# frozen_string_literal: true

#-- copyright
# OpenProject is an open source project management software.
# Copyright (C) the OpenProject GmbH
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License version 3.
#
# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
# Copyright (C) 2006-2013 Jean-Philippe Lang
# Copyright (C) 2010-2013 the ChiliProject Team
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
# See COPYRIGHT and LICENSE files for more details.
#++

class Day < ApplicationRecord
  include Tableless

  has_many :non_working_days,
           inverse_of: false,
           class_name: "NonWorkingDay",
           foreign_key: :date,
           primary_key: :date,
           dependent: nil

  attribute :date, :date, default: nil
  attribute :day_of_week, :integer, default: nil
  attribute :working, :boolean, default: "t"

  delegate :name, to: :week_day, allow_nil: true

  scope :working, -> { where(working: true) }

  class << self
    def default_scope
      today = Time.zone.today
      from = today.at_beginning_of_month
      to = today.next_month.at_end_of_month
      from_range(from:, to:)
        .includes(:non_working_days)
        .order("days.id")
    end

    def from_range(from:, to:)
      from(Arel.sql(from_sql(from:, to:)))
    end

    def from_sql(from:, to:)
      from = from.to_date
      to = to.to_date
      <<~SQL.squish
        (
          SELECT
            to_char(dd, 'YYYYMMDD')::integer id,
            date_trunc('day', dd)::date date,
            extract(isodow from dd) day_of_week,
            (
              COALESCE(
                POSITION(
                  extract(isodow from dd)::text IN settings.value
                ) > 0,
                TRUE
              )
              AND
              non_working_days.id IS NULL
            )::bool working
          FROM
            generate_series(
              '#{from}'::timestamp,
              '#{to}'::timestamp,
              '1 day'::interval
            ) dd
          LEFT JOIN settings
            ON settings.name = 'working_days'
          LEFT JOIN non_working_days
            ON dd = non_working_days.date
        ) days
      SQL
    end

    def last_working
      # Look up only from 8 days ago, because the Setting.working_days must have at least 1 working weekday.
      from_range(from: 8.days.ago, to: Time.zone.yesterday).where(working: true).last
    end

    def next_working(from: Time.zone.today)
      # Look up only the next 8 days, because the Setting.working_days must have at least 1 working weekday.
      # Exclude the current day
      from_range(from: from + 1.day, to: from + 9.days).where(working: true).first
    end
  end

  def week_day
    WeekDay.new(day: day_of_week)
  end
end