app/services/post_service.rb
# frozen_string_literal: true

class PostService
  def initialize(user=nil)
    @user = user
  end

  def find(id)
    if user
      user.find_visible_shareable_by_id(Post, id)
    else
      Post.find_by_id_and_public(id, true)
    end
  end

  def find!(id_or_guid)
    if user
      find_non_public_by_guid_or_id_with_user!(id_or_guid)
    else
      find_public!(id_or_guid)
    end
  end

  def present_json
    PostPresenter.new(post, user)
  end

  def present_interactions_json
    PostInteractionPresenter.new(post, user)
  end

  def mark_user_notifications(post_id)
    return unless user
    mark_comment_reshare_like_notifications_read(post_id)
    mark_mention_notifications_read(post_id)
    mark_like_on_comment_notifications_read(post_id)
  end

  def destroy(post_id, private_allowed=true)
    post = if private_allowed
             find_non_public_by_guid_or_id_with_user!(post_id)
           else
             find_public!(post_id)
           end
    raise Diaspora::NotMine unless post.author == user.person

    user.retract(post)
  end

  def mentionable_in_comment(post_id, query)
    post = find!(post_id)
    Person
      .allowed_to_be_mentioned_in_a_comment_to(post)
      .where.not(id: user.person_id)
      .find_by_substring(query)
      .sort_for_mention_suggestion(post, user)
      .for_json
      .limit(15)
  end

  private

  attr_reader :user

  def find_public!(id_or_guid)
    Post.where(post_key(id_or_guid) => id_or_guid).first.tap do |post|
      raise ActiveRecord::RecordNotFound, "could not find a post with id #{id_or_guid}" unless post
      raise Diaspora::NonPublic unless post.public?
    end
  end

  def find_non_public_by_guid_or_id_with_user!(id_or_guid)
    user.find_visible_shareable_by_id(Post, id_or_guid, key: post_key(id_or_guid)).tap do |post|
      raise ActiveRecord::RecordNotFound, "could not find a post with id #{id_or_guid} for user #{user.id}" unless post
    end
  end

  # We can assume a guid is at least 16 characters long as we have guids set to hex(8) since we started using them.
  def post_key(id_or_guid)
    id_or_guid.to_s.length < 16 ? :id : :guid
  end

  def mark_comment_reshare_like_notifications_read(post_id)
    Notification.where(recipient_id: user.id, target_type: "Post", target_id: post_id, unread: true)
      .update_all(unread: false)
  end

  def mark_mention_notifications_read(post_id)
    mention_ids = Mention.where(
      mentions_container_id:   post_id,
      mentions_container_type: "Post",
      person_id:               user.person_id
    ).ids
    mention_ids.concat(mentions_in_comments_for_post(post_id).pluck(:id))

    Notification.where(recipient_id: user.id, target_type: "Mention", target_id: mention_ids, unread: true)
                .update_all(unread: false) if mention_ids.any?
  end

  def mentions_in_comments_for_post(post_id)
    Mention
      .joins("INNER JOIN comments ON mentions_container_id = comments.id AND mentions_container_type = 'Comment'")
      .where(comments: {commentable_id: post_id, commentable_type: "Post"})
  end

  def mark_like_on_comment_notifications_read(post_id)
    Notification.where(recipient_id: user.id, target_type: "Comment",
                       target_id: Comment.where(commentable_id: post_id, author_id: user.person.id),
                       unread: true).update_all(unread: false) # rubocop:disable Rails/SkipsModelValidations
  end
end
