import {task} from 'gulp';
import {join} from 'path';
import {existsSync} from 'fs-extra';
import {spawnSync} from 'child_process';
import {isTravisMasterBuild} from '../util/travis-ci';
import {openFirebaseDashboardApp} from '../util/firebase';
import {buildConfig} from 'material2-build-tools';

/** Path to the file that includes all coverage information form Karma. */
const coverageResultFile = join(buildConfig.outputDir, 'coverage/coverage-summary.json');

task('coverage:upload', () => {
  if (!existsSync(coverageResultFile)) {
    throw new Error('No coverage file has been found!');
  }

  if (!isTravisMasterBuild()) {
    throw new Error('Coverage results will be only uploaded inside of Travis Push builds.');
  }

  const results = require(coverageResultFile)['total'];

  // Add a timestamp to the coverage result that will be uploaded to Firebase.
  // This is necessary for visual representation which should be displayed chronologically.
  results.timestamp = Date.now();

  // To reduce database payload, the covered lines won't be pushed to the Firebase database.
  delete results['linesCovered'];

  return uploadResults(results);
});

/** Uploads the coverage results to the firebase database. */
function uploadResults(results: any): Promise<void> {
  const latestSha = spawnSync('git', ['rev-parse', 'HEAD']).stdout.toString().trim();
  const dashboardApp = openFirebaseDashboardApp();
  const database = dashboardApp.database();

  return database.ref('coverage-reports').child(latestSha).set(results)
    .catch((err: any) => console.error(err))
    .then(() => dashboardApp.delete());
}