const fs = require('fs')
const gulp = require('gulp')
const watch = require('gulp-watch')
const source = require('vinyl-source-stream')
const buffer = require('vinyl-buffer')
const log = require('fancy-log')
const { assign } = require('lodash')
const watchify = require('watchify')
const browserify = require('browserify')
const envify = require('envify/custom')
const sourcemaps = require('gulp-sourcemaps')
const sesify = require('sesify')
const terser = require('gulp-terser-js')
const pify = require('pify')
const endOfStream = pify(require('end-of-stream'))
const { makeStringTransform } = require('browserify-transform-tools')

const conf = require('rc')('metamask', {})

const packageJSON = require('../../package.json')
const { createTask, composeParallel, composeSeries, runInChildProcess } = require('./task')

module.exports = createScriptTasks

const dependencies = Object.keys((packageJSON && packageJSON.dependencies) || {})
const materialUIDependencies = ['@material-ui/core']
const reactDepenendencies = dependencies.filter((dep) => dep.match(/react/u))
const d3Dependencies = ['c3', 'd3']

const externalDependenciesMap = {
  background: [
    '3box',
  ],
  ui: [
    ...materialUIDependencies, ...reactDepenendencies, ...d3Dependencies,
  ],
}

function createScriptTasks ({ browserPlatforms, livereload }) {

  // internal tasks
  const core = {
    // dev tasks (live reload)
    dev: createTasksForBuildJsExtension({ taskPrefix: 'scripts:core:dev', devMode: true }),
    testDev: createTasksForBuildJsExtension({ taskPrefix: 'scripts:core:test-live', devMode: true, testing: true }),
    // built for CI tests
    test: createTasksForBuildJsExtension({ taskPrefix: 'scripts:core:test', testing: true }),
    // production
    prod: createTasksForBuildJsExtension({ taskPrefix: 'scripts:core:prod' }),
  }
  const deps = {
    background: createTasksForBuildJsDeps({ filename: 'bg-libs', key: 'background' }),
    ui: createTasksForBuildJsDeps({ filename: 'ui-libs', key: 'ui' }),
  }

  // high level tasks

  const prod = composeParallel(
    deps.background,
    deps.ui,
    core.prod,
  )

  const { dev, testDev } = core

  const test = composeParallel(
    deps.background,
    deps.ui,
    core.test,
  )

  return { prod, dev, testDev, test }

  function createTasksForBuildJsDeps ({ key, filename }) {
    return createTask(`scripts:deps:${key}`, bundleTask({
      label: filename,
      filename: `${filename}.js`,
      buildLib: true,
      dependenciesToBundle: externalDependenciesMap[key],
      devMode: false,
    }))
  }

  function createTasksForBuildJsExtension ({ taskPrefix, devMode, testing }) {
    const standardBundles = [
      'background',
      'ui',
      'phishing-detect',
    ]

    const standardSubtasks = standardBundles.map((filename) => {
      return createTask(`${taskPrefix}:${filename}`,
        createBundleTaskForBuildJsExtensionNormal({ filename, devMode, testing }))
    })
    // inpage must be built before contentscript
    // because inpage bundle result is included inside contentscript
    const contentscriptSubtask = createTask(`${taskPrefix}:contentscript`,
      createTaskForBuildJsExtensionContentscript({ devMode, testing }))

    // task for initiating livereload
    const initiateLiveReload = async () => {
      if (devMode) {
        // trigger live reload when the bundles are updated
        // this is not ideal, but overcomes the limitations:
        // - run from the main process (not child process tasks)
        // - after the first build has completed (thus the timeout)
        // - build tasks never "complete" when run with livereload + child process
        setTimeout(() => {
          watch('./dist/*/*.js', (event) => {
            livereload.changed(event.path)
          })
        }, 75e3)
      }
    }

    // make each bundle run in a separate process
    const allSubtasks = [...standardSubtasks, contentscriptSubtask].map((subtask) => runInChildProcess(subtask))
    // const allSubtasks = [...standardSubtasks, contentscriptSubtask].map(subtask => (subtask))
    // make a parent task that runs each task in a child thread
    return composeParallel(initiateLiveReload, ...allSubtasks)
  }

  function createBundleTaskForBuildJsExtensionNormal ({ filename, devMode, testing }) {
    return bundleTask({
      label: filename,
      filename: `${filename}.js`,
      filepath: `./app/scripts/${filename}.js`,
      externalDependencies: devMode ? undefined : externalDependenciesMap[filename],
      devMode,
      testing,
    })
  }

  function createTaskForBuildJsExtensionContentscript ({ devMode, testing }) {
    const inpage = 'inpage'
    const contentscript = 'contentscript'
    return composeSeries(
      bundleTask({
        label: inpage,
        filename: `${inpage}.js`,
        filepath: `./app/scripts/${inpage}.js`,
        externalDependencies: devMode ? undefined : externalDependenciesMap[inpage],
        devMode,
        testing,
      }),
      bundleTask({
        label: contentscript,
        filename: `${contentscript}.js`,
        filepath: `./app/scripts/${contentscript}.js`,
        externalDependencies: devMode ? undefined : externalDependenciesMap[contentscript],
        devMode,
        testing,
      }),
    )
  }

  function bundleTask (opts) {
    let bundler

    return performBundle

    async function performBundle () {
      // initialize bundler if not available yet
      // dont create bundler until task is actually run
      if (!bundler) {
        bundler = generateBundler(opts, performBundle)
        // output build logs to terminal
        bundler.on('log', log)
      }

      let buildStream = bundler.bundle()

      // handle errors
      buildStream.on('error', (err) => {
        beep()
        if (opts.devMode) {
          console.warn(err.stack)
        } else {
          throw err
        }
      })

      // process bundles
      buildStream = buildStream
        // convert bundle stream to gulp vinyl stream
        .pipe(source(opts.filename))
        // buffer file contents (?)
        .pipe(buffer())

      // Initialize Source Maps
      buildStream = buildStream
        // loads map from browserify file
        .pipe(sourcemaps.init({ loadMaps: true }))

      // Minification
      if (!opts.devMode) {
        buildStream = buildStream
          .pipe(terser({
            mangle: {
              reserved: ['MetamaskInpageProvider'],
            },
            sourceMap: {
              content: true,
            },
          }))
      }

      // Finalize Source Maps
      if (opts.devMode) {
        // Use inline source maps for development due to Chrome DevTools bug
        // https://bugs.chromium.org/p/chromium/issues/detail?id=931675
        buildStream = buildStream
          .pipe(sourcemaps.write())
      } else {
        buildStream = buildStream
          .pipe(sourcemaps.write('../sourcemaps'))
      }

      // write completed bundles
      browserPlatforms.forEach((platform) => {
        const dest = `./dist/${platform}`
        buildStream = buildStream.pipe(gulp.dest(dest))
      })

      await endOfStream(buildStream)
    }
  }

  function configureBundleForSesify ({
    browserifyOpts,
    bundleName,
  }) {
    // add in sesify args for better globalRef usage detection
    Object.assign(browserifyOpts, sesify.args)

    // ensure browserify uses full paths
    browserifyOpts.fullPaths = true

    // record dependencies used in bundle
    fs.mkdirSync('./sesify', { recursive: true })
    browserifyOpts.plugin.push(['deps-dump', {
      filename: `./sesify/deps-${bundleName}.json`,
    }])

    const sesifyConfigPath = `./sesify/${bundleName}.json`

    // add sesify plugin
    browserifyOpts.plugin.push([sesify, {
      writeAutoConfig: sesifyConfigPath,
    }])

    // remove html comments that SES is alergic to
    const removeHtmlComment = makeStringTransform('remove-html-comment', { excludeExtension: ['.json'] }, (content, _, cb) => {
      const result = content.split('-->').join('-- >')
      cb(null, result)
    })
    browserifyOpts.transform.push([removeHtmlComment, { global: true }])
  }

  function generateBundler (opts, performBundle) {
    const browserifyOpts = assign({}, watchify.args, {
      plugin: [],
      transform: [],
      debug: true,
      fullPaths: opts.devMode,
    })

    const bundleName = opts.filename.split('.')[0]

    // activate sesify
    const activateAutoConfig = Boolean(process.env.SESIFY_AUTOGEN)
    // const activateSesify = activateAutoConfig
    const activateSesify = activateAutoConfig && ['background'].includes(bundleName)
    if (activateSesify) {
      configureBundleForSesify({ browserifyOpts, bundleName })
    }

    if (!activateSesify) {
      browserifyOpts.plugin.push('browserify-derequire')
    }

    if (!opts.buildLib) {
      if (opts.devMode && opts.filename === 'ui.js') {
        browserifyOpts.entries = ['./development/require-react-devtools.js', opts.filepath]
      } else {
        browserifyOpts.entries = [opts.filepath]
      }
    }

    let bundler = browserify(browserifyOpts)
      .transform('babelify')
      // Transpile any dependencies using the object spread/rest operator
      // because it is incompatible with `esprima`, which is used by `envify`
      // See https://github.com/jquery/esprima/issues/1927
      .transform('babelify', {
        only: [
          './**/node_modules/libp2p',
        ],
        global: true,
        plugins: ['@babel/plugin-proposal-object-rest-spread'],
      })
      .transform('brfs')

    if (opts.buildLib) {
      bundler = bundler.require(opts.dependenciesToBundle)
    }

    if (opts.externalDependencies) {
      bundler = bundler.external(opts.externalDependencies)
    }

    const environment = getEnvironment({ devMode: opts.devMode, test: opts.testing })
    if (environment === 'production' && !process.env.SENTRY_DSN) {
      throw new Error('Missing SENTRY_DSN environment variable')
    }

    // Inject variables into bundle
    bundler.transform(envify({
      METAMASK_DEBUG: opts.devMode,
      METAMASK_ENVIRONMENT: environment,
      METAMETRICS_PROJECT_ID: process.env.METAMETRICS_PROJECT_ID,
      NODE_ENV: opts.devMode ? 'development' : 'production',
      IN_TEST: opts.testing ? 'true' : false,
      PUBNUB_SUB_KEY: process.env.PUBNUB_SUB_KEY || '',
      PUBNUB_PUB_KEY: process.env.PUBNUB_PUB_KEY || '',
      ETH_GAS_STATION_API_KEY: process.env.ETH_GAS_STATION_API_KEY || '',
      CONF: opts.devMode ? conf : ({}),
      SENTRY_DSN: process.env.SENTRY_DSN,
    }), {
      global: true,
    })

    // Live reload - minimal rebundle on change
    if (opts.devMode) {
      bundler = watchify(bundler)
      // on any file update, re-runs the bundler
      bundler.on('update', () => {
        performBundle()
      })
    }

    return bundler
  }

}

function beep () {
  process.stdout.write('\x07')
}

function getEnvironment ({ devMode, test }) {
  // get environment slug
  if (devMode) {
    return 'development'
  } else if (test) {
    return 'testing'
  } else if (process.env.CIRCLE_BRANCH === 'master') {
    return 'production'
  } else if ((/^Version-v(\d+)[.](\d+)[.](\d+)/u).test(process.env.CIRCLE_BRANCH)) {
    return 'release-candidate'
  } else if (process.env.CIRCLE_BRANCH === 'develop') {
    return 'staging'
  } else if (process.env.CIRCLE_PULL_REQUEST) {
    return 'pull-request'
  }
  return 'other'
}