/**
 * @license
 * 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';

  const PATCH_SET_PREFIX_PATTERN = /^Patch Set (\d)+:[ ]?/;
  const COMMENTS_COUNT_PATTERN = /^\((\d+)( inline)? comments?\)$/;
  const LABEL_TITLE_SCORE_PATTERN = /^([A-Za-z0-9-]+)([+-]\d+)$/;

  Polymer({
    is: 'gr-message',

    /**
     * Fired when this message's permalink is tapped.
     *
     * @event scroll-to
     */

    /**
     * Fired when this message's reply link is tapped.
     *
     * @event reply
     */

    listeners: {
      tap: '_handleTap',
    },

    properties: {
      changeNum: Number,
      /** @type {?} */
      message: Object,
      author: {
        type: Object,
        computed: '_computeAuthor(message)',
      },
      comments: {
        type: Object,
        observer: '_commentsChanged',
      },
      config: Object,
      hideAutomated: {
        type: Boolean,
        value: false,
      },
      hidden: {
        type: Boolean,
        computed: '_computeIsHidden(hideAutomated, isAutomated)',
        reflectToAttribute: true,
      },
      isAutomated: {
        type: Boolean,
        computed: '_computeIsAutomated(message)',
      },
      showAvatar: {
        type: Boolean,
        computed: '_computeShowAvatar(author, config)',
      },
      showOnBehalfOf: {
        type: Boolean,
        computed: '_computeShowOnBehalfOf(message)',
      },
      showReplyButton: {
        type: Boolean,
        computed: '_computeShowReplyButton(message, _loggedIn)',
      },
      projectName: {
        type: String,
        observer: '_projectNameChanged',
      },

      /**
       * A mapping from label names to objects representing the minimum and
       * maximum possible values for that label.
       */
      labelExtremes: Object,

      /**
       * @type {{ commentlinks: Array }}
       */
      _projectConfig: Object,
      // Computed property needed to trigger Polymer value observing.
      _expanded: {
        type: Object,
        computed: '_computeExpanded(message.expanded)',
      },
      _loggedIn: {
        type: Boolean,
        value: false,
      },

      _parsedPatchNum: String,
      _parsedCommentCount: String,
      _parsedVotes: Array,
      _parsedChangeMessage: String,
      _successfulParse: Boolean,
    },

    observers: [
      '_updateExpandedClass(message.expanded)',
      '_consumeMessage(message.message)',
    ],

    ready() {
      this.$.restAPI.getConfig().then(config => {
        this.config = config;
      });
      this.$.restAPI.getLoggedIn().then(loggedIn => {
        this._loggedIn = loggedIn;
      });
    },

    _updateExpandedClass(expanded) {
      if (expanded) {
        this.classList.add('expanded');
      } else {
        this.classList.remove('expanded');
      }
    },

    _computeAuthor(message) {
      return message.author || message.updated_by;
    },

    _computeShowAvatar(author, config) {
      return !!(author && config && config.plugin && config.plugin.has_avatars);
    },

    _computeShowOnBehalfOf(message) {
      const author = message.author || message.updated_by;
      return !!(author && message.real_author &&
          author._account_id != message.real_author._account_id);
    },

    _computeShowReplyButton(message, loggedIn) {
      return !!message.message && loggedIn &&
          !this._computeIsAutomated(message);
    },

    _computeExpanded(expanded) {
      return expanded;
    },

    /**
     * If there is no value set on the message object as to whether _expanded
     * should be true or not, then _expanded is set to true if there are
     * inline comments (otherwise false).
     */
    _commentsChanged(value) {
      if (this.message && this.message.expanded === undefined) {
        this.set('message.expanded', Object.keys(value || {}).length > 0);
      }
    },

    _handleTap(e) {
      if (this.message.expanded) { return; }
      e.stopPropagation();
      this.set('message.expanded', true);
    },

    _handleAuthorTap(e) {
      if (!this.message.expanded) { return; }
      e.stopPropagation();
      this.set('message.expanded', false);
    },

    _computeIsAutomated(message) {
      return !!(message.reviewer ||
          this._computeIsReviewerUpdate(message) ||
          (message.tag && message.tag.startsWith('autogenerated')));
    },

    _computeIsHidden(hideAutomated, isAutomated) {
      return hideAutomated && isAutomated;
    },

    _computeIsReviewerUpdate(event) {
      return event.type === 'REVIEWER_UPDATE';
    },

    _computeScoreClass(score, labelExtremes) {
      const classes = [];
      if (score.value > 0) {
        classes.push('positive');
      } else if (score.value < 0) {
        classes.push('negative');
      }
      const extremes = labelExtremes[score.label];
      if (extremes) {
        const intScore = parseInt(score.value, 10);
        if (intScore === extremes.max) {
          classes.push('max');
        } else if (intScore === extremes.min) {
          classes.push('min');
        }
      }
      return classes.join(' ');
    },

    _computeClass(expanded, showAvatar, message) {
      const classes = [];
      classes.push(expanded ? 'expanded' : 'collapsed');
      classes.push(showAvatar ? 'showAvatar' : 'hideAvatar');
      return classes.join(' ');
    },

    _computeMessageHash(message) {
      return '#message-' + message.id;
    },

    _handleLinkTap(e) {
      e.preventDefault();

      this.fire('scroll-to', {message: this.message}, {bubbles: false});

      const hash = this._computeMessageHash(this.message);
      // 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);
    },

    _handleReplyTap(e) {
      e.preventDefault();
      this.fire('reply', {message: this.message});
    },

    _projectNameChanged(name) {
      this.$.restAPI.getProjectConfig(name).then(config => {
        this._projectConfig = config;
      });
    },

    _computeExpandToggleIcon(expanded) {
      return expanded ? 'gr-icons:expand-less' : 'gr-icons:expand-more';
    },

    _toggleExpanded(e) {
      e.stopPropagation();
      this.set('message.expanded', !this.message.expanded);
    },

    /**
     * Attempts to consume a change message to create a shorter and more legible
     * format. If the function encounters unexpected characters at any point, it
     * sets the _successfulParse flag to false and terminates, causing the UI to
     * fall back to displaying the entirety of the change message.
     *
     * A successful parse results in a one-liner that reads:
     * `${AVATAR} voted ${VOTES} and left ${NUM} comment(s) on ${PATCHSET}`
     *
     * @param {string} text
     */
    _consumeMessage(text) {
      this._parsedPatchNum = '';
      this._parsedCommentCount = '';
      this._parsedChangeMessage = '';
      this._parsedVotes = [];
      if (!text) {
        // No message body means nothing to parse.
        this._successfulParse = false;
        return;
      }
      const lines = text.split('\n');
      const messageLines = lines.shift().split(PATCH_SET_PREFIX_PATTERN);
      if (!messageLines[1]) {
        // Message is in an unexpected format.
        this._successfulParse = false;
        return;
      }
      this._parsedPatchNum = messageLines[1];
      if (messageLines[2]) {
        // Content after the colon is always vote information. If it is in the
        // most up to date schema, parse it. Otherwise, cancel the parsing
        // completely.
        let match;
        for (const score of messageLines[2].split(' ')) {
          match = score.match(LABEL_TITLE_SCORE_PATTERN);
          if (!match || match.length !== 3) {
            this._successfulParse = false;
            return;
          }
          this._parsedVotes.push({label: match[1], value: match[2]});
        }
      }
      // Remove empty line.
      lines.shift();
      if (lines.length) {
        const commentMatch = lines[0].match(COMMENTS_COUNT_PATTERN);
        if (commentMatch) {
          this._parsedCommentCount = commentMatch[1];
          // Remove comment line and the following empty line.
          lines.splice(0, 2);
        }
        this._parsedChangeMessage = lines.join('\n');
      }
      this._successfulParse = true;
    },

    _computeConversationalString(votes, patchNum, commentCount) {
      let clause = ' on Patch Set ' + patchNum;
      if (commentCount) {
        let commentStr = ' comment';
        if (parseInt(commentCount, 10) > 1) { commentStr += 's'; }
        clause = ' left ' + commentCount + commentStr + clause;
        if (votes.length) { clause = ' and' + clause; }
      }
      return clause;
    },
  });
})();