/**
 * @license
 * Copyright (C) 2017 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.
 */
import {GrAnnotationActionsContext} from './gr-annotation-actions-context.js';

/** @constructor */
export function GrAnnotationActionsInterface(plugin) {
  this.plugin = plugin;
  // Return this instance when there is an annotatediff event.
  plugin.on('annotatediff', this);

  // Collect all annotation layers instantiated by getLayer. Will be used when
  // notifying their listeners in the notify function.
  this._annotationLayers = [];

  this._coverageProvider = null;

  // Default impl is a no-op.
  this._addLayerFunc = annotationActionsContext => {};
}

/**
 * Register a function to call to apply annotations. Plugins should use
 * GrAnnotationActionsContext.annotateRange and
 * GrAnnotationActionsContext.annotateLineNumber to apply a CSS class to the
 * line content or the line number.
 *
 * @param {function(GrAnnotationActionsContext)} addLayerFunc The function
 *     that will be called when the AnnotationLayer is ready to annotate.
 */
GrAnnotationActionsInterface.prototype.addLayer = function(addLayerFunc) {
  this._addLayerFunc = addLayerFunc;
  return this;
};

/**
 * The specified function will be called with a notify function for the plugin
 * to call when it has all required data for annotation. Optional.
 *
 * @param {function(function(String, Number, Number, String))} notifyFunc See
 *     doc of the notify function below to see what it does.
 */
GrAnnotationActionsInterface.prototype.addNotifier = function(notifyFunc) {
  // Register the notify function with the plugin's function.
  notifyFunc(this.notify.bind(this));
  return this;
};

/**
 * The specified function will be called when a gr-diff component is built,
 * and feeds the returned coverage data into the diff. Optional.
 *
 * Be sure to call this only once and only from one plugin. Multiple coverage
 * providers are not supported. A second call will just overwrite the
 * provider of the first call.
 *
 * @param {function(changeNum, path, basePatchNum, patchNum):
 * !Promise<!Array<!Gerrit.CoverageRange>>} coverageProvider
 * @return {GrAnnotationActionsInterface}
 */
GrAnnotationActionsInterface.prototype.setCoverageProvider = function(
    coverageProvider) {
  if (this._coverageProvider) {
    console.warn('Overwriting an existing coverage provider.');
  }
  this._coverageProvider = coverageProvider;
  return this;
};

/**
 * Used by Gerrit to look up the coverage provider. Not intended to be called
 * by plugins.
 */
GrAnnotationActionsInterface.prototype.getCoverageProvider = function() {
  return this._coverageProvider;
};

/**
 * Returns a checkbox HTMLElement that can be used to toggle annotations
 * on/off. The checkbox will be initially disabled. Plugins should enable it
 * when data is ready and should add a click handler to toggle CSS on/off.
 *
 * Note1: Calling this method from multiple plugins will only work for the
 *        1st call. It will print an error message for all subsequent calls
 *        and will not invoke their onAttached functions.
 * Note2: This method will be deprecated and eventually removed when
 *        https://bugs.chromium.org/p/gerrit/issues/detail?id=8077 is
 *        implemented.
 *
 * @param {string} checkboxLabel Will be used as the label for the checkbox.
 *     Optional. "Enable" is used if this is not specified.
 * @param {function(HTMLElement)} onAttached The function that will be called
 *     when the checkbox is attached to the page.
 */
GrAnnotationActionsInterface.prototype.enableToggleCheckbox = function(
    checkboxLabel, onAttached) {
  this.plugin.hook('annotation-toggler').onAttached(element => {
    if (!element.content.hidden) {
      console.error(
          element.content.id + ' is already enabled. Cannot re-enable.');
      return;
    }
    element.content.removeAttribute('hidden');

    const label = element.content.querySelector('#annotation-label');
    if (checkboxLabel) {
      label.textContent = checkboxLabel;
    } else {
      label.textContent = 'Enable';
    }
    const checkbox = element.content.querySelector('#annotation-checkbox');
    onAttached(checkbox);
  });
  return this;
};

/**
 * The notify function will call the listeners of all required annotation
 * layers. Intended to be called by the plugin when all required data for
 * annotation is available.
 *
 * @param {string} path The file path whose listeners should be notified.
 * @param {number} start The line where the update starts.
 * @param {number} end The line where the update ends.
 * @param {string} side The side of the update ('left' or 'right').
 */
GrAnnotationActionsInterface.prototype.notify = function(
    path, startRange, endRange, side) {
  for (const annotationLayer of this._annotationLayers) {
    // Notify only the annotation layer that is associated with the specified
    // path.
    if (annotationLayer._path === path) {
      annotationLayer.notifyListeners(startRange, endRange, side);
      break;
    }
  }
};

/**
 * Should be called to register annotation layers by the framework. Not
 * intended to be called by plugins.
 *
 * @param {string} path The file path (eg: /COMMIT_MSG').
 * @param {string} changeNum The Gerrit change number.
 * @param {string} patchNum The Gerrit patch number.
 */
GrAnnotationActionsInterface.prototype.getLayer = function(
    path, changeNum, patchNum) {
  const annotationLayer = new AnnotationLayer(path, changeNum, patchNum,
      this._addLayerFunc);
  this._annotationLayers.push(annotationLayer);
  return annotationLayer;
};

/**
 * Used to create an instance of the Annotation Layer interface.
 *
 * @constructor
 * @param {string} path The file path (eg: /COMMIT_MSG').
 * @param {string} changeNum The Gerrit change number.
 * @param {string} patchNum The Gerrit patch number.
 * @param {function(GrAnnotationActionsContext)} addLayerFunc The function
 *     that will be called when the AnnotationLayer is ready to annotate.
 */
function AnnotationLayer(path, changeNum, patchNum, addLayerFunc) {
  this._path = path;
  this._changeNum = changeNum;
  this._patchNum = patchNum;
  this._addLayerFunc = addLayerFunc;

  this._listeners = [];
}

/**
 * Register a listener for layer updates.
 *
 * @param {Function} fn The update handler function.
 *     Should accept as arguments the line numbers for the start and end of
 *     the update and the side as a string.
 */
AnnotationLayer.prototype.addListener = function(fn) {
  this._listeners.push(fn);
};

/**
 * Layer method to add annotations to a line.
 *
 * @param {HTMLElement} contentEl The DIV.contentText element of the line
 *     content to apply the annotation to using annotateRange.
 * @param {HTMLElement} lineNumberEl The TD element of the line number to
 *     apply the annotation to using annotateLineNumber.
 * @param {GrDiffLine} line The line object.
 */
AnnotationLayer.prototype.annotate = function(contentEl, lineNumberEl, line) {
  const annotationActionsContext = new GrAnnotationActionsContext(
      contentEl, lineNumberEl, line, this._path, this._changeNum,
      this._patchNum);
  this._addLayerFunc(annotationActionsContext);
};

/**
 * Notify Layer listeners of changes to annotations.
 *
 * @param {number} start The line where the update starts.
 * @param {number} end The line where the update ends.
 * @param {string} side The side of the update. ('left' or 'right')
 */
AnnotationLayer.prototype.notifyListeners = function(
    startRange, endRange, side) {
  for (const listener of this._listeners) {
    listener(startRange, endRange, side);
  }
};