/**
 * @license
 * Copyright 2018 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @fileoverview Gulp script to generate the Typescript definition file (d.ts)
 * for Blockly.
 */

var gulp = require('gulp');
gulp.concat = require('gulp-concat');

var path = require('path');
var fs = require('fs');
var rimraf = require('rimraf');
var execSync = require('child_process').execSync;
var {TYPINGS_BUILD_DIR} = require('./config');

/**
 * Recursively generates a list of file paths with the specified extension
 * contained within the specified basePath.
 * @param {string} basePath The base path to use.
 * @param {string} filter The extension name to filter for.
 * @param {Array<string>} excludePaths The paths to exclude from search.
 * @return {Array<string>} The generated file paths.
 */
function getFilePath(basePath, filter, excludePaths) {
  const files = [];
  const dirContents = fs.readdirSync(basePath);
  dirContents.forEach((fn) => {
    const filePath = path.join(basePath, fn);
    const excluded =
        !excludePaths.every((exPath) => !filePath.startsWith(exPath));
    if (excluded) {
      return;
    }
    const stat = fs.lstatSync(filePath);
    if (stat.isDirectory()) {
      files.push(...getFilePath(filePath, filter, excludePaths));
    } else if (filePath.endsWith(filter)) {
      files.push(filePath);
    }
  });
  return files;
}

// Generates the TypeScript definition file (d.ts) for Blockly.
// As well as generating the typings of each of the files under core/ and msg/,
// the script also pulls in a number of part files from typings/parts.
// This includes the header (incl License), additional useful interfaces
// including Blockly Options and Google Closure typings.
function typings() {
  const tmpDir = path.join(TYPINGS_BUILD_DIR, 'tmp');

  // Clean directory if exists.
  if (fs.existsSync(tmpDir)) {
    rimraf.sync(tmpDir);
  }
  fs.mkdirSync(tmpDir, {recursive: true});

  const excludePaths = [
    "core/renderers/geras",
    "core/renderers/minimalist",
    "core/renderers/thrasos",
    "core/renderers/zelos",
  ];
  const blocklySrcs = [
      'core',
      'msg'
  ]
  // Find all files that will be included in the typings file.
  let files = [];
  blocklySrcs.forEach((basePath) => {
    files.push(...getFilePath(basePath, '.js', excludePaths));
  });

  // Generate typings file for each file.
  files.forEach((file) => {
    const typescriptFileName = `${path.join(tmpDir, file)}.d.ts`;
    if (file.indexOf('core/msg.js') > -1) {
      return;
    }
    const cmd = `node ./node_modules/typescript-closure-tools/definition-generator/src/main.js ${file} ${typescriptFileName}`;
    console.log(`Generating typings for ${file}`);
    execSync(cmd, { stdio: 'inherit' });
  });

  const srcs = [
    'typings/templates/blockly-header.template',
    'typings/templates/blockly-interfaces.template',
    `${tmpDir}/core/**/*`,
    `${tmpDir}/msg/**`
  ];
  return gulp.src(srcs)
    .pipe(gulp.concat('blockly.d.ts'))
    .pipe(gulp.dest(TYPINGS_BUILD_DIR))
    .on('end', function () {
      // Clean up tmp directory.
      if (fs.existsSync(tmpDir)) {
        rimraf.sync(tmpDir);
      }
    });
};

// Generates the TypeScript definition files (d.ts) for Blockly locales.
function msgTypings(cb) {
  const template = fs.readFileSync(path.join('typings/templates/msg.template'), 'utf-8');
  const msgFiles = fs.readdirSync(path.join('msg', 'json'));
  const msgDir = path.join(TYPINGS_BUILD_DIR, 'msg');
  if (!fs.existsSync(msgDir)) {
    fs.mkdirSync(msgDir, {recursive: true});
  }
  msgFiles.forEach(msg => {
    const localeName = msg.substring(0, msg.indexOf('.json'));
    const msgTypings = template.slice().replace(/<%= locale %>/gi, localeName);
    fs.writeFileSync(path.join(TYPINGS_BUILD_DIR, 'msg', localeName + '.d.ts'), msgTypings, 'utf-8');
  })
  cb();
}

/**
 * This task copies built files from BUILD_DIR back to the repository
 * so they can be committed to git.
 */
function checkinTypings() {
  return gulp.src([
    `${TYPINGS_BUILD_DIR}/**.d.ts`,
    `${TYPINGS_BUILD_DIR}/**/**.d.ts`,
  ]).pipe(gulp.dest('typings'));
};

module.exports = {
  typings: typings,
  msgTypings: msgTypings,
  checkinTypings: checkinTypings,
};