(function(Pitaya, window) {

  "use strict";

  // Load dependencies
  var path = require('path');
  var fs = require('fs');
  var Handlebars = require('handlebars');
  var cp = require("child_process");
  var gui = require('nw.gui');
  var minimist = require('minimist');

  // Load templates...
  var launcherViewTpl = Handlebars.compile(Pitaya.DOM.select('#launcher-view-tpl').innerHTML);

  // ... and partials
  Handlebars.registerPartial('itemListTpl', Pitaya.DOM.select('#items-list-tpl').innerHTML);
  Handlebars.registerPartial('itemTpl', Pitaya.DOM.select('#item-tpl').innerHTML);

  // Internal constants
  var DEFAULT_PROFILE = './default-profile.json';

  /**
   * Start the app
   *
   * @param rootEl The application root element selector
   * @return Pitaya
   */
  Pitaya.start = function(rootEl) {

    Pitaya._opts = minimist(gui.App.argv);
    Pitaya._rootEl = Pitaya.DOM.select(rootEl);
    Pitaya._initListeners();

    var profilePath = Pitaya._opts.profile || DEFAULT_PROFILE;

    return Pitaya.loadProfile(profilePath)
      .then(function() {
        return Pitaya;
      })
      .catch(Pitaya._onError)
    ;

  };

  /**
   * Load a profile file and render the application
   *
   * @param profilePath The path of the profile file
   * @return Promise
   */
  Pitaya.loadProfile = function(profilePath) {
    return Pitaya._loadJSONFile(profilePath)
      .then(function(profile) {
        Pitaya._profile = profile;
        Pitaya.renderLauncherView();
        return profile;
      })
    ;
  };

  /**
   * Update the application view
   *
   * @return Pitaya
   */
  Pitaya.renderLauncherView = function(currentItemPath) {

    currentItemPath = Pitaya._normalizeItemPath(currentItemPath);
    var rootEl = Pitaya._rootEl;
    var currentItem = Pitaya._getItemByPath(currentItemPath);

    var data = {
      currentItemPath: currentItemPath.join('.'),
      currentItem: currentItem,
      isRoot: currentItemPath.length === 0
    };

    rootEl.innerHTML = launcherViewTpl(data);

  };


  /**
   * Initialize DOM event listeners
   * @private
   */
  Pitaya._initListeners = function() {
    var rootEl = Pitaya._rootEl;
    rootEl.addEventListener('click', Pitaya._onItemClick);
    rootEl.addEventListener('click', Pitaya._onGoBackClick);
  };

  /**
   * App item click handler
   * @private
   */
  Pitaya._onItemClick = function(evt) {

    var appItemEl = evt.srcElement.matches( '.app-item') ? evt.srcElement :
      Pitaya.DOM.getClosestAncestor(evt.srcElement, '.app-item')
    ;

    if( !appItemEl ) return;

    var itemPath = appItemEl.dataset.itemPath;
    var item = Pitaya._getItemByPath(itemPath);

    if(!item) return;

    if('items' in item) {
      var rootEl = Pitaya._rootEl;
      Pitaya.Anim.play(rootEl, 'slide-out-left 250ms ease-in-out')
        .then(function() {
          Pitaya.renderLauncherView(itemPath);
          return Pitaya.Anim.play(rootEl, 'slide-in-right 250ms ease-in-out');
        })
      ;
    }

    if(item.exec) {

      console.info('Launching application "'+item.exec+'"...');
      appItemEl.classList.add('pulse');

      Pitaya._runApp(item.exec)
        .then(function() {
          appItemEl.classList.remove('pulse');
        })
        .catch(function(err) {
          Pitaya._onError(err);
          appItemEl.classList.remove('pulse');
        })
      ;

    }

  };

  /**
   * GoBack button click handler
   * @private
   */
  Pitaya._onGoBackClick = function(evt) {

    var goBackEl = evt.srcElement.matches( '.goback') ? evt.srcElement :
      Pitaya.DOM.getClosestAncestor(evt.srcElement, '.goback')
    ;

    if(!goBackEl) return;

    var currentItemPath = goBackEl.dataset.itemPath;
    var parentItemPath = Pitaya._normalizeItemPath(currentItemPath);

    parentItemPath.pop();

    var rootEl = Pitaya._rootEl;
    Pitaya.Anim.play(rootEl, 'slide-out-right 250ms ease-in-out')
      .then(function() {
        Pitaya.renderLauncherView(parentItemPath);
        return Pitaya.Anim.play(rootEl, 'slide-in-left 250ms ease-in-out');
      })
    ;

  };

  Pitaya._normalizeItemPath = function(itemPath) {

    if( Array.isArray(itemPath) ) return itemPath;

    if((typeof itemPath === 'string' && itemPath.length === 0) || !itemPath) return [];

    return itemPath.split('.').reduce(function(arr, index) {
      if(index !== '') {
        arr.push(+index);
      }
      return arr;
    }, []);

  };

  Pitaya._getItemByPath = function(itemPath, rootItem) {

    rootItem = rootItem || Pitaya._profile;
    itemPath = Pitaya._normalizeItemPath(itemPath);

    var itemIndex = itemPath[0];

    if(itemIndex === undefined) {
      return rootItem;
    }

    if(!('items' in rootItem)) {
      return undefined;
    }

    var subItem = rootItem.items[itemIndex];

    if(itemPath.length === 0) {
      return subItem;
    }

    return Pitaya._getItemByPath(itemPath.slice(1), subItem);

  };

  Pitaya._runApp = function(execPath) {
    return new Promise(function(resolve, reject) {
      cp.exec(execPath, function(err) {
        if(err) return reject(err);
        return resolve();
      });
    });
  };

  /**
   * Load a JSON file
   *
   * @private
   * @param filePath The path of the json file
   * @return Promise
   */
  Pitaya._loadJSONFile = function(filePath) {
    return new Promise(function(resolve, reject) {
      fs.readFile(filePath, 'utf8', function(err, fileContent) {
        if(err) return reject(err);
        try {
          var json = JSON.parse(fileContent);
          return resolve(json);
        } catch(err) {
          return reject(err);
        }
      });
    });
  };


  Pitaya._onError = function(err) {
    console.error(err.stack ? err.stack : err);
  };

}(window.Pitaya = window.Pitaya || {}, window));