(function(Kaki, window) {

  "use strict";

  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');

  // Templates
  var itemsListTpl = Handlebars.compile(select('#items-list-tpl').innerHTML);

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

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

    var profilePath = Kaki._opts.profile || './default-profile.json';

    return Kaki.loadProfile(profilePath)
      .then(function() {
        return Kaki;
      })
    ;

  };

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

  /**
   * Update the application view
   *
   * @return Kaki
   */
  Kaki.render = function() {
    var rootEl = Kaki._rootEl;
    var profile = Kaki._profile;
    rootEl.innerHTML = itemsListTpl(profile);
  };


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

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

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

    if( !appItemEl ) return;

    var execPath = appItemEl.dataset.exec;

    console.info('Launching application "'+execPath+'"...');

    if(execPath) {
      appItemEl.classList.add('loading');
      cp.exec(execPath, function(err) {
        appItemEl.classList.remove('loading');
        if(err) return console.error(err.stack || err);
        console.info('Application closed "'+execPath+'".');
      });
    }

  };

  /**
   * Load a JSON file
   *
   * @private
   * @param filePath The path of the json file
   * @return Promise
   */
  Kaki._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);
        }
      });
    });
  };

  // DOM manipulation helpers

  /**
   * Select an element in the DOM by its CSS selector
   *
   * @private
   * @param selector The CSS selector
   * @return The selected element or null
   */
  function select(selector) {
    return window.document.querySelector(selector);
  }

  /**
   * Select all elements in the DOM with a CSS selector
   *
   * @private
   * @param selector The CSS selector
   * @return An array of the selected elements (if any)
   */
  function selectAll(selector) {
    return window.document.querySelectorAll(selector);
  }

  /**
   * Find the closest ancestor matching the CSS selector
   *
   * @private
   * @param selector The CSS selector
   * @return An array of the selected elements (if any)
   */
  function getClosestAncestor(el, selector) {

    var parent = el.parentElement;

    if(parent) {
      if(parent.matches(selector)) {
        return parent;
      } else {
        return getClosestAncestor(parent, selector);
      }
    }

    return false;

  }


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