// Copyright (C) 2016 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the 'License');
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an 'AS IS' BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
(function(window, GrDiffBuilderSideBySide) {
  'use strict';

  // Prevent redefinition.
  if (window.GrDiffBuilderImage) { return; }

  function GrDiffBuilderImage(diff, comments, prefs, outputEl, baseImage,
      revisionImage) {
    GrDiffBuilderSideBySide.call(this, diff, comments, prefs, outputEl, []);
    this._baseImage = baseImage;
    this._revisionImage = revisionImage;
  }

  GrDiffBuilderImage.prototype = Object.create(
      GrDiffBuilderSideBySide.prototype);
  GrDiffBuilderImage.prototype.constructor = GrDiffBuilderImage;

  GrDiffBuilderImage.prototype.renderDiffImages = function() {
    var section = this._createElement('tbody', 'image-diff');

    this._emitImagePair(section);
    this._emitImageLabels(section);

    this._outputEl.appendChild(section);
  };

  GrDiffBuilderImage.prototype._emitImagePair = function(section) {
    var tr = this._createElement('tr');

    tr.appendChild(this._createElement('td'));
    tr.appendChild(this._createImageCell(this._baseImage, 'left', section));

    tr.appendChild(this._createElement('td'));
    tr.appendChild(this._createImageCell(
          this._revisionImage, 'right', section));

    section.appendChild(tr);
  };

  GrDiffBuilderImage.prototype._createImageCell =
      function(image, className, section) {
    var td = this._createElement('td', className);
    if (image) {
      var imageEl = this._createElement('img');
      imageEl.onload = function() {
        image._height = imageEl.naturalHeight;
        image._width = imageEl.naturalWidth;
        this._updateImageLabel(section, className, image);
      }.bind(this);
      imageEl.src = 'data:' + image.type + ';base64, ' + image.body;
      imageEl.addEventListener('error', function(e) {
        imageEl.remove();
        td.textContent = '[Image failed to load]';
      });
      td.appendChild(imageEl);
    return td;
    }
  };

  GrDiffBuilderImage.prototype._updateImageLabel =
      function(section, className, image) {
    var label = Polymer.dom(section)
        .querySelector('.' + className + ' span.label');
    this._setLabelText(label, image);
  };

  GrDiffBuilderImage.prototype._setLabelText = function(label, image) {
    label.textContent = this._getImageLabel(image);
  };

  GrDiffBuilderImage.prototype._emitImageLabels = function(section) {
    var tr = this._createElement('tr');

    var addNamesInLabel = false;

    if (this._baseImage._name !== this._revisionImage._name) {
      addNamesInLabel = true;
    }

    tr.appendChild(this._createElement('td'));
    var td = this._createElement('td', 'left');
    var label = this._createElement('label');
    var nameSpan;
    var labelSpan = this._createElement('span', 'label');

    if (addNamesInLabel) {
      nameSpan = this._createElement('span', 'name');
      nameSpan.textContent = this._baseImage._name;
      label.appendChild(nameSpan);
      label.appendChild(this._createElement('br'));
    }

    this._setLabelText(labelSpan, this._baseImage, addNamesInLabel);

    label.appendChild(labelSpan);
    td.appendChild(label);
    tr.appendChild(td);

    tr.appendChild(this._createElement('td'));
    td = this._createElement('td', 'right');
    label = this._createElement('label');
    labelSpan = this._createElement('span', 'label');

    if (addNamesInLabel) {
      nameSpan = this._createElement('span', 'name');
      nameSpan.textContent = this._revisionImage._name;
      label.appendChild(nameSpan);
      label.appendChild(this._createElement('br'));
    }

    this._setLabelText(labelSpan, this._revisionImage, addNamesInLabel);

    label.appendChild(labelSpan);
    td.appendChild(label);
    tr.appendChild(td);

    section.appendChild(tr);
  };

  GrDiffBuilderImage.prototype._getImageLabel = function(image) {
    if (image) {
      var type = image.type || image._expectedType;
      if (image._width && image._height) {
        return image._width + '⨉' + image._height + ' ' + type;
      } else {
        return type;
      }
    }
    return 'No image';
  };

  window.GrDiffBuilderImage = GrDiffBuilderImage;
})(window, GrDiffBuilderSideBySide);