<?php
/**
 * Named events, and the webhooks that carry them out of WordPress.
 *
 * @package AiRankSuite
 */

declare(strict_types=1);

namespace AiRankSuite\Support;

use WP_Error;

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

/**
 * The plugin already does the work: audits finish, scans finish, the score
 * moves, the autopilot writes. None of that reached anything outside the
 * WordPress process — no Slack channel, no Zapier zap, no agency dashboard.
 * A webhook is the smallest thing that fixes it: a URL, a subset of events,
 * a shared secret, and a signed POST when the thing happens.
 *
 * Every event also fires as a WordPress action (`airanksuite/event`, and
 * `airanksuite/event/{name}`), so a developer on the same install needs no HTTP at
 * all.
 */
final class Events {

	private const OPTION = 'airanksuite_webhooks';
	private const LOG    = 'airanksuite_webhook_log';
	private const LOG_MAX = 40;
	private const MAX_HOOKS = 20;

	/**
	 * The catalogue. Kept short and stable: an event is a contract, and a
	 * consumer that wrote a zap against it must not find it renamed.
	 *
	 * @return array<string, array{label: string, detail: string}>
	 */
	public static function catalogue(): array {
		return array(
			'audit.finished'      => array( 'label' => __( 'Site audit finished', 'ai-rank-suite' ), 'detail' => __( 'Score, totals by severity, pages checked, run id.', 'ai-rank-suite' ) ),
			'links.finished'      => array( 'label' => __( 'Link scan finished', 'ai-rank-suite' ), 'detail' => __( 'Links found, broken, redirected.', 'ai-rank-suite' ) ),
			'score.recalculated'  => array( 'label' => __( 'AI search score recalculated', 'ai-rank-suite' ), 'detail' => __( 'Overall score and its dimensions.', 'ai-rank-suite' ) ),
			'visibility.finished' => array( 'label' => __( 'Answer simulation run finished', 'ai-rank-suite' ), 'detail' => __( 'Prompts checked, mentions, run id.', 'ai-rank-suite' ) ),
			'autopilot.applied'   => array( 'label' => __( 'Autopilot applied a change', 'ai-rank-suite' ), 'detail' => __( 'Post id, task, before and after — one call per change.', 'ai-rank-suite' ) ),
			'content.analyzed'    => array( 'label' => __( 'Page analysed', 'ai-rank-suite' ), 'detail' => __( 'Post id and its GEO/SEO scores. Frequent during bulk runs.', 'ai-rank-suite' ) ),
			'cache.purged'        => array( 'label' => __( 'Caches purged', 'ai-rank-suite' ), 'detail' => __( 'Which caches were cleared.', 'ai-rank-suite' ) ),
			// Code that runs on the site changed hands: who, when and what — the
			// trail a security review asks for first.
			'snippet.saved'       => array( 'label' => __( 'Code snippet created or changed', 'ai-rank-suite' ), 'detail' => __( 'Snippet id, name, kind, whether it is active, and the user who saved it.', 'ai-rank-suite' ) ),
			'snippet.activated'   => array( 'label' => __( 'Code snippet switched on', 'ai-rank-suite' ), 'detail' => __( 'Snippet id, name, kind and the user who switched it on. Runs from the next request.', 'ai-rank-suite' ) ),
			'webhook.test'        => array( 'label' => __( 'Test ping', 'ai-rank-suite' ), 'detail' => __( 'Sent by the Test button.', 'ai-rank-suite' ) ),
		);
	}

	/**
	 * Announce an event: WordPress actions first, then every subscribed
	 * webhook. Delivery is deferred to shutdown so the request that did the
	 * work never waits on somebody else's server.
	 *
	 * @param string               $name    Event name from the catalogue.
	 * @param array<string, mixed> $payload Event data.
	 */
	public static function emit( string $name, array $payload = array() ): void {
		if ( ! isset( self::catalogue()[ $name ] ) ) {
			return;
		}
		$envelope = array(
			'event'   => $name,
			'site'    => home_url( '/' ),
			'time'    => time(),
			'version' => defined( 'AIRANKSUITE_VERSION' ) ? AIRANKSUITE_VERSION : '',
			'data'    => $payload,
		);

		/**
		 * Fires for every plugin event.
		 *
		 * @param string               $name     Event name.
		 * @param array<string, mixed> $envelope Full envelope (event, site, time, data).
		 */
		do_action( 'airanksuite/event', $name, $envelope );
		do_action( 'airanksuite/event/' . $name, $envelope );

		$targets = array_filter(
			self::hooks(),
			static fn( array $h ) => ! empty( $h['active'] ) && in_array( $name, (array) $h['events'], true )
		);
		if ( empty( $targets ) ) {
			return;
		}

		$deliver = static function () use ( $targets, $envelope ): void {
			foreach ( $targets as $hook ) {
				self::deliver( $hook, $envelope );
			}
		};
		if ( did_action( 'shutdown' ) || ( defined( 'WP_CLI' ) && WP_CLI ) || wp_doing_cron() ) {
			$deliver();
		} else {
			add_action( 'shutdown', $deliver, 99 );
		}
	}

	/**
	 * One signed POST. The signature is HMAC-SHA256 of the raw body with the
	 * hook's secret, in `X-AIRS-Signature` — the shape GitHub and Stripe use,
	 * so every consumer already knows how to verify it.
	 *
	 * @param array<string, mixed> $hook     Webhook record.
	 * @param array<string, mixed> $envelope Payload.
	 * @return array{ok: bool, status: int, ms: int, error: string}
	 */
	public static function deliver( array $hook, array $envelope ): array {
		$body   = (string) wp_json_encode( $envelope );
		$secret = isset( $hook['secret'] ) ? (string) Secret::decrypt( (string) $hook['secret'] ) : '';
		$start  = microtime( true );

		$response = wp_remote_post(
			(string) $hook['url'],
			array(
				'timeout'     => 8,
				'redirection' => 0,
				'headers'     => array(
					'Content-Type'      => 'application/json',
					'User-Agent'        => 'AI-Rank Suite-Webhook/' . ( defined( 'AIRANKSUITE_VERSION' ) ? AIRANKSUITE_VERSION : '0' ),
					'X-AIRS-Event'      => (string) $envelope['event'],
					'X-AIRS-Delivery'   => wp_generate_uuid4(),
					'X-AIRS-Signature'  => 'sha256=' . hash_hmac( 'sha256', $body, $secret ),
				),
				'body'        => $body,
			)
		);
		$ms = (int) round( ( microtime( true ) - $start ) * 1000 );

		if ( $response instanceof WP_Error ) {
			$result = array( 'ok' => false, 'status' => 0, 'ms' => $ms, 'error' => $response->get_error_message() );
		} else {
			$code   = (int) wp_remote_retrieve_response_code( $response );
			$result = array( 'ok' => $code >= 200 && $code < 300, 'status' => $code, 'ms' => $ms, 'error' => $code >= 300 ? substr( (string) wp_remote_retrieve_body( $response ), 0, 200 ) : '' );
		}

		self::log( (string) $hook['id'], (string) $envelope['event'], $result );
		self::touch( (string) $hook['id'], $result );

		return $result;
	}

	// ---------------------------------------------------------- storage --

	/** @return array<int, array<string, mixed>> */
	public static function hooks(): array {
		$hooks = get_option( self::OPTION, array() );
		return is_array( $hooks ) ? array_values( $hooks ) : array();
	}

	/**
	 * Hooks as the API returns them: secret masked, never decrypted.
	 *
	 * @return array<int, array<string, mixed>>
	 */
	public static function public_hooks(): array {
		return array_map(
			static function ( array $h ): array {
				$h['has_secret'] = ! empty( $h['secret'] );
				unset( $h['secret'] );
				return $h;
			},
			self::hooks()
		);
	}

	/**
	 * Create or update.
	 *
	 * @param array<string, mixed> $input id?, url, events[], secret?, active?
	 * @return array<string, mixed>|WP_Error The stored hook (masked).
	 */
	public static function save( array $input ) {
		$url = esc_url_raw( trim( (string) ( $input['url'] ?? '' ) ) );
		if ( '' === $url || ! preg_match( '#^https?://#i', $url ) ) {
			return new WP_Error( 'airanksuite_webhook_url', __( 'A webhook needs an http(s) URL.', 'ai-rank-suite' ), array( 'status' => 400 ) );
		}
		if ( ! self::url_is_public( $url ) ) {
			return new WP_Error( 'airanksuite_webhook_url', __( 'That address is private or local — a webhook must point at a public host.', 'ai-rank-suite' ), array( 'status' => 400 ) );
		}
		$events = array_values( array_intersect( array_map( 'strval', (array) ( $input['events'] ?? array() ) ), array_keys( self::catalogue() ) ) );
		if ( empty( $events ) ) {
			return new WP_Error( 'airanksuite_webhook_events', __( 'Pick at least one event.', 'ai-rank-suite' ), array( 'status' => 400 ) );
		}

		$hooks = self::hooks();
		$id    = (string) ( $input['id'] ?? '' );
		$index = null;
		foreach ( $hooks as $i => $h ) {
			if ( $id !== '' && $h['id'] === $id ) {
				$index = $i;
			}
		}
		if ( null === $index && count( $hooks ) >= self::MAX_HOOKS ) {
			/* translators: %d: maximum number of webhooks. */
			return new WP_Error( 'airanksuite_webhook_max', sprintf( __( 'Up to %d webhooks.', 'ai-rank-suite' ), self::MAX_HOOKS ), array( 'status' => 400 ) );
		}

		$current = null === $index ? array( 'id' => wp_generate_uuid4(), 'created' => time(), 'secret' => '' ) : $hooks[ $index ];
		$secret  = (string) ( $input['secret'] ?? '' );
		if ( '' !== $secret ) {
			$current['secret'] = Secret::encrypt( $secret );
		} elseif ( empty( $current['secret'] ) ) {
			// No secret given: mint one, and hand it back exactly once.
			$minted            = wp_generate_password( 32, false );
			$current['secret'] = Secret::encrypt( $minted );
			$current['minted'] = $minted;
		}
		$current['url']    = $url;
		$current['events'] = $events;
		$current['active'] = ! isset( $input['active'] ) || ! empty( $input['active'] );
		$current['label']  = sanitize_text_field( (string) ( $input['label'] ?? '' ) );

		if ( null === $index ) {
			$hooks[] = $current;
		} else {
			$hooks[ $index ] = $current;
		}
		update_option( self::OPTION, array_values( $hooks ), false );

		$out = $current;
		unset( $out['secret'] );
		$out['has_secret'] = true;
		return $out;
	}

	public static function delete( string $id ): void {
		$hooks = array_values( array_filter( self::hooks(), static fn( array $h ) => $h['id'] !== $id ) );
		update_option( self::OPTION, $hooks, false );
	}

	/** @return array<string, mixed>|null */
	public static function find( string $id ): ?array {
		foreach ( self::hooks() as $h ) {
			if ( $h['id'] === $id ) {
				return $h;
			}
		}
		return null;
	}

	/**
	 * Refuse loopback, private ranges and bare hostnames — a webhook that
	 * points at the server itself or at the internal network is the classic
	 * SSRF hole, and nothing legitimate needs it.
	 */
	private static function url_is_public( string $url ): bool {
		$host = strtolower( (string) wp_parse_url( $url, PHP_URL_HOST ) );
		if ( '' === $host || 'localhost' === $host || str_ends_with( $host, '.local' ) || str_ends_with( $host, '.internal' ) ) {
			return false;
		}
		if ( filter_var( $host, FILTER_VALIDATE_IP ) ) {
			return (bool) filter_var( $host, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE );
		}
		return str_contains( $host, '.' );
	}

	/**
	 * @param array{ok: bool, status: int, ms: int, error: string} $result Delivery result.
	 */
	private static function log( string $hook_id, string $event, array $result ): void {
		$log = get_option( self::LOG, array() );
		$log = is_array( $log ) ? $log : array();
		array_unshift(
			$log,
			array(
				'hook'   => $hook_id,
				'event'  => $event,
				'time'   => time(),
				'ok'     => $result['ok'],
				'status' => $result['status'],
				'ms'     => $result['ms'],
				'error'  => $result['error'],
			)
		);
		update_option( self::LOG, array_slice( $log, 0, self::LOG_MAX ), false );
	}

	/** @return array<int, array<string, mixed>> */
	public static function deliveries(): array {
		$log = get_option( self::LOG, array() );
		return is_array( $log ) ? $log : array();
	}

	/**
	 * @param array{ok: bool, status: int, ms: int, error: string} $result Delivery result.
	 */
	private static function touch( string $hook_id, array $result ): void {
		$hooks = self::hooks();
		foreach ( $hooks as $i => $h ) {
			if ( $h['id'] === $hook_id ) {
				$hooks[ $i ]['last']        = time();
				$hooks[ $i ]['last_ok']     = $result['ok'];
				$hooks[ $i ]['last_status'] = $result['status'];
				$hooks[ $i ]['failures']    = $result['ok'] ? 0 : ( (int) ( $h['failures'] ?? 0 ) ) + 1;
			}
		}
		update_option( self::OPTION, $hooks, false );
	}
}