discourse/lib/post_action_creator.rb

require_dependency 'post_action_result'

class PostActionCreator
  class CreateResult < PostActionResult
    attr_accessor :post_action, :reviewable, :reviewable_score
  end

  # Shortcut methods for easier invocation
  class << self
    def create(created_by, post, action_key, message: nil, created_at: nil)
      new(created_by, post, PostActionType.types[action_key], message: message, created_at: created_at).perform
    end

    [:like, :off_topic, :spam, :inappropriate, :bookmark].each do |action|
      define_method(action) do |created_by, post|
        create(created_by, post, action)
      end
    end
    [:notify_moderators, :notify_user].each do |action|
      define_method(action) do |created_by, post, message = nil|
        create(created_by, post, action, message: message)
      end
    end
  end

  def initialize(
    created_by,
    post,
    post_action_type_id,
    is_warning: false,
    message: nil,
    take_action: false,
    flag_topic: false,
    created_at: nil
  )
    @created_by = created_by
    @created_at = created_at || Time.zone.now

    @post = post
    @post_action_type_id = post_action_type_id
    @post_action_name = PostActionType.types[@post_action_type_id]

    @is_warning = is_warning
    @take_action = take_action && guardian.is_staff?

    @message = message
    @flag_topic = flag_topic
    @meta_post = nil
  end

  def perform
    result = CreateResult.new

    unless guardian.post_can_act?(
      @post,
      @post_action_name,
      opts: {
        is_warning: @is_warning,
        taken_actions: PostAction.counts_for([@post].compact, @created_by)[@post&.id]
      }
    )
      result.forbidden = true
      result.add_error(I18n.t("invalid_access"))
      return result
    end

    PostAction.limit_action!(@created_by, @post, @post_action_type_id)

    # create meta topic / post if needed
    if @message.present? && [:notify_moderators, :notify_user, :spam].include?(@post_action_name)
      creator = create_message_creator
      post = creator.create
      if creator.errors.present?
        result.add_errors_from(creator)
        return result
      end
      @meta_post = post
    end

    begin
      post_action = create_post_action

      if post_action.blank? || post_action.errors.present?
        result.add_errors_from(post_action)
      else
        create_reviewable(result)
        enforce_rules
        UserActionManager.post_action_created(post_action)
        PostActionNotifier.post_action_created(post_action)
        notify_subscribers

        result.success = true
        result.post_action = post_action

      end
    rescue ActiveRecord::RecordNotUnique
      # If the user already performed this action, it's proably due to a different browser tab
      # or non-debounced clicking. We can ignore.
      result.success = true
      result.post_action = PostAction.find_by(
        user: @created_by,
        post: @post,
        post_action_type_id: @post_action_type_id
      )
    end

    result
  end

private

  def notify_subscribers
    if self.class.notify_types.include?(@post_action_name)
      @post.publish_change_to_clients! :acted
    end
  end

  def self.notify_types
    @notify_types ||= ([:like] + PostActionType.notify_flag_types.keys)
  end

  def enforce_rules
    auto_close_if_threshold_reached
    auto_hide_if_needed
    SpamRule::AutoSilence.new(@post.user, @post).perform
  end

  def auto_close_if_threshold_reached
    return if topic.nil? || topic.closed?
    return unless topic.auto_close_threshold_reached?

    # the threshold has been reached, we will close the topic waiting for intervention
    topic.update_status("closed", true, Discourse.system_user,
      message: I18n.t(
        "temporarily_closed_due_to_flags",
        count: SiteSetting.num_hours_to_close_topic
      )
    )

    topic.set_or_create_timer(
      TopicTimer.types[:open],
      SiteSetting.num_hours_to_close_topic,
      by_user: Discourse.system_user
    )
  end

  def auto_hide_if_needed
    return if @post.hidden?
    return if !@created_by.staff? && @post.user&.staff?

    if @post_action_name == :spam &&
      @created_by.has_trust_level?(TrustLevel[3]) &&
      @post.user&.trust_level == TrustLevel[0]
      @post.hide!(@post_action_type_id, Post.hidden_reasons[:flagged_by_tl3_user])
    elsif PostActionType.auto_action_flag_types.include?(@post_action_name)
      if @created_by.has_trust_level?(TrustLevel[4]) &&
        !@created_by.staff? &&
        @post.user&.trust_level != TrustLevel[4]

        @post.hide!(@post_action_type_id, Post.hidden_reasons[:flagged_by_tl4_user])
      elsif SiteSetting.score_required_to_hide_post > 0
        score = ReviewableFlaggedPost.find_by(target: @post)&.score || 0
        if score >= SiteSetting.score_required_to_hide_post
          @post.hide!(@post_action_type_id)
        end
      end
    end
  end

  def create_post_action
    @targets_topic = !!(
      if @flag_topic && @post.topic
        @post.topic.reload.posts_count != 1
      end
    )

    where_attrs = {
      post_id: @post.id,
      user_id: @created_by.id,
      post_action_type_id: @post_action_type_id
    }

    action_attrs = {
      staff_took_action: @take_action,
      related_post_id: @meta_post&.id,
      targets_topic: @targets_topic,
      created_at: @created_at
    }

    # First try to revive a trashed record
    post_action = PostAction.where(where_attrs)
      .with_deleted
      .where("deleted_at IS NOT NULL")
      .first

    if post_action
      post_action.recover!
      action_attrs.each { |attr, val| post_action.send("#{attr}=", val) }
      post_action.save
      PostActionNotifier.post_action_created(post_action)
    else
      post_action = PostAction.create(where_attrs.merge(action_attrs))
      if post_action && post_action.errors.count == 0
        BadgeGranter.queue_badge_grant(Badge::Trigger::PostAction, post_action: post_action)
      end
    end

    if post_action && PostActionType.notify_flag_type_ids.include?(@post_action_type_id)
      DiscourseEvent.trigger(:flag_created, post_action)
    end

    GivenDailyLike.increment_for(@created_by.id) if @post_action_type_id == PostActionType.types[:like]

    # agree with other flags
    if @take_action && reviewable = @post.reviewable_flag
      reviewable.perform(@created_by, :agree_and_keep)
      post_action.try(:update_counters)
    end

    post_action
  rescue ActiveRecord::RecordNotUnique
    # can happen despite being .create
    # since already bookmarked
    PostAction.where(where_attrs).first
  end

  def create_message_creator
    title = I18n.t(
      "post_action_types.#{@post_action_name}.email_title",
      title: @post.topic.title,
      locale: SiteSetting.default_locale
    )

    body = I18n.t(
      "post_action_types.#{@post_action_name}.email_body",
      message: @message,
      link: "#{Discourse.base_url}#{@post.url}",
      locale: SiteSetting.default_locale
    )

    create_args = {
      archetype: Archetype.private_message,
      is_warning: @is_warning,
      title: title.truncate(SiteSetting.max_topic_title_length, separator: /\s/),
      raw: body
    }

    if [:notify_moderators, :spam].include?(@post_action_name)
      create_args[:subtype] = TopicSubtype.notify_moderators
      create_args[:target_group_names] = Group[:moderators].name
    else
      create_args[:subtype] = TopicSubtype.notify_user

      create_args[:target_usernames] =
        if @post_action_name == :notify_user
          @post.user.username
        elsif @post_action_name != :notify_moderators
          # this is a hack to allow a PM with no recipients, we should think through
          # a cleaner technique, a PM with myself is valid for flagging
          'x'
        end
    end

    PostCreator.new(@created_by, create_args)
  end

  def create_reviewable(result)
    return unless PostActionType.notify_flag_type_ids.include?(@post_action_type_id)
    return if @post.user_id.to_i < 0

    result.reviewable = ReviewableFlaggedPost.needs_review!(
      created_by: @created_by,
      target: @post,
      topic: @post.topic,
      reviewable_by_moderator: true,
      potential_spam: @post_action_type_id == PostActionType.types[:spam],
      payload: {
        targets_topic: @targets_topic
      }
    )
    result.reviewable_score = result.reviewable.add_score(
      @created_by,
      @post_action_type_id,
      created_at: @created_at,
      take_action: @take_action,
      meta_topic_id: @meta_post&.topic_id,
    )
  end

  def guardian
    @guardian ||= Guardian.new(@created_by)
  end

  def topic
    @post.topic
  end

end