<?php
/**
 * This source file is part of the open source project
 * ExpressionEngine (https://expressionengine.com)
 *
 * @link      https://expressionengine.com/
 * @copyright Copyright (c) 2003-2023, Packet Tide, LLC (https://www.packettide.com)
 * @license   https://expressionengine.com/license Licensed under Apache License, Version 2.0
 */

/**
 * Calendar Class
 *
 * This class enables the creation of calendars
 */
class EE_Calendar
{
    public $CI;
    public $lang;
    public $local_time;
    public $template = '';
    public $start_day = 'sunday';
    public $month_type = 'long';
    public $day_type = 'abr';
    public $show_next_prev = false;
    public $next_prev_url = '';

    /**
     * Constructor
     *
     * Loads the calendar language file and sets the default time reference
     */
    public function __construct($config = array())
    {
        if (! in_array('calendar_lang.php', ee()->lang->is_loaded, true)) {
            ee()->lang->load('calendar');
        }

        $this->local_time = time();

        if (count($config) > 0) {
            $this->initialize($config);
        }

        log_message('debug', "Calendar Class Initialized");
    }

    /**
     * Initialize the user preferences
     *
     * Accepts an associative array as input, containing display preferences
     *
     * @access	public
     * @param	array	config preferences
     * @return	void
     */
    public function initialize($config = array())
    {
        foreach ($config as $key => $val) {
            if (isset($this->$key)) {
                $this->$key = $val;
            }
        }
    }

    /**
     * Generate the calendar
     *
     * @access	public
     * @param	integer	the year
     * @param	integer	the month
     * @param	array	the data to be shown in the calendar cells
     * @return	string
     */
    public function generate($year = '', $month = '', $data = array())
    {
        // Set and validate the supplied month/year
        if ($year == '') {
            $year = date("Y", $this->local_time);
        }

        if ($month == '') {
            $month = date("m", $this->local_time);
        }

        if (strlen($year) == 1) {
            $year = '200' . $year;
        }

        if (strlen($year) == 2) {
            $year = '20' . $year;
        }

        if (strlen($month) == 1) {
            $month = '0' . $month;
        }

        $adjusted_date = $this->adjust_date($month, $year);

        $month = $adjusted_date['month'];
        $year = $adjusted_date['year'];

        // Determine the total days in the month
        $total_days = $this->get_total_days($month, $year);

        // Set the starting day of the week
        $start_days = array('sunday' => 0, 'monday' => 1, 'tuesday' => 2, 'wednesday' => 3, 'thursday' => 4, 'friday' => 5, 'saturday' => 6);
        $start_day = (! isset($start_days[$this->start_day])) ? 0 : $start_days[$this->start_day];

        // Set the starting day number
        $local_date = mktime(12, 0, 0, $month, 1, $year);
        $date = getdate($local_date);
        $day = $start_day + 1 - $date["wday"];

        while ($day > 1) {
            $day -= 7;
        }

        // Set the current month/year/day
        // We use this to determine the "today" date
        $cur_year = date("Y", $this->local_time);
        $cur_month = date("m", $this->local_time);
        $cur_day = date("j", $this->local_time);

        $is_current_month = ($cur_year == $year and $cur_month == $month) ? true : false;

        // Generate the template data array
        $this->parse_template();

        // Begin building the calendar output
        $out = $this->temp['table_open'];
        $out .= "\n";

        $out .= "\n";
        $out .= $this->temp['heading_row_start'];
        $out .= "\n";

        // "previous" month link
        if ($this->show_next_prev == true) {
            // Add a trailing slash to the  URL if needed
            $this->next_prev_url = preg_replace("/(.+?)\/*$/", "\\1/", $this->next_prev_url);

            $adjusted_date = $this->adjust_date($month - 1, $year);
            $out .= str_replace('{previous_url}', $this->next_prev_url . $adjusted_date['year'] . '/' . $adjusted_date['month'], $this->temp['heading_previous_cell']);
            $out .= "\n";
        }

        // Heading containing the month/year
        $colspan = ($this->show_next_prev == true) ? 5 : 7;

        $this->temp['heading_title_cell'] = str_replace('{colspan}', $colspan, $this->temp['heading_title_cell']);
        $this->temp['heading_title_cell'] = str_replace('{heading}', $this->get_month_name($month) . "&nbsp;" . $year, $this->temp['heading_title_cell']);

        $out .= $this->temp['heading_title_cell'];
        $out .= "\n";

        // "next" month link
        if ($this->show_next_prev == true) {
            $adjusted_date = $this->adjust_date($month + 1, $year);
            $out .= str_replace('{next_url}', $this->next_prev_url . $adjusted_date['year'] . '/' . $adjusted_date['month'], $this->temp['heading_next_cell']);
        }

        $out .= "\n";
        $out .= $this->temp['heading_row_end'];
        $out .= "\n";

        // Write the cells containing the days of the week
        $out .= "\n";
        $out .= $this->temp['week_row_start'];
        $out .= "\n";

        $day_names = $this->get_day_names();

        for ($i = 0; $i < 7; $i ++) {
            $out .= str_replace('{week_day}', $day_names[($start_day + $i) % 7], $this->temp['week_day_cell']);
        }

        $out .= "\n";
        $out .= $this->temp['week_row_end'];
        $out .= "\n";

        // Build the main body of the calendar
        while ($day <= $total_days) {
            $out .= "\n";
            $out .= $this->temp['cal_row_start'];
            $out .= "\n";

            for ($i = 0; $i < 7; $i++) {
                $out .= ($is_current_month == true and $day == $cur_day) ? $this->temp['cal_cell_start_today'] : $this->temp['cal_cell_start'];

                if ($day > 0 and $day <= $total_days) {
                    if (isset($data[$day])) {
                        // Cells with content
                        $temp = ($is_current_month == true and $day == $cur_day) ? $this->temp['cal_cell_content_today'] : $this->temp['cal_cell_content'];
                        $out .= str_replace('{day}', $day, str_replace('{content}', $data[$day], $temp));
                    } else {
                        // Cells with no content
                        $temp = ($is_current_month == true and $day == $cur_day) ? $this->temp['cal_cell_no_content_today'] : $this->temp['cal_cell_no_content'];
                        $out .= str_replace('{day}', $day, $temp);
                    }
                } else {
                    // Blank cells
                    $out .= $this->temp['cal_cell_blank'];
                }

                $out .= ($is_current_month == true and $day == $cur_day) ? $this->temp['cal_cell_end_today'] : $this->temp['cal_cell_end'];
                $day++;
            }

            $out .= "\n";
            $out .= $this->temp['cal_row_end'];
            $out .= "\n";
        }

        $out .= "\n";
        $out .= $this->temp['table_close'];

        return $out;
    }

    /**
     * Get Month Name
     *
     * Generates a textual month name based on the numeric
     * month provided.
     *
     * @access	public
     * @param	integer	the month
     * @return	string
     */
    public function get_month_name($month)
    {
        if ($this->month_type == 'short') {
            $month_names = array('01' => 'cal_jan', '02' => 'cal_feb', '03' => 'cal_mar', '04' => 'cal_apr', '05' => 'cal_may', '06' => 'cal_jun', '07' => 'cal_jul', '08' => 'cal_aug', '09' => 'cal_sep', '10' => 'cal_oct', '11' => 'cal_nov', '12' => 'cal_dec');
        } else {
            $month_names = array('01' => 'cal_january', '02' => 'cal_february', '03' => 'cal_march', '04' => 'cal_april', '05' => 'cal_mayl', '06' => 'cal_june', '07' => 'cal_july', '08' => 'cal_august', '09' => 'cal_september', '10' => 'cal_october', '11' => 'cal_november', '12' => 'cal_december');
        }

        $month = $month_names[$month];

        if (ee()->lang->line($month) === false) {
            return ucfirst(str_replace('cal_', '', $month));
        }

        return ee()->lang->line($month);
    }

    /**
     * Get Day Names
     *
     * Returns an array of day names (Sunday, Monday, etc.) based
     * on the type.  Options: long, short, abrev
     *
     * @access	public
     * @param	string
     * @return	array
     */
    public function get_day_names($day_type = '')
    {
        if ($day_type != '') {
            $this->day_type = $day_type;
        }

        if ($this->day_type == 'long') {
            $day_names = array('sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday');
        } elseif ($this->day_type == 'short') {
            $day_names = array('sun', 'mon', 'tue', 'wed', 'thu', 'fri', 'sat');
        } else {
            $day_names = array('su', 'mo', 'tu', 'we', 'th', 'fr', 'sa');
        }

        $days = array();
        foreach ($day_names as $val) {
            $days[] = (ee()->lang->line('cal_' . $val) === false) ? ucfirst($val) : ee()->lang->line('cal_' . $val);
        }

        return $days;
    }

    /**
     * Adjust Date
     *
     * This function makes sure that we have a valid month/year.
     * For example, if you submit 13 as the month, the year will
     * increment and the month will become January.
     *
     * @access	public
     * @param	integer	the month
     * @param	integer	the year
     * @return	array
     */
    public function adjust_date($month, $year, $pad = false)
    {
        $date = array();

        $date['month'] = $month;
        $date['year'] = $year;

        while ($date['month'] > 12) {
            $date['month'] -= 12;
            $date['year']++;
        }

        while ($date['month'] <= 0) {
            $date['month'] += 12;
            $date['year']--;
        }

        if ($pad == true and strlen($date['month']) == 1) {
            $date['month'] = '0' . $date['month'];
        }

        return $date;
    }

    /**
     * Total days in a given month
     *
     * @access	public
     * @param	integer	the month
     * @param	integer	the year
     * @return	integer
     */
    public function get_total_days($month, $year)
    {
        $days_in_month = array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);

        if ($month < 1 or $month > 12) {
            return 0;
        }

        // Is the year a leap year?
        if ($month == 2) {
            if ($year % 400 == 0 or ($year % 4 == 0 and $year % 100 != 0)) {
                return 29;
            }
        }

        return $days_in_month[$month - 1];
    }

    /**
     * Set Default Template Data
     *
     * This is used in the event that the user has not created their own template
     *
     * @access	public
     * @return array
     */
    public function default_template()
    {
        return  array(
            'table_open' => '<table border="0" cellpadding="4" cellspacing="0">',
            'heading_row_start' => '<tr>',
            'heading_previous_cell' => '<th><a href="{previous_url}">&lt;&lt;</a></th>',
            'heading_title_cell' => '<th colspan="{colspan}">{heading}</th>',
            'heading_next_cell' => '<th><a href="{next_url}">&gt;&gt;</a></th>',
            'heading_row_end' => '</tr>',
            'week_row_start' => '<tr>',
            'week_day_cell' => '<td>{week_day}</td>',
            'week_row_end' => '</tr>',
            'cal_row_start' => '<tr>',
            'cal_cell_start' => '<td>',
            'cal_cell_start_today' => '<td>',
            'cal_cell_content' => '<a href="{content}">{day}</a>',
            'cal_cell_content_today' => '<a href="{content}"><strong>{day}</strong></a>',
            'cal_cell_no_content' => '{day}',
            'cal_cell_no_content_today' => '<strong>{day}</strong>',
            'cal_cell_blank' => '&nbsp;',
            'cal_cell_end' => '</td>',
            'cal_cell_end_today' => '</td>',
            'cal_row_end' => '</tr>',
            'table_close' => '</table>'
        );
    }

    /**
     * Parse Template
     *
     * Harvests the data within the template {pseudo-variables}
     * used to display the calendar
     *
     * @access	public
     * @return	void
     */
    public function parse_template()
    {
        $this->temp = $this->default_template();

        if ($this->template == '') {
            return;
        }

        $today = array('cal_cell_start_today', 'cal_cell_content_today', 'cal_cell_no_content_today', 'cal_cell_end_today');

        foreach (array('table_open', 'table_close', 'heading_row_start', 'heading_previous_cell', 'heading_title_cell', 'heading_next_cell', 'heading_row_end', 'week_row_start', 'week_day_cell', 'week_row_end', 'cal_row_start', 'cal_cell_start', 'cal_cell_content', 'cal_cell_no_content',  'cal_cell_blank', 'cal_cell_end', 'cal_row_end', 'cal_cell_start_today', 'cal_cell_content_today', 'cal_cell_no_content_today', 'cal_cell_end_today') as $val) {
            if (preg_match("/\{" . $val . "\}(.*?)\{\/" . $val . "\}/si", $this->template, $match)) {
                $this->temp[$val] = $match['1'];
            } else {
                if (in_array($val, $today, true)) {
                    $this->temp[$val] = $this->temp[str_replace('_today', '', $val)];
                }
            }
        }
    }
}

// END CI_Calendar class

// EOF
