import { Logger } from './logger';
import { TaskRunner } from './taskrunner';
import * as glob from 'glob';

export interface Git {
  /**
   * If not in a git repo or no changes, findAllTypescriptFiles() is returned
   */
  findChangedFilesOrAllTypescriptFiles(sinceLastPush?: boolean): Promise<string[]>;
  findChangedFiles(sinceLastPush?: boolean): Promise<string[]>;
  findAllTypescriptFiles(): Promise<string[]>;
  isPristine(): Promise<boolean>;
  execute(args: string[]): Promise<string[]>;
  isOnBranch(): Promise<boolean>;
}

export let createGit = (dependencies: { taskRunner: TaskRunner, logger: Logger }): Git => {
  let { taskRunner, logger } = dependencies;

  let findAllTypescriptFiles = (): Promise<string[]> => {
    // Not using this mechanism anymore but a blacklist to allow multiple tsconfig files.
    // let tsConfig = JSON.parse(readFileSync(join(process.cwd(), 'tsconfig.json'), 'UTF-8'));
    // let globs: string[] = tsConfig && tsConfig.include ? tsConfig.include : ['src/**/*.ts', 'test/**/*.ts'];
    let blacklist = ['**/node_modules/**', 'typings/**', 'build/**', 'dist/**', '**/*.d.ts'];

    return new Promise((resolve, reject) => {
      glob('**/*.ts', { ignore: blacklist }, (error, matches) => {
        if (error) {
          reject(error);
        } else {
          resolve(matches);
        }
      });
    });
  };

  let git: Git = {
    findChangedFiles: (sinceLastPush) => {
      let args = sinceLastPush ? ['diff', '--name-only', '--diff-filter=ACMR', 'origin/HEAD', 'HEAD'] : ['diff', '--name-only', '--diff-filter=ACMR', 'HEAD'];
      return git.execute(args).then(
        (files) => {
          return files;
        }
      );
    },
    isPristine: () => {
      return git.execute(['status', '--porcelain']).then(modifiedFiles => {
        return modifiedFiles.length === 0;
      });
    },
    findChangedFilesOrAllTypescriptFiles: async (sinceLastPush): Promise<string[]> => {
      return git.findChangedFiles(sinceLastPush)
        .then(files => files.length === 0 ? findAllTypescriptFiles() : files) // no changed files found => All TS Files
        .catch(findAllTypescriptFiles); // If not inside a git repository
    },

    findAllTypescriptFiles,

    isOnBranch: async () => {
      let [stdout] = await git.execute(['rev-parse', '--abbrev-ref', 'HEAD']);
      let currentBranchName = stdout.toString().trim();

      // When in detached HEAD, assume it's master.
      if (currentBranchName === 'HEAD') {
        return false;
      }
      return currentBranchName !== 'master';
    },

    execute: (args: string[]) => {
      let lines: string[] = [];
      return taskRunner.runTask('git', args, {
        name: 'git',
        logger,
        handleOutput: (line: string) => {
          lines.push(line);
          return true;
        }
      }).result.then(() => {
        return lines;
      });
    }
  };
  return git;
};