class Entry < ApplicationRecord
	
	require 'csv'
	
	belongs_to :user
	
	validates :date, presence: true
	validates :hours, numericality: { only_integer: true, greater_than_or_equal_to: 0 }, unless: -> { start_time.present? && end_time.nil? }
	validates :minutes, numericality: { only_integer: true, greater_than_or_equal_to: 0, less_than: 60 }, unless: -> { start_time.present? && end_time.nil? }
	
	before_save :normalize_time
	
	PRAKTIKUMSTYPEN = %w[propädeutikum fachspezifikum]
	ENTRY_ARTEN     = %w[Praktikum Selbsterfahrung Supervision Fortbildung Semesterkosten]
	
	validates :praktikums_typ, inclusion: { in: PRAKTIKUMSTYPEN }
	validates :entry_art, inclusion: { in: ENTRY_ARTEN }
	validates :distance_km, numericality: { only_integer: true, greater_than_or_equal_to: 0 }
	
	after_initialize :set_default_date, if: :new_record?
	
	def set_default_date
		self.date ||= Date.today
	end
	
	def kilometer_pauschale
		return 0 unless distance_km.present?
		distance_km * 0.42
	end
	
	def self.total_kilometer_cost_by_year(user)
		yearly_distances = where(user: user)
			                   .where.not(distance_km: nil)
			                   .group(Arel.sql("EXTRACT(YEAR FROM date)"))
			                   .order(Arel.sql("EXTRACT(YEAR FROM date) DESC"))
			                   .sum(:distance_km)
		
		yearly_distances.each_with_object({}) do |(year, km_sum), result|
			rate = MileageRate.find_by(year: year.to_i)&.rate_per_km || 0.42
			result[year.to_i] = (km_sum * rate).round(2)
		end
	end
	
	def self.total_fortbildungskosten_by_year(user)
		where(user: user)
			 .where.not(kosten: nil)
			 .where(
				 Entry.arel_table[:entry_art].eq('Fortbildung')
				 .or(Entry.arel_table[:zaehlt_als_fortbildung].eq(true))
			 )
		.group(Arel.sql("DATE_PART('year', date)"))
		.order(Arel.sql("DATE_PART('year', date) DESC"))
		.pluck(Arel.sql("DATE_PART('year', date)::int"), Arel.sql("SUM(kosten)"))
		.to_h
	end
	
	def self.total_selbsterfahrungskosten_by_year(user)
		where(user: user, entry_art: 'Selbsterfahrung')
			.where.not(kosten: nil)
			.group(Arel.sql("DATE_PART('year', date)"))
			.order(Arel.sql("DATE_PART('year', date) DESC"))
			.pluck(Arel.sql("DATE_PART('year', date)::int"), Arel.sql("SUM(kosten)"))
			.to_h
	end
	
	def self.total_selbsterfahrungskosten_by_year(user)
		where(user: user, entry_art: 'Selbsterfahrung')
			.where.not(kosten: nil)
			.group(Arel.sql("DATE_PART('year', date)"))
			.order(Arel.sql("DATE_PART('year', date) DESC"))
			.pluck(Arel.sql("DATE_PART('year', date)::int"), Arel.sql("SUM(kosten)"))
			.to_h
	end
	
	def self.total_supervision_by_year(user)
		where(user: user, entry_art: 'Supervision')
			.where.not(kosten: nil)
			.group(Arel.sql("DATE_PART('year', date)"))
			.order(Arel.sql("DATE_PART('year', date) DESC"))
			.pluck(Arel.sql("DATE_PART('year', date)::int"), Arel.sql("SUM(kosten)"))
			.to_h
	end
	
	def self.total_semesterkosten_by_year(user)
		where(user: user)
			.where.not(kosten: nil)
			.group(Arel.sql("DATE_PART('year', date)"))
			.order(Arel.sql("DATE_PART('year', date) DESC"))
			.pluck(Arel.sql("DATE_PART('year', date)::int"), Arel.sql("SUM(kosten)"))
			.to_h
	end
	
	def jahr
		date.year
	end
	
	def total_minutes
		hours * 60 + minutes
	end
	
	def self.to_csv
		CSV.generate(headers: true, col_sep: ";") do |csv|
			csv << %w[Datum Stunden Minuten Typ Art Kilometer User]
			
			all.each do |entry|
				csv << [
					entry.date,
					entry.hours,
					entry.minutes,
					entry.praktikums_typ,
					entry.entry_art,
					entry.distance_km,
					entry.beschreibung,
					entry.kosten,
					entry.user.email
				]
			end
		end
	end
	

	
	def total_minutes_including_break
		return nil unless start_time && end_time
		minutes = ((end_time - start_time) / 60).to_i
		minutes -= lunch_break_minutes.to_i
		minutes = 0 if minutes < 0
		minutes
	end
	
	def hours_and_minutes
		mins = total_minutes_including_break
		return [0, 0] unless mins
		[mins / 60, mins % 60]
	end
	
	private
	
	def normalize_time
		
		self.minutes ||= 0
		self.hours   ||= 0
		
		self.hours   += minutes / 60
		self.minutes = minutes % 60
	end
end