<?php
/**
 * Feed
 *
 * @package SimpleCalendar/Feeds
 */
namespace SimpleCalendar\Abstracts;

use SimpleCalendar\plugin_deps\Carbon\Carbon;

if (!defined('ABSPATH')) {
	exit();
}

/**
 * The Feed.
 *
 * Source of events supplied to calendars.
 *
 * @since 3.0.0
 */
abstract class Feed
{
	/**
	 * Feed type.
	 *
	 * @access public
	 * @var string
	 */
	public $type = '';

	/**
	 * Feed name.
	 *
	 * @access public
	 * @var string
	 */
	public $name = '';

	/**
	 * Calendar post id.
	 *
	 * @access public
	 * @var int
	 */
	public $post_id = 0;

	/**
	 * Calendar opening.
	 *
	 * @access protected
	 * @var int
	 */
	protected $calendar_start = 0;

	/**
	 * Start of week.
	 *
	 * @access protected
	 * @var int
	 */
	protected $week_starts = 0;

	/**
	 * Events.
	 *
	 * @access public
	 * @var array
	 */
	public $events = [];

	/**
	 * Events template.
	 *
	 * @access protected
	 * @var string
	 */
	protected $events_template = '';

	/**
	 * Timezone setting.
	 *
	 * @access protected
	 * @var string
	 */
	protected $timezone_setting = '';

	/**
	 * Timezone.
	 *
	 * @access public
	 * @var string
	 */
	public $timezone = '';

	/**
	 * Earliest possible event.
	 *
	 * @access public
	 * @var int
	 */
	public $time_min = 0;

	/**
	 * Latest possible event.
	 *
	 * @access public
	 * @var int
	 */
	public $time_max = 0;

	/**
	 * Feed cache interval.
	 *
	 * @access protected
	 * @var int
	 */
	protected $cache = 7200;

	/**
	 * Feed settings.
	 *
	 * @access protected
	 * @var array
	 */
	protected $settings = [];

	/**
	 * Constructor.
	 *
	 * @since 3.0.0
	 *
	 * @param string|Calendar $calendar
	 */
	public function __construct($calendar = '')
	{
		if ($calendar instanceof Calendar) {
			if (isset($calendar->id)) {
				$this->post_id = $calendar->id;
			}
			if (isset($calendar->start)) {
				$this->calendar_start = $calendar->start;
			}
			$this->week_starts = isset($calendar->week_starts) ? $calendar->week_starts : get_option('start_of_week');
			$this->events_template = !empty($calendar->events_template)
				? $calendar->events_template
				: simcal_default_event_template();

			if ($this->post_id > 0) {
				$this->set_cache();
				$this->timezone_setting = get_post_meta($this->post_id, '_feed_timezone_setting', true);
				$this->timezone = $calendar->timezone;
				$this->set_earliest_event();
				$this->set_latest_event();
			}
		}
	}

	/**
	 * Input fields for settings page.
	 *
	 * @since  3.0.0
	 *
	 * @return false|array
	 */
	public function settings_fields()
	{
		return $this->settings;
	}

	/**
	 * Set earliest event.
	 *
	 * @since 3.0.0
	 *
	 * @param int $timestamp
	 */
	public function set_earliest_event($timestamp = 0)
	{
		$earliest = intval($timestamp);

		if ($earliest === 0) {
			$start = Carbon::createFromTimestamp($this->calendar_start, $this->timezone);

			$earliest_date = esc_attr(get_post_meta($this->post_id, '_feed_earliest_event_date', true));
			$earliest_range = max(absint(get_post_meta($this->post_id, '_feed_earliest_event_date_range', true)), 1);

			if ('days_before' == $earliest_date) {
				$earliest = $start->subDays($earliest_range)->getTimestamp();
			} elseif ('weeks_before' == $earliest_date) {
				$earliest = $start->subWeeks($earliest_range)->addDay()->getTimestamp();
			} elseif ('months_before' == $earliest_date) {
				$earliest = $start->subMonths($earliest_range)->addDay()->getTimestamp();
			} elseif ('years_before' == $earliest_date) {
				$earliest = $start->subYears($earliest_range)->addDay()->getTimestamp();
			} else {
				$earliest = $start->getTimestamp();
			}
		}

		$this->time_min = $earliest;
	}

	/**
	 * Set latest event.
	 *
	 * @since 3.0.0
	 *
	 * @param int $timestamp
	 */
	public function set_latest_event($timestamp = 0)
	{
		$latest = intval($timestamp);

		if ($latest === 0) {
			$start = Carbon::createFromTimestamp($this->calendar_start, $this->timezone)->endOfDay();

			$latest_date = esc_attr(get_post_meta($this->post_id, '_feed_latest_event_date', true));
			$latest_range = max(absint(get_post_meta($this->post_id, '_feed_latest_event_date_range', true)), 1);

			if ('days_after' == $latest_date) {
				$latest = $start->addDays($latest_range)->getTimestamp();
			} elseif ('weeks_after' == $latest_date) {
				$latest = $start->addWeeks($latest_range)->subDay()->getTimestamp();
			} elseif ('months_after' == $latest_date) {
				$latest = $start->addMonths($latest_range)->subDay()->getTimestamp();
			} elseif ('years_after' == $latest_date) {
				$latest = $start->addYears($latest_range)->subDay()->getTimestamp();
			} else {
				$latest = $start->getTimestamp();
			}
		}

		$this->time_max = $latest;
	}

	/**
	 * Set cache.
	 *
	 * @since 3.0.0
	 *
	 * @param int $time
	 */
	public function set_cache($time = 0)
	{
		if ($time === 0 || !is_numeric($time)) {
			$cache = get_post_meta($this->post_id, '_feed_cache', true);
			$time = is_numeric($cache) && $cache >= 0 ? absint($cache) : $this->cache;
		}
		$this->cache = absint($time);
	}

	/**
	 * Get events feed.
	 *
	 * @since 3.0.0
	 *
	 * @return array
	 */
	abstract public function get_events();
}