<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);

$now = date('d.n.Y H:i:s');

$startWork = 9;
$endWork = 18;

$weekend = [6,7];

$holidays = [date('01.01.2017'), date('23.02.2017')];

$countTasks = 2;

$hoursForTasks = [9, 1];

$priority = [10, 20];

$deadLines = [];


class TaskManager{
    private static $tasks = [];

    public static $datetime;
    public static $holidays = [];
    public static $startWork = 0;
    public static $endWork = 0;

    public $hours = 0;
    public $priority = 0;
    public $deadline;

    public static function init($params){
        self::$datetime = new DateTime(date('23.12.2016 12:15:00'));

        if(isset($params['start']) && !empty($params['start']))
            self::$startWork = $params['start'];

        if(isset($params['end']) && !empty($params['end']))
            self::$endWork = $params['end'];

    }

    function __construct($params){
        if(isset($params['hours']) && !empty($params['hours']))
            $this->hours = $params['hours'];

        if(isset($params['priority']) && !empty($params['priority']))
            $this->priority = $params['priority'];

        $this->deadline = self::$datetime;
        self::$tasks[] = $this;
    }

    /**
     * Сортировка по приоритету
     */
    public static function sort(&$tasksArr){
        function cmp($a, $b)
        {
            if ($a == $b) {
                return 0;
            }
            return ($a->priority > $b->priority) ? -1 : 1;
        }

        usort($tasksArr, "cmp");
    }

    public static function calcDeadLines($tasks){

    }

    public static function isWork($time){
        if($time >= self::$startWork && $time < self::$endWork)
            return true;
        else
            return false;
    }

    public static function isHoliday($date){
        return (boolean)in_array($date, self::$holidays);
    }

    public static function showDeadLines(){
        echo '<pre>';
        print_r(self::$tasks);
        echo '</pre>';
    }

    public static function count(){
        return count(self::$tasks);
    }
}


TaskManager::init([
    'start' => 9,
    'end'   => 18
]);

$tasks[] = new TaskManager([
    'hours'     => 9,
    'priority'  => 10
]);

$tasks[] = new TaskManager([
    'hours'     => 1,
    'priority'  => 20
]);

echo '<pre>';
print_r($tasks);
echo '</pre>';

TaskManager::sort($tasks); // Сортировка по приоритету
echo '<pre>';
print_r($tasks);
echo '</pre>';
$count = count($tasks);
for($i = 0; $i < $count; $i++){
    echo '<pre>';
    print_r('task');
    echo '</pre>';
    $task = &$tasks[$i];
    $task->deadline = TaskManager::$datetime;

    for($j = 0; $j < $task->hours; $j++){
        $time = TaskManager::$datetime->format('H');
        $date = TaskManager::$datetime->format('d.m.Y');
        echo 'time';
        echo '<pre>';
        print_r($time);
        echo '</pre>';

        if(TaskManager::isWork($time)){
            if(TaskManager::isHoliday($date))
                TaskManager::$datetime = new DateTime($date . '+ 1day');
            else
                TaskManager::$datetime->add(new DateInterval('PT1H'));

            echo '<pre>';
            print_r(TaskManager::$datetime);
            echo '</pre>';
        }else{
            TaskManager::$datetime = new DateTime($date . '+ 1day');
            TaskManager::$datetime->setTime(TaskManager::$startWork, 0,0);
        }
        echo '-------------------';
        echo '<pre>';
        print_r($tasks);
        echo '</pre>';
        echo '-------------------';
    }
    echo '<pre>';
    print_r('set deadline');
    echo '</pre>';
    echo '<pre>';
    print_r(TaskManager::$datetime);
    echo '</pre>';
    $task->deadline = TaskManager::$datetime;
    echo '<pre>';
    print_r($task);
    echo '</pre>';
    //$tasks[$i] = $task;
}

echo '<pre>';
print_r('tasks');
echo '</pre>';
echo '<pre>';
print_r($tasks);
echo '</pre>';

//TaskManager::showDeadLines();