# frozen_string_literal: true

class RequestForComment < ApplicationRecord
  include Creation
  include ActionCableHelper

  # SOLVED:      The author explicitly marked the RfC as solved.
  # SOFT_SOLVED: The author did not mark the RfC as solved but reached the maximum score in the corresponding exercise at any time.
  # ONGOING:     The author did not mark the RfC as solved and did not reach the maximum score in the corresponding exercise yet.
  STATE = [SOLVED = :solved, SOFT_SOLVED = :soft_solved, ONGOING = :unsolved].freeze

  belongs_to :submission
  belongs_to :exercise
  belongs_to :file, class_name: 'CodeOcean::File'

  has_many :comments, through: :submission
  has_many :subscriptions, dependent: :destroy

  scope :unsolved, -> { where(solved: [false, nil]) }
  scope :in_range, ->(from, to) { where(created_at: from..to) }
  scope :with_comments, -> { select { |rfc| rfc.comments.any? } }

  # after_save :trigger_rfc_action_cable

  # not used right now, finds the last submission for the respective user and exercise.
  # might be helpful to check whether the exercise has been solved in the meantime.
  def last_submission
    Submission.find_by_sql(" select * from submissions
            where exercise_id = #{exercise_id} AND
            user_id =  #{user_id}
            order by created_at desc
            limit 1").first
  end

  # not used any longer, since we directly saved the submission_id now.
  # Was used before that to determine the submission belonging to the request_for_comment.
  def last_submission_before_creation
    Submission.find_by_sql(" select * from submissions
            where exercise_id = #{exercise_id} AND
            user_id =  #{user_id} AND
            '#{created_at.localtime}' > created_at
            order by created_at desc
            limit 1").first
  end

  def comments_count
    submission.files.map { |file| file.comments.size }.sum
  end

  def commenters
    comments.map(&:user).uniq
  end

  def comments?
    comments.any?
  end

  def to_s
    "RFC-#{id}"
  end

  def current_state
    state(solved, full_score_reached)
  end

  def old_state
    state(solved_before_last_save, full_score_reached_before_last_save)
  end

  private

  def state(solved, full_score_reached)
    if solved
      SOLVED
    elsif full_score_reached
      SOFT_SOLVED
    else
      ONGOING
    end
  end

  class << self
    def with_last_activity
      joins('join "submissions" s on s.id = request_for_comments.submission_id
                left outer join "files" f on f.context_id = s.id
                left outer join "comments" c on c.file_id = f.id')
        .group('request_for_comments.id')
        .select('request_for_comments.*, max(c.updated_at) as last_comment')
    end

    def last_per_user(count = 5)
      from("(#{row_number_user_sql}) as request_for_comments")
        .where('row_number <= ?', count)
        .group('request_for_comments.id, request_for_comments.user_id, request_for_comments.user_type,
                  request_for_comments.exercise_id, request_for_comments.file_id, request_for_comments.question,
                request_for_comments.created_at, request_for_comments.updated_at, request_for_comments.solved,
                request_for_comments.full_score_reached, request_for_comments.submission_id, request_for_comments.row_number')
      # ugly, but necessary
    end

    private

    def row_number_user_sql
      select('id, user_id, user_type, exercise_id, file_id, question, created_at, updated_at, solved, full_score_reached, submission_id, row_number() OVER (PARTITION BY user_id, user_type ORDER BY created_at DESC) as row_number').to_sql
    end
  end
end