// 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() {
  'use strict';

  var STORAGE_DEBOUNCE_INTERVAL = 400;

  Polymer({
    is: 'gr-diff-comment',

    /**
     * Fired when the Reply action is triggered.
     *
     * @event reply
     */

    /**
     * Fired when the Done action is triggered.
     *
     * @event done
     */

    /**
     * Fired when this comment is discarded.
     *
     * @event comment-discard
     */

    /**
     * Fired when this comment is saved.
     *
     * @event comment-save
     */

    properties: {
      changeNum: String,
      comment: {
        type: Object,
        notify: true,
      },
      disabled: {
        type: Boolean,
        value: false,
        reflectToAttribute: true,
      },
      draft: {
        type: Boolean,
        value: false,
        observer: '_draftChanged',
      },
      editing: {
        type: Boolean,
        value: false,
        observer: '_editingChanged',
      },
      patchNum: String,
      showActions: Boolean,
      projectConfig: Object,

      _xhrPromise: Object,  // Used for testing.
      _messageText: {
        type: String,
        observer: '_messageTextChanged',
      },
    },

    ready: function() {
      this._loadLocalDraft().then(function(loadedLocal) {
        this._messageText = (this.comment && this.comment.message) || '';
        this.editing = !this._messageText.length || loadedLocal;
      }.bind(this));
    },

    save: function() {
      this.comment.message = this._messageText;
      this.disabled = true;

      this.$.storage.eraseDraftComment({
        changeNum: this.changeNum,
        patchNum: this.patchNum,
        path: this.comment.path,
        line: this.comment.line,
      });

      this._xhrPromise = this._saveDraft(this.comment).then(function(response) {
        this.disabled = false;
        if (!response.ok) { return response; }

        return this.$.restAPI.getResponseObject(response).then(function(obj) {
          var comment = obj;
          comment.__draft = true;
          // Maintain the ephemeral draft ID for identification by other
          // elements.
          if (this.comment.__draftID) {
            comment.__draftID = this.comment.__draftID;
          }
          this.comment = comment;
          this.editing = false;
          this.fire('comment-save');

          return obj;
        }.bind(this));
      }.bind(this)).catch(function(err) {
        this.disabled = false;
        throw err;
      }.bind(this));
    },

    _draftChanged: function(draft) {
      this.$.container.classList.toggle('draft', draft);
    },

    _editingChanged: function(editing) {
      this.$.container.classList.toggle('editing', editing);
      if (editing) {
        var textarea = this.$.editTextarea.textarea;
        // Put the cursor at the end always.
        textarea.selectionStart = textarea.value.length;
        textarea.selectionEnd = textarea.selectionStart;
        this.async(function() {
          textarea.focus();
        }.bind(this));
      }
      if (this.comment && this.comment.id) {
        this.$$('.cancel').hidden = !editing;
      }
    },

    _computeLinkToComment: function(comment) {
      return '#' + comment.line;
    },

    _computeSaveDisabled: function(draft) {
      return draft == null || draft.trim() == '';
    },

    _handleTextareaKeydown: function(e) {
      if (e.keyCode == 27) {  // 'esc'
        this._handleCancel(e);
      }
    },

    _messageTextChanged: function(newValue, oldValue) {
      if (this.comment && this.comment.id) { return; }

      this.debounce('store', function() {
        var message = this._messageText;

        var commentLocation = {
          changeNum: this.changeNum,
          patchNum: this.patchNum,
          path: this.comment.path,
          line: this.comment.line,
        };

        if ((!this._messageText || !this._messageText.length) && oldValue) {
          // If the draft has been modified to be empty, then erase the storage
          // entry.
          this.$.storage.eraseDraftComment(commentLocation);
        } else {
          this.$.storage.setDraftComment(commentLocation, message);
        }
      }, STORAGE_DEBOUNCE_INTERVAL);
    },

    _handleLinkTap: function(e) {
      e.preventDefault();
      var hash = this._computeLinkToComment(this.comment);
      // Don't add the hash to the window history if it's already there.
      // Otherwise you mess up expected back button behavior.
      if (window.location.hash == hash) { return; }
      // Change the URL but don’t trigger a nav event. Otherwise it will
      // reload the page.
      page.show(window.location.pathname + hash, null, false);
    },

    _handleReply: function(e) {
      this._preventDefaultAndBlur(e);
      this.fire('reply', {comment: this.comment}, {bubbles: false});
    },

    _handleQuote: function(e) {
      this._preventDefaultAndBlur(e);
      this.fire('reply', {comment: this.comment, quote: true},
          {bubbles: false});
    },

    _handleDone: function(e) {
      this._preventDefaultAndBlur(e);
      this.fire('done', {comment: this.comment}, {bubbles: false});
    },

    _handleEdit: function(e) {
      this._preventDefaultAndBlur(e);
      this._messageText = this.comment.message;
      this.editing = true;
    },

    _handleSave: function(e) {
      this._preventDefaultAndBlur(e);
      this.save();
    },

    _handleCancel: function(e) {
      this._preventDefaultAndBlur(e);
      if (this.comment.message == null || this.comment.message.length == 0) {
        this.fire('comment-discard');
        return;
      }
      this._messageText = this.comment.message;
      this.editing = false;
    },

    _handleDiscard: function(e) {
      this._preventDefaultAndBlur(e);
      if (!this.comment.__draft) {
        throw Error('Cannot discard a non-draft comment.');
      }
      this.disabled = true;
      if (!this.comment.id) {
        this.fire('comment-discard');
        return;
      }

      this._xhrPromise =
          this._deleteDraft(this.comment).then(function(response) {
        this.disabled = false;
        if (!response.ok) { return response; }

        this.fire('comment-discard');
      }.bind(this)).catch(function(err) {
        this.disabled = false;
        throw err;
      }.bind(this));;
    },

    _preventDefaultAndBlur: function(e) {
      e.preventDefault();
      Polymer.dom(e).rootTarget.blur();
    },

    _saveDraft: function(draft) {
      return this.$.restAPI.saveDiffDraft(this.changeNum, this.patchNum, draft);
    },

    _deleteDraft: function(draft) {
      return this.$.restAPI.deleteDiffDraft(this.changeNum, this.patchNum,
          draft);
    },

    _loadLocalDraft: function() {
      // Use an async promise to avoid blocking render on potentially slow
      // localStorage calls.
      return new Promise(function(resolve) {
        this.async(function() {
          // Only apply local drafts to comments that haven't been saved
          // remotely, and haven't been given a default message already.
          if (!this.comment || this.comment.id || this.comment.message) {
            resolve(false);
            return;
          }

          var draft = this.$.storage.getDraftComment({
            changeNum: this.changeNum,
            patchNum: this.patchNum,
            path: this.comment.path,
            line: this.comment.line,
          });

          if (draft) {
            this.comment.message = draft.message;
            resolve(true);
            return;
          }

          resolve(false);
        }.bind(this));
      }.bind(this));
    },
  });
})();