class CreateWatchVideoService < ApplicationService
  attr_reader :user, :params, :request

  def initialize(user, request, params)
    @user    = user
    @request = request
    @params  = params
  end

  def call
    ActiveRecord::Base.transaction do
      current_time = Time.now
      if params[:log_id].present?
        if params[:total_duration].to_f < params[:watch_duration].to_f || params[:watch_duration].to_f < 0
          raise Error, '观看时长错误'
        end
        # 更新观看时长
        watch_video_history = user.watch_video_histories.find(params[:log_id])

        if watch_video_history.present? && watch_video_history.watch_duration <= params[:watch_duration].to_f && params[:total_duration].to_f > watch_video_history.total_duration
         # 如果观看总时长没变，说明视频没有播放，无需再去记录

          watch_video_history.end_at = current_time
          watch_video_history.total_duration = params[:total_duration]
          watch_video_history.watch_duration = params[:watch_duration].to_f > watch_video_history.duration ? watch_video_history.duration : params[:watch_duration]
          watch_video_history.is_finished = (watch_video_history.duration <= params[:watch_duration].to_f)
          watch_video_history.save!

          watch_course_video = watch_video_history.watch_course_video

          if watch_course_video.present? && !watch_course_video.is_finished && watch_course_video.watch_duration < params[:watch_duration].to_f
            # 更新课程视频的时长及是否看完状态
            watch_course_video.watch_duration = params[:watch_duration]
            watch_course_video.is_finished = (watch_course_video.duration <= params[:watch_duration].to_f)
            watch_course_video.end_at = current_time
            watch_course_video.save!
          end
        end
      else
        # 开始播放时记录一次
        if params[:course_id].present?
          # 课堂视频
          course_video = CourseVideo.find_by(course_id: params[:course_id], video_id: params[:video_id])
          watch_course_video = WatchCourseVideo.find_or_initialize_by(course_video_id: course_video.id, user_id: user.id) do |d|
            d.start_at = current_time
            d.duration = params[:duration]
          end
          
          watch_video_history = build_video_log(current_time, course_video.video_id, watch_course_video.id)
          watch_video_history.save!

          watch_course_video.save! unless watch_course_video.persisted?
        else
          # 非课堂视频
          video = Video.find_by(params[:video_id])
          watch_video_history = build_video_log(current_time, video.id)
          watch_video_history.save!
        end
      end
      watch_video_history
    end
  end


  def build_video_log(current_time, video_id, watch_course_video_id=nil)
    WatchVideoHistory.new(
      user_id: user.id,
      watch_course_video_id: watch_course_video_id,
      start_at: current_time,
      duration: params[:duration],
      video_id: video_id,
      device: params[:device],
      ip: request.remote_ip
    )
  end
end