lib/models/blueprint.js

'use strict';

/**
@module ember-cli
*/
const FileInfo = require('./file-info');
const RSVP = require('rsvp');
const chalk = require('chalk');
const MarkdownColor = require('../utilities/markdown-color');
const sequence = require('../utilities/sequence');
const printCommand = require('../utilities/print-command');
const insertIntoFile = require('../utilities/insert-into-file');
const cleanRemove = require('../utilities/clean-remove');
const fs = require('fs-extra');
const inflector = require('inflection');
const minimatch = require('minimatch');
const path = require('path');
const stringUtils = require('ember-cli-string-utils');
const _ = require('ember-cli-lodash-subset');
const walkSync = require('walk-sync');
const SilentError = require('silent-error');
const CoreObject = require('core-object');
const EOL = require('os').EOL;
const bowEpParser = require('bower-endpoint-parser');
const logger = require('heimdalljs-logger')('ember-cli:blueprint');
const normalizeEntityName = require('ember-cli-normalize-entity-name');
const isAddon = require('../utilities/is-addon');

const Promise = RSVP.Promise;
const stat = RSVP.denodeify(fs.stat);
const writeFile = RSVP.denodeify(fs.outputFile);

const initialIgnoredFiles = [
  '.DS_Store',
];

/**
  A blueprint is a bundle of template files with optional install
  logic.

  Blueprints follow a simple structure. Let's take the built-in
  `controller` blueprint as an example:

  ```
  blueprints/controller
  ├── files
  │   ├── app
  │   │   └── __path__
  │   │       └── __name__.js
  └── index.js

  blueprints/controller-test
  ├── files
  │   └── tests
  │       └── unit
  │           └── controllers
  │               └── __test__.js
  └── index.js
  ```

  ## Files

  `files` contains templates for the all the files to be
  installed into the target directory.

  The `__name__` token is subtituted with the dasherized
  entity name at install time. For example, when the user
  invokes `ember generate controller foo` then `__name__` becomes
  `foo`. When the `--pod` flag is used, for example `ember
  generate controller foo --pod` then `__name__` becomes
  `controller`.

  The `__path__` token is substituted with the blueprint
  name at install time. For example, when the user invokes
  `ember generate controller foo` then `__path__` becomes
  `controller`. When the `--pod` flag is used, for example
  `ember generate controller foo --pod` then `__path__`
  becomes `foo` (or `<podModulePrefix>/foo` if the
  podModulePrefix is defined). This token is primarily for
  pod support, and is only necessary if the blueprint can be
  used in pod structure. If the blueprint does not require pod
  support, simply use the blueprint name instead of the
  `__path__` token.

  The `__test__` token is substituted with the dasherized
  entity name and appended with `-test` at install time.
  This token is primarily for pod support and only necessary
  if the blueprint requires support for a pod structure. If
  the blueprint does not require pod support, simply use the
  `__name__` token instead.

  ## Template Variables (AKA Locals)

  Variables can be inserted into templates with
  `<%= someVariableName %>`.

  For example, the built-in `util` blueprint
  `files/app/utils/__name__.js` looks like this:

  ```js
  export default function <%= camelizedModuleName %>() {
    return true;
  }
  ```

  `<%= camelizedModuleName %>` is replaced with the real
  value at install time.

  The following template variables are provided by default:

  - `dasherizedPackageName`
  - `classifiedPackageName`
  - `dasherizedModuleName`
  - `classifiedModuleName`
  - `camelizedModuleName`

  `packageName` is the project name as found in the project's
  `package.json`.

  `moduleName` is the name of the entity being generated.

  The mechanism for providing custom template variables is
  described below.

  ## Index.js

  Custom installation and uninstallation behavior can be added
  by overriding the hooks documented below. `index.js` should
  export a plain object, which will extend the prototype of the
  `Blueprint` class. If needed, the original `Blueprint` prototype
  can be accessed through the `_super` property.

  ```js
  module.exports = {
    locals(options) {
      // Return custom template variables here.
      return {};
    },

    normalizeEntityName(entityName) {
      // Normalize and validate entity name here.
      return entityName;
    },

    fileMapTokens(options) {
      // Return custom tokens to be replaced in your files
      return {
        __token__(options){
          // logic to determine value goes here
          return 'value';
        }
      }
    },

    filesPath(options) {
      return path.join(this.path, 'files');
    },

    beforeInstall(options) {},
    afterInstall(options) {},
    beforeUninstall(options) {},
    afterUninstall(options) {}

  };
  ```

  ## Blueprint Hooks

  ### beforeInstall & beforeUninstall

  Called before any of the template files are processed and receives
  the the `options` and `locals` hashes as parameters. Typically used for
  validating any additional command line options or for any asynchronous
  setup that is needed.   As an example, the `controller` blueprint validates
  its `--type` option in this hook.  If you need to run any asynchronous code,
  wrap it in a promise and return that promise from these hooks.  This will
  ensure that your code is executed correctly.

  ### afterInstall & afterUninstall

  The `afterInstall` and `afterUninstall` hooks receives the same
  arguments as `locals`. Use it to perform any custom work after the
  files are processed. For example, the built-in `route` blueprint
  uses these hooks to add and remove relevant route declarations in
  `app/router.js`.

  ### Overriding Install

  If you don't want your blueprint to install the contents of
  `files` you can override the `install` method. It receives the
  same `options` object described above and must return a promise.
  See the built-in `resource` blueprint for an example of this.

  @class Blueprint
  @constructor
  @extends CoreObject
  @param {String} [blueprintPath]
*/
let Blueprint = CoreObject.extend({
  availableOptions: [],
  anonymousOptions: ['name'],

  _printableProperties: [
    'name',
    'description',
    'availableOptions',
    'anonymousOptions',
    'overridden',
  ],

  init(blueprintPath) {
    this._super();

    this.path = blueprintPath;
    this.name = path.basename(blueprintPath);
  },

  /**
    Hook to specify the path to the blueprint's files. By default this is
    `path.join(this.path, 'files)`.

    This can be used to customize which set of files to install based on options
    or environmental variables. It defaults to the `files` directory within the
    blueprint's folder.

    @public
    @method filesPath
    @param {Object} options
    @return {String} Path to the blueprints files directory.
  */
  filesPath(/* options */) {
    return path.join(this.path, 'files');
  },

  /**
    Used to retrieve files for blueprint.

    @public
    @method files
    @return {Array} Contents of the blueprint's files directory
  */
  files() {
    if (this._files) { return this._files; }

    let filesPath = this.filesPath(this.options);
    if (Blueprint._existsSync(filesPath)) {
      this._files = walkSync(filesPath);
    } else {
      this._files = [];
    }

    return this._files;
  },

  /**
    @method srcPath
    @param {String} file
    @return {String} Resolved path to the file
  */
  srcPath(file) {
    return path.resolve(this.filesPath(this.options), file);
  },

  /**
    Hook for normalizing entity name

    Use the `normalizeEntityName` hook to add custom normalization and
    validation of the provided entity name. The default hook does not
    make any changes to the entity name, but makes sure an entity name
    is present and that it doesn't have a trailing slash.

    This hook receives the entity name as its first argument. The string
    returned by this hook will be used as the new entity name.

    @public
    @method normalizeEntityName
    @param {String} entityName
    @return {null}
  */
  normalizeEntityName(entityName) {
    return normalizeEntityName(entityName);
  },

  /**
    Write a status and message to the UI
    @private
    @method _writeStatusToUI
    @param {Function} chalkColor
    @param {String} keyword
    @param {String} message
  */
  _writeStatusToUI(chalkColor, keyword, message) {
    if (this.ui) {
      this.ui.writeLine(`  ${chalkColor(keyword)} ${message}`);
    }
  },

  /**
    @private
    @method _writeFile
    @param {Object} info
    @return {Promise}
  */
  _writeFile(info) {
    if (!this.dryRun) {
      return writeFile(info.outputPath, info.render());
    }
  },

  /**
    Actions lookup
    @private
    @property _actions
    @type Object
  */
  _actions: {
    write(info) {
      this._writeStatusToUI(chalk.green, 'create', info.displayPath);
      return this._writeFile(info);
    },
    skip(info) {
      let label = 'skip';

      if (info.resolution === 'identical') {
        label = 'identical';
      }

      this._writeStatusToUI(chalk.yellow, label, info.displayPath);
    },

    overwrite(info) {
      this._writeStatusToUI(chalk.yellow, 'overwrite', info.displayPath);
      return this._writeFile(info);
    },

    edit(info) {
      this._writeStatusToUI(chalk.green, 'edited', info.displayPath);
    },

    remove(info) {
      this._writeStatusToUI(chalk.red, 'remove', info.displayPath);
      if (!this.dryRun) {
        return cleanRemove(info);
      }
    },
  },

  /**
    Calls an action.
    @private
    @method _commit
    @param {Object} result
    @return {Promise}
    @throws {Error} Action doesn't exist.
  */
  _commit(result) {
    let action = this._actions[result.action];

    if (action) {
      return action.call(this, result);
    } else {
      throw new Error(`Tried to call action "${result.action}" but it does not exist`);
    }
  },

  /**
    Prints warning for pod unsupported.
    @private
    @method _checkForPod
  */
  _checkForPod(verbose) {
    if (!this.hasPathToken && this.pod && verbose) {
      this.ui.writeLine(chalk.yellow('You specified the pod flag, but this' +
        ' blueprint does not support pod structure. It will be generated with' +
        ' the default structure.'));
    }
  },

  /**
    @private
    @method _normalizeEntityName
    @param {Object} entity
  */
  _normalizeEntityName(entity) {
    if (entity) {
      entity.name = this.normalizeEntityName(entity.name);
    }
  },

  /**
    @private
    @method _checkInRepoAddonExists
    @param {Object} options
  */
  _checkInRepoAddonExists(options) {
    let addon;

    if (options.inRepoAddon) {
      addon = findAddonByName(this.project, options.inRepoAddon);

      if (!addon) {
        throw new SilentError(`You specified the 'in-repo-addon' flag, but the ` +
          `in-repo-addon '${options.inRepoAddon}' does not exist. Please check the name and try again.`);
      }
    }

    if (options.in) {
      if (!ensureTargetDirIsAddon(options.in)) {
        throw new SilentError(`You specified the 'in' flag, but the ` +
          `in repo addon '${options.in}' does not exist. Please check the name and try again.`);
      }
    }
  },

  /**
    @private
    @method _process
    @param {Object} options
    @param {Function} beforeHook
    @param {Function} process
    @param {Function} afterHook
  */
  _process(options, beforeHook, process, afterHook) {
    let intoDir = options.target;

    return this._locals(options)
      .then(locals => Promise.resolve()
        .then(beforeHook.bind(this, options, locals))
        .then(process.bind(this, intoDir, locals))
        .then(promises => RSVP.map(promises, this._commit.bind(this)))
        .then(afterHook.bind(this, options)));
  },

  /**
    @method install
    @param {Object} options
    @return {Promise}
  */
  install(options) {
    let ui = this.ui = options.ui;
    let dryRun = this.dryRun = options.dryRun;
    this.project = options.project;
    this.pod = options.pod;
    this.options = options;
    this.hasPathToken = hasPathToken(this.files());

    ui.writeLine(`installing ${this.name}`);

    if (dryRun) {
      ui.writeLine(chalk.yellow('You specified the dry-run flag, so no' +
        ' changes will be written.'));
    }

    this._normalizeEntityName(options.entity);
    this._checkForPod(options.verbose);
    this._checkInRepoAddonExists(options);

    logger.info('START: processing blueprint: `%s`', this.name);
    let start = new Date();
    return this._process(options, this.beforeInstall, this.processFiles, this.afterInstall)
      .finally(() => logger.info('END: processing blueprint: `%s` in (%dms)', this.name, new Date() - start));
  },

  /**
    @method uninstall
    @param {Object} options
    @return {Promise}
  */
  uninstall(options) {
    let ui = this.ui = options.ui;
    let dryRun = this.dryRun = options.dryRun;
    this.project = options.project;
    this.pod = options.pod;
    this.options = options;
    this.hasPathToken = hasPathToken(this.files());

    ui.writeLine(`uninstalling ${this.name}`);

    if (dryRun) {
      ui.writeLine(chalk.yellow('You specified the dry-run flag, so no' +
        ' files will be deleted.'));
    }

    this._normalizeEntityName(options.entity);
    this._checkForPod(options.verbose);

    return this._process(
      options,
      this.beforeUninstall,
      this.processFilesForUninstall,
      this.afterUninstall);
  },

  /**
    Hook for running operations before install.
    @method beforeInstall
    @return {Promise|null}
  */
  beforeInstall() {},

  /**
    Hook for running operations after install.
    @method afterInstall
    @return {Promise|null}
  */
  afterInstall() {},

  /**
    Hook for running operations before uninstall.
    @method beforeUninstall
    @return {Promise|null}
  */
  beforeUninstall() {},

  /**
    Hook for running operations after uninstall.
    @method afterUninstall
    @return {Promise|null}
  */
  afterUninstall() {},

  filesToRemove: [],

  /**
    Hook for adding custom template variables.

    When the following is called on the command line:

    ```sh
    ember generate controller foo --type=array --dry-run
    ```

    The object passed to `locals` looks like this:

    ```js
    {
      entity: {
        name: 'foo',
        options: {
          type: 'array'
        }
      },
      dryRun: true
    }
    ```

    This hook must return an object or a Promise which resolves to an object.
    The resolved object will be merged with the aforementioned default locals.

    @public
    @method locals
    @param {Object} options General and entity-specific options
    @return {Object|Promise|null}
  */
  locals(/* options */) {},

  /**
    Hook to add additional or override existing fileMap tokens.

    Use `fileMapTokens` to add custom fileMap tokens for use
    in the `mapFile` method. The hook must return an object in the
    following pattern:

    ```js
    {
      __token__(options){
        // logic to determine value goes here
        return 'value';
      }
    }
    ```

    It will be merged with the default `fileMapTokens`, and can be used
    to override any of the default tokens.

    Tokens are used in the files folder (see `files`), and get replaced with
    values when the `mapFile` method is called.

    @public
    @method fileMapTokens
    @return {Object|null}
  */
  fileMapTokens() {},

  /**
    @private
    @method _fileMapTokens
    @param {Object} options
    @return {Object}
  */
  _fileMapTokens(options) {
    let { project } = this;
    let standardTokens = {
      __name__(options) {
        if (options.pod && options.hasPathToken) {
          return options.blueprintName;
        }
        return options.dasherizedModuleName;
      },
      __path__(options) {
        let blueprintName = options.blueprintName;

        if (/-test/.test(blueprintName)) {
          blueprintName = options.blueprintName.slice(0, options.blueprintName.indexOf('-test'));
        }
        if (options.pod && options.hasPathToken) {
          return path.join(options.podPath, options.dasherizedModuleName);
        }
        return inflector.pluralize(blueprintName);
      },
      __root__(options) {
        if (options.inRepoAddon) {
          let addon = findAddonByName(project, options.inRepoAddon);
          let relativeAddonPath = path.relative(project.root, addon.root);
          return path.join(relativeAddonPath, 'addon');
        }
        if (options.in) {
          let relativeAddonPath = path.relative(project.root, options.in);
          return path.join(relativeAddonPath, 'addon');
        }
        if (options.inDummy) {
          return path.join('tests', 'dummy', 'app');
        }
        if (options.inAddon) {
          return 'addon';
        }
        return 'app';
      },
      __test__(options) {
        if (options.pod && options.hasPathToken) {
          return options.blueprintName;
        }
        return `${options.dasherizedModuleName}-test`;
      },
    };

    let customTokens = this.fileMapTokens(options) || options.fileMapTokens || {};
    return _.merge(standardTokens, customTokens);
  },

  /**
    Used to generate fileMap tokens for mapFile.

    @method generateFileMap
    @param {Object} fileMapVariables
    @return {Object}
  */
  generateFileMap(fileMapVariables) {
    let tokens = this._fileMapTokens(fileMapVariables);
    let fileMapValues = _.values(tokens);
    let tokenValues = fileMapValues.map(token => token(fileMapVariables));
    let tokenKeys = Object.keys(tokens);
    return _.zipObject(tokenKeys, tokenValues);
  },

  /**
    @method buildFileInfo
    @param {Function} destPath
    @param {Object} templateVariables
    @param {String} file
    @return {FileInfo}
  */
  buildFileInfo(intoDir, templateVariables, file) {
    let mappedPath = this.mapFile(file, templateVariables);

    return new FileInfo({
      action: 'write',
      outputBasePath: path.normalize(intoDir),
      outputPath: path.join(intoDir, mappedPath),
      displayPath: path.normalize(mappedPath),
      inputPath: this.srcPath(file),
      templateVariables,
      ui: this.ui,
    });
  },

  /**
    @method isUpdate
    @return {Boolean}
  */
  isUpdate() {
    if (this.project && this.project.isEmberCLIProject) {
      return this.project.isEmberCLIProject();
    }
  },

  /**
    @private
    @method _getFileInfos
    @param {Array} files
    @param {String} intoDir
    @param {Object} templateVariables
    @return {Array} file infos
  */
  _getFileInfos(files, intoDir, templateVariables) {
    return files.map(this.buildFileInfo.bind(this, intoDir, templateVariables));
  },

  /**
    Add update files to ignored files or reset them
    @private
    @method _ignoreUpdateFiles
  */
  _ignoreUpdateFiles() {
    if (this.isUpdate()) {
      Blueprint.ignoredFiles = Blueprint.ignoredFiles.concat(Blueprint.ignoredUpdateFiles);
    } else {
      Blueprint.ignoredFiles = initialIgnoredFiles;
    }
  },

  /**
    @private
    @method _getFilesForInstall
    @param {Array} targetFiles
    @return {Array} files
  */
  _getFilesForInstall(targetFiles) {
    let files = this.files();

    // if we've defined targetFiles, get file info on ones that match
    return (targetFiles && targetFiles.length > 0 && _.intersection(files, targetFiles)) || files;
  },

  /**
    @private
    @method _checkForNoMatch
    @param {Array} fileInfos
    @param {String} rawArgs
  */
  _checkForNoMatch(fileInfos, rawArgs) {
    if (fileInfos.filter(isFilePath).length < 1 && rawArgs) {
      this.ui.writeLine(chalk.yellow(`The globPattern "${rawArgs}" ` +
        `did not match any files, so no file updates will be made.`));
    }
  },

  /**
    @method processFiles
    @param {String} intoDir
    @param {Object} templateVariables
  */
  processFiles(intoDir, templateVariables) {
    let files = this._getFilesForInstall(templateVariables.targetFiles);
    let fileInfos = this._getFileInfos(files, intoDir, templateVariables);
    this._checkForNoMatch(fileInfos, templateVariables.rawArgs);

    this._ignoreUpdateFiles();

    let fileInfosToRemove = this._getFileInfos(this.filesToRemove, intoDir, templateVariables);

    fileInfosToRemove = finishProcessingForUninstall(fileInfosToRemove);

    return RSVP.filter(fileInfos, isValidFile)
      .then(promises => RSVP.map(promises, prepareConfirm))
      .then(finishProcessingForInstall)
      .then(fileInfos => fileInfos.concat(fileInfosToRemove));
  },

  /**
    @method processFilesForUninstall
    @param {String} intoDir
    @param {Object} templateVariables
  */
  processFilesForUninstall(intoDir, templateVariables) {
    let fileInfos = this._getFileInfos(this.files(), intoDir, templateVariables);

    this._ignoreUpdateFiles();

    return RSVP.filter(fileInfos, isValidFile).
      then(finishProcessingForUninstall);
  },

  /**
    @method mapFile
    @param {String} file
    @param locals
    @return {String}
  */
  mapFile(file, locals) {
    let pattern, i;
    let fileMap = locals.fileMap || { __name__: locals.dasherizedModuleName };
    file = Blueprint.renamedFiles[file] || file;
    for (i in fileMap) {
      pattern = new RegExp(i, 'g');
      file = file.replace(pattern, fileMap[i]);
    }
    return file;
  },

  /**
    Looks for a __root__ token in the files folder. Must be present for
    the blueprint to support addon tokens. The `server`, `blueprints`, and `test`

    @private
    @method supportsAddon
    @return {Boolean}
  */
  supportsAddon() {
    return (/__root__/).test(this.files().join());
  },

  /**
    @private
    @method _generateFileMapVariables
    @param {String} moduleName
    @param locals
    @param {Object} options
    @return {Object}
  */
  _generateFileMapVariables(moduleName, locals, options) {
    let originBlueprintName = options.originBlueprintName || this.name;
    let podModulePrefix = this.project.config().podModulePrefix || '';
    let podPath = podModulePrefix.substr(podModulePrefix.lastIndexOf('/') + 1);
    let inAddon = this.project.isEmberCLIAddon() || !!options.inRepoAddon;
    let inDummy = this.project.isEmberCLIAddon() ? options.dummy : false;

    return {
      pod: this.pod,
      podPath,
      hasPathToken: this.hasPathToken,
      inAddon,
      inRepoAddon: options.inRepoAddon,
      in: options.in,
      inDummy,
      blueprintName: this.name,
      originBlueprintName,
      dasherizedModuleName: stringUtils.dasherize(moduleName),
      locals,
    };
  },

  /**
    @private
    @method _locals
    @param {Object} options
    @return {Object}
  */
  _locals(options) {
    let packageName = options.project.name();
    let moduleName = (options.entity && options.entity.name) || packageName;
    let sanitizedModuleName = moduleName.replace(/\//g, '-');

    return new Promise(resolve => {
      resolve(this.locals(options));
    }).then(customLocals => {
      let fileMapVariables = this._generateFileMapVariables(moduleName, customLocals, options);
      let fileMap = this.generateFileMap(fileMapVariables);
      let standardLocals = {
        dasherizedPackageName: stringUtils.dasherize(packageName),
        classifiedPackageName: stringUtils.classify(packageName),
        dasherizedModuleName: stringUtils.dasherize(moduleName),
        classifiedModuleName: stringUtils.classify(sanitizedModuleName),
        camelizedModuleName: stringUtils.camelize(sanitizedModuleName),
        decamelizedModuleName: stringUtils.decamelize(sanitizedModuleName),
        fileMap,
        hasPathToken: this.hasPathToken,
        targetFiles: options.targetFiles,
        rawArgs: options.rawArgs,
      };

      return _.merge({}, standardLocals, customLocals);
    });
  },

  /**
    Used to add a package to the project's `package.json`.

    Generally, this would be done from the `afterInstall` hook, to
    ensure that a package that is required by a given blueprint is
    available.

    @method addPackageToProject
    @param {String} packageName
    @param {String} target
    @return {Promise}
  */
  addPackageToProject(packageName, target) {
    let packageObject = { name: packageName };

    if (target) {
      packageObject.target = target;
    }

    return this.addPackagesToProject([packageObject]);
  },

  /**
    Used to add multiple packages to the project's `package.json`.

    Generally, this would be done from the `afterInstall` hook, to
    ensure that a package that is required by a given blueprint is
    available.

    Expects each array item to be an object with a `name`.  Each object
    may optionally have a `target` to specify a specific version.

    @method addPackagesToProject
    @param {Array} packages
    @return {Promise}

    @example
    ```js
    this.addPackagesToProject([
      { name: 'lodash' },
      { name: 'moment', target: '^2.17.0' },
    ]);
    ```
  */
  addPackagesToProject(packages) {
    let task = this.taskFor('npm-install');
    let installText = (packages.length > 1) ? 'install packages' : 'install package';
    let packageNames = [];
    let packageArray = [];

    for (let i = 0; i < packages.length; i++) {
      packageNames.push(packages[i].name);

      let packageNameAndVersion = packages[i].name;

      if (packages[i].target) {
        packageNameAndVersion += `@${packages[i].target}`;
      }

      packageArray.push(packageNameAndVersion);
    }

    this._writeStatusToUI(chalk.green, installText, packageNames.join(', '));

    return task.run({
      'save-dev': true,
      verbose: false,
      packages: packageArray,
    });
  },

  /**
    Used to remove a package from the project's `package.json`.

    Generally, this would be done from the `afterInstall` hook, to
    ensure that any package conflicts can be resolved before the
    addon is used.

    @method removePackageFromProject
    @param {String} packageName
    @return {Promise}
  */
  removePackageFromProject(packageName) {
    let packageObject = { name: packageName };

    return this.removePackagesFromProject([packageObject]);
  },

  /**
    Used to remove multiple packages from the project's `package.json`.

    Generally, this would be done from the `afterInstall` hook, to
    ensure that any package conflicts can be resolved before the
    addon is used.

    Expects each array item to be an object with a `name` property.

    @method removePackagesFromProject
    @param {Array} packages
    @return {Promise}
  */
  removePackagesFromProject(packages) {
    let task = this.taskFor('npm-uninstall');
    let installText = (packages.length > 1) ? 'uninstall packages' : 'uninstall package';
    let packageNames = [];

    let projectDependencies = this.project.dependencies();

    for (let i = 0; i < packages.length; i++) {
      let packageName = packages[i].name;
      if (packageName in projectDependencies) {
        packageNames.push(packageName);
      }
    }

    if (packageNames.length === 0) {
      this._writeStatusToUI(chalk.yellow, 'remove', 'Skipping uninstall because no matching package is installed.');
      return Promise.resolve();
    }

    this._writeStatusToUI(chalk.green, installText, packageNames.join(', '));

    return task.run({
      'save-dev': true,
      verbose: false,
      packages: packageNames,
    });
  },

  /**
    Used to add a package to the projects `bower.json`.

    Generally, this would be done from the `afterInstall` hook, to
    ensure that a package that is required by a given blueprint is
    available.

    `localPackageName` and `target` may be thought of as equivalent
    to the key-value pairs in the `dependency` or `devDepencency`
    objects contained within a bower.json file.
    @method addBowerPackageToProject
    @param {String} localPackageName
    @param {String} target
    @param {Object} installOptions
    @return {Promise}

    @example
    ```js
    addBowerPackageToProject('jquery', '~1.11.1');
    addBowerPackageToProject('old_jquery', 'jquery#~1.9.1');
    addBowerPackageToProject('bootstrap-3', 'https://twitter.github.io/bootstrap/assets/bootstrap');
    ```
  */
  addBowerPackageToProject(localPackageName, target, installOptions) {
    let lpn = localPackageName;
    let tar = target;
    let packageObject = bowEpParser.json2decomposed(lpn, tar);
    return this.addBowerPackagesToProject([packageObject], installOptions);
  },

  /**
    Used to add an array of packages to the projects `bower.json`.

    Generally, this would be done from the `afterInstall` hook, to
    ensure that a package that is required by a given blueprint is
    available.

    Expects each array item to be an object with a `name`.  Each object
    may optionally have a `target` to specify a specific version, or a
    `source` to specify a non-local name to be resolved.

    @method addBowerPackagesToProject
    @param {Array} packages
    @param {Object} installOptions
    @return {Promise}
  */
  addBowerPackagesToProject(packages, installOptions) {
    let task = this.taskFor('bower-install');
    let installText = (packages.length > 1) ? 'install bower packages' : 'install bower package';
    let packageNames = [];
    let packageNamesAndVersions = packages.map(pkg => {
      pkg.source = pkg.source || pkg.name;
      packageNames.push(pkg.name);
      return pkg;
    }).map(bowEpParser.compose);

    this._writeStatusToUI(chalk.green, installText, packageNames.join(', '));

    return task.run({
      verbose: true,
      packages: packageNamesAndVersions,
      installOptions: installOptions || { save: true },
    });
  },

  /**
    Used to add an addon to the project's `package.json` and run it's
    `defaultBlueprint` if it provides one.

    Generally, this would be done from the `afterInstall` hook, to
    ensure that a package that is required by a given blueprint is
    available.

    @method addAddonToProject
    @param {Object} options
    @return {Promise}
  */
  addAddonToProject(options) {
    return this.addAddonsToProject({
      packages: [options],
      extraArgs: options.extraArgs || {},
      blueprintOptions: options.blueprintOptions || {},
    });
  },

  /**
    Used to add multiple addons to the project's `package.json` and run their
    `defaultBlueprint` if they provide one.

    Generally, this would be done from the `afterInstall` hook, to
    ensure that a package that is required by a given blueprint is
    available.

    @method addAddonsToProject
    @param {Object} options
    @return {Promise}
  */
  addAddonsToProject(options) {
    let taskOptions = {
      packages: [],
      extraArgs: options.extraArgs || [],
      blueprintOptions: options.blueprintOptions || {},
    };

    let packages = options.packages;
    if (packages && packages.length) {
      taskOptions.packages = packages.map(pkg => {
        if (typeof pkg === 'string') {
          return pkg;
        }

        if (!pkg.name) {
          throw new SilentError('You must provide a package `name` to addAddonsToProject');
        }

        if (pkg.target) {
          pkg.name += `@${pkg.target}`;
        }

        return pkg.name;
      });
    } else {
      throw new SilentError('You must provide package to addAddonsToProject');
    }

    let installText = (packages.length > 1) ? 'install addons' : 'install addon';
    this._writeStatusToUI(chalk.green, installText, taskOptions['packages'].join(', '));

    return this.taskFor('addon-install').run(taskOptions);
  },

  /**
    Used to retrieve a task with the given name. Passes the new task
    the standard information available (like `ui`, `analytics`, `project`, etc).

    @method taskFor
    @param dasherizedName
    @public
  */
  taskFor(dasherizedName) {
    const Task = require(`../tasks/${dasherizedName}`);

    return new Task({
      ui: this.ui,
      project: this.project,
      analytics: this.analytics,
    });
  },

  /**
    Inserts the given content into a file. If the `contentsToInsert` string is already
    present in the current contents, the file will not be changed unless `force` option
    is passed.

    If `options.before` is specified, `contentsToInsert` will be inserted before
    the first instance of that string.  If `options.after` is specified, the
    contents will be inserted after the first instance of that string.
    If the string specified by options.before or options.after is not in the file,
    no change will be made.

    If neither `options.before` nor `options.after` are present, `contentsToInsert`
    will be inserted at the end of the file.

    Example:
    ```
    // app/router.js
    Router.map(function() {
    });
    ```

    ```
    insertIntoFile('app/router.js', '  this.route("admin");', {
      after: 'Router.map(function() {' + EOL
    }).then(function() {
      // file has been inserted into!
    });


    ```

    ```
    // app/router.js
    Router.map(function() {
      this.route("admin");
    });
    ```

    @method insertIntoFile
    @param {String} pathRelativeToProjectRoot
    @param {String} contentsToInsert
    @param {Object} providedOptions
    @return {Promise}
  */
  insertIntoFile(pathRelativeToProjectRoot, contentsToInsert, providedOptions) {
    let fullPath = path.join(this.project.root, pathRelativeToProjectRoot);
    return insertIntoFile(fullPath, contentsToInsert, providedOptions);
  },

  _printCommand: printCommand,

  printBasicHelp(verbose) {
    let initialMargin = '      ';
    let output = initialMargin;
    if (this.overridden) {
      output += chalk.grey(`(overridden) ${this.name}`);
    } else {
      output += this.name;

      output += this._printCommand(initialMargin, true);

      if (verbose) {
        output += EOL + this.printDetailedHelp(this.availableOptions);
      }
    }

    return output;
  },

  printDetailedHelp() {
    let markdownColor = new MarkdownColor();
    let filePath = getDetailedHelpPath(this.path);

    if (Blueprint._existsSync(filePath)) {
      return markdownColor.renderFile(filePath, { indent: '        ' });
    }
    return '';
  },

  getJson(verbose) {
    let json = {};
    this._printableProperties.forEach(key => {
      let value = this[key];
      if (key === 'availableOptions') {
        value = _.cloneDeep(value);
        value.forEach(option => {
          if (typeof option.type === 'function') {
            option.type = option.type.name;
          }
        });
      }
      json[key] = value;
    });

    if (verbose) {
      let detailedHelp = this.printDetailedHelp(this.availableOptions);
      if (detailedHelp) {
        json.detailedHelp = detailedHelp;
      }
    }

    return json;
  },

  /**
    Used to retrieve a blueprint with the given name.

    @method lookupBlueprint
    @param {String} dasherizedName
    @return {Blueprint}
    @public
  */
  lookupBlueprint(dasherizedName) {
    let projectPaths = this.project ? this.project.blueprintLookupPaths() : [];

    return Blueprint.lookup(dasherizedName, {
      paths: projectPaths,
    });
  },
});

/**
  @static
  @method lookup
  @namespace Blueprint
  @param {String} name
  @param {Object} [options]
  @param {Array} [options.paths] Extra paths to search for blueprints
  @param {Boolean} [options.ignoreMissing] Throw a `SilentError` if a
    matching Blueprint could not be found
  @return {Blueprint}
*/
Blueprint.lookup = function(name, options) {
  options = options || {};

  let lookupPaths = generateLookupPaths(options.paths);

  let lookupPath;
  for (let i = 0; (lookupPath = lookupPaths[i]); i++) {
    let blueprintPath = path.resolve(lookupPath, name);

    if (Blueprint._existsSync(blueprintPath)) {
      return Blueprint.load(blueprintPath);
    }
  }

  if (!options.ignoreMissing) {
    throw new SilentError(`Unknown blueprint: ${name}`);
  }
};

/**
  Loads a blueprint from given path.
  @static
  @method load
  @namespace Blueprint
  @param {String} blueprintPath
  @return {Blueprint} blueprint instance
*/
Blueprint.load = function(blueprintPath) {
  if (fs.lstatSync(blueprintPath).isDirectory()) {
    let Constructor = Blueprint;

    let constructorPath = path.resolve(blueprintPath, 'index.js');
    if (Blueprint._existsSync(constructorPath)) {
      const blueprintModule = require(constructorPath);

      if (typeof blueprintModule === 'function') {
        Constructor = blueprintModule;
      } else {
        Constructor = Blueprint.extend(blueprintModule);
      }
    }

    return new Constructor(blueprintPath);
  }
};

/**
  @static
  @method list
  @namespace Blueprint
  @param {Object} [options]
  @param {Array} [options.paths] Extra paths to search for blueprints
  @return {Array}
*/
Blueprint.list = function(options) {
  options = options || {};

  let lookupPaths = generateLookupPaths(options.paths);
  let seen = [];

  return lookupPaths.map(lookupPath => {
    let source;
    let packagePath = path.join(lookupPath, '../package.json');
    if (Blueprint._existsSync(packagePath)) {
      source = require(packagePath).name;
    } else {
      source = path.basename(path.join(lookupPath, '..'));
    }

    let blueprints = dir(lookupPath).map(blueprintPath => {
      let blueprint = Blueprint.load(blueprintPath);
      if (blueprint) {
        let name = blueprint.name;
        blueprint.overridden = _.includes(seen, name);
        seen.push(name);

        return blueprint;
      }
    });

    return {
      source,
      blueprints: _.compact(blueprints),
    };
  });
};

Blueprint._existsSync = function(path, parent) {
  return fs.existsSync(path, parent);
};

Blueprint._readdirSync = function(path) {
  return fs.readdirSync(path);
};

/**
  Files that are renamed when installed into the target directory.
  This allows including files in the blueprint that would have an effect
  on another process, such as a file named `.gitignore`.

  The keys are the filenames used in the files folder.
  The values are the filenames used in the target directory.

  @static
  @property renamedFiles
*/
Blueprint.renamedFiles = {
  'gitignore': '.gitignore',
};

/**
  @static
  @property ignoredFiles
*/
Blueprint.ignoredFiles = initialIgnoredFiles;

/**
  @static
  @property ignoredUpdateFiles
*/
Blueprint.ignoredUpdateFiles = [
  '.gitkeep',
  'app.css',
  'LICENSE.md',
];

/**
  @static
  @property defaultLookupPaths
*/
Blueprint.defaultLookupPaths = function() {
  return [
    path.resolve(__dirname, '..', '..', 'blueprints'),
  ];
};

/**
  @private
  @method prepareConfirm
  @param {FileInfo} info
  @return {Promise}
*/
function prepareConfirm(info) {
  return info.checkForConflict().then(resolution => {
    info.resolution = resolution;
    return info;
  });
}

/**
  @private
  @method markIdenticalToBeSkipped
  @param {FileInfo} info
*/
function markIdenticalToBeSkipped(info) {
  if (info.resolution === 'identical') {
    info.action = 'skip';
  }
}

/**
  @private
  @method markToBeRemoved
  @param {FileInfo} info
*/
function markToBeRemoved(info) {
  info.action = 'remove';
}

/**
  @private
  @method gatherConfirmationMessages
  @param {Array} collection
  @param {FileInfo} info
  @return {Array}
*/
function gatherConfirmationMessages(collection, info) {
  if (info.resolution === 'confirm') {
    collection.push(info.confirmOverwriteTask());
  }
  return collection;
}

/**
  @private
  @method isFile
  @param {FileInfo} info
  @return {Promise}
*/
function isFile(info) {
  return stat(info.inputPath).then(it => it.isFile());
}

/**
  @private
  @method isIgnored
  @param {FileInfo} info
  @return {Boolean}
*/
function isIgnored(info) {
  let fn = info.inputPath;

  return Blueprint.ignoredFiles.some(ignoredFile => minimatch(fn, ignoredFile, { matchBase: true }));
}

/**
  Combines provided lookup paths with defaults and removes
  duplicates.

  @private
  @method generateLookupPaths
  @param {Array} lookupPaths
  @return {Array}
*/
function generateLookupPaths(lookupPaths) {
  lookupPaths = lookupPaths || [];
  lookupPaths = lookupPaths.concat(Blueprint.defaultLookupPaths());
  return _.uniq(lookupPaths);
}

/**
  Looks for a __path__ token in the files folder. Must be present for
  the blueprint to support pod tokens.

  @private
  @method hasPathToken
  @param {files} files
  @return {Boolean}
*/
function hasPathToken(files) {
  return (/__path__/).test(files.join());
}

function findAddonByName(addonOrProject, name) {
  let addon = addonOrProject.addons.find(addon => addon.name === name);

  if (addon) {
    return addon;
  }

  return addonOrProject.addons.find(addon => findAddonByName(addon, name));
}

function ensureTargetDirIsAddon(addonPath) {
  let projectInfo;

  try {
    projectInfo = require(path.join(addonPath, 'package.json'));
  } catch (err) {
    if (err.code === 'MODULE_NOT_FOUND') {
      throw new Error(`The directory ${addonPath} does not appear to be a valid addon directory.`);
    } else {
      throw err;
    }
  }

  return isAddon(projectInfo.keywords);
}

/**
  @private
  @method isValidFile
  @param {Object} fileInfo
  @return {Promise}
*/
function isValidFile(fileInfo) {
  if (isIgnored(fileInfo)) {
    return Promise.resolve(false);
  } else {
    return isFile(fileInfo);
  }
}

/**
  @private
  @method isFilePath
  @param {Object} fileInfo
  @return {Promise}
*/
function isFilePath(fileInfo) {
  return fs.statSync(fileInfo.inputPath).isFile();
}

/**
 @private
 @method dir
 @return {Array} list of files in the given directory or and empty array if no directory exists
*/
function dir(fullPath) {
  if (Blueprint._existsSync(fullPath)) {
    return Blueprint._readdirSync(fullPath).map(fileName => path.join(fullPath, fileName));
  } else {
    return [];
  }
}

/**
  @private
  @method getDetailedHelpPath
  @param {String} thisPath
  @return {String} help path
*/
function getDetailedHelpPath(thisPath) {
  return path.join(thisPath, './HELP.md');
}

function finishProcessingForInstall(infos) {
  infos.forEach(markIdenticalToBeSkipped);

  let infosNeedingConfirmation = infos.reduce(gatherConfirmationMessages, []);

  return sequence(infosNeedingConfirmation).then(() => infos);
}

function finishProcessingForUninstall(infos) {
  let validInfos = infos.filter(info => fs.existsSync(info.outputPath));
  validInfos.forEach(markToBeRemoved);

  return validInfos;
}

module.exports = Blueprint;