<?php
/**
 * Private iCal (.ics) subscription link with all orders (and Pro calendar entries)
 * for Google / Apple / Outlook calendars.
 */

defined( 'ABSPATH' ) || exit;

/**
 * Secret token for the feed URL (created on first use, can be replaced).
 */
function dayslot_ical_token() {
	$token = get_option( 'dayslot_ical_token' );
	if ( ! $token || strlen( $token ) < 40 ) {
		$token = wp_generate_password( 48, false, false );
		update_option( 'dayslot_ical_token', $token, false );
	}
	return $token;
}

function dayslot_ical_feed_url() {
	return add_query_arg( 'dys-ical', dayslot_ical_token(), home_url( '/' ) );
}

add_action(
	'init',
	function () {
		// "edc-ical": the link of the old plugin (Event Date Calendar) — calendars subscribed to it keep working.
		$param = isset( $_GET['dys-ical'] ) ? 'dys-ical' : ( isset( $_GET['edc-ical'] ) ? 'edc-ical' : '' ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- secret token instead of a nonce (calendar apps can't log in).
		if ( ! $param ) {
			return;
		}
		$token = sanitize_text_field( wp_unslash( $_GET[ $param ] ) ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended, WordPress.Security.ValidatedSanitizedInput.InputNotValidated -- checked above.
		if ( ! hash_equals( dayslot_ical_token(), $token ) ) {
			status_header( 403 );
			exit;
		}
		dayslot_output_ical();
		exit;
	},
	20
);

add_action(
	'admin_post_dayslot_ical_reset',
	function () {
		if ( ! current_user_can( 'manage_woocommerce' ) ) {
			wp_die( esc_html__( 'You are not allowed to do this.', 'dayslot' ) );
		}
		check_admin_referer( 'dayslot_ical_reset' );
		delete_option( 'dayslot_ical_token' );
		dayslot_ical_token();
		wp_safe_redirect( admin_url( 'admin.php?page=dayslot-settings&tab=calendars&dayslot_reset=1' ) );
		exit;
	}
);

/**
 * Feed items: array( uid, date, slot, summary, location, description, url, modified ).
 */
function dayslot_ical_items( $start, $end ) {
	$items = array();
	foreach ( dayslot_booking_rows( $start, $end ) as $row ) {
		if ( 'order' !== $row['kind'] ) {
			continue;
		}
		$order = wc_get_order( $row['id'] );
		if ( ! $order ) {
			continue;
		}
		$name = trim( $order->get_billing_first_name() . ' ' . $order->get_billing_last_name() );
		$desc = array();
		foreach ( $order->get_items() as $item ) {
			$desc[] = $item->get_quantity() . '× ' . $item->get_name();
		}
		$desc[] = '';
		foreach ( dayslot_order_summary_rows( $order ) as $r ) {
			$desc[] = $r['label'] . ': ' . $r['value'];
		}
		$desc[] = __( 'Total', 'dayslot' ) . ': ' . wp_strip_all_tags( wc_price( $order->get_total(), array( 'currency' => $order->get_currency() ) ) );
		$desc[] = __( 'Status', 'dayslot' ) . ': ' . wc_get_order_status_name( $order->get_status() );
		if ( $order->get_billing_phone() ) {
			$desc[] = __( 'Phone', 'dayslot' ) . ': ' . $order->get_billing_phone();
		}
		if ( $order->get_customer_note() ) {
			$desc[] = __( 'Note', 'dayslot' ) . ': ' . $order->get_customer_note();
		}
		$desc[]   = '';
		$desc[]   = $order->get_edit_order_url();
		$pickup   = 'pickup' === $row['mode'];
		$address  = $order->has_shipping_address()
			? implode( ', ', array_filter( array( $order->get_shipping_address_1(), $order->get_shipping_address_2(), $order->get_shipping_postcode(), $order->get_shipping_city() ) ) )
			: implode( ', ', array_filter( array( $order->get_billing_address_1(), $order->get_billing_address_2(), $order->get_billing_postcode(), $order->get_billing_city() ) ) );
		$modified = $order->get_date_modified();
		$items[]  = array(
			'uid'         => 'dys-order-' . $order->get_id(),
			'date'        => $row['date'],
			'slot'        => $row['slot'],
			'variant'     => isset( $row['variant'] ) ? $row['variant'] : '',
			'summary'     => ( $pickup ? '⇱ ' : '' ) . '#' . $order->get_order_number() . ( $name ? ' ' . $name : '' ),
			'location'    => $pickup ? '' : $address,
			'description' => implode( "\n", $desc ),
			'url'         => $order->get_edit_order_url(),
			'modified'    => $modified ? $modified->getTimestamp() : 0,
		);
	}
	return apply_filters( 'dayslot_ical_items', $items, $start, $end );
}

function dayslot_output_ical() {
	$s     = dayslot_get_settings();
	$today = dayslot_today();
	$start = $today->modify( '-90 days' )->format( 'Y-m-d' );
	$end   = $today->modify( '+' . max( 365, (int) $s['max_days'] ) . ' days' )->format( 'Y-m-d' );
	$host  = wp_parse_url( home_url(), PHP_URL_HOST );
	$now   = gmdate( 'Ymd\THis\Z' );

	$lines = array(
		'BEGIN:VCALENDAR',
		'VERSION:2.0',
		'PRODID:-//Creonix//Dayslot//EN',
		'CALSCALE:GREGORIAN',
		'METHOD:PUBLISH',
		'X-WR-CALNAME:' . dayslot_ical_text( get_bloginfo( 'name' ) . ' – ' . __( 'orders', 'dayslot' ) ),
		'X-WR-TIMEZONE:' . wp_timezone_string(),
		'REFRESH-INTERVAL;VALUE=DURATION:PT1H',
		'X-PUBLISHED-TTL:PT1H',
	);

	foreach ( dayslot_ical_items( $start, $end ) as $item ) {
		if ( ! dayslot_parse_date( $item['date'] ) ) {
			continue;
		}
		$lines[] = 'BEGIN:VEVENT';
		$lines[] = 'UID:' . $item['uid'] . '@' . $host;
		$lines[] = 'DTSTAMP:' . $now;
		if ( ! empty( $item['modified'] ) ) {
			$lines[] = 'LAST-MODIFIED:' . gmdate( 'Ymd\THis\Z', $item['modified'] );
		}
		foreach ( dayslot_ical_times( $item['date'], $item['slot'], isset( $item['variant'] ) ? $item['variant'] : '' ) as $line ) {
			$lines[] = $line;
		}
		$lines[] = 'SUMMARY:' . dayslot_ical_text( $item['summary'] );
		if ( ! empty( $item['location'] ) ) {
			$lines[] = 'LOCATION:' . dayslot_ical_text( $item['location'] );
		}
		$lines[] = 'DESCRIPTION:' . dayslot_ical_text( $item['description'] );
		if ( ! empty( $item['url'] ) ) {
			$lines[] = 'URL:' . $item['url'];
		}
		$lines[] = 'STATUS:CONFIRMED';
		$lines[] = 'END:VEVENT';
	}
	$lines[] = 'END:VCALENDAR';

	nocache_headers();
	header( 'Content-Type: text/calendar; charset=utf-8' );
	header( 'Content-Disposition: inline; filename="orders.ics"' );
	header( 'X-Robots-Tag: noindex' );
	foreach ( $lines as $line ) {
		echo dayslot_ical_fold( $line ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- iCal text, escaped by dayslot_ical_text().
	}
}

/**
 * "Calendar sync" tab.
 */
function dayslot_render_ical_settings( $s ) {
	?>
	<?php if ( isset( $_GET['dayslot_reset'] ) ) : // phpcs:ignore WordPress.Security.NonceVerification.Recommended ?>
		<div class="notice notice-warning inline"><p><?php esc_html_e( 'New link created. The old link no longer works — add the new one to your calendar.', 'dayslot' ); ?></p></div>
	<?php endif; ?>
	<table class="form-table" role="presentation">
		<tr>
			<th scope="row"><?php esc_html_e( 'Orders → your calendar', 'dayslot' ); ?></th>
			<td>
				<input type="text" readonly class="large-text code" id="dayslot_feed_url" value="<?php echo esc_attr( dayslot_ical_feed_url() ); ?>">
				<p>
					<button type="button" class="button dys-copy" data-target="dayslot_feed_url"><?php esc_html_e( 'Copy link', 'dayslot' ); ?></button>
					<a class="button dys-confirm" data-confirm="<?php esc_attr_e( 'The current link will stop working. Continue?', 'dayslot' ); ?>" href="<?php echo esc_url( wp_nonce_url( admin_url( 'admin-post.php?action=dayslot_ical_reset' ), 'dayslot_ical_reset' ) ); ?>"><?php esc_html_e( 'Create new link', 'dayslot' ); ?></a>
				</p>
				<p class="description">
					<?php esc_html_e( 'Google Calendar: Other calendars → + → From URL → paste the link.', 'dayslot' ); ?><br>
					<?php esc_html_e( 'iPhone / Mac: Calendar → File (or Settings → Accounts) → New Calendar Subscription → paste the link.', 'dayslot' ); ?><br>
					<?php esc_html_e( 'Outlook: Add calendar → Subscribe from web.', 'dayslot' ); ?><br>
					<strong><?php esc_html_e( 'The link contains customer data — do not share it. If it leaks, create a new link.', 'dayslot' ); ?></strong>
					<?php esc_html_e( 'Google refreshes subscribed calendars on its own schedule (usually every few hours).', 'dayslot' ); ?>
				</p>
			</td>
		</tr>
		<?php do_action( 'dayslot_calendar_settings_rows', $s ); ?>
	</table>
	<?php
}