import * as cp from 'child_process';
import * as fs from 'fs-extra';
import * as os from 'os';
import * as path from 'path';

const rootPath = path.resolve(__dirname, '..');
const gniPath = path.resolve(__dirname, '../filenames.auto.gni');

const allDocs = fs.readdirSync(path.resolve(__dirname, '../docs/api'))
  .map(doc => `docs/api/${doc}`)
  .concat(
    fs.readdirSync(path.resolve(__dirname, '../docs/api/structures'))
      .map(doc => `docs/api/structures/${doc}`)
  );

const typingFiles = fs.readdirSync(path.resolve(__dirname, '../typings')).map(child => `typings/${child}`);

const main = async () => {
  const webpackTargets = [
    {
      name: 'sandbox_bundle_deps',
      config: 'webpack.config.sandboxed_renderer.js'
    },
    {
      name: 'isolated_bundle_deps',
      config: 'webpack.config.isolated_renderer.js'
    },
    {
      name: 'browser_bundle_deps',
      config: 'webpack.config.browser.js'
    },
    {
      name: 'renderer_bundle_deps',
      config: 'webpack.config.renderer.js'
    },
    {
      name: 'worker_bundle_deps',
      config: 'webpack.config.worker.js'
    },
    {
      name: 'asar_bundle_deps',
      config: 'webpack.config.asar.js'
    }
  ];

  const webpackTargetsWithDeps = await Promise.all(webpackTargets.map(async webpackTarget => {
    const tmpDir = await fs.mkdtemp(path.resolve(os.tmpdir(), 'electron-filenames-'));
    const child = cp.spawn('node', [
      './node_modules/webpack-cli/bin/cli.js',
      '--config', `./build/webpack/${webpackTarget.config}`,
      '--display', 'errors-only',
      `--output-path=${tmpDir}`,
      `--output-filename=${webpackTarget.name}.measure.js`,
      '--env.PRINT_WEBPACK_GRAPH'
    ], {
      cwd: path.resolve(__dirname, '..')
    });
    let output = '';
    child.stdout.on('data', chunk => {
      output += chunk.toString();
    });
    child.stderr.on('data', chunk => console.error(chunk.toString()));
    await new Promise((resolve, reject) => child.on('exit', (code) => {
      if (code !== 0) {
        console.error(output);
        return reject(new Error(`Failed to list webpack dependencies for entry: ${webpackTarget.name}`));
      }

      resolve();
    }));

    const webpackTargetWithDeps = {
      ...webpackTarget,
      dependencies: (JSON.parse(output) as string[])
        // Remove whitespace
        .map(line => line.trim())
        // Get the relative path
        .map(line => path.relative(rootPath, line).replace(/\\/g, '/'))
        // Only care about files in //electron
        .filter(line => !line.startsWith('..'))
        // Only care about our own files
        .filter(line => !line.startsWith('node_modules'))
        // All webpack builds depend on the tsconfig  and package json files
        .concat(['tsconfig.json', 'tsconfig.electron.json', 'package.json', ...typingFiles])
        // Make the generated list easier to read
        .sort()
    };
    await fs.remove(tmpDir);
    return webpackTargetWithDeps;
  }));

  fs.writeFileSync(
    gniPath,
    `# THIS FILE IS AUTO-GENERATED, PLEASE DO NOT EDIT BY HAND
auto_filenames = {
  api_docs = [
${allDocs.map(doc => `    "${doc}",`).join('\n')}
  ]

${webpackTargetsWithDeps.map(target => `  ${target.name} = [
${target.dependencies.map(dep => `    "${dep}",`).join('\n')}
  ]`).join('\n\n')}
}
`);
};

if (require.main === module) {
  main().catch((err) => {
    console.error(err);
    process.exit(1);
  });
}