class PostsController < ApplicationController
  before_action :authenticate_user!, only: [:create, :update]

  def index
    posts = Post
      .select(
        :id,
        :title,
        :description,
        :post_status_id,
        'COUNT(DISTINCT likes.id) AS likes_count',
        'COUNT(DISTINCT comments.id) AS comments_count',
        '((LOG(COUNT(DISTINCT likes.id) + 1) + LOG(COUNT(DISTINCT comments.id) + 1)) + (EXTRACT(EPOCH FROM posts.created_at) / 45000)) AS hotness',
        "(SELECT COUNT(*) AS liked FROM likes WHERE likes.user_id=#{current_user ? current_user.id : -1} AND likes.post_id=posts.id)"
      )
      .left_outer_joins(:likes)
      .left_outer_joins(:comments)
      .group('posts.id')
      .where(filter_params)
      .search_by_name_or_description(params[:search])
      .order('hotness DESC')
      .page(params[:page])
    
    render json: posts
  end

  def create
    post = Post.new(post_params)

    if post.save
      Follow.create(post_id: post.id, user_id: current_user.id)
      
      render json: post, status: :created
    else
      render json: {
        error: post.errors.full_messages
      }, status: :unprocessable_entity
    end
  end

  def show
    @post = Post.find(params[:id])
    @post_statuses = PostStatus.select(:id, :name, :color).order(order: :asc)
    @board = @post.board

    respond_to do |format|
      format.html

      format.json { render json: @post }
    end
  end

  def update
    post = Post.find(params[:id])
    
    if !current_user.power_user? && current_user.id != post.user_id
      render json: t('backend.errors.unauthorized'), status: :unauthorized
      return
    end

    post.board_id = params[:post][:board_id] if params[:post].has_key?(:board_id)
    
    post_status_changed = false
    
    if params[:post].has_key?(:post_status_id) and
       params[:post][:post_status_id] != post.post_status_id
      
      post_status_changed = true
      post.post_status_id = params[:post][:post_status_id]
    end

    if post.save
      if post_status_changed
        PostStatusChange.create(
          user_id: current_user.id,
          post_id: post.id,
          post_status_id: post.post_status_id
        )

        send_notifications(post)
      end

      render json: post, status: :no_content
    else
      render json: {
        error: post.errors.full_messages
      }, status: :unprocessable_entity
    end
  end

  private
  
    def filter_params
      defaults = { board_id: Board.first.id }

      params
        .permit(:board_id, :post_status_id, :page, :search)
        .with_defaults(defaults)
        .except(:page, :search)
    end
    
    def post_params
      params
        .require(:post)
        .permit(:title, :description, :board_id)
        .merge(user_id: current_user.id)
    end

    def send_notifications(post)
      UserMailer.notify_followers_of_post_status_change(post: post).deliver_later
    end
end