'use strict';

/**
 * Action: ModuleInstall
 * - downloads module from github url
 * - validate downloaded module
 * - copy downloaded module into project module dir and install deps
 * - update project CF template
 *
 * Event Properties:
 * - github-url:     (String) github url of the module in this format:
 *                                 https://github.com/serverless/serverless
 */

module.exports = function(S) {

  const path  = require('path'),
    BbPromise = require('bluebird'),
    fs        = BbPromise.promisifyAll(require('fs')),
    wrench    = BbPromise.promisifyAll(require('wrench')),
    temp      = BbPromise.promisifyAll(require('temp')),
    SUtils    = S.utils,
    SError    = require(S.getServerlessPath('Error')),
    SCli      = require(S.getServerlessPath('utils/cli')),
    URL       = require('url'),
    Download  = require('download');

  temp.track();


  /**
   * ModuleInstall Class
   */

  class ModuleInstall extends S.classes.Plugin {

    static getName() {
      return 'serverless.core.' + this.name;
    }

    registerActions() {
      S.addAction(this.moduleInstall.bind(this), {
        handler:       'moduleInstall',
        description:   `Downloads and installs a new module from github.
usage: serverless module install <github-url>`,
        context:       'module',
        contextAction: 'install',
        options:       [],
        parameters: [
        {
          parameter: 'url',
          description: 'Github repo url of the Serverless Module you want to install',
          position: '0'
        }
      ]
      });
      return BbPromise.resolve();
    }

    /**
     * Action
     */

    moduleInstall(evt) {

      let _this         = this;
      _this.evt         = evt;

      return _this._downloadModule()
          .bind(_this)
          .then(_this._validateAndPrepare)
          .then(_this._installModule)
          .then(function() {
            SCli.log('Successfully installed "' + _this.evt.data.module + '" module.');

            /**
             * Return EVT
             */

            return _this.evt;
          });
    }

    /**
     * Downloads the module from github
     */

    _downloadModule() {

      // If URL is not provided, throw error.
      if(!this.evt.options.url) {
        return BbPromise.reject(new SError('Github URL is required. (eg. serverless module install <github-url>)', SError.errorCodes.UNKNOWN));
      }

      let _this = this,
          spinner = SCli.spinner(),
          url = URL.parse(_this.evt.options.url),
          parts = url.pathname.split('/'),
          repo = {
            owner: parts[1],
            repo: parts[2],
            branch: 'master'
          };

      //TODO: support github tree URLS (branch): https://github.com/serverless/serverless/tree/cf-deploy
      if (~repo.repo.indexOf('#')) {
        url[2].split('#');
        repo.repo = url[2].split('#')[0];
        repo.branch = url[2].split('#')[1];
      }

      if (url.hostname !== 'github.com' || !repo.owner || !repo.repo) {
        spinner.stop(true);
        return BbPromise.reject(new SError('Must be a github url in this format: https://github.com/serverless/serverless', SError.errorCodes.UNKNOWN));
      }

      let downloadUrl = 'https://github.com/' + repo.owner + '/' + repo.repo + '/archive/' + repo.branch + '.zip';

      return temp.mkdirAsync('module')
          .then(function(tempModulePath) {
            return new BbPromise(function(resolve, reject) {
              SCli.log('Downloading module ...');
              spinner.start();

              new Download({
                timeout: 30000,
                extract: true,
                strip: 1,
                mode: '755',
              }).get(downloadUrl)
                .dest(tempModulePath)
                .run(function(error) {
                  spinner.stop(true);
                  if (error) {
                    return BbPromise.reject(new SError('Module Download and installation failed: ' + error, SError.errorCodes.UNKNOWN));
                  }
                  _this.pathTempModule = tempModulePath;
                  resolve();
                });
            });
          });
    };

    /**
     * Validate and prepare data before installing the downloaded module
     */

    _validateAndPrepare() {
      let _this = this,
          srcModuleJsonPath = path.join(_this.pathTempModule, 's-module.json');

      // if s-module.json doesn't exist in downloaded module, throw error
      if (!SUtils.fileExistsSync(srcModuleJsonPath)) {
        return BbPromise.reject(new SError('Missing s-module.json file in module root', SError.errorCodes.UNKNOWN));
      }

      let srcModuleJson = SUtils.readFileSync(srcModuleJsonPath);

      // if name is missing from s-module.json, throw error
      if (!srcModuleJson.name) {
        return BbPromise.reject(new SError('s-module.json for downloaded module missing name attr', SError.errorCodes.UNKNOWN));
      }

      _this.evt.data.module = srcModuleJson.name;
      _this.pathModule      = S.getProject().getRootPath('back', 'modules', _this.evt.data.module);

      // if same module name exists, throw error
      if (SUtils.doesModuleExist(srcModuleJson.name, S.getProject().getRootPath())) {
        return BbPromise.reject(new SError(
            'Module ' + _this.evt.data.module + ' already exists',
            SError.errorCodes.INVALID_PROJECT_SERVERLESS
        ));
      }

      // if required cloudformation attrs are missing, throw error
      if (
          (!srcModuleJson.cloudFormation) ||
          (!srcModuleJson.cloudFormation.lambdaIamPolicyDocumentStatements)
         ) {
           return BbPromise.reject(new SError('Module does not have required cloudFormation attributes', SError.errorCodes.UNKNOWN));
      }

      return BbPromise.resolve();
    };


    /**
     * Installs the downloaded module
     */

    _installModule() {
      let _this = this;

      // all good! copy/install module
      wrench.copyDirSyncRecursive(_this.pathTempModule, _this.pathModule, {
        forceDelete: true,
        excludeHiddenUnix: false
      });

      return BbPromise.resolve();
    };

  }

  return( ModuleInstall );
};