import userSearch from 'discourse/lib/user-search';
import { default as computed, observes, on } from 'ember-addons/ember-computed-decorators';
import { linkSeenMentions, fetchUnseenMentions } from 'discourse/lib/link-mentions';
import { linkSeenCategoryHashtags, fetchUnseenCategoryHashtags } from 'discourse/lib/link-category-hashtags';
import { linkSeenTagHashtags, fetchUnseenTagHashtags } from 'discourse/lib/link-tag-hashtag';
import Composer from 'discourse/models/composer';
import { load } from 'pretty-text/oneboxer';
import { applyInlineOneboxes } from 'pretty-text/inline-oneboxer';
import { ajax } from 'discourse/lib/ajax';
import InputValidation from 'discourse/models/input-validation';
import { findRawTemplate } from 'discourse/lib/raw-templates';
import { tinyAvatar,
         displayErrorForUpload,
         getUploadMarkdown,
         validateUploadedFiles,
         formatUsername,
         clipboardData
} from 'discourse/lib/utilities';
import { cacheShortUploadUrl, resolveAllShortUrls } from 'pretty-text/image-short-url';

const REBUILD_SCROLL_MAP_EVENTS = [
  'composer:resized',
  'composer:typed-reply'
];

export default Ember.Component.extend({
  classNameBindings: ['showToolbar:toolbar-visible', ':wmd-controls'],

  uploadProgress: 0,
  _xhr: null,
  shouldBuildScrollMap: true,
  scrollMap: null,

  @computed
  uploadPlaceholder() {
    return `[${I18n.t('uploading')}]() `;
  },

  @observes('composer.uploadCancelled')
  _cancelUpload() {
    if (!this.get('composer.uploadCancelled')) { return; }
    this.set('composer.uploadCancelled', false);

    if (this._xhr) {
      this._xhr._userCancelled = true;
      this._xhr.abort();
    }
    this._resetUpload(true);
  },

  @computed
  markdownOptions() {
    return {
      previewing: true,

      formatUsername,

      lookupAvatarByPostNumber: (postNumber, topicId) => {
        const topic = this.get('topic');
        if (!topic) { return; }

        const posts = topic.get('postStream.posts');
        if (posts && topicId === topic.get('id')) {
          const quotedPost = posts.findBy("post_number", postNumber);
          if (quotedPost) {
            return tinyAvatar(quotedPost.get('avatar_template'));
          }
        }
      },

      lookupPrimaryUserGroupByPostNumber: (postNumber, topicId) => {
        const topic = this.get('topic');
        if (!topic) { return; }

        const posts = topic.get('postStream.posts');
        if (posts && topicId === topic.get('id')) {
          const quotedPost = posts.findBy("post_number", postNumber);
          if (quotedPost) {
            return quotedPost.primary_group_name;
          }
        }
      }
    };
  },

  @on('didInsertElement')
  _composerEditorInit() {
    const topicId = this.get('topic.id');
    const $input = this.$('.d-editor-input');
    const $preview = this.$('.d-editor-preview-wrapper');

    if (this.siteSettings.enable_mentions) {
      $input.autocomplete({
        template: findRawTemplate('user-selector-autocomplete'),
        dataSource: term => userSearch({
          term,
          topicId,
          includeMentionableGroups: true
        }),
        key: "@",
        transformComplete: v => v.username || v.name
      });
    }

    if (this._enableAdvancedEditorPreviewSync()) {
      this._initInputPreviewSync($input, $preview);
    } else {
      $input.on('scroll', () => Ember.run.throttle(this,
        this._syncEditorAndPreviewScroll,
        $input,
        $preview,
        20
      ));
    }

    // Focus on the body unless we have a title
    if (!this.get('composer.canEditTitle') && !this.capabilities.isIOS) {
      this.$('.d-editor-input').putCursorAtEnd();
    }

    this._bindUploadTarget();
    this.appEvents.trigger('composer:will-open');
  },

  @computed('composer.reply', 'composer.replyLength', 'composer.missingReplyCharacters', 'composer.minimumPostLength', 'lastValidatedAt')
  validation(reply, replyLength, missingReplyCharacters, minimumPostLength, lastValidatedAt) {
    const postType = this.get('composer.post.post_type');
    if (postType === this.site.get('post_types.small_action')) { return; }

    let reason;
    if (replyLength < 1) {
      reason = I18n.t('composer.error.post_missing');
    } else if (missingReplyCharacters > 0) {
      reason = I18n.t('composer.error.post_length', {min: minimumPostLength});
      const tl = Discourse.User.currentProp("trust_level");
      if (tl === 0 || tl === 1) {
        reason += "<br/>" + I18n.t('composer.error.try_like');
      }
    }

    if (reason) {
      return InputValidation.create({ failed: true, reason, lastShownAt: lastValidatedAt });
    }
  },

  _enableAdvancedEditorPreviewSync() {
    return this.siteSettings.enable_advanced_editor_preview_sync;
  },

  _resetShouldBuildScrollMap() {
    this.set('shouldBuildScrollMap', true);
  },

  _initInputPreviewSync($input, $preview) {
    REBUILD_SCROLL_MAP_EVENTS.forEach(event => {
      this.appEvents.on(event, this, this._resetShouldBuildScrollMap);
    });

    Ember.run.scheduleOnce("afterRender", () => {
      $input.on('touchstart mouseenter', () => {
        if (!$preview.is(":visible")) return;
        $preview.off('scroll');

        $input.on('scroll', () => {
          this._syncScroll(this._syncEditorAndPreviewScroll, $input, $preview);
        });
      });

      $preview.on('touchstart mouseenter', () => {
        $input.off('scroll');

        $preview.on('scroll', () => {
          this._syncScroll(this._syncPreviewAndEditorScroll, $input, $preview);
        });
      });
    });
  },

  _syncScroll($callback, $input, $preview) {
    if (!this.get('scrollMap') || this.get('shouldBuildScrollMap')) {
      this.set('scrollMap', this._buildScrollMap($input, $preview));
      this.set('shouldBuildScrollMap', false);
    }

    Ember.run.throttle(this, $callback, $input, $preview, this.get('scrollMap'), 20);
  },

  _teardownInputPreviewSync() {
    [this.$('.d-editor-input'), this.$('.d-editor-preview-wrapper')].forEach($element => {
      $element.off("mouseenter touchstart");
      $element.off("scroll");
    });

    REBUILD_SCROLL_MAP_EVENTS.forEach(event => {
      this.appEvents.off(event, this, this._resetShouldBuildScrollMap);
    });;
  },

  // Adapted from https://github.com/markdown-it/markdown-it.github.io
  _buildScrollMap($input, $preview) {
    let sourceLikeDiv = $('<div />').css({
      position: 'absolute',
      height: 'auto',
      visibility: 'hidden',
      width: $input[0].clientWidth,
      'font-size': $input.css('font-size'),
      'font-family': $input.css('font-family'),
      'line-height': $input.css('line-height'),
      'white-space': $input.css('white-space')
    }).appendTo('body');

    const linesMap = [];
    let numberOfLines = 0;

    $input.val().split('\n').forEach(text => {
      linesMap.push(numberOfLines);

      if (text.length === 0) {
        numberOfLines++;
      } else {
        sourceLikeDiv.text(text);

        let height;
        let lineHeight;
        height = parseFloat(sourceLikeDiv.css('height'));
        lineHeight = parseFloat(sourceLikeDiv.css('line-height'));
        numberOfLines += Math.round(height / lineHeight);
      }
    });

    linesMap.push(numberOfLines);
    sourceLikeDiv.remove();

    const previewOffsetTop = $preview.offset().top;
    const offset = $preview.scrollTop() - previewOffsetTop - ($input.offset().top - previewOffsetTop);
    const nonEmptyList = [];
    const scrollMap = [];
    for (let i = 0; i < numberOfLines; i++) { scrollMap.push(-1); };

    nonEmptyList.push(0);
    scrollMap[0] = 0;

    $preview.find('.preview-sync-line').each((_, element) => {
      let $element = $(element);
      let lineNumber = $element.data('line-number');
      let linesToTop = linesMap[lineNumber];
      if (linesToTop !== 0) { nonEmptyList.push(linesToTop); }
      scrollMap[linesToTop] = Math.round($element.offset().top + offset);
    });

    nonEmptyList.push(numberOfLines);
    scrollMap[numberOfLines] = $preview[0].scrollHeight;

    let position = 0;

    for (let i = 1; i < numberOfLines; i++) {
      if (scrollMap[i] !== -1) {
        position++;
        continue;
      }

      let top = nonEmptyList[position];
      let bottom = nonEmptyList[position + 1];

      scrollMap[i] =
        ((
          scrollMap[bottom] * (i - top) +
          scrollMap[top] * (bottom - i)
        ) / (bottom - top)).toFixed(2);
    };

    return scrollMap;
  },

  _syncEditorAndPreviewScroll($input, $preview, scrollMap) {
    if (this._enableAdvancedEditorPreviewSync()) {
      let scrollTop;
      const inputHeight = $input.height();
      const inputScrollHeight = $input[0].scrollHeight;
      const inputClientHeight = $input[0].clientHeight;
      const scrollable = inputScrollHeight > inputClientHeight;

      if (scrollable && ((inputHeight + $input.scrollTop() + 100) > inputScrollHeight)) {
        scrollTop = $preview[0].scrollHeight;
      } else {
        const lineHeight = parseFloat($input.css('line-height'));
        const lineNumber = Math.floor($input.scrollTop() / lineHeight);
        scrollTop = scrollMap[lineNumber];
      }

      $preview.stop(true).animate({ scrollTop }, 100, 'linear');
    } else {
      if (!$input) { return; }

      if ($input.scrollTop() === 0) {
        $preview.scrollTop(0);
        return;
      }

      const inputHeight = $input[0].scrollHeight;
      const previewHeight = $preview[0].scrollHeight;

      if (($input.height() + $input.scrollTop() + 100) > inputHeight) {
        // cheat, special case for bottom
        $preview.scrollTop(previewHeight);
        return;
      }

      const scrollPosition = $input.scrollTop();
      const factor = previewHeight / inputHeight;
      const desired = scrollPosition * factor;
      $preview.scrollTop(desired + 50);
    }
  },

  _syncPreviewAndEditorScroll($input, $preview, scrollMap) {
    if (scrollMap.length < 1) return;

    let scrollTop;
    const previewScrollTop = $preview.scrollTop();

    if (($preview.height() + previewScrollTop + 100) > $preview[0].scrollHeight) {
      scrollTop = $input[0].scrollHeight;
    } else {
      const lineHeight = parseFloat($input.css('line-height'));
      scrollTop = lineHeight * scrollMap.findIndex(offset => offset > previewScrollTop);
    }

    $input.stop(true).animate({ scrollTop }, 100, 'linear');
  },

  _renderUnseenMentions($preview, unseen) {
    // 'Create a New Topic' scenario is not supported (per conversation with codinghorror)
    // https://meta.discourse.org/t/taking-another-1-7-release-task/51986/7
    fetchUnseenMentions(unseen, this.get('composer.topic.id')).then(() => {
      linkSeenMentions($preview, this.siteSettings);
      this._warnMentionedGroups($preview);
      this._warnCannotSeeMention($preview);
    });
  },

  _renderUnseenCategoryHashtags($preview, unseen) {
    fetchUnseenCategoryHashtags(unseen).then(() => {
      linkSeenCategoryHashtags($preview);
    });
  },

  _renderUnseenTagHashtags($preview, unseen) {
    fetchUnseenTagHashtags(unseen).then(() => {
      linkSeenTagHashtags($preview);
    });
  },

  _loadInlineOneboxes(inline) {
    applyInlineOneboxes(inline, ajax);
  },

  _loadOneboxes($oneboxes) {
    const post = this.get('composer.post');
    let refresh = false;

    // If we are editing a post, we'll refresh its contents once.
    if (post && !post.get('refreshedPost')) {
      refresh = true;
      post.set('refreshedPost', true);
    }

    $oneboxes.each((_, o) => load(o, refresh, ajax, this.currentUser.id));
  },

  _warnMentionedGroups($preview) {
    Ember.run.scheduleOnce('afterRender', () => {
      var found = this.get('warnedGroupMentions') || [];
      $preview.find('.mention-group.notify').each((idx,e) => {
        const $e = $(e);
        var name = $e.data('name');
        if (found.indexOf(name) === -1){
          this.sendAction('groupsMentioned', [{name: name, user_count: $e.data('mentionable-user-count'), max_mentions: $e.data('max-mentions')}]);
          found.push(name);
        }
      });

      this.set('warnedGroupMentions', found);
    });
  },

  _warnCannotSeeMention($preview) {
    const composerDraftKey = this.get('composer.draftKey');

    if (composerDraftKey === Composer.CREATE_TOPIC ||
        composerDraftKey === Composer.NEW_PRIVATE_MESSAGE_KEY ||
        composerDraftKey === Composer.REPLY_AS_NEW_TOPIC_KEY ||
        composerDraftKey === Composer.REPLY_AS_NEW_PRIVATE_MESSAGE_KEY) {

      return;
    }

    Ember.run.scheduleOnce('afterRender', () => {
      let found = this.get('warnedCannotSeeMentions') || [];

      $preview.find('.mention.cannot-see').each((idx,e) => {
        const $e = $(e);
        let name = $e.data('name');

        if (found.indexOf(name) === -1) {
          this.sendAction('cannotSeeMention', [{ name: name }]);
          found.push(name);
        }
      });

      this.set('warnedCannotSeeMentions', found);
    });
  },

  _resetUpload(removePlaceholder) {
    if (this._validUploads > 0) {
      this._validUploads--;
    }
    if (this._validUploads === 0) {
      this.setProperties({ uploadProgress: 0, isUploading: false, isCancellable: false });
    }
    if (removePlaceholder) {
      this.appEvents.trigger('composer:replace-text', this.get('uploadPlaceholder'), "");
    }
  },

  _bindUploadTarget() {
    this._unbindUploadTarget(); // in case it's still bound, let's clean it up first

    this._pasted = false;

    const $element = this.$();
    const csrf = this.session.get('csrfToken');
    const uploadPlaceholder = this.get('uploadPlaceholder');

    $element.fileupload({
      url: Discourse.getURL(`/uploads.json?client_id=${this.messageBus.clientId}&authenticity_token=${encodeURIComponent(csrf)}`),
      dataType: "json",
      pasteZone: $element,
    });

    $element.on('fileuploadpaste', (e) => {
      this._pasted = true;

      if (!$(".d-editor-input").is(":focus")) {
        return;
      }

      const { canUpload, canPasteHtml } = clipboardData(e, true);

      if (!canUpload || canPasteHtml) {
        e.preventDefault();
      }
    });

    $element.on('fileuploadsubmit', (e, data) => {
      const isPrivateMessage = this.get("composer.privateMessage");

      data.formData = { type: "composer" };
      if (isPrivateMessage) data.formData.for_private_message = true;
      if (this._pasted) data.formData.pasted = true;

      const opts = {
        isPrivateMessage,
        allowStaffToUploadAnyFileInPm: this.siteSettings.allow_staff_to_upload_any_file_in_pm,
      };

      const isUploading = validateUploadedFiles(data.files, opts);

      this.setProperties({ uploadProgress: 0, isUploading });

      return isUploading;
    });

    $element.on("fileuploadprogressall", (e, data) => {
      this.set("uploadProgress", parseInt(data.loaded / data.total * 100, 10));
    });

    $element.on("fileuploadsend", (e, data) => {
      this._pasted = false;
      this._validUploads++;
      this.appEvents.trigger('composer:insert-text', uploadPlaceholder);

      if (data.xhr && data.originalFiles.length === 1) {
        this.set("isCancellable", true);
        this._xhr = data.xhr();
      }
    });

    $element.on("fileuploaddone", (e, data) => {
      let upload = data.result;

      if (!this._xhr || !this._xhr._userCancelled) {
        const markdown = getUploadMarkdown(upload);
        cacheShortUploadUrl(upload.short_url, upload.url);
        this.appEvents.trigger('composer:replace-text', uploadPlaceholder, markdown);
        this._resetUpload(false);
      } else {
        this._resetUpload(true);
      }
    });

    $element.on("fileuploadfail", (e, data) => {
      this._resetUpload(true);

      const userCancelled = this._xhr && this._xhr._userCancelled;
      this._xhr = null;

      if (!userCancelled) {
        displayErrorForUpload(data);
      }
    });

    if (this.site.mobileView) {
      $("#reply-control .mobile-file-upload").on("click.uploader", function () {
        // redirect the click on the hidden file input
        $("#mobile-uploader").click();
      });
    }

    this._firefoxPastingHack();
  },

  // Believe it or not pasting an image in Firefox doesn't work without this code
  _firefoxPastingHack() {
    const uaMatch = navigator.userAgent.match(/Firefox\/(\d+)\.\d/);
    if (uaMatch) {
      let uaVersion = parseInt(uaMatch[1]);
      if (uaVersion < 24 || 50 <= uaVersion) {
        // The hack is no longer required in FF 50 and later.
        // See: https://bugzilla.mozilla.org/show_bug.cgi?id=906420
        return;
      }
      this.$().append( Ember.$("<div id='contenteditable' contenteditable='true' style='height: 0; width: 0; overflow: hidden'></div>") );
      this.$("textarea").off('keydown.contenteditable');
      this.$("textarea").on('keydown.contenteditable', event => {
        // Catch Ctrl+v / Cmd+v and hijack focus to a contenteditable div. We can't
        // use the onpaste event because for some reason the paste isn't resumed
        // after we switch focus, probably because it is being executed too late.
        if ((event.ctrlKey || event.metaKey) && (event.keyCode === 86)) {
          // Save the current textarea selection.
          const textarea = this.$("textarea")[0];
          const selectionStart = textarea.selectionStart;
          const selectionEnd = textarea.selectionEnd;

          // Focus the contenteditable div.
          const contentEditableDiv = this.$('#contenteditable');
          contentEditableDiv.focus();

          // The paste doesn't finish immediately and we don't have any onpaste
          // event, so wait for 100ms which _should_ be enough time.
          setTimeout(() => {
            const pastedImg  = contentEditableDiv.find('img');

            if ( pastedImg.length === 1 ) {
              pastedImg.remove();
            }

            // For restoring the selection.
            textarea.focus();
            const textareaContent = $(textarea).val(),
                startContent = textareaContent.substring(0, selectionStart),
                endContent = textareaContent.substring(selectionEnd);

            const restoreSelection = function(pastedText) {
              $(textarea).val( startContent + pastedText + endContent );
              textarea.selectionStart = selectionStart + pastedText.length;
              textarea.selectionEnd = textarea.selectionStart;
            };

            if (contentEditableDiv.html().length > 0) {
              // If the image wasn't the only pasted content we just give up and
              // fall back to the original pasted text.
              contentEditableDiv.find("br").replaceWith("\n");
              restoreSelection(contentEditableDiv.text());
            } else {
              // Depending on how the image is pasted in, we may get either a
              // normal URL or a data URI. If we get a data URI we can convert it
              // to a Blob and upload that, but if it is a regular URL that
              // operation is prevented for security purposes. When we get a regular
              // URL let's just create an <img> tag for the image.
              const imageSrc = pastedImg.attr('src');

              if (imageSrc.match(/^data:image/)) {
                // Restore the cursor position, and remove any selected text.
                restoreSelection("");

                // Create a Blob to upload.
                const image = new Image();
                image.onload = () => {
                  // Create a new canvas.
                  const canvas = document.createElementNS('http://www.w3.org/1999/xhtml', 'canvas');
                  canvas.height = image.height;
                  canvas.width = image.width;
                  const ctx = canvas.getContext('2d');
                  ctx.drawImage(image, 0, 0);

                  canvas.toBlob(blob => this.$().fileupload('add', {files: blob}));
                };
                image.src = imageSrc;
              } else {
                restoreSelection("<img src='" + imageSrc + "'>");
              }
            }

            contentEditableDiv.html('');
          }, 100);
        }
      });
    }
  },

  @on('willDestroyElement')
  _unbindUploadTarget() {
    this._validUploads = 0;
    $("#reply-control .mobile-file-upload").off("click.uploader");
    this.messageBus.unsubscribe("/uploads/composer");
    const $uploadTarget = this.$();
    try { $uploadTarget.fileupload("destroy"); }
    catch (e) { /* wasn't initialized yet */ }
    $uploadTarget.off();
  },

  @on('willDestroyElement')
  _composerClosed() {
    this.appEvents.trigger('composer:will-close');
    Ember.run.next(() => {
      $('#main-outlet').css('padding-bottom', 0);
      // need to wait a bit for the "slide down" transition of the composer
      Ember.run.later(() => this.appEvents.trigger("composer:closed"), 400);
    });

    if (this._enableAdvancedEditorPreviewSync()) this._teardownInputPreviewSync();
  },

  actions: {
    importQuote(toolbarEvent) {
      this.sendAction('importQuote', toolbarEvent);
    },

    onExpandPopupMenuOptions(toolbarEvent) {
      const selected = toolbarEvent.selected;
      toolbarEvent.selectText(selected.start, selected.end - selected.start);
      this.sendAction('storeToolbarState', toolbarEvent);
    },

    togglePreview() {
      this.sendAction('togglePreview');
    },

    showUploadModal(toolbarEvent) {
      this.sendAction('showUploadSelector', toolbarEvent);
    },

    extraButtons(toolbar) {
      toolbar.addButton({
        id: 'quote',
        group: 'fontStyles',
        icon: 'comment-o',
        sendAction: 'importQuote',
        title: 'composer.quote_post_title',
        unshift: true
      });

      toolbar.addButton({
        id: 'upload',
        group: 'insertions',
        icon: 'upload',
        title: 'upload',
        sendAction: 'showUploadModal'
      });

      toolbar.addButton({
        id: 'options',
        group: 'extras',
        icon: 'gear',
        title: 'composer.options',
        sendAction: 'onExpandPopupMenuOptions',
        popupMenu: true
      });

      if (this.site.mobileView) {
        toolbar.addButton({
          id: 'preview',
          group: 'mobileExtras',
          icon: 'television',
          title: 'composer.show_preview',
          sendAction: 'togglePreview'
        });
      }
    },

    previewUpdated($preview) {
      // Paint mentions
      const unseenMentions = linkSeenMentions($preview, this.siteSettings);
      if (unseenMentions.length) {
        Ember.run.debounce(this, this._renderUnseenMentions, $preview, unseenMentions, 450);
      }

      this._warnMentionedGroups($preview);
      this._warnCannotSeeMention($preview);

      // Paint category hashtags
      const unseenCategoryHashtags = linkSeenCategoryHashtags($preview);
      if (unseenCategoryHashtags.length) {
        Ember.run.debounce(this, this._renderUnseenCategoryHashtags, $preview, unseenCategoryHashtags, 450);
      }

      // Paint tag hashtags
      if (this.siteSettings.tagging_enabled) {
        const unseenTagHashtags = linkSeenTagHashtags($preview);
        if (unseenTagHashtags.length) {
          Ember.run.debounce(this, this._renderUnseenTagHashtags, $preview, unseenTagHashtags, 450);
        }
      }

      // Paint oneboxes
      const $oneboxes = $('a.onebox', $preview);
      if ($oneboxes.length > 0 && $oneboxes.length <= this.siteSettings.max_oneboxes_per_post) {
        Ember.run.debounce(this, this._loadOneboxes, $oneboxes, 450);
      }

      // Short upload urls need resolution
      resolveAllShortUrls(ajax);

      let inline = {};
      $('a.inline-onebox-loading', $preview).each(function(index, link) {
        let $link = $(link);
        $link.removeClass('inline-onebox-loading');
        let text = $link.text();
        inline[text] = inline[text] || [];
        inline[text].push($link);
      });
      if (Object.keys(inline).length > 0) {
        Ember.run.debounce(this, this._loadInlineOneboxes, inline, 450);
      }

      if (this._enableAdvancedEditorPreviewSync()) {
        this._syncScroll(
          this._syncEditorAndPreviewScroll,
          this.$('.d-editor-input'),
          $preview
        );
      }

      this.trigger('previewRefreshed', $preview);
      this.sendAction('afterRefresh', $preview);
    },
  }
});