Add photo export and receipt list sorting/search

Photo export (hamburger menu) zips every receipt's photo as
IMG_YYYYMMDD_HHMMSS.jpg, named from the receipt's own extracted
date/time rather than the photo's capture time, with collision-safe
naming for same-timestamp receipts.

The receipt list's Date/Litres/Total column headers are now tappable
to sort (tap again to flip direction), and a search field does a
case-insensitive substring match across every exported field, not
just the three shown in the list.

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

@@ -0,0 +1,68 @@
+package de.ladkau.fuelish.export
+
+import android.content.ContentResolver
+import android.net.Uri
+import de.ladkau.fuelish.data.Receipt
+import java.io.OutputStream
+import java.text.ParseException
+import java.text.SimpleDateFormat
+import java.util.Locale
+import java.util.zip.ZipEntry
+import java.util.zip.ZipOutputStream
+
+/** IMG_YYYYMMDD_HHMMSS.jpg, built from the receipt's own extracted
+ * date/time (Receipt.date/time - DD.MM.YYYY / HH:MM:SS), not the photo
+ * file's own capture timestamp or when it was saved in the app - so the
+ * exported name reflects what's on the receipt. Null if date or time is
+ * missing or doesn't parse, since there's then no valid name to build. */
+fun Receipt.photoExportName(): String? {
+    val d = date ?: return null
+    val t = time ?: return null
+    val parsed = try {
+        SOURCE_FORMAT.parse("$d $t")
+    } catch (e: ParseException) {
+        null
+    } ?: return null
+    return "IMG_${TARGET_FORMAT.format(parsed)}.jpg"
+}
+
+private val SOURCE_FORMAT = SimpleDateFormat("dd.MM.yyyy HH:mm:ss", Locale.GERMANY)
+private val TARGET_FORMAT = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US)
+
+/** Zips every receipt's photo (skipping receipts with no photo, or no
+ * parseable date/time to name it with) under photoExportName(), appending
+ * "_2", "_3", ... on a name collision (e.g. two receipts logged with the
+ * same date and time to the second) so nothing silently overwrites
+ * another entry. Returns the count actually written. */
+fun exportPhotos(receipts: List<Receipt>, resolver: ContentResolver, out: OutputStream): Int {
+    val usedNames = mutableSetOf<String>()
+    var written = 0
+    ZipOutputStream(out).use { zip ->
+        for (receipt in receipts) {
+            val imageUri = receipt.imageUri ?: continue
+            val baseName = receipt.photoExportName() ?: continue
+            val name = uniqueName(baseName, usedNames)
+            usedNames += name
+
+            val bytes = try {
+                resolver.openInputStream(Uri.parse(imageUri))?.use { it.readBytes() }
+            } catch (e: Exception) {
+                null
+            } ?: continue
+
+            zip.putNextEntry(ZipEntry(name))
+            zip.write(bytes)
+            zip.closeEntry()
+            written++
+        }
+    }
+    return written
+}
+
+private fun uniqueName(baseName: String, used: Set<String>): String {
+    if (baseName !in used) return baseName
+    val stem = baseName.removeSuffix(".jpg")
+    var n = 2
+    while ("${stem}_$n.jpg" in used) n++
+    return "${stem}_$n.jpg"
+}

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

@@ -9,6 +9,7 @@ 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 de.ladkau.fuelish.export.exportPhotos as writePhotosZip
 import de.ladkau.fuelish.log.AppLog
 import java.io.File
 import java.io.OutputStream
@@ -27,6 +28,25 @@ class ExportViewModel(application: Application) : AndroidViewModel(application)
 
     fun exportOds(onReady: (Uri) -> Unit) = export("fuelish-receipts.ods", ::writeOdsRows, onReady)
 
+    /** Zips every receipt's photo as IMG_YYYYMMDD_HHMMSS.jpg (from the
+     * receipt's own date/time, not the photo's capture time) - see
+     * export/PhotoExporter.kt's photoExportName(). Receipts with no photo
+     * or no parseable date/time are skipped, not failed. */
+    fun exportPhotos(onReady: (Uri) -> Unit) {
+        val app = getApplication<Application>()
+        viewModelScope.launch {
+            val receipts = repository.receipts.first()
+            val (uri, written) = withContext(Dispatchers.IO) {
+                val dir = File(app.cacheDir, "exports").apply { mkdirs() }
+                val file = File(dir, "fuelish-photos.zip")
+                val count = file.outputStream().use { writePhotosZip(receipts, app.contentResolver, it) }
+                FileProvider.getUriForFile(app, "${app.packageName}.fileprovider", file) to count
+            }
+            AppLog.log("Exported $written of ${receipts.size} photo(s) to fuelish-photos.zip")
+            onReady(uri)
+        }
+    }
+
     private fun export(fileName: String, write: (List<Receipt>, OutputStream) -> Unit, onReady: (Uri) -> Unit) {
         val app = getApplication<Application>()
         viewModelScope.launch {

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

@@ -117,6 +117,15 @@ fun FuelishApp() {
                     },
                     modifier = Modifier.padding(horizontal = 12.dp),
                 )
+                NavigationDrawerItem(
+                    label = { Text(stringResource(R.string.overview_export_photos)) },
+                    selected = false,
+                    onClick = {
+                        scope.launch { drawerState.close() }
+                        exportViewModel.exportPhotos { uri -> shareFile(context, uri, "application/zip") }
+                    },
+                    modifier = Modifier.padding(horizontal = 12.dp),
+                )
             }
         },
     ) {

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

@@ -10,11 +10,16 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Clear
 import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.KeyboardArrowDown
+import androidx.compose.material.icons.filled.KeyboardArrowUp
+import androidx.compose.material.icons.filled.Search
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.collectAsState
@@ -32,14 +37,25 @@ private val DELETE_COLUMN_WIDTH = 48.dp
 @Composable
 fun OverviewScreen(onReceiptClick: (Long) -> Unit, viewModel: OverviewViewModel = viewModel()) {
     val receipts by viewModel.receipts.collectAsState()
+    val sort by viewModel.sort.collectAsState()
+    val searchQuery by viewModel.searchQuery.collectAsState()
 
     Column(modifier = Modifier.fillMaxSize()) {
-        ReceiptTableHeader()
+        SearchField(
+            query = searchQuery,
+            onQueryChange = viewModel::setSearchQuery,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
+        )
+        ReceiptTableHeader(sort = sort, onColumnClick = viewModel::setSortColumn)
         HorizontalDivider()
 
         if (receipts.isEmpty()) {
             Text(
-                text = stringResource(R.string.overview_empty),
+                text = if (searchQuery.isBlank()) {
+                    stringResource(R.string.overview_empty)
+                } else {
+                    stringResource(R.string.overview_empty_search, searchQuery)
+                },
                 modifier = Modifier.padding(16.dp),
             )
         } else {
@@ -58,32 +74,80 @@ fun OverviewScreen(onReceiptClick: (Long) -> Unit, viewModel: OverviewViewModel
 }
 
 @Composable
-private fun ReceiptTableHeader() {
+private fun SearchField(query: String, onQueryChange: (String) -> Unit, modifier: Modifier = Modifier) {
+    OutlinedTextField(
+        value = query,
+        onValueChange = onQueryChange,
+        placeholder = { Text(stringResource(R.string.overview_search_placeholder)) },
+        leadingIcon = { Icon(Icons.Filled.Search, contentDescription = null) },
+        trailingIcon = {
+            if (query.isNotEmpty()) {
+                IconButton(onClick = { onQueryChange("") }) {
+                    Icon(Icons.Filled.Clear, contentDescription = stringResource(R.string.overview_search_clear))
+                }
+            }
+        },
+        singleLine = true,
+        modifier = modifier.fillMaxWidth(),
+    )
+}
+
+@Composable
+private fun ReceiptTableHeader(sort: SortState, onColumnClick: (SortColumn) -> Unit) {
     Row(
         modifier = Modifier
             .fillMaxWidth()
             .padding(horizontal = 16.dp, vertical = 8.dp),
         verticalAlignment = Alignment.CenterVertically,
     ) {
-        Text(
-            text = stringResource(R.string.overview_column_date),
-            style = MaterialTheme.typography.labelLarge,
+        SortableHeaderCell(
+            label = stringResource(R.string.overview_column_date),
+            column = SortColumn.DATE,
+            sort = sort,
+            onClick = onColumnClick,
             modifier = Modifier.weight(1f),
         )
-        Text(
-            text = stringResource(R.string.overview_column_litres),
-            style = MaterialTheme.typography.labelLarge,
+        SortableHeaderCell(
+            label = stringResource(R.string.overview_column_litres),
+            column = SortColumn.LITRES,
+            sort = sort,
+            onClick = onColumnClick,
             modifier = Modifier.weight(1f),
         )
-        Text(
-            text = stringResource(R.string.overview_column_total),
-            style = MaterialTheme.typography.labelLarge,
+        SortableHeaderCell(
+            label = stringResource(R.string.overview_column_total),
+            column = SortColumn.TOTAL_PRICE,
+            sort = sort,
+            onClick = onColumnClick,
             modifier = Modifier.weight(1f),
         )
         Row(modifier = Modifier.width(DELETE_COLUMN_WIDTH)) {}
     }
 }
 
+@Composable
+private fun SortableHeaderCell(
+    label: String,
+    column: SortColumn,
+    sort: SortState,
+    onClick: (SortColumn) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    Row(
+        modifier = modifier.clickable { onClick(column) },
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Text(text = label, style = MaterialTheme.typography.labelLarge)
+        if (sort.column == column) {
+            Icon(
+                imageVector = if (sort.direction == SortDirection.ASCENDING) Icons.Filled.KeyboardArrowUp else Icons.Filled.KeyboardArrowDown,
+                contentDescription = null,
+                modifier = Modifier.padding(start = 2.dp).width(16.dp),
+            )
+        }
+    }
+}
+
 @Composable
 private fun ReceiptRow(receipt: Receipt, onClick: () -> Unit, onDelete: () -> Unit) {
     Row(

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

@@ -5,17 +5,56 @@ 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.toExportRow
 import de.ladkau.fuelish.log.AppLog
+import java.text.ParseException
+import java.text.SimpleDateFormat
+import java.util.Locale
+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.stateIn
 import kotlinx.coroutines.launch
 
+/** The overview table's 3 visible/sortable columns (price/litre and
+ * discount are detail-only, not shown in the list - see
+ * ReceiptDetailScreen). DATE sorts by the combined date+time instant,
+ * not the date string alone, since within-day ordering still matters for
+ * a fuel-cost log. */
+enum class SortColumn { DATE, LITRES, TOTAL_PRICE }
+
+enum class SortDirection { ASCENDING, DESCENDING }
+
+data class SortState(val column: SortColumn, val direction: SortDirection)
+
 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())
+    private val _sort = MutableStateFlow(SortState(SortColumn.DATE, SortDirection.DESCENDING))
+    val sort: StateFlow<SortState> = _sort.asStateFlow()
+
+    private val _searchQuery = MutableStateFlow("")
+    val searchQuery: StateFlow<String> = _searchQuery.asStateFlow()
+
+    val receipts: StateFlow<List<Receipt>> = combine(repository.receipts, _searchQuery, _sort) { all, query, sort ->
+        all.filter { matchesQuery(it, query) }.sortedWith(comparator(sort))
+    }.stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), emptyList())
+
+    fun setSearchQuery(query: String) {
+        _searchQuery.value = query
+    }
+
+    /** Tapping the already-active column flips its direction; tapping a
+     * different one switches to it, ascending. */
+    fun setSortColumn(column: SortColumn) {
+        _sort.value = if (_sort.value.column == column) {
+            _sort.value.copy(direction = _sort.value.direction.flipped())
+        } else {
+            SortState(column, SortDirection.ASCENDING)
+        }
+    }
 
     fun delete(receipt: Receipt) {
         viewModelScope.launch {
@@ -24,3 +63,47 @@ class OverviewViewModel(application: Application) : AndroidViewModel(application
         }
     }
 }
+
+private fun SortDirection.flipped() =
+    if (this == SortDirection.ASCENDING) SortDirection.DESCENDING else SortDirection.ASCENDING
+
+/** Substring match (case-insensitive) against the same formatted field
+ * values CSV/ODS export uses (export/ReceiptRow.kt's toExportRow()) -
+ * "fulltext" across the table's actual fields, not just the three shown
+ * in the overview list. */
+private fun matchesQuery(receipt: Receipt, query: String): Boolean {
+    if (query.isBlank()) return true
+    val needle = query.trim()
+    return receipt.toExportRow().any { it.contains(needle, ignoreCase = true) }
+}
+
+private val DATE_TIME_FORMAT = SimpleDateFormat("dd.MM.yyyy HH:mm:ss", Locale.GERMANY)
+
+/** Receipts with no parseable date+time sort to the very end regardless
+ * of direction, rather than jumping between "first" and "last" depending
+ * on which way the column is currently sorted. */
+private fun dateTimeSortKey(receipt: Receipt): Long {
+    val date = receipt.date ?: return Long.MAX_VALUE
+    val time = receipt.time ?: "00:00:00"
+    return try {
+        DATE_TIME_FORMAT.parse("$date $time")?.time ?: Long.MAX_VALUE
+    } catch (e: ParseException) {
+        Long.MAX_VALUE
+    }
+}
+
+private fun comparator(sort: SortState): Comparator<Receipt> {
+    val base: Comparator<Receipt> = when (sort.column) {
+        SortColumn.DATE -> compareBy { dateTimeSortKey(it) }
+        SortColumn.LITRES -> nullsLastDouble { it.litres }
+        SortColumn.TOTAL_PRICE -> nullsLastDouble { it.totalPrice }
+    }
+    return if (sort.direction == SortDirection.DESCENDING) base.reversed() else base
+}
+
+/** compareBy(nullsLast()) alone would put nulls first when .reversed() is
+ * applied for descending order - build the null-handling into the base
+ * comparator instead so nulls stay last in both directions, same as
+ * dateTimeSortKey()'s Long.MAX_VALUE approach. */
+private fun nullsLastDouble(selector: (Receipt) -> Double?): Comparator<Receipt> =
+    compareBy { selector(it) ?: Double.MAX_VALUE }

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

@@ -34,12 +34,16 @@
     <string name="receipt_delete">Delete</string>
 
     <string name="overview_empty">No receipts have been scanned yet</string>
+    <string name="overview_empty_search">No receipts match “%1$s”</string>
+    <string name="overview_search_placeholder">Search</string>
+    <string name="overview_search_clear">Clear search</string>
     <string name="overview_column_date">Date</string>
     <string name="overview_column_litres">Litres</string>
     <string name="overview_column_total">Total</string>
     <string name="overview_delete">Delete</string>
     <string name="overview_export_csv">Export CSV</string>
     <string name="overview_export_ods">Export ODS</string>
+    <string name="overview_export_photos">Export photos</string>
     <string name="overview_export_done">Exported to %1$s</string>
 
     <string name="settings_server_url">Server URL</string>