<?php
/**
 * iCal Import (subscribe to external .ics URL)
 *
 * Fetches .ics from external URL (e.g. Google Calendar public iCal link)
 * and blocks dates in yacht availability.
 *
 * @package YachtBooking
 */

namespace YachtBooking\Integrations\ICal;

use YachtBooking\Availability;
use YachtBooking\Settings;
use YachtBooking\Yacht;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * ICal Import class
 */
class ICal_Import {

	/**
	 * Booking source identifier for iCal imports (globalny — wspólny GCal,
	 * podział po prefiksie nazwy jachtu w SUMMARY).
	 */
	const GLOBAL_IMPORT_SOURCE = 'ical_import_global';

	/**
	 * Booking source identifier dla trybu "wspólny kalendarz" (sync_mode=global).
	 *
	 * Eventy z tym source nie blokują dostępności jachtów (yacht_id=0) i są pokazywane
	 * tylko na widgecie zbiorczym "wszystkie jachty".
	 */
	const GLOBAL_CALENDAR_SOURCE = 'ical_global_calendar';

	/**
	 * Separator między prefiksem nazwy jachtu a resztą tytułu eventu.
	 *
	 * Przykład SUMMARY: "Maja - Kowalski 5 osób" → prefix="Maja", reszta="Kowalski 5 osób".
	 */
	const SUMMARY_SEPARATOR = ' - ';

	/**
	 * Register cron actions
	 */
	public static function register() {
		add_action( 'yacht_booking_ical_global_import', array( __CLASS__, 'run_global_import' ) );
	}

	/**
	 * Setup cron schedule
	 */
	public static function setup_cron() {
		if ( ! wp_next_scheduled( 'yacht_booking_ical_global_import' ) ) {
			wp_schedule_event( time(), 'hourly', 'yacht_booking_ical_global_import' );
		}
	}

	/**
	 * Clear cron
	 */
	public static function clear_cron() {
		wp_clear_scheduled_hook( 'yacht_booking_ical_global_import' );
	}

	/**
	 * Globalny iCal import — pobiera jeden URL kalendarza Google z ustawień
	 * globalnych, parsuje eventy i przypisuje je do jachtów po prefiksie w SUMMARY.
	 *
	 * Format SUMMARY: "{nazwa_jachtu_lub_alias} - {opis}".
	 * Eventy bez separatora lub bez dopasowanego jachtu są ignorowane (logowane).
	 *
	 * @return bool True przy sukcesie HTTP, false przy błędzie pobrania/braku URL.
	 */
	public static function run_global_import() {
		$url = get_option( 'yacht_booking_global_ical_import_url', '' );
		$url = is_string( $url ) ? trim( $url ) : '';

		if ( empty( $url ) ) {
			return false;
		}

		$response = wp_remote_get(
			$url,
			array(
				'timeout'   => 30,
				'sslverify' => true,
			)
		);

		if ( is_wp_error( $response ) ) {
			self::log( sprintf( 'Global iCal fetch failed: %s', $response->get_error_message() ), 'error' );
			return false;
		}

		$body = wp_remote_retrieve_body( $response );
		if ( empty( $body ) ) {
			self::log( 'Global iCal: empty response body', 'error' );
			return false;
		}

		$events = self::parse_ics( $body );
		$mode   = Settings::get_ical_sync_mode();

		if ( 'global' === $mode ) {
			self::run_global_calendar_mode( $events );
		} else {
			self::run_per_yacht_mode( $events );
		}

		update_option( 'yacht_booking_global_ical_last_import', current_time( 'mysql' ) );
		return true;
	}

	/**
	 * Tryb per-jacht: dopasowanie po prefiksie SUMMARY, wpisy do availability.
	 *
	 * @param array $events Sparsowane eventy iCal.
	 */
	protected static function run_per_yacht_mode( $events ) {
		$yacht_map = self::build_yacht_lookup_map();

		if ( empty( $yacht_map ) ) {
			self::log( 'Per-yacht iCal: no yachts in DB — nothing to match', 'error' );
			return;
		}

		$existing_map = self::get_existing_global_import_map();
		$seen_uids    = array();

		foreach ( $events as $event ) {
			if ( empty( $event['uid'] ) || empty( $event['start'] ) || empty( $event['end'] ) ) {
				continue;
			}

			// Skip past events.
			if ( strtotime( $event['end'] ) < time() ) {
				continue;
			}

			$summary  = isset( $event['summary'] ) ? (string) $event['summary'] : '';
			$yacht_id = self::match_yacht_by_prefix( $summary, $yacht_map );

			if ( ! $yacht_id ) {
				self::log( sprintf( 'Per-yacht iCal: skip event "%s" — no yacht match for prefix', $summary ) );
				continue;
			}

			$seen_uids[] = $event['uid'];
			$existing_id = isset( $existing_map[ $event['uid'] ] ) ? (int) $existing_map[ $event['uid'] ] : 0;

			$booking_id = self::upsert_global_booking( $yacht_id, $event, $existing_id );

			if ( ! $booking_id ) {
				self::log( sprintf( 'Per-yacht iCal: failed to upsert event %s', $event['uid'] ), 'error' );
			}
		}

		// Stale cleanup — usuń bookingi których UID nie ma już w feedzie.
		// Ograniczone do GLOBAL_IMPORT_SOURCE (per-yacht) — nie tyka GLOBAL_CALENDAR_SOURCE.
		foreach ( $existing_map as $uid => $booking_id ) {
			if ( ! in_array( $uid, $seen_uids, true ) ) {
				\YachtBooking\Availability::clear_booking_availability( $booking_id );
				wp_delete_post( $booking_id, true );
			}
		}
	}

	/**
	 * Tryb global: wszystkie eventy (bez filtrowania) zapisane jako wspólne wydarzenia
	 * kalendarza. yacht_id=0, brak wpisów do wp_yacht_availability.
	 *
	 * @param array $events Sparsowane eventy iCal.
	 */
	protected static function run_global_calendar_mode( $events ) {
		$existing_map = self::get_existing_global_calendar_map();
		$seen_uids    = array();
		$imported     = 0;
		$updated      = 0;

		foreach ( $events as $event ) {
			if ( empty( $event['uid'] ) || empty( $event['start'] ) || empty( $event['end'] ) ) {
				continue;
			}

			// Skip past events.
			if ( strtotime( $event['end'] ) < time() ) {
				continue;
			}

			$seen_uids[] = $event['uid'];
			$existing_id = isset( $existing_map[ $event['uid'] ] ) ? (int) $existing_map[ $event['uid'] ] : 0;

			$booking_id = self::upsert_global_calendar_event( $event, $existing_id );

			if ( ! $booking_id ) {
				self::log( sprintf( 'Global calendar iCal: failed to upsert event %s', $event['uid'] ), 'error' );
				continue;
			}

			if ( $existing_id > 0 ) {
				$updated++;
			} else {
				$imported++;
			}
		}

		// Stale cleanup — usuń tylko eventy z GLOBAL_CALENDAR_SOURCE których UID brakuje.
		$deleted = 0;
		foreach ( $existing_map as $uid => $booking_id ) {
			if ( ! in_array( $uid, $seen_uids, true ) ) {
				wp_delete_post( $booking_id, true );
				$deleted++;
			}
		}

		self::log(
			sprintf(
				'Global calendar iCal: imported=%d, updated=%d, deleted=%d',
				$imported,
				$updated,
				$deleted
			)
		);
	}

	/**
	 * Buduje mapę: lowercase(alias|post_title) => yacht_id.
	 *
	 * Alias (`_yacht_gcal_alias`) ma priorytet nad post_title. Klucze są
	 * znormalizowane przez mb_strtolower + trim, dla matchowania case-insensitive
	 * i niezależnego od białych znaków.
	 *
	 * @return array
	 */
	protected static function build_yacht_lookup_map() {
		$yachts = get_posts(
			array(
				'post_type'      => 'yacht',
				'post_status'    => 'publish',
				'posts_per_page' => -1,
			)
		);

		$map = array();
		foreach ( $yachts as $yacht ) {
			$alias = \YachtBooking\Yacht::get_gcal_alias( $yacht->ID );
			$key   = '' !== trim( (string) $alias ) ? $alias : $yacht->post_title;
			$key   = mb_strtolower( trim( (string) $key ) );

			if ( '' === $key ) {
				continue;
			}

			// Nie nadpisuj — w razie kolizji wygrywa pierwszy. Kolizje są
			// wpisem do logu w czasie matchowania (nie tutaj — bezgłośnie pierwszy).
			if ( ! isset( $map[ $key ] ) ) {
				$map[ $key ] = (int) $yacht->ID;
			}
		}

		return $map;
	}

	/**
	 * Wyciąga prefiks (przed pierwszym " - ") z SUMMARY i dopasowuje do jachtu
	 * w mapie (case-insensitive).
	 *
	 * @param string $summary SUMMARY eventu.
	 * @param array  $yacht_map Mapa lowercase(klucz) => yacht_id.
	 * @return int 0 gdy brak dopasowania.
	 */
	protected static function match_yacht_by_prefix( $summary, $yacht_map ) {
		if ( '' === $summary ) {
			return 0;
		}

		$pos = mb_strpos( $summary, self::SUMMARY_SEPARATOR );
		if ( false === $pos ) {
			return 0;
		}

		$prefix = mb_substr( $summary, 0, $pos );
		$prefix = mb_strtolower( trim( $prefix ) );

		if ( '' === $prefix ) {
			return 0;
		}

		return isset( $yacht_map[ $prefix ] ) ? (int) $yacht_map[ $prefix ] : 0;
	}

	/**
	 * Zwraca mapę istniejących globalnych importów: uid => booking_id.
	 *
	 * @return array
	 */
	protected static function get_existing_global_import_map() {
		$bookings = get_posts(
			array(
				'post_type'      => 'yacht_booking',
				'post_status'    => 'publish',
				'posts_per_page' => -1,
				'fields'         => 'ids',
				'meta_query'     => array(
					array(
						'key'   => '_booking_source',
						'value' => self::GLOBAL_IMPORT_SOURCE,
					),
				),
			)
		);

		$map = array();
		foreach ( $bookings as $booking_id ) {
			$uid = get_post_meta( $booking_id, '_ical_event_uid', true );
			if ( $uid ) {
				$map[ $uid ] = (int) $booking_id;
			}
		}

		return $map;
	}

	/**
	 * Tworzy lub aktualizuje booking placeholder z globalnego importu.
	 *
	 * @param int   $yacht_id Yacht ID.
	 * @param array $event Parsed event data.
	 * @param int   $existing_id Existing booking ID (0 dla nowego).
	 * @return int|false
	 */
	protected static function upsert_global_booking( $yacht_id, $event, $existing_id = 0 ) {
		$summary    = ! empty( $event['summary'] ) ? sanitize_text_field( $event['summary'] ) : __( 'Blokada Google Calendar', 'yacht-booking' );
		$start_date = $event['start'];
		$end_date   = $event['end'];

		$post_data = array(
			'post_type'   => 'yacht_booking',
			'post_status' => 'publish',
			'post_title'  => sprintf(
				/* translators: %s: event summary */
				__( 'GCal: %s', 'yacht-booking' ),
				$summary
			),
		);

		if ( $existing_id > 0 ) {
			$post_data['ID'] = $existing_id;
			$booking_id      = wp_update_post( $post_data, true );
		} else {
			$booking_id = wp_insert_post( $post_data, true );
		}

		if ( is_wp_error( $booking_id ) || ! $booking_id ) {
			return false;
		}

		update_post_meta( $booking_id, '_booking_yacht_id', (int) $yacht_id );
		update_post_meta( $booking_id, '_booking_start_date', $start_date );
		update_post_meta( $booking_id, '_booking_end_date', $end_date );
		update_post_meta( $booking_id, '_booking_status', 'confirmed' );
		update_post_meta( $booking_id, '_booking_customer_name', __( 'Google Calendar (import)', 'yacht-booking' ) );
		update_post_meta( $booking_id, '_booking_customer_email', '' );
		update_post_meta( $booking_id, '_booking_customer_phone', '' );
		update_post_meta( $booking_id, '_booking_total_price', 0 );
		update_post_meta( $booking_id, '_booking_source', self::GLOBAL_IMPORT_SOURCE );
		update_post_meta( $booking_id, '_ical_event_uid', $event['uid'] );
		update_post_meta( $booking_id, '_booking_notes', $summary );

		\YachtBooking\Availability::clear_booking_availability( $booking_id );
		\YachtBooking\Availability::mark_as_booked( $yacht_id, $start_date, $end_date, $booking_id );

		return (int) $booking_id;
	}

	/**
	 * Mapa istniejących eventów GLOBAL_CALENDAR_SOURCE (tryb global): uid => booking_id.
	 *
	 * @return array
	 */
	protected static function get_existing_global_calendar_map() {
		$bookings = get_posts(
			array(
				'post_type'      => 'yacht_booking',
				'post_status'    => 'publish',
				'posts_per_page' => -1,
				'fields'         => 'ids',
				'meta_query'     => array(
					array(
						'key'   => '_booking_source',
						'value' => self::GLOBAL_CALENDAR_SOURCE,
					),
				),
			)
		);

		$map = array();
		foreach ( $bookings as $booking_id ) {
			$uid = get_post_meta( $booking_id, '_ical_event_uid', true );
			if ( $uid ) {
				$map[ $uid ] = (int) $booking_id;
			}
		}

		return $map;
	}

	/**
	 * Tworzy lub aktualizuje wspólne wydarzenie kalendarza (sync_mode=global).
	 *
	 * yacht_id=0, brak wpisów do availability — event tylko informacyjny na widgecie zbiorczym.
	 *
	 * @param array $event Parsed event data.
	 * @param int   $existing_id Existing booking ID (0 dla nowego).
	 * @return int|false
	 */
	protected static function upsert_global_calendar_event( $event, $existing_id = 0 ) {
		$summary = ! empty( $event['summary'] )
			? sanitize_text_field( $event['summary'] )
			: __( 'Wydarzenie kalendarza', 'yacht-booking' );

		$post_data = array(
			'post_type'   => 'yacht_booking',
			'post_status' => 'publish',
			'post_title'  => sprintf(
				/* translators: %s: event summary */
				__( 'GCal (wspólny): %s', 'yacht-booking' ),
				$summary
			),
		);

		if ( $existing_id > 0 ) {
			$post_data['ID'] = $existing_id;
			$booking_id      = wp_update_post( $post_data, true );
		} else {
			$booking_id = wp_insert_post( $post_data, true );
		}

		if ( is_wp_error( $booking_id ) || ! $booking_id ) {
			return false;
		}

		update_post_meta( $booking_id, '_booking_yacht_id', 0 );
		update_post_meta( $booking_id, '_booking_start_date', $event['start'] );
		update_post_meta( $booking_id, '_booking_end_date', $event['end'] );
		update_post_meta( $booking_id, '_booking_status', 'confirmed' );
		update_post_meta( $booking_id, '_booking_customer_name', __( 'Google Calendar (kalendarz wspólny)', 'yacht-booking' ) );
		update_post_meta( $booking_id, '_booking_customer_email', '' );
		update_post_meta( $booking_id, '_booking_customer_phone', '' );
		update_post_meta( $booking_id, '_booking_total_price', 0 );
		update_post_meta( $booking_id, '_booking_source', self::GLOBAL_CALENDAR_SOURCE );
		update_post_meta( $booking_id, '_ical_event_uid', $event['uid'] );
		update_post_meta( $booking_id, '_booking_notes', $summary );

		// CELOWO BEZ Availability::mark_as_booked() — wspólne eventy nie blokują dostępności jachtów.
		// Defensywnie: jeśli kiedyś existing_id miał wpisy availability (np. po przełączeniu trybu),
		// usuń je, by nie zostawiały śmieci.
		if ( $existing_id > 0 ) {
			\YachtBooking\Availability::clear_booking_availability( $existing_id );
		}

		return (int) $booking_id;
	}

	/**
	 * Parse .ics content into array of events.
	 *
	 * @param string $ics_content Raw .ics content.
	 * @return array
	 */
	protected static function parse_ics( $ics_content ) {
		$events    = array();
		$lines     = preg_split( '/\r\n|\r|\n/', $ics_content );
		$in_event  = false;
		$event     = array();

		// Unfold lines (RFC 5545: lines starting with space/tab are continuations)
		$unfolded = array();
		foreach ( $lines as $line ) {
			if ( strlen( $line ) > 0 && ( ' ' === $line[0] || "\t" === $line[0] ) && count( $unfolded ) > 0 ) {
				$unfolded[ count( $unfolded ) - 1 ] .= substr( $line, 1 );
			} else {
				$unfolded[] = $line;
			}
		}

		foreach ( $unfolded as $line ) {
			$line = trim( $line );

			if ( 'BEGIN:VEVENT' === $line ) {
				$in_event = true;
				$event    = array(
					'uid'     => '',
					'summary' => '',
					'start'   => '',
					'end'     => '',
				);
				continue;
			}

			if ( 'END:VEVENT' === $line ) {
				$in_event = false;
				if ( ! empty( $event['uid'] ) ) {
					$events[] = $event;
				}
				continue;
			}

			if ( ! $in_event ) {
				continue;
			}

			// Parse property
			if ( self::line_starts_with( $line, 'UID:' ) ) {
				$event['uid'] = self::extract_value( $line );
			} elseif ( self::line_starts_with( $line, 'SUMMARY' ) ) {
				$event['summary'] = self::unescape_ical( self::extract_value( $line ) );
			} elseif ( self::line_starts_with( $line, 'DTSTART' ) ) {
				$event['start'] = self::parse_ical_date( $line );
			} elseif ( self::line_starts_with( $line, 'DTEND' ) ) {
				$event['end'] = self::parse_ical_date( $line );
			}
		}

		return $events;
	}

	/**
	 * Check if line starts with prefix (case-insensitive for property name).
	 *
	 * @param string $line Line.
	 * @param string $prefix Prefix.
	 * @return bool
	 */
	private static function line_starts_with( $line, $prefix ) {
		return 0 === strncasecmp( $line, $prefix, strlen( $prefix ) );
	}

	/**
	 * Extract value from iCal line (handles parameters like DTSTART;VALUE=DATE:20260315).
	 *
	 * @param string $line Line.
	 * @return string
	 */
	private static function extract_value( $line ) {
		$pos = strpos( $line, ':' );
		return false !== $pos ? substr( $line, $pos + 1 ) : '';
	}

	/**
	 * Parse iCal date to Y-m-d format.
	 *
	 * @param string $line Full iCal line.
	 * @return string
	 */
	private static function parse_ical_date( $line ) {
		$value = self::extract_value( $line );
		$value = trim( $value );

		// All-day: 20260315
		if ( preg_match( '/^(\d{4})(\d{2})(\d{2})$/', $value, $m ) ) {
			return $m[1] . '-' . $m[2] . '-' . $m[3];
		}

		// DateTime: 20260315T100000Z or 20260315T100000
		if ( preg_match( '/^(\d{4})(\d{2})(\d{2})T/', $value ) ) {
			$ts = strtotime( $value );
			return false !== $ts ? gmdate( 'Y-m-d', $ts ) : '';
		}

		return '';
	}

	/**
	 * Unescape iCal text.
	 *
	 * @param string $text Text.
	 * @return string
	 */
	private static function unescape_ical( $text ) {
		$text = str_replace( '\\n', "\n", $text );
		$text = str_replace( '\\,', ',', $text );
		$text = str_replace( '\\;', ';', $text );
		$text = str_replace( '\\\\', '\\', $text );
		return $text;
	}

	/**
	 * Log message.
	 *
	 * @param string $message Message.
	 * @param string $type Type (info|error).
	 */
	private static function log( $message, $type = 'info' ) {
		if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
			$prefix = 'error' === $type ? 'ERROR' : 'INFO';
			error_log( sprintf( '[Yacht Booking - iCal] [%s] %s', $prefix, $message ) );
		}
	}
}