calendar.php

<?php

class Calendar
{
    protected $date;
    
    public $timezone    = 'America/New_York';
    public $yearFormat  = 'Y';
    public $monthFormat = 'n';
    public $dayFormat   = 'd';
    
    public function __construct ($date)
    {
        $this->setTimezone($this->timezone);
        $this->setDate($date);
    }
    
    public function setTimezone($timezone)
    {
        date_default_timezone_set($timezone);
    }
    
    public function getDate($format = null)
    {
        if ($format === null) {
            return $this->date;
        }
        else {
            return date($format, $this->date);
        }
    }

    public function setDate($date)
    {
        $this->date = strtotime($date);
    }
    
    public function getYear($format = 'Y')
    {
        return $this->getDate($this->yearFormat);
    }
    
    public function setYear($year)
    {
        $this->setDate(sprintf(
            '%s-%s-%s',
            (int) $year, $this->getMonth(), $this->getDay()
        ));
    }
    
    public function getMonth()
    {
        return $this->getDate($this->monthFormat);
    }
    
    public function setMonth($month)
    {
        $this->setDate(sprintf(
            '%s-%s-%s',
            $this->getYear(), (int) $month, $this->getDay()
        ));
    }
    
    public function getDay()
    {
        return $this->getDate($this->dayFormat);
    }
    
    public function setDay($day)
    {
        $this->setDate(sprintf(
            '%s-%s-%s',
            $this->getYear(), $this->getMonth(), (int) $day
        ));
    }
    
    public function getCalendar()
    {
        $out    = array();
        $month  = $this->getMonth();
        $year   = $this->getYear();
        $count  = self::countDaysInMonth($month, $year);
        $offset = self::monthStartOffset($month, $year);
        $wom    = 1;
        $dow    = 1;
        
        for ($i = 1; $i <= $count + $offset; $i++) {
            $day = $i - $offset;
            
            if ($dow > 7) {
                $wom += 1;
                $dow = 1;
            }
            
            if (empty($out[$wom])) {
                $out[$wom] = array();
            }
            
            $out[$wom][$dow] = $day;
            $dow++;
        }
        
        return $out;
    }
    
    public static function countDaysInMonth($month, $year)
    {
        // Fixme: This is awful.
        return $month == 2 ? ($year % 4 ? 28 : ($year % 100 ? 29 : ($year % 400 ? 28 : 29))) : (($month - 1) % 7 % 2 ? 30 : 31);
    }
    
    public static function monthStartOffset($month, $year)
    {
        return (int) date('w', mktime(0, 0, 0, $month, 1, $year));
    }
}