'use strict';

var utils = window.utils || {};
(function() {
  utils.overlay = {};

  var overlay = document.querySelector('#loading-overlay'),
      statusContainer = overlay.querySelector('p[role="status"]'),
      progressActivity = document.querySelector('#progress-activity'),
      progressTitle = document.querySelector('#progress-title'),
      progressElement = document.querySelector('#progress-element'),
      progressMsg = document.querySelector('#progress-msg'),
      menu = document.querySelector('#loading-overlay menu'),
      cancelButton = document.querySelector('#cancel-overlay');

  // Constructor for the progress element
  function ProgressBar(pMsgId, pClass) {
    var counter = 0;
    var total = 0;
    var progressTextId = pMsgId || 'genericProgress';
    var clazz = pClass;

    progressElement.setAttribute('value', 0);

    function showMessage() {
      var attributes = progressTextId == 'infiniteProgress' ?
                       { n: counter }                       :
                       { current: counter, total: total };
      document.l10n.setAttributes(progressMsg,
                                  progressTextId,
                                  attributes);
    }

    /**
     * Updates progress bar and message. It takes an optional `value` parameter
     * to overwrite the internal counter with this value.
     * @param {Number} value Overrides internal counter.
     */
    this.update = function(value) {
      if (value && value <= total && value >= counter) {
        counter = value;
      } else {
        counter++;
      }
      progressElement.setAttribute('value',
        ((counter * 100) / total).toFixed()); // Percent fraction is not needed.
      showMessage();
    };

    this.setTotal = function(ptotal) {
      total = ptotal;
    };

    this.setClass = function(clazzName) {
      setClass(clazzName);
      clazz = clazzName;
      // To refresh the message according to the new clazzName
      if (clazzName === 'activityBar' || clazzName === 'spinner') {
        progressMsg.removeAttribute('data-l10n-id');
      }
    };

    this.setHeaderMsg = function(headerMsgId) {
      progressTitle.setAttribute('data-l10n-id', headerMsgId);
    };
  } // ProgressBar

  utils.overlay.isAnimationPlaying = false;
  utils.overlay.isShown = false;
  utils.overlay._show = function _show(messageId, progressClass, textId) {
    progressActivity.classList.remove('hide');
    if (typeof messageId === 'string') {
      progressTitle.setAttribute('data-l10n-id', messageId);
    } else {
      document.l10n.setAttributes(progressTitle,
                                  messageId.id,
                                  messageId.args);
    }
    progressMsg.textContent = null;
    progressMsg.removeAttribute('data-l10n-id');
    if (utils.overlay.isShown) {
      return;
    }
    overlay.classList.remove('hide');
    overlay.classList.remove('fade-out');
    overlay.classList.add('fade-in');
    utils.overlay.isAnimationPlaying = true;
    // Custom event that can be used to apply (screen reader) visibility
    // changes.
    window.dispatchEvent(new CustomEvent('loadingoverlayshowing'));
    overlay.addEventListener('animationend', function ov_onFadeIn(ev) {
      utils.overlay.isAnimationPlaying = false;
      overlay.removeEventListener('animationend', ov_onFadeIn);
      overlay.classList.remove('no-opacity');
      utils.overlay.isShown = true;
    });
  };

  utils.overlay.show = function show(messageId, progressClass, textId) {
    var out;
    // In the case of an spinner this object will not be really used
    out = new ProgressBar(textId, progressClass);
    setClass(progressClass);
    utils.overlay.hideMenu(); // By default
    if (!utils.overlay.isAnimationPlaying) {
      utils.overlay._show(messageId, progressClass, textId);
      return out;
    }
    overlay.addEventListener('animationend',
      function ov_showWhenFinished(ev) {
        overlay.removeEventListener('animationend', ov_showWhenFinished);
        utils.overlay._show(messageId, progressClass, textId);
      }
    );
    return out;
  };

  utils.overlay.showMenu = function showMenu() {
    menu.classList.add('showed');
  };

  utils.overlay.hideMenu = function hideMenu() {
    menu.classList.remove('showed');
  };

  Object.defineProperty(utils.overlay, 'oncancel', {
    set: function(cancelCb) {
      if (typeof cancelCb === 'function') {
        cancelButton.disabled = false;
        cancelButton.onclick = function on_cancel(e) {
          delete cancelButton.onclick;
          cancelCb();
          return false;
        };
      }
    }
  });

  function setAsProgress() {
    statusContainer.classList.remove('loading-icon');
    progressElement.setAttribute('max', '100');
    progressElement.setAttribute('value', '0');
  }

  function setClass(clazzName) {
    switch (clazzName) {
      case 'spinner':
        progressElement.classList.remove('pack-activity');
        statusContainer.classList.add('loading-icon');
        progressElement.removeAttribute('max');
        progressElement.removeAttribute('value');
      break;
      case 'activityBar':
      case 'progressActivity':
        progressElement.classList.add('pack-activity');
        setAsProgress();
      break;
      case 'progressBar':
        progressElement.classList.remove('pack-activity');
        setAsProgress();
      break;
    }
  }

  utils.overlay._hide = function ov__hide() {
    if (!utils.overlay.isShown) {
      return;
    }
    overlay.classList.remove('fade-in');
    overlay.classList.add('fade-out');
    utils.overlay.isAnimationPlaying = true;
    // Custom event that can be used to apply (screen reader) visibility
    // changes.
    window.dispatchEvent(new CustomEvent('loadingoverlayhiding'));
    overlay.addEventListener('animationend', function ov_onFadeOut(ev) {
      utils.overlay.isAnimationPlaying = false;
      overlay.removeEventListener('animationend', ov_onFadeOut);
      progressActivity.classList.add('hide');
      overlay.classList.add('no-opacity');
      overlay.classList.add('hide');
      utils.overlay.isShown = false;
    });
  };
  utils.overlay.hide = function ov_hide() {
    if (!utils.overlay.isAnimationPlaying) {
      utils.overlay._hide();
      return;
    }
    overlay.addEventListener('animationend',
      function ov_hideWhenFinished(ev) {
        overlay.removeEventListener('animationend', ov_hideWhenFinished);
        utils.overlay._hide();
      }
    );
  };
})();