'use strict';

import * as firebaseFunctions from 'firebase-functions';
import * as firebaseAdmin from 'firebase-admin';

import {verifyJwtAndTransferResultToTrustedLocation} from './verify-and-copy-report';
import {copyGoldImagesToDatabase} from './image-data';
import {writeTestImagesToFiles} from './data-image';
import {copyTestImagesToGoldens} from './test-goldens';
import {updateGithubStatus} from './github';

/**
 * Usage: Firebase functions only accept javascript file index.js
 *   tsc -p tools/screenshot-test/functions/tsconfig.json
 *   cd functions
 *   npm install
 *   firebase deploy --only functions
 *
 *
 * Data and images handling for Screenshot test.
 *
 * All users can post data to temporary folder. These Functions will check the data with
 * JsonWebToken and move the valid data out of temporary folder.
 *
 * For valid data posted to database /$temp/screenshot/reports/$prNumber/$secureToken, move it to
 * /screenshot/reports/$prNumber.
 * These are data for screenshot results (success or failure), GitHub PR/commit and TravisCI job
 * information.
 *
 * For valid image results written to database /$temp/screenshot/images/$prNumber/$secureToken/,
 * save the image data to image files and upload to google cloud storage under
 * location /screenshots/$prNumber
 * These are screenshot test result images, and difference images generated from screenshot
 * comparison.
 *
 * For golden images uploaded to /goldens, read the data from images files and write the data to
 * Firebase database under location /screenshot/goldens
 * Screenshot tests can only read restricted database data with no credentials, and they cannot
 * access.
 * Google Cloud Storage. Therefore we copy the image data to database to make it available to
 * screenshot tests.
 *
 * The JWT is stored in the data path, so every write to database needs a valid JWT to be copied to
 * database/storage.
 * All invalid data will be removed.
 * The JWT has 3 parts: header, payload and signature. These three parts are joint by '/' in path.
 */

// Initialize the admin app
firebaseAdmin.initializeApp(firebaseFunctions.config().firebase);

/** The valid data types database accepts */
const dataTypes = ['result', 'sha', 'travis'];

/** The Json Web Token format. The token is stored in data path. */
const jwtFormat = '{jwtHeader}/{jwtPayload}/{jwtSignature}';

/** The temporary folder name for screenshot data that needs to be validated via JWT.  */
const tempFolder = '/untrustedInbox';


/** Untrusted report data for a PR */
const reportPath = `${tempFolder}/screenshot/reports/{prNumber}/${jwtFormat}/`;
/** Untrusted image data for a PR */
const imagePath =  `${tempFolder}/screenshot/images/{prNumber}/${jwtFormat}/`;
/** Trusted report data for a PR */
const trustedReportPath = `screenshot/reports/{prNumber}`;

/**
 * Copy valid data from /$temp/screenshot/reports/$prNumber/$secureToken/
 *   to /screenshot/reports/$prNumber
 * Data copied: filenames(image results names), commit(github PR info),
 *     sha (github PR info), result (true or false for all the tests), travis job number
 */
const testDataPath = `${reportPath}/{dataType}`;
export let testData = firebaseFunctions.database.ref(testDataPath)
    .onWrite((event: any) => {
  const dataType = event.params.dataType;
  if (dataTypes.includes(dataType)) {
    return verifyJwtAndTransferResultToTrustedLocation(event, dataType);
  }
});

/**
 * Copy valid data from /$temp/screenshot/reports/$prNumber/$secureToken/
 *   to /screenshot/reports/$prNumber
 * Data copied: test result for each file/test with ${filename}. The value should be true or false.
 */
const testResultsPath = `${reportPath}/results/{filename}`;
export let testResults = firebaseFunctions.database.ref(testResultsPath)
    .onWrite((event: any) => {
  return verifyJwtAndTransferResultToTrustedLocation(event, `results/${event.params.filename}`);
});

/**
 * Copy valid data from database /$temp/screenshot/images/$prNumber/$secureToken/
 *   to storage /screenshots/$prNumber
 * Data copied: test result images. Convert from data to image files in storage.
 */
const imageDataToFilePath = `${imagePath}/{dataType}/{filename}`;
export let imageDataToFile = firebaseFunctions.database.ref(imageDataToFilePath)
  .onWrite(writeTestImagesToFiles);

/**
 * Copy valid goldens from storage /goldens/ to database /screenshot/goldens/
 * so we can read the goldens without credentials.
 */
export let goldenImageToData = firebaseFunctions.storage.bucket(
    firebaseFunctions.config().firebase.storageBucket).object().onChange((event: any) => {
  return copyGoldImagesToDatabase(event.data.name, event.data.resourceState, event.data.bucket);
});

/**
 * Copy test result images for PR to Goldens.
 * Copy images from /screenshot/$prNumber/test/ to /goldens/
 */
const approveImagesPath = `${trustedReportPath}/approved`;
export let approveImages = firebaseFunctions.database.ref(approveImagesPath)
    .onWrite((event: any) => {
  return copyTestImagesToGoldens(event.params.prNumber);
});

/**
 * Update github status. When the result is true, update github commit status to `success`,
 * otherwise update github status to `failure`.
 * The Github Status Token is set in config.secret.github
 */
const githubStatusPath = `${trustedReportPath}/result/{sha}`;
export let githubStatus = firebaseFunctions.database.ref(githubStatusPath)
    .onWrite(updateGithubStatus);