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

import sharp from 'sharp';
import {
  describe,
  expect,
  it
} from 'vitest';

import {
  ADAPTIVE_FOREGROUND_ICON_RATIO,
  BRAND_LAUNCHER_BACKGROUND_COLOR,
  findMissingLauncherResources,
  findStockCapacitorResources,
  isBrandLauncherBackgroundColor,
  NOTIFICATION_STATUS_ICON_NAME,
  readAdaptiveIconBackgroundColor,
  REQUIRED_LAUNCHER_ICON_FILES,
  REQUIRED_NOTIFICATION_ICON_FILES,
  REQUIRED_SPLASH_FILES,
  resolveIconPixelSize,
  SPLASH_ICON_RATIO
} from './mobile-android-launcher-icon.rules';

const RES_DIR = resolve(process.cwd(), 'android/app/src/main/res');

function sha256OfResource(resRelativePath: string): string {
  const bytes = readFileSync(resolve(RES_DIR, resRelativePath));

  return createHash('sha256').update(bytes)
    .digest('hex');
}

describe('mobile-android-launcher-icon.rules', () => {
  const allRequired = [
    ...REQUIRED_LAUNCHER_ICON_FILES,
    ...REQUIRED_SPLASH_FILES,
    ...REQUIRED_NOTIFICATION_ICON_FILES
  ];
  const presentFiles = allRequired.filter((file) => existsSync(resolve(RES_DIR, file)));

  it('keeps the brand mark inside the adaptive-icon safe zone', () => {
    expect(ADAPTIVE_FOREGROUND_ICON_RATIO).toBeCloseTo(66 / 108, 5);
    expect(resolveIconPixelSize(432)).toBe(264);
    expect(SPLASH_ICON_RATIO).toBeLessThan(0.4);
  });

  it('ships a launcher icon and splash for every required density', () => {
    expect(findMissingLauncherResources(presentFiles)).toEqual([]);
  });

  it('ships a notification status-bar icon for every density', () => {
    expect(findMissingLauncherResources(presentFiles, REQUIRED_NOTIFICATION_ICON_FILES)).toEqual([]);
  });

  it('references the notification status icon from the Capacitor config', () => {
    const capacitorConfig = readFileSync(resolve(process.cwd(), 'capacitor.config.ts'), 'utf8');

    expect(capacitorConfig).toContain(`smallIcon: '${NOTIFICATION_STATUS_ICON_NAME}'`);
  });

  it('renders the notification status icon as an alpha-only white glyph', async () => {
    const iconPath = resolve(RES_DIR, 'drawable-xxxhdpi/ic_stat_metoyou.png');
    const { data, info } = await sharp(iconPath).ensureAlpha()
      .raw()
      .toBuffer({ resolveWithObject: true });

    let opaquePixels = 0;
    let transparentPixels = 0;

    for (let offset = 0; offset < data.length; offset += info.channels) {
      const alpha = data[offset + 3];

      if (alpha > 224) {
        opaquePixels += 1;
        expect(data[offset]).toBeGreaterThan(224);
        expect(data[offset + 1]).toBeGreaterThan(224);
        expect(data[offset + 2]).toBeGreaterThan(224);
      } else if (alpha < 32) {
        transparentPixels += 1;
      }
    }

    expect(opaquePixels).toBeGreaterThan(0);
    expect(transparentPixels).toBeGreaterThan(0);
  });

  it('replaces every stock Capacitor placeholder with the brand asset', () => {
    const hashByFile = Object.fromEntries(presentFiles.map((file) => [file, sha256OfResource(file)]));

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

  it('uses the brand purple as the adaptive-icon background, not stock white', () => {
    const valuesXml = readFileSync(resolve(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());
  });

  it('insets the adaptive foreground so launcher masks do not clip the cat face', async () => {
    const foregroundPath = resolve(RES_DIR, 'mipmap-xxxhdpi/ic_launcher_foreground.png');
    const { data, info } = await sharp(foregroundPath).ensureAlpha()
      .raw()
      .toBuffer({ resolveWithObject: true });
    const topCenterOffset = (0 * info.width + Math.floor(info.width / 2)) * info.channels;
    const topCenterAlpha = data[topCenterOffset + 3];

    expect(topCenterAlpha).toBeLessThan(32);
  });
});