/*
 * Copyright (C) 2018 StApps
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <https://www.gnu.org/licenses/>.
 */
import {join} from 'path';
import {cwd} from 'process';
import {
  deleteFileIfExistingAndPacked,
  globPromisified,
  logger,
  readFilePromisified,
  writeFilePromisified,
} from '../common';
import {PACK_IDENTIFIER} from '../configuration';

/**
 * Get a list containing the contents of all type definition files
 */
async function getAllTypeDefinitions(): Promise<string[]> {
  const fileNames = await globPromisified(join(cwd(), '*(lib|src)', '**', '*.d.ts'), {
    ignore: [
      join(cwd(), 'lib', 'doc', '**', '*.d.ts'),
      join(cwd(), 'lib', 'test', '**', '*.d.ts'),
      join(cwd(), 'lib', 'cli.d.ts'),
    ],
  });

  const promises = fileNames.map((fileName) => {
    return readFilePromisified(fileName, 'utf8');
  });

  return await Promise.all(promises);
}

/**
 * Pack a list of type definitions into one file
 */
export async function packTypeDefinitions(): Promise<void> {
  logger.info('Packing TypeScript definition files...');

  const path = join(cwd(), 'lib', 'index.d.ts');

  await deleteFileIfExistingAndPacked(path);

  const typeDefinitions = await getAllTypeDefinitions();

  // pack TypeScript definition files
  const imports: { [k: string]: string[] } = {};

  const referenceLines: string[] = [];

  let allDefinitions = typeDefinitions
  // concat them separated by new lines
    .join('\n\n\n\n\n')
    // split all lines
    .split('\n')
    .map((line) => {
      if (line.indexOf('export =') !== -1) {
        throw new Error('`export =` is not allowed by pack. Use named imports instead.');
      }

      if (line.indexOf('/// <reference') === 0) {
        referenceLines.push(line);
        return '// moved referenced line';
      }

      // match import lines
      const match = line.match(/^import {([^}].*)} from '([^'].*)';$/);

      if (match !== null) {
        // extract module
        const module = match[2];

        // extract imported objects
        const importedObjects = match[1].split(',').map((object) => {
          return object.trim();
        });

        // add list of already imported objects for module
        if (typeof imports[module] === 'undefined') {
          imports[module] = [];
        }

        // count already imported objects and objects to import now
        const objectsToImport: string[] = [];
        importedObjects.forEach((object) => {
          if (imports[module].indexOf(object) === -1) {
            imports[module].push(object);
            objectsToImport.push(object);
          }
        });

        // replace import line
        if (objectsToImport.length === 0) {
          return '// extraneous removed import';
        } else {
          return 'import { ' + objectsToImport.join(', ') + ' } from \'' + module + '\';';
        }
      }

      return line;
    })
    // filter lines which contain "local" imports
    .filter((line) => {
      return !line.match(/^import .* from '\./);
    })
    // concat all lines separated by new lines
    .join('\n');

  if (allDefinitions.length > 0) {
    if (referenceLines.length > 0) {
      allDefinitions = referenceLines.join('\n') + '\n\n' + allDefinitions;
    }

    // write packed TypeScript definition files
    return await writeFilePromisified(path, PACK_IDENTIFIER + '\n\n' + allDefinitions);
  }
}