package main

import (
	"encoding/binary"
	"regexp"
	"time"
)

func Int32toByteArray(i int32) (arr [4]byte) {
	binary.BigEndian.PutUint32(arr[0:4], uint32(i))
	return
}

func Int64toByteArray(i int64) (arr [8]byte) {
	binary.BigEndian.PutUint64(arr[0:8], uint64(i))
	return
}

// Find all the words in a string
// return [][2]int of index,length
func find_words(text string) [][]int {
	word, _ := regexp.Compile("([A-Za-z]+)")
	return word.FindAllStringIndex(text, -1)
}

// int version of Abs
func Abs(x int) int {
	if x < 0 {
		return -x
	}
	return x
}

// Adjust date to 2:00 AM
func NormalizeDate(date *time.Time) {
	offset := time.Duration(date.Second())*time.Second +
		time.Duration(date.Minute())*time.Minute +
		time.Duration(date.Hour()-2)*time.Hour +
		time.Duration(date.Nanosecond())*time.Nanosecond
	*date = date.Add(-offset)
}

// Find the 1st of the Month (Normalized) 2:00 AM
func FirstOfMonthDate(date *time.Time) {
	if date.Day() != 1 {
		*date = date.AddDate(0, 0, 1-date.Day())
	}
	NormalizeDate(date)
}

// Find 1st of the Month (Normalize) Unix
func FirstOfMonthDateUnix(dateUnix *int64) {
	var date time.Time = time.Unix(*dateUnix, 0)
	FirstOfMonthDate(&date)
	*dateUnix = date.Unix()
}

// See:
// https://yourbasic.org/golang/format-parse-string-time-date-example/
// for all your time.Time.Format needs.

func FormatDate(dateUnix int64, format string) string {
	var date time.Time = time.Unix(dateUnix, 0)
	return date.Format(format)
}

func CurrentMonth(date time.Time) string {
	return date.Format("January")
}