<?php
/* *************************************************************************** *
file :          calendar.php
description :   Calendar of day actions
date :          2009-01-01
author :        Jiri Urbasek
version :       0.1

* *************************************************************************** */

date_default_timezone_set("Europe/Prague");

/**
 * Represents action in month
 */
class Action
{
    /** Title of action */
    public $title;
    
    /** date of action */
    public $date;

    /** short description of action */
    public $description;

    /** user who created (or last modified) this action */
    public $author;

    /**
     * Creates new instance of Action
     * @param   $title  title of action
     * @param   $date   date of action
     * @param   $author author who owned this action
     * @param   $description (optional) description of this action 
     */
    public function __construct($title, $date, $author, $description = '')
    {
        $this->title    = $title;
        $this->date     = $date;
        $this->author   = $author;
        $this->description = $description;
    }
}

/**
 * Calendar exception
 */
class CalendarException extends Exception
{}

/**
 * Wrong month
 */ 
class NoSuchMonthException extends CalendarException
{
    public function __construct($message)
    {
        parrent::__construct($message);
    }

    public function __toString() {
        return __CLASS__ . ": [{$this->code}]: {$this->message}\n";
    }
}

/**
 * Wrong day in month
 */
class NoSuchDayException extends CalendarException
{
    public function __construct($message)
    {
        parent::__construct($message);
    }

    public function __toString() {
        return __CLASS__ . ": [{$this->code}]: {$this->message}\n";
    }
}

/**
 * Represents each day of month
 */
class Day
{
    /** number of day in calendar */
    public $number;

    /** day date in database date format */
    public $date;

    /** is action today? */
    public $isAction = false;

    /** an action held this day */
    public $action = null;

    /**
     * creates new instance of Day
     * @param   $number number of day in month
     * @param   $action Action which is held this day
     * @throw   NoSuchDayException when bad $number specified
     */
    public function __construct($number, $date, Action $action = null)
    {
        //if ($number <= 0 || $number > 31)
        //    throw new NoSuchDayException("Bad day number: '$number'!");

        $this->number   = $number;
        $this->date     = $date;

        if (isset($action) && $action != null) {
            $this->isAction = true;
            $this->action   = $action;
        }
    }

    /**
     * Tels if this day is some action set or not
     * @return  true if this day is some action, false if not
     */
    public function isAction()
    {
        return $this->isAction;
    }
}

/**
 * IView shows data to user
 */
interface IView
{
    function show();
}


/**
 * Handles main component logic. Is able to get or modify data from DB
 */
interface IModel
{
    function getDays();              //returns Day[]

    function setDay(Action $a);
    
    function getMonth();              //returns int

    function setMonth($month);

    function getYear();              //returns int

    function setYear($year);
}

/* ============================= Controler ================================== */
/**
 * Controls interaction between Modes and View
 */
class Controler
{
    /** instance of IModel to be controled */
    private /*final*/ $model;

    /** instance of IView to be controled */
    private /*final*/ $view;

    /* instance of IDatabase handling database acces */
    //private IDatabase $db;        //not here, but in Model (probably...)

    /**
     * creates new instance of Controler
     * @param   $model  instance of IModel, which operates raw data
     * @param   $view   instance if IView, which shows data
     */
    public function __construct(IModel $model, IView $view/*, IDatabase $db*/)
    {
        $this->model    = $model;
        $this->view     = $view;
        //$this->view     = new CalViewer($model);
        //$this->db       = $db;
    }

    /**
     * When calendar location changed (it means month and year is changed)
     * need to get new data, and reshow calendar
     * @param   $month  current month
     * @param   $year   current year
     */
    public function calLocationChanged($month, $year)
    {
        // year can be very big number and also very small or negative number
        // if not alow this, 
        if ($month <= 0 || $month > 12)
            throw new NoSuchMonthException("No such mont can exists '$month'!");

        $this->model->setMonth($month);
        $this->model->setYear($year);
        $this->view->show();
    }
}

/* ================================ View ==================================== */
define('N',     "\n");          //new line
define('NL',    "<br />".N);    //"GUI" new line
define('T',     "    ");        //tabulator

/**
 * Viewer
 */
class CalViewer implements IView
{
    /** instance of IModel to be shown */
    private /*final*/ $model;

    /** language used for localization texts */
    private $lang = 'cs_CZ';

    /** localization of calendar months */
    private $i18n_months = array(
            'cs_CZ' => array(
                1 => 'Leden', 'Únor', 'Březen', 'Duben',
                'Květen','Červen', 'Červenec', 'Srpen', 'Září', 'Říjen',
                'Listopad','Prosinec')
            );

    /** localization of calendar days */
    private $i18n_days = array(
            'cs_CZ' => array(
                'Po', 'Út', 'St', 'Čt', 'Pá', 'So', 'Ne')
            );

    /** localization of calendar action headers */
    private $i18n_action = array(
            'cs_CZ' => array(
                /* 'title'     => */ 'Titulek',
                /* 'date'      => */ 'Datum',
                /* 'descr'     => */ 'Popis',
                /* 'author'    => */ 'Vložil')
            );


    /**
     * creates new instance of IView
     * @param   $model  istance of IModel which will be shown
     */
    public function __construct($model)
    {
        $this->model = $model;
    }

    /**
     * Shows calendar
     */
    public function show()
    {
        $numOfColumns = $this->numberOfColumns();

        print "<table>".N;
        print T.'<tr>'.N;
        print T.T.'<td colspan="'.$numOfColumns.'" class="location"> '.
            $this->i18n_months[$this->lang][$this->model->getMonth()].'&nbsp;'.
            $this->model->getYear().'</td>'.N;
        print T.'</tr>'.N;

        $days = $this->model->getDays();
        for ($r = 0; $r < 7; $r++) {   //7 days in week = 7 rows
            print T.'<tr>'.N.T.T;
            
            for($c = 0; $c < $numOfColumns; $c++) {
                $month  = $this->model->getMonth();
                $year   = $this->model->getYear();
                
                $day = $this->celContent($r, $c);
                
                //is today?
                if ($day->date == $this->today())
                    print '<td class="today">'.$day->number;
                else if ($c == 0)
                    print '<td class="highlight">'.$day->number;
                else
                    print '<td>'.$day->number;

                //is an action this day?
                if ($day->isAction()) {
                    print $this->actionToHTML($day->action);
                }
                print '</td>';
            }
            print N.T.'</tr>'.N;
        }
        print '</table>'.N;
    }

    /**
     * Sets language to be used. Also 
     * @param   $lang language abbreviation specifying used language
     */
    public function setLang($lang)
    {
        $this->lang = $lang;
    }

    /**
     * Sets localization for month names in calendar
     * @param   $lang language of localization
     * @param   $months array of month titles
     */
    public function addI18nMonths($lang, array $months)
    {
        // need to start array from 1 not from 0
        for ($i = 0; $i < count($months); $i++)
            $this->i18n_months[$lang][$i + 1] = $months[$i];
    }

    /**
     * Sets localization for day names in calendar
     * @param   $lang language of localization
     * @param   $days array of day titles
     */
    public function addI18nDays($lang, array $days)
    {
        $this->i18n_days[$lang] = $days;
    }

    /**
     * Sets localization for action names in calendar
     * @param   $lang language of localization
     * @param   $action array of action titles
     */
    public function addI18nAction($lang, array $action)
    {
        $this->i18n_action[$lang] = $action;
    }

    /**
     * Gets controls to enable browsing calendar months, years, etc.
     */
    private function getControls()
    {
        return '';
    }

    /**
     * Gets number of columns required to draw calendar
     * @return  number of columns of calendar
     * in czech ------ 
     * funkce zjisti pocet sloupcu kalendare = pocet tydnu (s tim, ze prvniho
     * muze byt treba v sobotu a 31. v pondeli).
     * Vyuziva se f-ce date: "W" je cislo tydne v roce. Protoze prelom dvou
     * mesicu je problematicky, pocita se od druheho tydne mesice do 
     * predposledniho, pak se prictou tyto dva mesice + 2 sloupce navic 
     * (jeden pro zapis dne druhy kvuli matematice operaci odcitani:
     *  23 - 20 = 3, ale jsou to 4 sloupce )
     */
    private function numberOfColumns()
    {
        $month  = $this->model->getMonth();
        $year   = $this->model->getYear();
        $days   = cal_days_in_month(CAL_GREGORIAN, $month, $year);
        $daysInMonth =  cal_days_in_month(CAL_GREGORIAN, $month, $year);

        return (date("W", mktime(0, 0, 0, $month, $days - 7, $year) ) - 
                date("W", mktime(0, 0, 0, $month,1 +7, $year) ) + 2 + 2 );
    }

    /**
     * Gets today date in database format
     * @return  today date in database format
     */
    private function today()
    {
        return date("Y-m-j");
    }

    /**
     * Gets content of current callendar cel
     * @param
     * @param
     * @return
     * in czech -----
     * funkce zjisti obsah bunky tabuky kalendare.
     * Obsah je zavisly na aktualnim radku, sloupci, jaky je prvni den a 
     * celkovem poctu dnu mesice
     */
    private function celContent($row, $col)
    {
        if ($col == 0)
            return new Day($this->i18n_days[$this->lang][$row], '');

        $firstDay = date("w", mktime(0, 0, 0, $this->model->getMonth(), 1,
                    $this->model->getYear()) );
        $firstDay = ($firstDay == 0) ? 7 : $firstDay;    //ternarni operator
        $totalDays = cal_days_in_month(CAL_GREGORIAN, $this->model->getMonth(),
                $this->model->getYear());

        $numberOfDay = ($col - 1) * 7 + $row  - $firstDay + 2 ;
        
        if($numberOfDay <= 0 || $numberOfDay > $totalDays)
            return new Day('&nbsp', '');
        else
            foreach ($this->model->getDays() as $day)
                if ($day->number == $numberOfDay)
                    return $day;
    }

    /**
     * Exports action data into HTML code to be shown
     * @param   $action action to be exported
     * @return  action exported into HTML
     */
    private function actionToHTML(Action $action)
    {
        $ret  = '<span class="action">';
        $ret .= '<strong>'.$this->i18n_action[$this->lang][1].':</strong> ';
        $ret .= $action->title;
        $ret .= '<strong>'.$this->i18n_action[$this->lang][2].':</strong> ';
        $ret .= $action->date;
        $ret .= '<strong>'.$this->i18n_action[$this->lang][3].':</strong> ';
        $ret .= $action->description;
        $ret .= '<strong>'.$this->i18n_action[$this->lang][4].':</strong> ';
        $ret .= $action->author;
        $ret .= '</span>'; 
    }
}

/* ================================ Model =================================== */

/**
 *
 */
class CalendarData implements IModel
{
    private $month;
    private $year;
    /**
     *
     */
    public function getDays()
    {
        $days = array();
        for ($i = 1;
             $i <= cal_days_in_month(CAL_GREGORIAN, $this->month, $this->year);
             $i++) {
           $days[] = new Day($i, '2009-01-'.$i, null); 
        }
        return $days;
    }

    public function setDay(Action $a)
    {}
    
    public function getMonth()
    {
        return $this->month;
    }

    public function setMonth($month)
    {
        $this->month = $month;
    }

    public function getYear()
    {
        return $this->year;
    }

    public function setYear($year)
    {
        $this->year = $year;
    }
}


/* =============================== main app ================================= */

$model = new CalendarData();

$view  = new CalViewer($model);
$controler = new Controler($model, $view);

?>
<style type="text/css">
.highlight { background-color: #ddd; }
.today { background-color: #bbb; }
</style>

<?php
print '<pre>';
$controler->calLocationChanged(1, 2009);

print '--------------------';
$view->addI18nMonths('en_US', array('January', 'February', 'March', 'April',
            'May', 'June', 'July', 'August', 'September', 'October', 'November',
            'December'));
$view->addI18nDays('en_US', array('Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat',
            'Sun'));
$view->addI18nAction('en_US', array('Title', 'Date', 'Description', 'Author'));
$view->setLang('en_US');

$controler->calLocationChanged(2, 2009);

print '--------------------';
$controler->calLocationChanged(3, 2009);

print '--------------------';
$view->setLang('cs_CZ');
$controler->calLocationChanged(4, 2009);
print '</pre>';

?>