PHP Dates Helper Class

php_date_helper_class.php

<?php


namespace App\Onstream;


class DateHelper
{
    public static function GetDaysRemaining($date_from,$date_to): float
    {
        $dt_to_future = strtotime($date_to);
        $dt_from_src = strtotime($date_from);
        $time_remain = $dt_to_future - $dt_from_src;
        $days_remain = round((($time_remain/24)/60)/60);

        return $days_remain;
    }

    public static function GetQuarterStartEndDates($the_date,$year,$dt_fmt = 'F'): array
    {
        $quarters = array(
            "q1"=>array("01-01","03-31"),
            "q2"=>array("04-01","06-30"),
            "q3"=>array("07-01","09-30"),
            "q4" => array("10-01","12-31")
        );

        $dates = [];

        foreach ($quarters as $key=>$dt){
            $start_date = $year.'-'.$dt[0];
            $end_date = $year.'-'.$dt[1];

            if(self::DateWithinRange($start_date,$end_date,$the_date)){
                //return full text representation of the month eg. April
                $dates = array(
                    'start_month'=>date($dt_fmt, strtotime($start_date)),
                    'end_month'=>date($dt_fmt, strtotime($end_date)),
                    'quarter'=>$key
                );
                break;
            }
        }

        return $dates;
    }

    public static function DateWithinRangeByNumberOfDays($date_to_start_from, $date_range_start, $date_range_end, $days): bool
    {
        $prefix = ($days < 0 ) ? '-' : '+';
        $date = strtotime($prefix.$days." day", $date_to_start_from);
        $selected_date = date('Y-m-d', $date);

        return self::DateWithinRange($date_range_start,$date_range_end, $selected_date);
    }

    public static function DateWithinRange($start_date, $end_date, $selected_date): bool
    {
        $start_ts = strtotime($start_date);
        $end_ts = strtotime($end_date);
        $selected_ts = strtotime($selected_date);

        return (($selected_ts >= $start_ts) && ($selected_ts <= $end_ts));
    }

    public static function GetTimespanDateSet($selected_month, $selected_year): array
    {
        //['start_date'], ['end_date'], ['start_date_six_months_ago'];
        $numMonths = 0;
        $dt['start_date'] = self::GetFirstDayOfXMonths($selected_month, $numMonths, $selected_year);
        $dt['end_date'] = self::GetLastDayOfXMonths($selected_month, $numMonths, $selected_year);
        $dt['start_date_six_months_ago'] = self::GetFirstDayOfXMonths($selected_month, -6, $selected_year);

        return $dt;
    }

    public static function GetFirstDayOfXMonths(string $selected_month, $offset = 0, $year = 'this year'):string
    {
        $offset = ($offset >= 0) ? '+'.$offset : $offset;
        return date('Y-m-d', strtotime('first day of '.$selected_month.' '.$year.$offset.' months'));
    }

    public static function GetLastDayOfXMonths(string $selected_month, $offset = 0, $year = 'this year'):string
    {
        //past or future months
        $offset = ($offset >= 0) ? '+'.$offset : $offset;
        return date('Y-m-d', strtotime('last day of '.$selected_month.' '.$year.$offset.' months'));
    }

    public static function FirstDayOfYear($year_offset=0, $fmt='Y-m-d')
    {
        $yr =  date('Y') + $year_offset;
        return date($fmt, strtotime('first day of january ' . $yr));
    }

    public static function LastDayOfYear($year_offset=0, $fmt='Y-m-d')
    {
        $yr =  date('Y') + $year_offset;
        return date($fmt, strtotime('last day of december ' . $yr));
    }

    public static function TodaysDate($fmt='Y-m-d', $year_offset=0, $month_offset=0, $day_offset=0)
    {
        return date($fmt, strtotime('now '.$year_offset.' year ' . $month_offset . ' month ' . $day_offset . ' day'));
    }

    public static $MonthsFullString = array(
        0=>'december',
        1=>'january',
        2=>'february',
        3=>'march',
        4=>'april',
        5=>'may',
        6=>'june',
        7=>'july',
        8=>'august',
        9=>'september',
        10=>'october',
        11=>'november',
        12=>'december'
    );

    public static function GetAdvancedDateSet($month, $year): array
    {
        $dates_set['curr_month']['start_date'] = DateHelper::GetFirstDayOfXMonths($month, 0, $year);
        $dates_set['curr_month']['end_date'] = DateHelper::GetLastDayOfXMonths($month, 0, $year);
        $dates_set['curr_month']['start_date_six_months_ago'] = DateHelper::GetFirstDayOfXMonths($month, -6, $year);

        $dates_set['prev_month']['start_date'] = DateHelper::GetFirstDayOfXMonths($month, -1, $year);
        $dates_set['prev_month']['end_date'] = DateHelper::GetLastDayOfXMonths($month, -1, $year);
        $dates_set['prev_month']['start_date_six_months_ago'] = DateHelper::GetFirstDayOfXMonths($month, -6, $year);

        $dates_set['last_year']['start_date'] = DateHelper::GetFirstDayOfXMonths($month, 0, $year - 1);
        $dates_set['last_year']['end_date'] = DateHelper::GetLastDayOfXMonths($month, 0, $year - 1);
        $dates_set['last_year']['start_date_six_months_ago'] = DateHelper::GetFirstDayOfXMonths($month, -6, $year - 1);

        return $dates_set;
    }

}