic_launcher_background, for API <26 devices that
+  can't use the adaptive-icon XML at all.
+- drawable-nodpi/splash_icon.png - the mark on a transparent background,
+  referenced by Theme.Fuelish.Splash's windowSplashScreenAnimatedIcon
+  (see values/themes.xml).
+
+Generated output, not committed (see the repo's root .gitignore's
+/android/app/src/main/res/{mipmap-*,drawable-nodpi} entries) - regenerate
+by running this script directly or via Gradle's generateAppIcons task
+(wired into app's preBuild, see ../app/build.gradle.kts). Requires
+Pillow.
+"""
+import os
+import sys
+
+from PIL import Image
+
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+LOGO_PATH = os.path.normpath(os.path.join(SCRIPT_DIR, "..", "..", "logo.png"))
+RES_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, "..", "app", "src", "main", "res"))
+
+BACKGROUND_RGBA = (255, 255, 255, 255)  # matches @color/ic_launcher_background
+
+# (density qualifier, adaptive-icon canvas px, legacy launcher px)
+DENSITIES = [
+    ("mdpi", 108, 48),
+    ("hdpi", 162, 72),
+    ("xhdpi", 216, 96),
+    ("xxhdpi", 324, 144),
+    ("xxxhdpi", 432, 192),
+]
+
+# Adaptive icons render only the inner ~66% "safe zone" reliably across
+# launchers that apply their own mask shape.
+SAFE_ZONE_RATIO = 0.66
+
+# Fraction of logo.png's height (from the top) that contains the graphic
+# mark, before the "fuelish" wordmark begins.
+MARK_REGION_HEIGHT_RATIO = 0.60
+
+SPLASH_CANVAS_PX = 480
+SPLASH_ICON_RATIO = 0.75
+
+
+def extract_mark(logo: Image.Image) -> Image.Image:
+    width, height = logo.size
+    region = logo.crop((0, 0, width, round(height * MARK_REGION_HEIGHT_RATIO)))
+    bbox = region.getchannel("A").getbbox()
+    if bbox is None:
+        raise ValueError(f"{LOGO_PATH}: no non-transparent pixels found in the top "
+                          f"{MARK_REGION_HEIGHT_RATIO:.0%} of the image")
+    mark = region.crop(bbox)
+
+    # Pad to square so downstream scaling doesn't distort the aspect ratio.
+    side = max(mark.width, mark.height)
+    square = Image.new("RGBA", (side, side), (0, 0, 0, 0))
+    square.paste(mark, ((side - mark.width) // 2, (side - mark.height) // 2), mark)
+    return square
+
+
+def resized(image: Image.Image, target_px: int) -> Image.Image:
+    ratio = target_px / max(image.width, image.height)
+    size = (round(image.width * ratio), round(image.height * ratio))
+    return image.resize(size, Image.LANCZOS)
+
+
+def centered_on(canvas_px: int, content: Image.Image, background: tuple) -> Image.Image:
+    canvas = Image.new("RGBA", (canvas_px, canvas_px), background)
+    offset = ((canvas_px - content.width) // 2, (canvas_px - content.height) // 2)
+    canvas.paste(content, offset, content)
+    return canvas
+
+
+def main():
+    logo = Image.open(LOGO_PATH).convert("RGBA")
+    mark = extract_mark(logo)
+
+    for density, canvas_px, legacy_px in DENSITIES:
+        mipmap_dir = os.path.join(RES_DIR, f"mipmap-{density}")
+        os.makedirs(mipmap_dir, exist_ok=True)
+
+        foreground = centered_on(canvas_px, resized(mark, round(canvas_px * SAFE_ZONE_RATIO)), (0, 0, 0, 0))
+        foreground.save(os.path.join(mipmap_dir, "ic_launcher_foreground.png"))
+
+        legacy = centered_on(legacy_px, resized(mark, round(legacy_px * SAFE_ZONE_RATIO)), BACKGROUND_RGBA)
+        legacy.convert("RGB").save(os.path.join(mipmap_dir, "ic_launcher.png"))
+        legacy.convert("RGB").save(os.path.join(mipmap_dir, "ic_launcher_round.png"))
+
+    drawable_dir = os.path.join(RES_DIR, "drawable-nodpi")
+    os.makedirs(drawable_dir, exist_ok=True)
+    splash = centered_on(SPLASH_CANVAS_PX, resized(mark, round(SPLASH_CANVAS_PX * SPLASH_ICON_RATIO)), (0, 0, 0, 0))
+    splash.save(os.path.join(drawable_dir, "splash_icon.png"))
+
+    print(f"wrote launcher icons for {len(DENSITIES)} densities + splash icon to {RES_DIR}", file=sys.stderr)
+
+
+if __name__ == "__main__":
+    main()

android/settings.gradle.kts

@@ -0,0 +1,26 @@
+pluginManagement {
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+// Auto-provisions the JDK 17 toolchain app/build.gradle.kts requests (see
+// its jvmToolchain(17) call) - this host's only JDKs otherwise are system
+// JDK 11 (too old for AGP 9) and Android Studio's bundled JBR 25 (newer
+// than Kotlin's compiler officially targets yet).
+plugins {
+    id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
+}
+
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "fuelish-android"
+include(":app")

build-image.sh

@@ -1,7 +1,9 @@
 #!/usr/bin/env bash
 # Builds the fuelish tools image (tooling-container/Dockerfile) locally, tagged with
-# tooling-container/VERSION and :latest. Does not push - test it with the numbered
+# tooling-container/VERSION and :latest, and pulls the other image the pipeline
-# pipeline scripts first, then publish with ./upload-image.sh.
+# needs (ollama/ollama, used by 0_run_ollama.sh) so all images are ready before
+# a pipeline run. Does not push - test it with the numbered pipeline scripts
+# first, then publish with ./upload-image.sh.
 set -euo pipefail
 
 cd "$(dirname "${BASH_SOURCE[0]}")"
@@ -29,6 +31,9 @@ docker build \
     -t "$IMAGE:latest" \
     "$ROOT/tooling-container"
 
+echo "== Pulling ollama/ollama (used by 0_run_ollama.sh) =="
+docker pull ollama/ollama
+
 echo "== Done =="
 echo "Image: $IMAGE:$VERSION (and :latest)"
 echo "Test it with the numbered pipeline scripts, then publish with ./upload-image.sh"

docker-compose.yml

@@ -0,0 +1,35 @@
+# Runs the pipeline as a long-lived HTTP API for the Android app, on top
+# of the same tooling-container image the numbered host scripts use.
+# `docker compose up` alone is enough: the api service waits for Ollama
+# and pulls the model itself (see tooling-container/src/server.py).
+#
+# The numbered host scripts (0_run_ollama.sh, 1/2/3_*.sh) and
+# test_batch.sh are untouched and remain the way to inspect/test the
+# pipeline stage by stage; this is the additive "serve it for real" path.
+#
+# Usage: docker compose up -d
+# API reachable at http://<this-host>:8080 from any device on the LAN.
+services:
+  ollama:
+    image: ollama/ollama
+    volumes:
+      - fuelish-ollama-data:/root/.ollama
+    restart: unless-stopped
+
+  api:
+    build:
+      context: ./tooling-container
+    restart: unless-stopped
+    depends_on:
+      - ollama
+    environment:
+      OLLAMA_URL: http://ollama:11434/api/chat
+      OLLAMA_BASE_URL: http://ollama:11434
+      OLLAMA_MODEL: qwen2.5:3b
+    command: ["uvicorn", "server:app", "--app-dir", "/opt/app/src", "--host", "0.0.0.0", "--port", "8000"]
+    ports:
+      - "8080:8000"
+
+volumes:
+  fuelish-ollama-data:
+    name: fuelish-ollama-data

tooling-container/Dockerfile

@@ -11,7 +11,10 @@ RUN pip install --no-cache-dir \
         pillow==11.0.0 \
         pytesseract==0.3.13 \
         requests==2.32.3 \
-        odfpy==1.4.1
+        odfpy==1.4.1 \
+        fastapi==0.115.5 \
+        uvicorn[standard]==0.32.1 \
+        python-multipart==0.0.17
 
 COPY src/ /opt/app/src/
 RUN chmod -R a+rX /opt/app/src

tooling-container/src/server.py

@@ -0,0 +1,128 @@
+#!/usr/bin/env python3
+"""HTTP API that serves the pipeline (preprocess -> ocr -> structure) to
+the Android app. Runs the same in-process functions the numbered host
+scripts drive via `docker run` per stage, but skips the per-stage
+container start-up since a live server has no need for that
+inspectability - the host scripts remain the way to inspect each stage
+independently during pipeline development.
+
+Jobs are processed asynchronously so the app can show real per-stage
+progress: POST /jobs returns immediately with a job id; GET /jobs/{id}
+reports which of preprocessing/ocr/extracting is currently running, and
+the final result once done. Job state lives in memory only - this is a
+personal, LAN-only, single-instance server with no need for persistence
+here (the Android app is the system of record for confirmed receipts).
+"""
+import os
+import shutil
+import tempfile
+import threading
+import time
+import uuid
+
+import requests
+from fastapi import FastAPI, HTTPException, UploadFile
+from fastapi.responses import JSONResponse
+
+from extract import structure
+from ocr import ocr as run_ocr
+from preprocess import preprocess
+
+OLLAMA_BASE_URL = os.environ.get("OLLAMA_BASE_URL", "http://127.0.0.1:11434")
+OLLAMA_MODEL = os.environ.get("OLLAMA_MODEL", "qwen2.5:3b")
+
+app = FastAPI(title="fuelish")
+
+_jobs: dict[str, dict] = {}
+_jobs_lock = threading.Lock()
+
+
+def _set_job(job_id: str, **fields) -> None:
+    with _jobs_lock:
+        _jobs[job_id].update(fields)
+
+
+def _ensure_model_pulled() -> None:
+    """Best-effort: wait for Ollama to come up (compose starts `api` and
+    `ollama` together, with no ordering guarantee beyond container start)
+    and pull OLLAMA_MODEL if it isn't already present, so a bare `docker
+    compose up` is enough without a manual `ollama pull` step. Runs in a
+    background thread - jobs submitted before this finishes will simply
+    fail with a clear error from Ollama."""
+    tags = None
+    for _ in range(60):
+        try:
+            tags = requests.get(f"{OLLAMA_BASE_URL}/api/tags", timeout=5).json()
+            break
+        except requests.RequestException:
+            time.sleep(2)
+    if tags is None:
+        return
+
+    have = {m["name"] for m in tags.get("models", [])}
+    if OLLAMA_MODEL in have or any(m.startswith(OLLAMA_MODEL + ":") for m in have):
+        return
+    try:
+        requests.post(
+            f"{OLLAMA_BASE_URL}/api/pull",
+            json={"name": OLLAMA_MODEL},
+            timeout=1800,
+        )
+    except requests.RequestException:
+        pass
+
+
+@app.on_event("startup")
+def _on_startup() -> None:
+    threading.Thread(target=_ensure_model_pulled, daemon=True).start()
+
+
+@app.get("/health")
+def health() -> dict:
+    return {"status": "ok"}
+
+
+def _process_job(job_id: str, image_path: str, scratch_dir: str) -> None:
+    try:
+        _set_job(job_id, status="preprocessing")
+        final_path = preprocess(image_path, scratch_dir)
+
+        _set_job(job_id, status="ocr")
+        ocr_txt_path = run_ocr(final_path, scratch_dir)
+        with open(ocr_txt_path, "r", encoding="utf-8") as f:
+            ocr_text = f.read()
+
+        _set_job(job_id, status="extracting")
+        result = structure(ocr_text)
+
+        _set_job(job_id, status="done", result=result)
+    except Exception as exc:  # noqa: BLE001 - reported to the client, not swallowed
+        _set_job(job_id, status="error", error=str(exc))
+    finally:
+        shutil.rmtree(scratch_dir, ignore_errors=True)
+
+
+@app.post("/jobs", status_code=201)
+async def create_job(image: UploadFile) -> JSONResponse:
+    job_id = uuid.uuid4().hex
+    scratch_dir = tempfile.mkdtemp(prefix=f"fuelish-{job_id}-")
+    image_path = os.path.join(scratch_dir, "upload" + os.path.splitext(image.filename or "")[1])
+    with open(image_path, "wb") as f:
+        f.write(await image.read())
+
+    with _jobs_lock:
+        _jobs[job_id] = {"status": "queued", "result": None, "error": None, "_created": time.time()}
+
+    thread = threading.Thread(target=_process_job, args=(job_id, image_path, scratch_dir), daemon=True)
+    thread.start()
+
+    return JSONResponse({"job_id": job_id}, status_code=201)
+
+
+@app.get("/jobs/{job_id}")
+def get_job(job_id: str) -> dict:
+    with _jobs_lock:
+        job = _jobs.get(job_id)
+        if job is None:
+            raise HTTPException(status_code=404, detail="job not found")
+        return {"status": job["status"], "result": job["result"], "error": job["error"]}