import { createHash } from 'node:crypto';
import { existsSync, readFileSync } from 'node:fs';
import { join } from 'node:path';

import sharp from 'sharp';

import { test, expect } from '../../fixtures/base';
import {
  BRAND_LAUNCHER_BACKGROUND_COLOR,
  findMissingLauncherResources,
  findStockCapacitorResources,
  isBrandLauncherBackgroundColor,
  readAdaptiveIconBackgroundColor,
  REQUIRED_LAUNCHER_ICON_FILES,
  REQUIRED_SPLASH_FILES
} from '../../../toju-app/src/app/infrastructure/mobile/logic/mobile-android-launcher-icon.rules';

/**
 * Regression coverage for: "No android app icon" - the Capacitor shell shipped
 * the stock Ionic placeholder launcher icon instead of the Toju brand mark.
 *
 * A native launcher icon cannot be asserted through a running browser, so this
 * spec verifies the committed Android resources directly: every density is
 * present, none still match a stock Capacitor placeholder, the adaptive-icon
 * background is the brand purple, and the generated bitmaps actually contain the
 * brand mark (white cat on a purple disc). This is deterministic - no emulator,
 * no timing - so it stays reliable in CI.
 */

const REPO_ROOT = join(__dirname, '..', '..', '..');
const RES_DIR = join(REPO_ROOT, 'toju-app', 'android', 'app', 'src', 'main', 'res');
const BRAND_PURPLE = { r: 0x4a, g: 0x21, b: 0x7a };
const WHITE = { r: 255, g: 255, b: 255 };
const COLOR_TOLERANCE = 24;

function sha256(resRelativePath: string): string {
  return createHash('sha256').update(readFileSync(join(RES_DIR, resRelativePath)))
    .digest('hex');
}

function colorDistance(
  left: { r: number; g: number; b: number },
  right: { r: number; g: number; b: number }
): number {
  return Math.max(Math.abs(left.r - right.r), Math.abs(left.g - right.g), Math.abs(left.b - right.b));
}

async function samplePixel(
  resRelativePath: string,
  xRatio: number,
  yRatio: number
): Promise<{ r: number; g: number; b: number }> {
  const { data, info } = await sharp(join(RES_DIR, resRelativePath)).raw()
    .toBuffer({ resolveWithObject: true });
  const x = Math.min(info.width - 1, Math.floor(info.width * xRatio));
  const y = Math.min(info.height - 1, Math.floor(info.height * yRatio));
  const offset = (y * info.width + x) * info.channels;

  return { r: data[offset], g: data[offset + 1], b: data[offset + 2] };
}

test.describe('Android brand app icon', () => {
  test('ships a launcher icon and splash for every required density', () => {
    const allRequired = [...REQUIRED_LAUNCHER_ICON_FILES, ...REQUIRED_SPLASH_FILES];
    const present = allRequired.filter((file) => existsSync(join(RES_DIR, file)));

    expect(findMissingLauncherResources(present)).toEqual([]);
  });

  test('replaces every stock Capacitor placeholder with the brand asset', () => {
    const allRequired = [...REQUIRED_LAUNCHER_ICON_FILES, ...REQUIRED_SPLASH_FILES];
    const hashByFile = Object.fromEntries(
      allRequired.filter((file) => existsSync(join(RES_DIR, file))).map((file) => [file, sha256(file)])
    );

    expect(findStockCapacitorResources(hashByFile)).toEqual([]);
  });

  test('uses the brand purple as the adaptive-icon background', () => {
    const valuesXml = readFileSync(join(RES_DIR, 'values', 'ic_launcher_background.xml'), 'utf8');
    const color = readAdaptiveIconBackgroundColor(valuesXml);

    expect(color).not.toBe('#FFFFFF');
    expect(isBrandLauncherBackgroundColor(color)).toBe(true);
    expect(color?.toLowerCase()).toBe(BRAND_LAUNCHER_BACKGROUND_COLOR.toLowerCase());
  });

  test('renders the brand mark (white cat on a purple disc) in the launcher bitmap', async () => {
    const launcher = 'mipmap-xxxhdpi/ic_launcher.png';
    const ringTop = await samplePixel(launcher, 0.5, 0.12);
    const ringLeft = await samplePixel(launcher, 0.12, 0.5);
    const faceCenter = await samplePixel(launcher, 0.5, 0.5);

    expect(colorDistance(ringTop, BRAND_PURPLE)).toBeLessThanOrEqual(COLOR_TOLERANCE);
    expect(colorDistance(ringLeft, BRAND_PURPLE)).toBeLessThanOrEqual(COLOR_TOLERANCE);
    expect(colorDistance(faceCenter, WHITE)).toBeLessThanOrEqual(COLOR_TOLERANCE);
  });

  test('renders the splash art as the brand mark centred on a purple field', async () => {
    const splash = 'drawable-port-xhdpi/splash.png';
    const corner = await samplePixel(splash, 0.04, 0.04);
    const center = await samplePixel(splash, 0.5, 0.5);

    expect(colorDistance(corner, BRAND_PURPLE)).toBeLessThanOrEqual(COLOR_TOLERANCE);
    expect(colorDistance(center, WHITE)).toBeLessThanOrEqual(COLOR_TOLERANCE);
  });
});