const {
  AndroidConfig,
  withAndroidColors,
  withAndroidColorsNight,
  withAndroidStyles,
  withAppBuildGradle,
  withDangerousMod,
} = require('@expo/config-plugins');
const fs = require('fs');
const path = require('path');

const BUILD_TYPES_MARKER = '// @generated by with-android-customizations';

const BUILD_TYPES_APPLY = `${BUILD_TYPES_MARKER}
apply from: new File(
    rootDir,
    "../plugins/android/android-build-types.gradle",
)
`;

const ANDROID_ASSET_VARIANTS = [
  { source: 'release', target: 'main' },
  { source: 'preview', target: 'preRelease' },
  { source: 'debug', target: 'debug' },
];

const LAUNCHER_RESOURCE_NAMES = [
  'ic_launcher',
  'ic_launcher_background',
  'ic_launcher_foreground',
  'ic_launcher_monochrome',
  'ic_launcher_round',
];

const DRAWABLE_RESOURCE_NAMES = [
  'notification_icon',
  'splash_icon',
  'splashscreen_logo',
];
const ANDROID_DENSITIES = ['mdpi', 'hdpi', 'xhdpi', 'xxhdpi', 'xxxhdpi'];

/**
 * `AppTheme` inherits `android:windowBackground` from
 * `Theme.AppCompat.DayNight.NoActionBar`, which resolves to a near-white colour
 * whenever the system is in light mode. The window is visible for the frames
 * between the splash screen going away and React drawing its first frame, so
 * the app opens with a white flash for anyone using a dark theme on a light
 * system. These are the backgrounds of the default light and dark themes.
 */
const WINDOW_BACKGROUND_RESOURCE = 'lnreaderWindowBackground';
const WINDOW_BACKGROUND_LIGHT = '#FEFBFF';
const WINDOW_BACKGROUND_DARK = '#1B1B1F';

const withWindowBackgroundColors = config => {
  config = withAndroidColors(config, config => {
    config.modResults = AndroidConfig.Colors.assignColorValue(
      config.modResults,
      { name: WINDOW_BACKGROUND_RESOURCE, value: WINDOW_BACKGROUND_LIGHT },
    );

    return config;
  });

  return withAndroidColorsNight(config, config => {
    config.modResults = AndroidConfig.Colors.assignColorValue(
      config.modResults,
      { name: WINDOW_BACKGROUND_RESOURCE, value: WINDOW_BACKGROUND_DARK },
    );

    return config;
  });
};

const withWindowBackgroundStyle = config =>
  withAndroidStyles(config, config => {
    config.modResults = AndroidConfig.Styles.assignStylesValue(
      config.modResults,
      {
        add: true,
        parent: AndroidConfig.Styles.getAppThemeGroup(),
        name: 'android:windowBackground',
        value: `@color/${WINDOW_BACKGROUND_RESOURCE}`,
      },
    );

    return config;
  });

const withBuildGradleCustomizations = config =>
  withAppBuildGradle(config, config => {
    const { contents } = config.modResults;

    if (!contents.includes(BUILD_TYPES_MARKER)) {
      config.modResults.contents = `${contents.trimEnd()}

${BUILD_TYPES_APPLY}`;
    }

    return config;
  });

const removeGeneratedIconResources = resDir => {
  if (!fs.existsSync(resDir)) {
    return;
  }

  for (const resourceDirName of fs.readdirSync(resDir)) {
    const resourceDir = path.join(resDir, resourceDirName);

    if (!fs.statSync(resourceDir).isDirectory()) {
      continue;
    }

    if (resourceDirName.startsWith('mipmap-')) {
      for (const resourceName of LAUNCHER_RESOURCE_NAMES) {
        for (const extension of ['png', 'webp', 'xml']) {
          fs.rmSync(path.join(resourceDir, `${resourceName}.${extension}`), {
            force: true,
          });
        }
      }
    }

    if (resourceDirName.startsWith('drawable-')) {
      for (const resourceName of DRAWABLE_RESOURCE_NAMES) {
        for (const extension of ['png', 'webp', 'xml']) {
          fs.rmSync(path.join(resourceDir, `${resourceName}.${extension}`), {
            force: true,
          });
        }
      }
    }
  }
};

const installVariantSplashIcons = resDir => {
  for (const density of ANDROID_DENSITIES) {
    const drawableDir = path.join(resDir, `drawable-${density}`);
    const sourcePath = path.join(drawableDir, 'splash_icon.png');
    const splashPath = path.join(drawableDir, 'splashscreen_logo.png');
    const nightDrawableDir = path.join(resDir, `drawable-night-${density}`);
    const nightSplashPath = path.join(
      nightDrawableDir,
      'splashscreen_logo.png',
    );

    fs.renameSync(sourcePath, splashPath);
    fs.mkdirSync(nightDrawableDir, { recursive: true });
    fs.copyFileSync(splashPath, nightSplashPath);
  }
};

const withAndroidVariantAssets = config =>
  withDangerousMod(config, [
    'android',
    config => {
      const { projectRoot, platformProjectRoot } = config.modRequest;

      for (const variant of ANDROID_ASSET_VARIANTS) {
        const sourceResDir = path.join(
          projectRoot,
          'assets',
          'android-icons',
          variant.source,
          'res',
        );
        const targetResDir = path.join(
          platformProjectRoot,
          'app',
          'src',
          variant.target,
          'res',
        );

        removeGeneratedIconResources(targetResDir);
        fs.mkdirSync(targetResDir, { recursive: true });
        fs.cpSync(sourceResDir, targetResDir, { recursive: true });
        installVariantSplashIcons(targetResDir);
      }

      return config;
    },
  ]);

module.exports = config => {
  config = withBuildGradleCustomizations(config);
  config = withWindowBackgroundColors(config);
  config = withWindowBackgroundStyle(config);
  return withAndroidVariantAssets(config);
};