<?php
namespace AdvancedAddons;

use WordPress\AiClient\AiClient;
use WordPress\AiClientDependencies\Psr\SimpleCache\CacheInterface;

/**
 * Persistent, site-scoped metadata cache for the WordPress AI Client.
 *
 * The upstream client requests a 24 hour model-directory TTL. Keep the cache
 * deliberately shorter so provider model changes propagate reasonably quickly.
 */
class AI_Client_Transient_Cache implements CacheInterface {
	private const MAX_TTL = 6 * HOUR_IN_SECONDS;
	private const VERSION_OPTION = 'advanced_addons_ai_cache_version';

	private function normalize_key( $key ): string {
		return 'aa_ai_' . get_current_blog_id() . '_' . $this->version() . '_' . hash( 'sha256', strval( $key ) );
	}

	private function version(): string {
		$version = get_site_option( self::VERSION_OPTION, '' );
		if ( ! is_string( $version ) || '' === $version ) {
			$version = wp_generate_uuid4();
			add_site_option( self::VERSION_OPTION, $version );
			$version = strval( get_site_option( self::VERSION_OPTION, $version ) );
		}
		return hash( 'sha256', $version );
	}

	private function ttl_seconds( $ttl ): int {
		if ( $ttl instanceof \DateInterval ) {
			$now = new \DateTimeImmutable();
			$ttl = $now->add( $ttl )->getTimestamp() - $now->getTimestamp();
		}
		if ( null === $ttl ) {
			return self::MAX_TTL;
		}
		return min( self::MAX_TTL, max( 0, intval( $ttl ) ) );
	}

	public function get( $key, $default = null ) {
		$value = get_site_transient( $this->normalize_key( $key ) );
		if ( ! is_array( $value ) || ! array_key_exists( 'value', $value ) ) {
			return $default;
		}
		return $value['value'];
	}

	public function set( $key, $value, $ttl = null ) {
		$seconds = $this->ttl_seconds( $ttl );
		if ( 0 === $seconds ) {
			return $this->delete( $key );
		}
		return set_site_transient( $this->normalize_key( $key ), array( 'value' => $value ), $seconds );
	}

	public function delete( $key ) {
		return delete_site_transient( $this->normalize_key( $key ) );
	}

	public function clear() {
		return update_site_option( self::VERSION_OPTION, wp_generate_uuid4() );
	}

	public function getMultiple( $keys, $default = null ) {
		$values = array();
		foreach ( $keys as $key ) {
			$values[ $key ] = $this->get( $key, $default );
		}
		return $values;
	}

	public function setMultiple( $values, $ttl = null ) {
		$success = true;
		foreach ( $values as $key => $value ) {
			$success = $this->set( $key, $value, $ttl ) && $success;
		}
		return $success;
	}

	public function deleteMultiple( $keys ) {
		$success = true;
		foreach ( $keys as $key ) {
			$success = $this->delete( $key ) && $success;
		}
		return $success;
	}

	public function has( $key ) {
		$missing = new \stdClass();
		return $missing !== $this->get( $key, $missing );
	}
}

/** Wires the cache and model-list request safeguards into WordPress. */
class AI_Client_Cache_Manager {
	private ?AI_Client_Transient_Cache $owned_cache = null;

	public function __construct() {
		if ( class_exists( AiClient::class ) && null === AiClient::getCache() ) {
			$this->owned_cache = new AI_Client_Transient_Cache();
			AiClient::setCache( $this->owned_cache );
		}

		add_filter( 'http_request_args', array( $this, 'set_model_list_timeout' ), 10, 2 );
		add_action( 'updated_option', array( $this, 'invalidate_for_credential_change' ), 10, 3 );
		add_action( 'added_option', array( $this, 'invalidate_for_added_credential' ), 10, 2 );
		add_action( 'deleted_option', array( $this, 'invalidate_for_deleted_credential' ), 10, 1 );
	}

	public function set_model_list_timeout( array $args, string $url ): array {
		$method = strtoupper( strval( $args['method'] ?? 'GET' ) );
		$path   = strval( wp_parse_url( $url, PHP_URL_PATH ) );
		if ( 'GET' === $method && preg_match( '#/models/?$#', $path ) ) {
			$args['timeout'] = 15;
		}
		return $args;
	}

	public function invalidate_for_credential_change( string $option, $old_value, $value ): void {
		if ( $old_value !== $value ) {
			$this->maybe_invalidate( $option );
		}
	}

	public function invalidate_for_added_credential( string $option, $value ): void {
		$this->maybe_invalidate( $option );
	}

	public function invalidate_for_deleted_credential( string $option ): void {
		$this->maybe_invalidate( $option );
	}

	private function maybe_invalidate( string $option ): void {
		if ( $this->owned_cache && 0 === strpos( $option, 'connectors_ai_' ) && '_api_key' === substr( $option, -8 ) ) {
			$this->owned_cache->clear();
		}
	}
}