<?php
/**
 * Registers [bookline_booking] and conditionally enqueues the Preact widget.
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline\Presentation\Frontend;

use Bookline\Application\BookingForm\BookingFormThemeCss;
use Bookline\Domain\BookingForm\BookingForm;
use Bookline\Domain\BookingForm\BookingFormRepository;
use Bookline\Domain\Edition\NamedFeatureGate;
use Bookline\Domain\Payment\PaymentGatewayRegistry;
use Bookline\Plugin;
use Bookline\Presentation\CommercialRuntime;

/**
 * Primary booking form shortcode (docs/09 §3).
 */
final class BookingShortcode {

	private const SHORTCODE = 'bookline_booking';

	/**
	 * Normalise a WP timezone string into something the JS widget and PHP
	 * `DateTimeZone` constructor both accept.
	 *
	 * WP returns either an IANA name (`Europe/London`) or a fixed offset
	 * (`+00:00`, `-05:00`). PHP's `DateTimeZone` constructor accepts `UTC`
	 * and the IANA name but rejects `+00:00` on PHP < 8.3 and is fragile
	 * across versions, so we convert offsets into POSIX Etc/GMT names that
	 * PHP and JS both accept reliably (`Etc/GMT+5` ≡ UTC-5).
	 *
	 * Fallback: UTC. Better to lose the user's local zone than to crash the
	 * validator with a malformed zone and block every booking at this step.
	 *
	 * @param string $tz Timezone string from `wp_timezone_string()`.
	 */
	public static function normalise_timezone( string $tz ): string {
		$tz = trim( $tz );
		if ( '' === $tz ) {
			return 'UTC';
		}

		// Pass through known-safe values.
		if (
			'UTC' === strtoupper( $tz )
			|| 0 === strpos( $tz, 'Etc/' )
			|| preg_match( '/^[A-Z][a-zA-Z_\/]+$/', $tz ) === 1
		) {
			return $tz;
		}

		// Offset like "+00:00", "-05:00", "+00", or "UTC+0".
		if ( preg_match( '/^([+\-])(\d{1,2})(?::?(\d{2}))?$/', $tz, $m ) === 1 ) {
			$sign    = $m[1];
			$hours   = (int) $m[2];
			$minutes = isset( $m[3] ) ? (int) $m[3] : 0;
			if ( $hours > 14 || $minutes > 59 ) {
				return 'UTC';
			}
			// POSIX Etc/GMT names invert the sign intentionally
			// (PHP/JS standard): Etc/GMT+5 ≡ UTC-5.
			$posix_sign = ( '-' === $sign ) ? '+' : '-';
			$offset     = sprintf( 'Etc/GMT%s%d', $posix_sign, $hours );
			if ( 0 !== $minutes ) {
				// Half-hour and 45-minute zones: pick the closest canonical Etc/GMT.
				// PHP/JS only support whole-hour in `Etc/GMT*`, so fall back to UTC
				// for non-standard offsets rather than round (the BookingSession
				// still records the original offset separately — see docs/09 §6).
				return 'UTC';
			}
			return $offset;
		}

		// `UTC+0`, `UTC-5` form.
		if ( preg_match( '/^UTC([+\-])(\d{1,2})$/i', $tz, $m ) === 1 ) {
			$sign  = strtoupper( $m[1] );
			$hours = (int) $m[2];
			if ( $hours > 14 ) {
				return 'UTC';
			}
			$posix_sign = ( '-' === $sign ) ? '+' : '-';
			return sprintf( 'Etc/GMT%s%d', $posix_sign, $hours );
		}

		return 'UTC';
	}

	/**
	 * Hook registration.
	 */
	public static function register(): void {
		add_shortcode( self::SHORTCODE, [ self::class, 'render' ] );
		add_action( 'wp_enqueue_scripts', [ self::class, 'maybe_enqueue' ], 20 );
		add_action( 'wp_footer', [ self::class, 'footer_fallback_enqueue' ], 5 );
	}

	/**
	 * Whether the current request should load widget assets.
	 */
	public static function should_enqueue(): bool {
		if ( ! CommercialRuntime::is_operational() ) {
			return false;
		}

		/**
		 * Filter whether widget assets should load on this request.
		 *
		 * @var bool $forced
		 */
		$forced = apply_filters( 'bookline/frontend/should_enqueue', false );
		if ( $forced ) {
			return true;
		}

		if ( ! is_singular() ) {
			return false;
		}

		$post = get_post();
		if ( ! $post instanceof \WP_Post ) {
			return false;
		}

		return has_shortcode( $post->post_content, self::SHORTCODE );
	}

	/**
	 * Enqueue widget script when the shortcode is on the page.
	 */
	public static function maybe_enqueue(): void {
		if ( ! self::should_enqueue() ) {
			return;
		}
		self::enqueue_assets();
	}

	/**
	 * Late fallback for builder-injected shortcodes.
	 */
	public static function footer_fallback_enqueue(): void {
		if ( wp_script_is( 'bookline-widget', 'enqueued' ) ) {
			return;
		}
		if ( ! self::should_enqueue() ) {
			return;
		}
		self::enqueue_assets();
	}

	/**
	 * Register and enqueue built widget assets.
	 */
	private static function enqueue_assets(): void {
		$asset_file = BOOKLINE_PATH . 'assets/dist/widget.asset.php';
		$script     = BOOKLINE_URL . 'assets/dist/widget.js';

		$deps    = [];
		$version = BOOKLINE_VERSION;

		if ( is_readable( $asset_file ) ) {
			/**
			 * Built asset metadata from @wordpress/scripts.
			 *
			 * @var array{dependencies?: string[], version?: string} $asset
			 */
			$asset   = require $asset_file;
			$deps    = $asset['dependencies'] ?? [];
			$version = $asset['version'] ?? BOOKLINE_VERSION;
		}

		wp_enqueue_style(
			'bookline-widget-tokens',
			BOOKLINE_URL . 'assets/tokens.css',
			[],
			(string) filemtime( BOOKLINE_PATH . 'assets/tokens.css' )
		);

		wp_enqueue_style(
			'bookline-widget-fonts',
			BOOKLINE_URL . 'assets/fonts.css',
			[],
			(string) filemtime( BOOKLINE_PATH . 'assets/fonts.css' )
		);

		$style = BOOKLINE_URL . 'assets/dist/widget.css';
		wp_enqueue_style(
			'bookline-widget',
			$style,
			[ 'bookline-widget-tokens', 'bookline-widget-fonts' ],
			$version
		);
		wp_register_script(
			'bookline-widget',
			$script,
			$deps,
			$version,
			true
		);
		wp_enqueue_script( 'bookline-widget' );
	}

	/**
	 * Render widget mount point.
	 *
	 * @param array<string, string>|string $atts Shortcode attributes.
	 */
	public static function render( $atts = [] ): string {
		if ( ! CommercialRuntime::is_operational() ) {
			return '<div class="bookline-widget bookline-widget--unavailable" role="status">'
				. esc_html__( 'Booking is unavailable.', 'buildler' )
				. '</div>';
		}

		$atts = shortcode_atts(
			[
				'form'     => '1',
				'service'  => '',
				'agent'    => '',
				'location' => '',
				'category' => '',
				'mode'     => 'inline',
			],
			is_array( $atts ) ? $atts : [],
			self::SHORTCODE
		);

		$form_id = max( 1, (int) $atts['form'] );
		$theme   = self::theme_for_form( $form_id );
		$payload = [
			'restUrl'  => esc_url_raw( rest_url( 'bookline/v1' ) ),
			'nonce'    => wp_create_nonce( 'wp_rest' ),
			'formId'   => $form_id,
			'timezone' => self::normalise_timezone( wp_timezone_string() ),
			'locale'   => str_replace( '_', '-', get_locale() ),
			'theme'    => $theme,
		];
		$listed = self::named_entitlements();
		if ( is_array( $listed ) ) {
			$payload['entitlements'] = $listed;
		}
		$paypal = self::paypal_widget_config();
		if ( is_array( $paypal ) ) {
			$payload = array_merge( $payload, $paypal );
		}

		$config = wp_json_encode( $payload );

		if ( ! is_string( $config ) ) {
			$config = '{}';
		}

		$classes = 'bookline-widget bookline-widget-root bookline-surface';
		if ( 'inline' !== $atts['mode'] ) {
			$classes .= ' bookline-widget--' . sanitize_html_class( (string) $atts['mode'] );
		}

		$extra = '';
		foreach ( BookingFormThemeCss::html_attributes( $theme ) as $name => $value ) {
			$extra .= sprintf( ' %s="%s"', esc_attr( $name ), esc_attr( $value ) );
		}

		return sprintf(
			'<div class="%1$s" id="bookline-widget-%2$s" data-config="%3$s" data-form-id="%4$d"%5$s></div>',
			esc_attr( $classes ),
			esc_attr( wp_unique_id( 'bl' ) ),
			esc_attr( $config ),
			$form_id,
			$extra
		);
	}

	/**
	 * Load the six theme knobs for a published form, or the product defaults.
	 *
	 * @param int $form_id Form id from the shortcode.
	 * @return array<string, string>
	 */
	private static function theme_for_form( int $form_id ): array {
		$theme = BookingForm::default_theme();
		try {
			$forms = Plugin::container()->get( BookingFormRepository::class );
			if ( ! $forms instanceof BookingFormRepository ) {
				return $theme;
			}
			$form = $forms->find_by_id( $form_id );
			if ( $form instanceof BookingForm ) {
				return $form->theme();
			}
		} catch ( \Throwable ) {
			return $theme;
		}
		return $theme;
	}

	/**
	 * Commercial plan keys, or null when this zip is unrestricted.
	 *
	 * @return list<string>|null
	 */
	private static function named_entitlements(): ?array {
		try {
			$gate = Plugin::container()->get( NamedFeatureGate::class );
			if ( $gate instanceof NamedFeatureGate ) {
				return $gate->listed();
			}
		} catch ( \Throwable ) {
			return null;
		}
		return null;
	}

	/**
	 * Public PayPal JS config when the commercial gateway is registered and configured.
	 *
	 * @return array{paypalClientId: string, paypalSandbox: bool}|null
	 */
	private static function paypal_widget_config(): ?array {
		try {
			$registry = Plugin::container()->get( PaymentGatewayRegistry::class );
			if ( ! $registry instanceof PaymentGatewayRegistry || ! $registry->has( 'paypal' ) ) {
				return null;
			}
			$gateway = $registry->get( 'paypal' );
			if ( ! $gateway->is_configured() ) {
				return null;
			}
			$cfg = $gateway->client_config();
			$id  = is_string( $cfg['client_id'] ?? null ) ? trim( (string) $cfg['client_id'] ) : '';
			if ( '' === $id ) {
				return null;
			}
			return [
				'paypalClientId' => $id,
				'paypalSandbox'  => (bool) ( $cfg['sandbox'] ?? true ),
			];
		} catch ( \Throwable ) {
			return null;
		}
	}
}