const { join, relative, resolve, sep } = require('path');
const fs = require('fs');

const webpack = require('webpack');
const nsWebpack = require('@nativescript/webpack');
const nativescriptTarget = require('@nativescript/webpack/nativescript-target');
const { CleanWebpackPlugin } = require('clean-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer');
const { NativeScriptWorkerPlugin } = require('nativescript-worker-loader/NativeScriptWorkerPlugin');
const TerserPlugin = require('terser-webpack-plugin');
const hashSalt = Date.now().toString();

module.exports = (env) => {
	const platform = env && ((env.android && 'android') || (env.ios && 'ios') || env.platform);
	if (!platform) {
		throw new Error('You need to provide a target platform!');
	}

	const platforms = ['ios', 'android'];
	const projectRoot = __dirname;

	if (env.platform) {
		platforms.push(env.platform);
	}

	// Default destination inside platforms/<platform>/...
	const dist = resolve(projectRoot, nsWebpack.getAppPath(platform, projectRoot));

	const {
		// The 'appPath' and 'appResourcesPath' values are fetched from
		// the nsconfig.json configuration file.
		appPath = 'src',
		appResourcesPath = 'App_Resources',

		// You can provide the following flags when running 'tns run android|ios'
		snapshot, // --env.snapshot
		production, // --env.production
		uglify, // --env.uglify
		report, // --env.report
		sourceMap, // --env.sourceMap
		hiddenSourceMap, // --env.hiddenSourceMap
		hmr, // --env.hmr,
		unitTesting, // --env.unitTesting,
		testing, // --env.testing
		verbose, // --env.verbose
		snapshotInDocker, // --env.snapshotInDocker
		skipSnapshotTools, // --env.skipSnapshotTools
		ci, // --env.ci
		compileSnapshot, // --env.compileSnapshot
		appComponents = [],
		entries = {},
	} = env;

	const useLibs = compileSnapshot;
	const isAnySourceMapEnabled = !!sourceMap || !!hiddenSourceMap;
	const externals = nsWebpack.getConvertedExternals(env.externals);

	let appFullPath = resolve(projectRoot, appPath);
	if (!fs.existsSync(appFullPath)) {
		// some apps use 'app' directory
		appFullPath = resolve(projectRoot, 'app');
	}
	const hasRootLevelScopedModules = nsWebpack.hasRootLevelScopedModules({ projectDir: projectRoot });
	let coreModulesPackageName = 'tns-core-modules';
	const alias = env.alias || {};
	alias['~/package.json'] = resolve(projectRoot, 'package.json');
	alias['~'] = appFullPath;

	if (hasRootLevelScopedModules) {
		coreModulesPackageName = '@nativescript/core';
		alias['tns-core-modules'] = coreModulesPackageName;
	}
	const appResourcesFullPath = resolve(projectRoot, appResourcesPath);

	const copyIgnore = { ignore: [`${relative(appPath, appResourcesFullPath)}/**`] };

	const entryModule = nsWebpack.getEntryModule(appFullPath, platform);
	const entryPath = `.${sep}${entryModule}.js`;
	Object.assign(entries, { bundle: entryPath }, entries);

	const areCoreModulesExternal = Array.isArray(env.externals) && env.externals.some((e) => e.indexOf('@nativescript') > -1);
	if (platform === 'ios' && !areCoreModulesExternal && !testing) {
		entries['tns_modules/inspector_modules'] = '@nativescript/core/inspector_modules';
	}

	let sourceMapFilename = nsWebpack.getSourceMapFilename(hiddenSourceMap, __dirname, dist);

	const itemsToClean = [`${dist}/**/*`];
	if (platform === 'android') {
		itemsToClean.push(`${join(projectRoot, 'platforms', 'android', 'app', 'src', 'main', 'assets', 'snapshots')}`);
		itemsToClean.push(`${join(projectRoot, 'platforms', 'android', 'app', 'build', 'configurations', 'nativescript-android-snapshot')}`);
	}

	// Add your custom Activities, Services and other android app components here.
	appComponents.push('@nativescript/core/ui/frame', '@nativescript/core/ui/frame/activity');

	nsWebpack.processAppComponents(appComponents, platform);
	const config = {
		mode: production ? 'production' : 'development',
		context: appFullPath,
		externals,
		watchOptions: {
			ignored: [
				appResourcesFullPath,
				// Don't watch hidden files
				'**/.*',
			],
		},
		target: nativescriptTarget,
		entry: entries,
		output: {
			pathinfo: false,
			path: dist,
			sourceMapFilename,
			libraryTarget: 'commonjs2',
			filename: '[name].js',
			globalObject: 'global',
			hashSalt,
		},
		resolve: {
			extensions: ['.js', '.scss', '.css'],
			// Resolve {N} system modules from @nativescript/core
			modules: [resolve(__dirname, `node_modules/${coreModulesPackageName}`), resolve(__dirname, 'node_modules'), `node_modules/${coreModulesPackageName}`, 'node_modules'],
			alias,
			// resolve symlinks to symlinked modules
			symlinks: true,
		},
		resolveLoader: {
			// don't resolve symlinks to symlinked loaders
			symlinks: false,
		},
		node: {
			// Disable node shims that conflict with NativeScript
			http: false,
			timers: false,
			setImmediate: false,
			fs: 'empty',
			__dirname: false,
		},
		devtool: hiddenSourceMap ? 'hidden-source-map' : sourceMap ? 'inline-source-map' : 'none',
		optimization: {
			runtimeChunk: 'single',
			noEmitOnErrors: true,
			splitChunks: {
				cacheGroups: {
					vendor: {
						name: 'vendor',
						chunks: 'all',
						test: (module, chunks) => {
							const moduleName = module.nameForCondition ? module.nameForCondition() : '';
							return /[\\/]node_modules[\\/]/.test(moduleName) || appComponents.some((comp) => comp === moduleName);
						},
						enforce: true,
					},
				},
			},
			minimize: !!uglify,
			minimizer: [
				new TerserPlugin({
					parallel: true,
					cache: !ci,
					sourceMap: isAnySourceMapEnabled,
					terserOptions: {
						output: {
							comments: false,
							semicolons: !isAnySourceMapEnabled,
						},
						compress: {
							// The Android SBG has problems parsing the output
							// when these options are enabled
							collapse_vars: platform !== 'android',
							sequences: platform !== 'android',
							// For v8 Compatibility
							keep_infinity: true, // for V8
							reduce_funcs: false, // for V8
							// custom
							drop_console: production,
							drop_debugger: true,
							global_defs: {
								__UGLIFIED__: true,
							},
						},
						// Required for Element Level CSS, Observable Events, & Android Frame
						keep_classnames: true,
					},
				}),
			],
		},
		module: {
			rules: [
				{
					include: join(appFullPath, entryPath),
					use: [
						// Require all Android app components
						platform === 'android' && {
							loader: '@nativescript/webpack/helpers/android-app-components-loader',
							options: { modules: appComponents },
						},

						{
							loader: '@nativescript/webpack/bundle-config-loader',
							options: {
								loadCss: !snapshot, // load the application css if in debug mode
								unitTesting,
								appFullPath,
								projectRoot,
								ignoredFiles: nsWebpack.getUserDefinedEntries(entries, platform),
							},
						},
					].filter((loader) => !!loader),
				},

				{
					test: /\.(js|css|scss|html|xml)$/,
					use: '@nativescript/webpack/hmr/hot-loader',
				},

				{ test: /\.(html|xml)$/, use: '@nativescript/webpack/helpers/xml-namespace-loader' },

				{
					test: /\.css$/,
					use: '@nativescript/webpack/helpers/css2json-loader',
				},

				{
					test: /\.scss$/,
					use: ['@nativescript/webpack/helpers/css2json-loader', 'sass-loader'],
				},
			],
		},
		plugins: [
			// Define useful constants like TNS_WEBPACK
			new webpack.DefinePlugin({
				'global.TNS_WEBPACK': 'true',
				'global.isAndroid': platform === 'android',
				'global.isIOS': platform === 'ios',
				process: 'global.process',
			}),
			// Remove all files from the out dir.
			new CleanWebpackPlugin({
				cleanOnceBeforeBuildPatterns: itemsToClean,
				verbose: !!verbose,
			}),
			// Copy assets
			new CopyWebpackPlugin([{ from: { glob: 'assets/**', dot: false } }, { from: { glob: 'fonts/**', dot: false } }, { from: { glob: '**/*.jpg', dot: false } }, { from: { glob: '**/*.png', dot: false } }], copyIgnore),
			new nsWebpack.GenerateNativeScriptEntryPointsPlugin('bundle'),

			// For instructions on how to set up workers with webpack
			// check out https://github.com/nativescript/worker-loader
			new NativeScriptWorkerPlugin(),
			new nsWebpack.PlatformFSPlugin({
				platform,
				platforms,
			}),
			// Does IPC communication with the {N} CLI to notify events when running in watch mode.
			new nsWebpack.WatchStateLoggerPlugin(),
		],
	};

	if (report) {
		// Generate report files for bundles content
		config.plugins.push(
			new BundleAnalyzerPlugin({
				analyzerMode: 'static',
				openAnalyzer: false,
				generateStatsFile: true,
				reportFilename: resolve(projectRoot, 'report', `report.html`),
				statsFilename: resolve(projectRoot, 'report', `stats.json`),
			})
		);
	}

	if (snapshot) {
		config.plugins.push(
			new nsWebpack.NativeScriptSnapshotPlugin({
				chunk: 'vendor',
				requireModules: ['@nativescript/core/bundle-entry-points'],
				projectRoot,
				webpackConfig: config,
				snapshotInDocker,
				skipSnapshotTools,
				useLibs,
			})
		);
	}

	if (hmr) {
		config.plugins.push(new webpack.HotModuleReplacementPlugin());
	}

	return config;
};
