workingTime

time.php

<?php
class workingTime {

    public $start = 9;
    public $end = 17; // 17:XX so also 17:59
    public $freeWeekDays = array(0 => true,
                                 6 => true); // week 0-6; true = free;
    public $freeYearDays = []; // year 0-365; true = free;

    public function __construct(array $config = []){
        foreach($config as $setting => $value){
            $this->$setting = $value;
        }
    }

    public function isItWorkingTime($time){

        if($this->isItWorkingHour($time) && $this->isItWorkingDay($time)){
            return true;
        } else {
            return false;
        }

    }

    public function isItWorkingHour($time){

        $hour = date('G', $time); // 0-23 format

        if($hour >= $this->start && $hour <= $this->end){
            return true;
        } else {
            return false;
        }

    }

    public function isItWorkingDay($time){

        $weekDay = date('w', $time); // 0-6 format
        $yearDay = date('z', $time); // 0-365 format

        $isItFreeWeekDay = isset($this->freeWeekDays[$weekDay]) && $this->freeWeekDays[$weekDay];
        $isItFreeYearDay = isset($this->freeYearDays[$yearDay]) && $this->freeYearDays[$yearDay];

        return !$isItFreeWeekDay && !$isItFreeYearDay;

    }

    public function nextWorkingDay($time){
        $tomorrow = strtotime('tomorrow '.$this->start.' hour', $time);
        if($this->isItWorkingDay($tomorrow)){
            return $tomorrow;
        } else{
            $nextMonday = strtotime('next monday '.$this->start.' hour', $time);
            return $nextMonday;
        }
    }

}

class pretendWorking {

    protected $workingTime;

    public function __construct(workingTime $workingTime){
        $this -> workingTime = $workingTime;
    }

    public function whenToSend($whenRecived){

        $howLongPretend = $this->howLongPretend();
        $whenToSend = $whenRecived + $howLongPretend;

        if($this->workingTime->isItWorkingTime($whenRecived)){
            if($this->workingTime->isItWorkingTime($whenToSend)){
                return $whenToSend;
            } else {
                $howLongPretended = strtotime('today '.($this->workingTime->end+1).' hour', $whenRecived) - $whenRecived;
                return $this->workingTime->nextWorkingDay($whenRecived) + $howLongPretend - $howLongPretended;
            }
        } else {
            return $this->workingTime->nextWorkingDay($whenRecived) + $howLongPretend;
        }
    }

    // 4 h of pretending of working + 0-60 min random
    protected function howLongPretend(){
        return 4*60*60 + rand(0, 60)*rand(0, 60);
    }
}

//$now = time();
$now = 1403880535;
echo 'It is: '.date(DATE_COOKIE, $now).'<br>';
$workingTime = new workingTime();
$pretendWorking = new pretendWorking($workingTime);
$whenToSend = $pretendWorking->whenToSend($now);
echo 'You should send this on: '.date(DATE_COOKIE, $whenToSend);