// ------------------------------------------------------------------------
//   Project atila
//   Active Thing (activething.com) git.activething.com/go
//
//   File name  gogo.go
//   Created by DEV
//   Modified   21/02/2024
//
//   Copyright 2024 activething.com 
// ------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------

package times

import "errs"

const(

	secondsDay =  24 * 60 * 60

)


var (

	G = struct {

		ErrInvalidDateRange 	Err
	}{

		ErrInvalidDateRange 	: Err{ errs.ErrCode ("invalid-date-range")},
	}

)




func IsYearLeap (year int) bool {
	return year%4 == 0 && (year%100 != 0 || year%400 == 0) }


func DaysInYear (year int) int  {
	if IsYearLeap(year) {
		return 366 }
	return 365
}


func DaysIn     (year, month int) int {
	if month <= 0 || month > 12 {
		return 0 }
	d := [12]int{ 31,28,31,30,31,30,31,30,31,30,31 }
	if month == 2 && IsYearLeap(year) {
		return 29 }
	return d[month]
}


func DayOfWeek (year, month, day int) int {
	if month < 3 {
		month += 12
		year--
	}
	J := year / 100
	K := year % 100
	h := (day + (13*(month+1))/5 + K + K/4 + J/4 + 5*J) % 7
	if h <= 1 {
		return h+6
	}
	return h-1
}