#!/usr/bin/env python3
"""Generates the Android launcher icon from ../../res/logo.png.

Produces:
- mipmap-<density>/ic_launcher_foreground.png - the logo centered,
  scaled to fit 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
  logo flattened onto ic_launcher_background, for API <26 devices that
  can't use the adaptive-icon XML at all.

Generated output, not committed (see the repo's root .gitignore's
/android/app/src/main/res/mipmap-* entries) - regenerate by running this
script directly or via Gradle's generateLauncherIcon task (wired into
app's preBuild, see ../app/build.gradle.kts). Requires Pillow, already
part of build-image's toolchain.
"""
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, "..", "..", "res", "logo.png"))
RES_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, "..", "app", "src", "main", "res"))

BACKGROUND_RGBA = (27, 27, 47, 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


def resized_logo(logo, target_px):
    ratio = target_px / max(logo.width, logo.height)
    size = (round(logo.width * ratio), round(logo.height * ratio))
    return logo.resize(size, Image.LANCZOS)


def main():
    logo = Image.open(LOGO_PATH).convert("RGBA")

    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)

        # Adaptive-icon foreground: transparent canvas, logo scaled to the
        # safe zone and centered.
        foreground = Image.new("RGBA", (canvas_px, canvas_px), (0, 0, 0, 0))
        fg_logo = resized_logo(logo, round(canvas_px * SAFE_ZONE_RATIO))
        offset = ((canvas_px - fg_logo.width) // 2, (canvas_px - fg_logo.height) // 2)
        foreground.paste(fg_logo, offset, fg_logo)
        foreground.save(os.path.join(mipmap_dir, "ic_launcher_foreground.png"))

        # Legacy (<API26) flattened fallback, same for round and square -
        # launchers on those versions apply their own circular crop.
        legacy = Image.new("RGBA", (legacy_px, legacy_px), BACKGROUND_RGBA)
        legacy_logo = resized_logo(logo, round(legacy_px * SAFE_ZONE_RATIO))
        legacy_offset = ((legacy_px - legacy_logo.width) // 2, (legacy_px - legacy_logo.height) // 2)
        legacy.paste(legacy_logo, legacy_offset, legacy_logo)
        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"))

    print(f"wrote launcher icons for {len(DENSITIES)} densities to {RES_DIR}", file=sys.stderr)


if __name__ == "__main__":
    main()