var gulp = require('gulp');
var gutil = require('gulp-util');
var taskListing = require('gulp-task-listing');
var path = require('canonical-path');
var del = require('del');
var _ = require('lodash');
var argv = require('yargs').argv;
var env = require('gulp-env');
var Q = require("q");
// delPromise is a 'promise' version of del
var delPromise =  Q.denodeify(del);
var Minimatch = require("minimatch").Minimatch;
var Dgeni = require('dgeni');
var Package = require('dgeni').Package;
var fsExtra = require('fs-extra');
var fs = fsExtra;
var exec = require('child_process').exec;
var execPromise = Q.denodeify(exec);
// cross platform version of spawn that also works on windows.
var xSpawn = require('cross-spawn');
var prompt = require('prompt');
var globby = require("globby");
// Ugh... replacement needed to kill processes on any OS
// - because childProcess.kill does not work properly on windows
var treeKill = require("tree-kill");
var blc = require("broken-link-checker");

var tslint = require('gulp-tslint');

// TODO:
//  1. Think about using runSequence
//  2. Think about using spawn instead of exec in case of long error messages.

var TOOLS_PATH = './tools';
var ANGULAR_PROJECT_PATH = '../angular';
var PUBLIC_PATH = './public';
var TEMP_PATH = './_temp';
var DOCS_PATH = path.join(PUBLIC_PATH, 'docs');

var EXAMPLES_PATH = path.join(DOCS_PATH, '_examples');
var NOT_API_DOCS_GLOB = path.join(PUBLIC_PATH, './{docs/*/latest/!(api),!(docs)}/**/*');
var RESOURCES_PATH = path.join(PUBLIC_PATH, 'resources');
var LIVE_EXAMPLES_PATH = path.join(RESOURCES_PATH, 'live-examples');

var docShredder = require(path.resolve(TOOLS_PATH, 'doc-shredder/doc-shredder'));
var exampleZipper = require(path.resolve(TOOLS_PATH, '_example-zipper/exampleZipper'));
var plunkerBuilder = require(path.resolve(TOOLS_PATH, 'plunker-builder/plunkerBuilder'));
var fsUtils = require(path.resolve(TOOLS_PATH, 'fs-utils/fsUtils'));


var _devguideShredOptions =  {
  examplesDir: path.join(DOCS_PATH, '_examples'),
  fragmentsDir: path.join(DOCS_PATH, '_fragments'),
  zipDir: path.join(RESOURCES_PATH, 'zips')
};

var _devguideShredJadeOptions =  {
  jadeDir: DOCS_PATH

};

var _apiShredOptions =  {
  examplesDir: path.join(ANGULAR_PROJECT_PATH, 'modules/angular2/examples'),
  fragmentsDir: path.join(DOCS_PATH, '_fragments/_api'),
  zipDir: path.join(RESOURCES_PATH, 'zips/api')
};

var _excludePatterns = ['**/node_modules/**', '**/typings/**', '**/packages/**'];

var _excludeMatchers = _excludePatterns.map(function(excludePattern){
  return new Minimatch(excludePattern)
});

var _exampleBoilerplateFiles = [
  '.editorconfig',
  'karma.conf.js',
  'karma-test-shim.js',
  'package.json',
  'styles.css',
  'systemjs.config.js',
  'tsconfig.json',
  'tslint.json',
  'typings.json',
  'wallaby.js'
 ];

var _exampleDartWebBoilerPlateFiles = ['styles.css'];

/**
 * Run Protractor End-to-End Tests for Doc Samples
 *
 * Flags
 *   --filter to filter/select _example app subdir names
 *    e.g. gulp run-e2e-tests --filter=foo  // all example apps with 'foo' in their folder names.
 *
 *    --fast by-passes the npm install and webdriver update
 *    Use it for repeated test runs (but not the FIRST run)
 *    e.g. gulp run-e2e-tests --fast
 *
 *   --lang to filter by code language
 *     e.g. gulp run-e2e-tests --lang=ts  // only TypeScript apps
 *     default is (ts|js)
 *     all means (ts|js|dart)
 */
gulp.task('run-e2e-tests', function() {
  var promise;
  if (argv.fast) {
    // fast; skip all setup
    promise = Promise.resolve(true);
  } else  {
    // Not 'fast'; do full setup
    var spawnInfo = spawnExt('npm', ['install'], { cwd: EXAMPLES_PATH});
    promise = spawnInfo.promise.then(function() {
      copyExampleBoilerplate();
      spawnInfo = spawnExt('npm', ['run', 'webdriver:update'], {cwd: EXAMPLES_PATH});
      return spawnInfo.promise;
    });
  }

  promise.then(function() {
    return findAndRunE2eTests(argv.filter);
  }).then(function(status) {
    reportStatus(status);
    if (status.failed.length > 0){
      return Promise.reject('Some test suites failed');
    }
  }).catch(function(e) {
    gutil.log(e);
    process.exit(1);
  });
});

// finds all of the *e2e-spec.tests under the _examples folder along
// with the corresponding apps that they should run under. Then run
// each app/spec collection sequentially.
function findAndRunE2eTests(filter) {
  var lang = (argv.lang || '(ts|js)').toLowerCase();
  if (lang === 'all') { lang = '(ts|js|dart)'; }
  var startTime = new Date().getTime();
  // create an output file with header.
  var outputFile = path.join(process.cwd(), 'protractor-results.txt');

  var header = `Doc Sample Protractor Results for ${lang} on ${new Date().toLocaleString()}\n`;
  header += argv.fast ?
    '  Fast Mode (--fast): no npm install, webdriver update, or boilerplate copy\n' :
    '  Slow Mode: npm install, webdriver update, and boilerplate copy\n';
  header += `  Filter: ${filter ? filter : 'All tests'}\n\n`;

  fs.writeFileSync(outputFile, header);

  // create an array of combos where each
  // combo consists of { examplePath: ... , protractorConfigFilename:  ... }
  var exeConfigs = [];
  var e2eSpecPaths = getE2eSpecPaths(EXAMPLES_PATH);
  var srcConfig = path.join(EXAMPLES_PATH, 'protractor.config.js');
  e2eSpecPaths.forEach(function(specPath) {
    var destConfig = path.join(specPath, 'protractor.config.js');
    fsExtra.copySync(srcConfig, destConfig);
    // get all of the examples under each dir where a pcFilename is found
    examplePaths = getExamplePaths(specPath, true);
    // Filter by language
    examplePaths = examplePaths.filter(function (fn) {
      return fn.match('/'+lang+'$') != null;
    });
    if (filter) {
      examplePaths = examplePaths.filter(function (fn) {
        return fn.match(filter) != null;
      })
    }
    examplePaths.forEach(function(exPath) {
      exeConfigs.push( { examplePath: exPath, protractorConfigFilename: destConfig });
    })
  });

  // run the tests sequentially
  var status = { passed: [], failed: [] };
  return exeConfigs.reduce(function (promise, combo) {
    return promise.then(function () {
      var isDart = combo.examplePath.indexOf('/dart') > -1;
      var runTests = isDart ? runE2eDartTests : runE2eTsTests;
      return runTests(combo.examplePath, combo.protractorConfigFilename, outputFile).then(function(ok) {
        var arr = ok ? status.passed : status.failed;
        arr.push(combo.examplePath);
      })
    });
  }, Q.resolve()).then(function() {
    var stopTime = new Date().getTime();
    status.elapsedTime = (stopTime - startTime)/1000;
    fs.appendFileSync(outputFile, '\nElaped Time: ' + status.elapsedTime + ' seconds');
    return status;
  });
}

// start the example in appDir; then run protractor with the specified
// fileName; then shut down the example.  All protractor output is appended
// to the outputFile.
function runE2eTsTests(appDir, protractorConfigFilename, outputFile) {
  // start the app
  var appRunSpawnInfo = spawnExt('npm',['run','http-server:e2e', '--', '-s' ], { cwd: appDir });
  var tscRunSpawnInfo = spawnExt('npm',['run','tsc'], { cwd: appDir });

  return runProtractor(tscRunSpawnInfo.promise, appDir, appRunSpawnInfo, protractorConfigFilename, outputFile);
}

function runProtractor(prepPromise, appDir, appRunSpawnInfo, protractorConfigFilename, outputFile) {
  return prepPromise
    .catch(function(){
      var emsg = `AppDir failed during compile: ${appDir}\n\n`;
      gutil.log(emsg);
      fs.appendFileSync(outputFile, emsg);
      return Promise.reject(emsg);
    })
    .then(function (data) {
      // start protractor
      var pcFilename = path.resolve(protractorConfigFilename); // need to resolve because we are going to be running from a different dir
      var spawnInfo = spawnExt('npm', [ 'run', 'protractor', '--', pcFilename, 
        '--params.appDir=' + appDir, '--params.outputFile=' + outputFile], { cwd: EXAMPLES_PATH });
      return spawnInfo.promise
    })
    .then(
       function() { return finish(true);},
       function() { return finish(false);}
    )

    function finish(ok){
      // Ugh... proc.kill does not work properly on windows with child processes.
      // appRun.proc.kill();
      treeKill(appRunSpawnInfo.proc.pid);
      return ok;
    }
}

// start the server in appDir/build/web; then run protractor with the specified
// fileName; then shut down the example.  All protractor output is appended
// to the outputFile.
function runE2eDartTests(appDir, protractorConfigFilename, outputFile) {
  var deployDir = path.resolve(path.join(appDir, 'build/web'));
  gutil.log('AppDir for Dart e2e: ' + appDir);
  gutil.log('Deploying from: ' + deployDir);

  var appRunSpawnInfo = spawnExt('npm', ['run', 'http-server:e2e', '--', deployDir, '-s'], { cwd: EXAMPLES_PATH });
  if (!appRunSpawnInfo.proc.pid) {
    gutil.log('http-server failed to launch over ' + deployDir);
    return false;
  }
  var pubUpgradeSpawnInfo = spawnExt('pub', ['upgrade'], { cwd: appDir });
  var prepPromise = pubUpgradeSpawnInfo.promise.then(function (data) {
    return spawnExt('pub', ['build'], { cwd: appDir }).promise;
  });
  return runProtractor(prepPromise, appDir, appRunSpawnInfo, protractorConfigFilename, outputFile);
}

function reportStatus(status) {
  gutil.log('Suites passed:');
  status.passed.forEach(function(val) {
    gutil.log('  ' + val);
  });

  if (status.failed.length == 0) {
    gutil.log('All tests passed');
  } else {
    gutil.log('Suites failed:');
    status.failed.forEach(function (val) {
      gutil.log('  ' + val);
    });
  }
  gutil.log('Elapsed time: ' +  status.elapsedTime + ' seconds');
}

// returns both a promise and the spawned process so that it can be killed if needed.
function spawnExt(command, args, options) {
  var deferred = Q.defer();
  var descr = command + " " + args.join(' ');
  var proc;
  gutil.log('running: ' + descr);
  try {
    proc = xSpawn.spawn(command, args, options);
  } catch(e) {
    gutil.log(e);
    deferred.reject(e);
    return { proc: null, promise: deferred.promise };
  }
  proc.stdout.on('data', function (data) {
    gutil.log(data.toString());
  });
  proc.stderr.on('data', function (data) {
    gutil.log(data.toString());
  });
  proc.on('close', function (returnCode) {
    gutil.log('completed: ' + descr);
    // Many tasks (e.g., tsc) complete but are actually errors;
    // Confirm return code is zero.
    returnCode === 0 ? deferred.resolve(0) : deferred.reject(returnCode);
  });
  proc.on('error', function (data) {
    gutil.log('completed with error:' + descr);
    gutil.log(data.toString());
    deferred.reject(data);
  });
  return { proc: proc, promise: deferred.promise };
}

// Public tasks

gulp.task('default', ['help']);

gulp.task('help', taskListing.withFilters(function(taskName) {
  var isSubTask = taskName.substr(0,1) == "_";
  return isSubTask;
}, function(taskName) {
  var shouldRemove = taskName === 'default';
  return shouldRemove;
}));

// requires admin access
gulp.task('add-example-boilerplate', function() {
  var realPath = path.join(EXAMPLES_PATH, '/node_modules');
  var nodeModulesPaths = getNodeModulesPaths(EXAMPLES_PATH);

  nodeModulesPaths.forEach(function(linkPath) {
    gutil.log("symlinking " + linkPath + ' -> ' + realPath)
    fsUtils.addSymlink(realPath, linkPath);
  });

  realPath = path.join(EXAMPLES_PATH, '/typings');
  var typingsPaths = getTypingsPaths(EXAMPLES_PATH);
  typingsPaths.forEach(function(linkPath) {
    gutil.log("symlinking " + linkPath + ' -> ' + realPath)
    fsUtils.addSymlink(realPath, linkPath);
  });

  return copyExampleBoilerplate();
});

// copies boilerplate files to locations
// where an example app is found
// also copies certain web files (e.g., styles.css) to ~/_examples/**/dart/**/web
// also copies protractor.config.js file
function copyExampleBoilerplate() {
  var sourceFiles = _exampleBoilerplateFiles.map(function(fn) {
    return path.join(EXAMPLES_PATH, fn);
  });
  var examplePaths = getExamplePaths(EXAMPLES_PATH);

  var dartWebSourceFiles = _exampleDartWebBoilerPlateFiles.map(function(fn){
    return path.join(EXAMPLES_PATH, fn);
  });
  var dartExampleWebPaths = getDartExampleWebPaths(EXAMPLES_PATH);

  return copyFiles(sourceFiles, examplePaths)
    .then(function() {
      return copyFiles(dartWebSourceFiles, dartExampleWebPaths);
    })
    // copy protractor.config.js from _examples dir to each subdir that
    // contains a e2e-spec file.
    .then(function() {
      var sourceFiles = [ path.join(EXAMPLES_PATH, 'protractor.config.js') ];
      var e2eSpecPaths = getE2eSpecPaths(EXAMPLES_PATH);
      return copyFiles(sourceFiles, e2eSpecPaths);
    });
}

gulp.task('remove-example-boilerplate', function() {
  var nodeModulesPaths = getNodeModulesPaths(EXAMPLES_PATH);
  nodeModulesPaths.forEach(function(linkPath) {
    fsUtils.removeSymlink(linkPath);
  });

  var typingsPaths = getTypingsPaths(EXAMPLES_PATH);
  typingsPaths.forEach(function(linkPath) {
    fsUtils.removeSymlink(linkPath);
  });

  var examplePaths = getExamplePaths(EXAMPLES_PATH);
  var dartExampleWebPaths = getDartExampleWebPaths(EXAMPLES_PATH);

  return deleteFiles(_exampleBoilerplateFiles, examplePaths)
    .then(function() {
      return deleteFiles(_exampleDartWebBoilerPlateFiles, dartExampleWebPaths);
    })
    .then(function() {
      var e2eSpecPaths = getE2eSpecPaths(EXAMPLES_PATH);
      return deleteFiles(['protractor.config.js'], e2eSpecPaths);
    })
});

gulp.task('serve-and-sync', ['build-docs'], function (cb) {
  // watchAndSync({devGuide: true, apiDocs: true, apiExamples: true, localFiles: true}, cb);
  watchAndSync({devGuide: true, devGuideJade: true, apiDocs: true, apiExamples: true, localFiles: true}, cb);
});

gulp.task('serve-and-sync-api', ['build-docs'], function (cb) {
  watchAndSync({apiDocs: true, apiExamples: true}, cb);
});

gulp.task('serve-and-sync-devguide', ['build-devguide-docs', 'build-plunkers' ], function (cb) {
  watchAndSync({devGuide: true, devGuideJade: true, localFiles: true}, cb);
});

gulp.task('_serve-and-sync-jade', function (cb) {
  watchAndSync({devGuideJade: true, localFiles: true}, cb);
});

gulp.task('build-and-serve', ['build-docs'], function (cb) {
  watchAndSync({localFiles: true}, cb);
});

gulp.task('build-docs', ['build-devguide-docs', 'build-api-docs', 'build-plunkers']);
// Stop zipping examples Feb 28, 2016
//gulp.task('build-docs', ['build-devguide-docs', 'build-api-docs', 'build-plunkers', '_zip-examples']);

gulp.task('build-api-docs', ['build-js-api-docs', 'build-ts-api-docs', 'build-dart-cheatsheet']);

gulp.task('build-devguide-docs', ['_shred-devguide-examples', '_shred-devguide-shared-jade'], function() {
  return buildShredMaps(true);
});

gulp.task('build-ts-api-docs', ['_shred-api-examples'], function() {
  return buildApiDocs('ts');
});

gulp.task('build-js-api-docs', ['_shred-api-examples'], function() {
  return buildApiDocs('js');
});

gulp.task('build-plunkers', function() {
  return copyExampleBoilerplate()
    .then(function() {
      return plunkerBuilder.buildPlunkers(EXAMPLES_PATH, LIVE_EXAMPLES_PATH, { errFn: gutil.log });
    });
});

gulp.task('build-dart-cheatsheet', [], function() {
  return buildApiDocs('dart');
});

gulp.task('git-changed-examples', ['_shred-devguide-examples'], function(){
  var after, sha, messageSuffix;
  if (argv.after) {
    try {
      after = new Date(argv.after);
      messageSuffix = ' after: ' + argv.after;
    } catch (e) {
      throw argv.after + " is not a valid date.";
    }
  } else if (argv.sha) {
    sha = argv.sha;
    messageSuffix = ' on commit: ' + (argv.sha.length ? argv.sha : '[last commit]');
  } else {
    gutil.log('git-changed-examples may be called with either an "--sha" argument like this:');
    gutil.log('   gulp git-changed-examples --sha=4d2ac96fa247306ddd2d4c4e0c8dee2223502eb2');
    gutil.log('or with an "--after" argument like this')
    gutil.log('   gulp git-changed-examples --after="August 1, 2015"');
    return;
  }
  var jadeShredMap;
  return buildShredMaps(false).then(function(docs) {
    jadeShredMap = docs[0];
    if (after) {
      return getChangedExamplesAfter(after);
    } else if (sha) {
      return getChangedExamples(sha);
    } else {
      gutil.log('git-changed-examples may be called with either an "--sha" argument like this:');
      gutil.log('   gulp git-changed-examples --sha=4d2ac96fa247306ddd2d4c4e0c8dee2223502eb2');
      gutil.log('or with an "--after" argument like this')
      gutil.log('   gulp git-changed-examples --after="August 1, 2015"');
    }
  }).then(function(examplePaths) {
    examplePaths = filterOutExcludedPatterns(examplePaths, _excludeMatchers);
    gutil.log('\nExamples changed ' + messageSuffix);
    gutil.log(examplePaths)
    gutil.log("\nJade files affected by changed example files " + messageSuffix);
    var jadeExampleMap = jadeShredMapToJadeExampleMap(jadeShredMap, examplePaths);
    gutil.log(JSON.stringify(jadeExampleMap, null, "  "));
    gutil.log("-----");
  }).catch(function(err) {
    gutil.log(err);
    throw err;
  });
});

gulp.task('check-deploy', ['build-docs'], function() {
  return harpCompile().then(function() {
    gutil.log('compile ok');
    if(argv.dryRun) {
      return false;
    } else {
      gutil.log('running live server ...');
      execPromise('npm run live-server ./www');
      return askDeploy();
    }
  }).then(function(shouldDeploy) {
    if (shouldDeploy) {
      gutil.log('deploying...');
      return execPromise('firebase deploy');
    } else {
      return ['Not deploying'];
    }
  }).then(function(s) {
    gutil.log(s.join(''));
  }).catch(function(e) {
    gutil.log(e);
  });
});

gulp.task('test-api-builder', function (cb) {
  execCommands(['npm run test-api-builder'], {}, cb);
});

// Usage:
//   angular.io:  gulp link-checker
//   local site:  gulp link-checker --url=http://localhost:3000
gulp.task('link-checker', function(done) {
  return linkChecker();
});


// Internal tasks
gulp.task('set-prod-env', function () {
  // Supposedly running in production makes harp faster
  // and less likely to drown in node_modules.
  env({
    vars: { NODE_ENV: "production" }
  });
  gutil.log("NODE_ENV: " + process.env.NODE_ENV);
});

// used to test just harpCompile without a build step
gulp.task('_harp-compile', function() {
  return harpCompile().then(function() {
    gutil.log('compile ok');
  }).catch(function(e) {
    gutil.log('compile failed');
  });
});

gulp.task('_shred-devguide-examples', ['_shred-clean-devguide'], function() {
  return docShredder.shred( _devguideShredOptions);
});

gulp.task('_shred-devguide-shared-jade', ['_shred-clean-devguide-shared-jade'],  function() {
  return docShredder.shred( _devguideShredJadeOptions);
});

gulp.task('_shred-clean-devguide-shared-jade', function(cb) {
  // oldCleanPath is only needed to cleanup any jade fragments still sitting in the old location
  var oldCleanPath = path.join(DOCS_PATH, '**/_.*.jade');
  // jade fragments now all go into _fragments subdirs under their source.
  var newCleanPath = path.join(DOCS_PATH, '**/_fragments/*.jade');
  // Much slower 8-9x then using globby first ... ???
  // return delPromise([ newCleanPath, oldCleanPath]);
  var files = globby.sync( [newCleanPath, oldCleanPath]);
  return delPromise(files);
});

gulp.task('_shred-clean-devguide', function(cb) {
  var cleanPath = path.join(_devguideShredOptions.fragmentsDir, '**/*.*')
  return delPromise([ cleanPath, '!**/*.ovr.*', '!**/_api/**']);
});

gulp.task('_shred-api-examples', ['_shred-clean-api'], function() {
  checkAngularProjectPath();
  return docShredder.shred( _apiShredOptions);
});

gulp.task('_shred-clean-api', function(cb) {
  var cleanPath = path.join(_apiShredOptions.fragmentsDir, '**/*.*')
  return delPromise([ cleanPath, '!**/*.ovr.*' ]);
});

gulp.task('_zip-examples', function() {
  exampleZipper.zipExamples(_devguideShredOptions.examplesDir, _devguideShredOptions.zipDir);
  exampleZipper.zipExamples(_apiShredOptions.examplesDir, _apiShredOptions.zipDir);
});


// Linting

gulp.task('lint', function() {
  return gulp.src(['./public/docs/_examples/style-guide/ts/**/*.ts', '!./public/docs/_examples/style-guide/ts/**/*.avoid.ts'])
    .pipe(tslint({
      rulesDirectory: ['node_modules/codelyzer'],
      configuration: require('./tslint.json')
    }))
    .pipe(tslint.report('prose', {
      summarizeFailureOutput: true
    }));
});


// Helper functions

function harpCompile() {
  // Supposedly running in production makes harp faster
  // and less likely to drown in node_modules.
  env({
    vars: { NODE_ENV: "production" }
  });
  gutil.log("NODE_ENV: " + process.env.NODE_ENV);

  var deferred = Q.defer();
  gutil.log('running harp compile...');
  showHideExampleNodeModules('hide');
  var spawnInfo = spawnExt('npm',['run','harp', '--', 'compile', '.', './www' ]);
  spawnInfo.promise.then(function(x) {
    gutil.log("NODE_ENV: " + process.env.NODE_ENV);
    showHideExampleNodeModules('show');
    if (x !== 0) {
      deferred.reject(x)
    } else {
      deferred.resolve(x);
    }
  }).catch(function(e) {
    gutil.log("NODE_ENV: " + process.env.NODE_ENV);
    showHideExampleNodeModules('show');
    deferred.reject(e);
  });
  return deferred.promise;
}

function linkChecker(options) {
  var deferred = Q.defer();
  var options = options || {};

  var blcOptions = options.blcOptions || {};
  var customData = options.customData || {};

  var excludeBad; // don't bother reporting bad links matching this RegExp
  if (argv.excludeBad) {
    excludeBad = new RegExp(argv.excludeBad);
  } else {
    excludeBad = options.excludeBad === undefined ? /docs\/dart\/latest\/api/ : '';
  }

  var previousPage;
  var siteUrl = argv.url || options.url || 'https://angular.io/';

  // See https://github.com/stevenvachon/broken-link-checker#blcsitecheckeroptions-handlers
  var handlers = {
    robots: function(robots, customData){},
    html: function(tree, robots, response, pageUrl, customData){
      //gutil.log('Scanning ' + pageUrl);docs/ts/latest/api/core/
    },
    junk: function(result, customData){},

    // Analyze links
    link: function(result, customData){
      if (!result.broken) { return; }
      if (excludeBad && excludeBad.test(result.url.resolved)) { return; }

      var currentPage = result.base.resolved
      if (previousPage !== currentPage) {
        previousPage = currentPage;
        fs.appendFileSync(outputFile, '\n' + currentPage);
        gutil.log('broken: ' + currentPage);
      }
      var msg = '\n  [' + result.html.location.line + ', ' + result.brokenReason + '] ' + result.url.resolved;
      fs.appendFileSync(outputFile, msg);
      //gutil.log(msg);
      //gutil.log(result);
    },

    page: function(error, pageUrl, customData){},
    site: function(error, siteUrl, customData){},

    end: function(){
      var stopTime = new Date().getTime();
      var elapsed = 'Elapsed link-checking time: ' + ((stopTime - startTime)/1000) + ' seconds';
      gutil.log(elapsed);
      fs.appendFileSync(outputFile, '\n'+elapsed);
      gutil.log('Output in file: ' + outputFile);
      deferred.resolve(true);
    }
  };

  // create an output file with header.
  var outputFile = path.join(process.cwd(), 'link-checker-results.txt');
  var header = 'Link checker results for: ' + siteUrl +
               '\nStarted: ' + (new Date()).toLocaleString() +
               '\nSkipping bad links matching regex: ' +excludeBad.toString() + '\n\n';
  gutil.log(header);
  fs.writeFileSync(outputFile, header);

  var siteChecker = new blc.SiteChecker(blcOptions, handlers);
  var startTime = new Date().getTime();

  try {
    siteChecker.enqueue(siteUrl, customData);
  } catch (err) {
    deferred.reject(err);
  }
  return deferred.promise;
}

// harp has issues with node_modules under the public dir
// but we need them there for example testing and development
// this method allows the node modules folder under '_examples'
// to be temporarily moved out from under 'public' while harp
// compilation is occurring.
function showHideExampleNodeModules(showOrHide) {
  var nmPath = path.join(EXAMPLES_PATH, "/node_modules");
  var nmHiddenPath = path.join(TEMP_PATH, "/node_modules");
  if (showOrHide == 'hide' && fs.existsSync(nmPath)) {
    if (!fs.existsSync(TEMP_PATH)) {
      fs.mkdirSync(TEMP_PATH);
    }
    fs.renameSync(nmPath, nmHiddenPath);
  } else if (showOrHide == 'show' && fs.existsSync(nmHiddenPath)) {
    fs.renameSync(nmHiddenPath, nmPath);
    fs.rmdirSync(TEMP_PATH);
  }
}


// returns a promise
function copyFiles(fileNames, destPaths) {
  var copy = Q.denodeify(fsExtra.copy);
  var copyPromises = [];
  destPaths.forEach(function(destPath) {
    fileNames.forEach(function(fileName) {
      var baseName = path.basename(fileName);
      var destName = path.join(destPath, baseName);
      var p = copy(fileName, destName, { clobber: true});
      copyPromises.push(p);
    });
  });
  return Q.all(copyPromises);
}

function deleteFiles(baseFileNames, destPaths) {
  var remove = Q.denodeify(fsExtra.remove);
  var delPromises = [];
  destPaths.forEach(function(destPath) {
    baseFileNames.forEach(function(baseFileName) {
      var destFileName = path.join(destPath, baseFileName);
      var p = remove(destFileName);
      delPromises.push(p);
    });
  });
  return Q.all(delPromises);
}

// TODO: filter out all paths that are subdirs of another
// path in the result.
function getE2eSpecPaths(basePath) {
  var paths = getPaths(basePath, '*e2e-spec.js', true);
  return _.uniq(paths);
}

function getNodeModulesPaths(basePath) {
  var paths = getExamplePaths(basePath).map(function(examplePath) {
    return path.join(examplePath, "/node_modules");
  });
  return paths;
}

function getTypingsPaths(basePath) {
  var paths = getExamplePaths(basePath).map(function(examplePath) {
    return path.join(examplePath, "/typings");
  });
  return paths;
}

function getExamplePaths(basePath, includeBase) {
  // includeBase defaults to false
  return getPaths(basePath, "example-config.json", includeBase)
}

function getDartExampleWebPaths(basePath) {
  var paths = globby.sync([path.join(basePath,"**/dart/**/web")])
  return paths;
}

function getPaths(basePath, filename, includeBase) {
  var filenames = getFilenames(basePath, filename, includeBase);
  var paths = filenames.map(function(fileName) {
    return path.dirname(fileName);
  });
  return paths;
}

function getFilenames(basePath, filename, includeBase) {
  // includeBase defaults to false
  var includePatterns = [path.join(basePath, "**/" + filename)];
  if (!includeBase) {
    // ignore (skip) the top level version.
    includePatterns.push("!" + path.join(basePath, "/" + filename));
  }
  var nmPattern = path.join(basePath, "**/node_modules/**");
  var filenames = globby.sync(includePatterns, {ignore: [nmPattern]});
  return filenames;
}

function watchAndSync(options, cb) {
  // Supposedly running in production makes harp faster
  // and less likely to drown in node_modules.
  env({
    vars: { NODE_ENV: "production" }
  });

  execCommands(['npm run harp -- server .'], {}, cb);

  var browserSync = require('browser-sync').create();
  browserSync.init({proxy: 'localhost:9000'});

  if (options.devGuide) {
    devGuideExamplesWatch(_devguideShredOptions, browserSync.reload);
  }
  if (options.devGuideJade) {
    devGuideSharedJadeWatch( { jadeDir: DOCS_PATH}, browserSync.reload);
  }
  if (options.apiDocs) {
    apiSourceWatch(browserSync.reload);
  }
  if (options.apiExamples) {
    apiExamplesWatch(browserSync.reload);
  }
  if (options.localFiles) {
    gulp.watch(NOT_API_DOCS_GLOB, browserSync.reload);
  }
}

// returns a promise;
function askDeploy() {

  prompt.start();
  var schema = {
    name: 'shouldDeploy',
    description: 'Deploy to Firebase? (y/n): ',
    type: 'string',
    pattern: /Y|N|y|n/,
    message: "Respond with either a 'y' or 'n'",
    required: true
  }
  var getPromise = Q.denodeify(prompt.get);
  return getPromise([schema]).then(function(result) {
    return result.shouldDeploy.toLowerCase() === 'y';
  });
}


function filterOutExcludedPatterns(fileNames, excludeMatchers) {
  return fileNames.filter(function(fileName) {
    return !excludeMatchers.some(function(excludeMatcher) {
      return excludeMatcher.match(fileName);
    });
  });
}

function apiSourceWatch(postBuildAction) {
  var srcPattern = [path.join(ANGULAR_PROJECT_PATH, 'modules/angular2/src/**/*.*')];
  gulp.watch(srcPattern, {readDelay: 500}, function (event, done) {
    gutil.log('API source changed');
    gutil.log('Event type: ' + event.event); // added, changed, or deleted
    gutil.log('Event path: ' + event.path); // The path of the modified file

    return Q.all([buildApiDocs('ts'), buildApiDocs('js')]).then(postBuildAction);
  });
}

function apiExamplesWatch(postShredAction) {
  var examplesPath = path.join(ANGULAR_PROJECT_PATH, 'modules/angular2/examples/**');
  var includePattern = path.join(examplesPath, '**/*.*');
  var excludePattern = '!' + path.join(examplesPath, '**/node_modules/**/*.*');
  var cleanPath = [path.join(_apiShredOptions.fragmentsDir, '**/*.*'), '!**/*.ovr.*'];

  gulp.watch([includePattern, excludePattern], {readDelay: 500}, function (event, done) {
    gutil.log('API example changed');
    gutil.log('Event type: ' + event.type); // added, changed, or deleted
    gutil.log('Event path: ' + event.path); // The path of the modified file

    return delPromise(cleanPath).then(function() {
      return docShredder.shred(_apiShredOptions);
    }).then(postShredAction);
  });
}

function devGuideExamplesWatch(shredOptions, postShredAction) {
  var includePattern = path.join(shredOptions.examplesDir, '**/*.*');
  // removed this version because gulp.watch has the same glob issue that dgeni has.
  // var excludePattern = '!' + path.join(shredOptions.examplesDir, '**/node_modules/**/*.*');
  // gulp.watch([includePattern, excludePattern], {readDelay: 500}, function (event, done) {
  var files = globby.sync( [includePattern], { ignore: [ '**/node_modules/**', '**/_fragments/**',
                                                         '**/dart/build/**' ]});
  gulp.watch([files], {readDelay: 500}, function (event, done) {
    gutil.log('Dev Guide example changed')
    gutil.log('Event type: ' + event.type); // added, changed, or deleted
    gutil.log('Event path: ' + event.path); // The path of the modified file
    return docShredder.shredSingleDir(shredOptions, event.path).then(postShredAction);
  });
}

function devGuideSharedJadeWatch(shredOptions, postShredAction) {
  var includePattern = path.join(DOCS_PATH, '**/*.jade');
  // removed this version because gulp.watch has the same glob issue that dgeni has.
  // var excludePattern = '!' + path.join(shredOptions.jadeDir, '**/node_modules/**/*.*');
  // gulp.watch([includePattern, excludePattern], {readDelay: 500}, function (event, done) {
  var files = globby.sync( [includePattern], { ignore: [ '**/node_modules/**', '**/_fragments/**']});
  gulp.watch([files], {readDelay: 500}, function (event, done) {
    gutil.log('Dev Guide jade file changed')
    gutil.log('Event type: ' + event.type); // added, changed, or deleted
    gutil.log('Event path: ' + event.path); // The path of the modified file
    return docShredder.shredSingleJadeDir(shredOptions, event.path).then(postShredAction);
  });
}


// Generate the API docs for the specified language, if not specified then it defaults to ts
function buildApiDocs(targetLanguage) {
  var ALLOWED_LANGUAGES = ['ts', 'js', 'dart'];
  var GENERATE_API_LANGUAGES = ['ts', 'js'];
  checkAngularProjectPath();
  try {
    // Build a specialized package to generate different versions of the API docs
    var package = new Package('apiDocs', [require(path.resolve(TOOLS_PATH, 'api-builder/angular.io-package'))]);
    package.config(function(targetEnvironments, writeFilesProcessor, readTypeScriptModules) {
      ALLOWED_LANGUAGES.forEach(function(target) { targetEnvironments.addAllowed(target); });
      if (targetLanguage) {
        targetEnvironments.activate(targetLanguage);

        if (GENERATE_API_LANGUAGES.indexOf(targetLanguage) === -1) {
          // Don't read TypeScript modules if we are not generating API docs - Dart I am looking at you!
          readTypeScriptModules.$enabled = false;
        }
        writeFilesProcessor.outputFolder  = targetLanguage + '/latest/api';
      }
    });

    var dgeni = new Dgeni([package]);
    return dgeni.generate();
  } catch(err) {
    gutil.log(err);
    gutil.log(err.stack);
    throw err;
  }

  function copyApiDocsToJsFolder() {
    // Make a copy of the JS API docs to the TS folder
    return gulp.src([path.join(DOCS_PATH, 'ts/latest/api/**/*.*'), '!' + path.join(DOCS_PATH, 'ts/latest/api/index.jade')])
      .pipe(gulp.dest('./public/docs/js/latest/api'));
  }
}

function buildShredMaps(shouldWrite) {
  var options = {
    devguideExamplesDir: _devguideShredOptions.examplesDir,
    apiExamplesDir: _apiShredOptions.examplesDir,
    fragmentsDir: _devguideShredOptions.fragmentsDir,
    jadeDir: './public/docs',
    outputDir: './public/docs',
    writeFilesEnabled: shouldWrite
  };
  return docShredder.buildShredMap(options).then(function(docs) {
    return docs;
  });
}

// returns a promise containing filePaths with any changed or added examples;
function getChangedExamples(sha) {
  var Git = require("nodegit");
  var examplesPath = _devguideShredOptions.examplesDir;
  var relativePath = path.relative(process.cwd(), examplesPath);
  return Git.Repository.open(".").then(function(repo) {
    if (sha.length) {
      return repo.getCommit(sha);
    } else {
      return repo.getHeadCommit();
    }
  }).then(function(commit) {
    return getChangedExamplesForCommit(commit, relativePath);
  }).catch(function(err) {

  });
}

function getChangedExamplesAfter(date, relativePath) {
  var Git = require("nodegit");
  var examplesPath = _devguideShredOptions.examplesDir;
  var relativePath = path.relative(process.cwd(), examplesPath);
  return Git.Repository.open(".").then(function(repo) {
    return repo.getHeadCommit();
  }).then(function(commit) {
    var repo = commit.owner();
    var revWalker = repo.createRevWalk();
    revWalker.sorting(Git.Revwalk.SORT.TIME);
    revWalker.push(commit.id());
    return revWalker.getCommitsUntil(function (commit) {
      return commit.date().getTime() > date.getTime();
    });
  }).then(function(commits) {
    return Q.all(commits.map(function(commit) {
      return getChangedExamplesForCommit(commit, relativePath);
    }));
  }).then(function(arrayOfPaths) {
    var pathMap = {};
    arrayOfPaths.forEach(function(paths) {
      paths.forEach(function(path) {
        pathMap[path] = true;
      });
    });
    var uniqPaths = _.keys(pathMap);
    return uniqPaths;
  }).catch(function(err) {
    var x = err;
  });

}

function getChangedExamplesForCommit(commit, relativePath) {
  return commit.getDiff().then(function(diffList) {
    var filePaths = [];
    diffList.forEach(function (diff) {
      diff.patches().forEach(function (patch) {
        if (patch.isAdded() || patch.isModified) {
          var filePath = path.normalize(patch.newFile().path());
          var isExample = filePath.indexOf(relativePath) >= 0;
          // gutil.log(filePath + " isExample: " + isExample);
          if (isExample) {
            filePaths.push(filePath);
          }
        }
      });
    });
    return filePaths;
  });
}



function jadeShredMapToJadeExampleMap(jadeShredMap, examplePaths) {
  // remove dups in examplePaths
  var exampleSet = {};
  examplePaths.forEach(function(examplePath) {
    exampleSet[examplePath] = examplePath;
  });
  var basePath = path.resolve(".");
  var jadeToFragMap = jadeShredMap.jadeToFragMap;
  var jadeExampleMap = {};
  for (var jadePath in jadeToFragMap) {
    var relativeJadePath = path.relative(basePath, jadePath);
    var vals = jadeToFragMap[jadePath];
    vals.forEach(function(val) {
      var relativeExamplePath = path.relative(basePath, val.examplePath);
      if (exampleSet[relativeExamplePath] != null) {
        addKeyValue(jadeExampleMap, relativeJadePath, relativeExamplePath);
      }
    });
  }
  return jadeExampleMap;
}

function jadeShredMapToExampleJadeMap(jadeShredMap) {

  var jadeToFragMap = jadeShredMap.jadeToFragMap;
  var exampleJadeMap = {};
  for (var jadePath in jadeToFragMap) {
    var vals = jadeToFragMap[jadePath];
    vals.forEach(function(val) {
      var examplePath = val.examplePath;
      addKeyValue(exampleJadeMap, examplePath, jadePath);
    });
  }
  return exampleJadeMap;
}

function addKeyValue(map, key, value) {
  var vals = map[key];
  if (vals) {
    if (vals.indexOf(value) == -1) {
      vals.push(value);
    }
  } else {
    map[key] = [value];
  }
}


// Synchronously execute a chain of commands.
// cmds: an array of commands
// options: { shouldLog: true,  shouldThrow: true }
// cb: function(err, stdout, stderr)
function execCommands(cmds, options, cb) {
  options = options || {};
  options.shouldThrow = options.shouldThrow == null ? true : options.shouldThrow;
  options.shouldLog = options.shouldLog == null ? true : options.shouldLog;
  if (!cmds || cmds.length == 0) cb(null, null, null);
  var exec = require('child_process').exec;  // just to make it more portable.
  gutil.log("NODE_ENV: " + process.env.NODE_ENV);

  exec(cmds[0], options, function(err, stdout, stderr) {
    if (err == null) {
      if (options.shouldLog) {
        gutil.log('cmd: ' + cmds[0]);
        gutil.log('stdout: ' + stdout);
      }
      if (cmds.length == 1) {
        cb(err, stdout, stderr);
      } else {
        execCommands(cmds.slice(1), options, cb);
      }
    } else {
      if (options.shouldLog) {
        gutil.log('exec error on cmd: ' + cmds[0]);
        gutil.log('exec error: ' + err);
        if (stdout) gutil.log('stdout: ' + stdout);
        if (stderr) gutil.log('stderr: ' + stderr);
      }
      if (err && options.shouldThrow) throw err;
      cb(err, stdout, stderr);
    }
  });
}

function checkAngularProjectPath() {
  if (!fs.existsSync(ANGULAR_PROJECT_PATH)) {
    throw new Error('API related tasks require the angular2 repo to be at ' + path.resolve(ANGULAR_PROJECT_PATH));
  }
}