<?php
/**
 * WP AI Client: WP_AI_Client_HTTP_Client class
 *
 * @package WordPress
 * @subpackage AI
 * @since 7.0.0
 */

use WordPress\AiClientDependencies\Psr\Http\Client\ClientInterface;
use WordPress\AiClientDependencies\Psr\Http\Message\RequestInterface;
use WordPress\AiClientDependencies\Psr\Http\Message\ResponseInterface;
use WordPress\AiClientDependencies\Psr\Http\Message\ResponseFactoryInterface;
use WordPress\AiClientDependencies\Psr\Http\Message\StreamFactoryInterface;
use WordPress\AiClient\Providers\Http\Contracts\ClientWithOptionsInterface;
use WordPress\AiClient\Providers\Http\DTO\RequestOptions;
use WordPress\AiClient\Providers\Http\Exception\NetworkException;

/**
 * PSR-18 HTTP Client adapter using WordPress HTTP API.
 *
 * Allows WordPress HTTP functions to be used as a PSR-18 compliant HTTP client
 * for the AI Client SDK.
 *
 * @since 7.0.0
 * @internal Intended only to wire up the PHP AI Client SDK to WordPress's HTTP client.
 * @access private
 */
class WP_AI_Client_HTTP_Client implements ClientInterface, ClientWithOptionsInterface {

    /**
     * Response factory instance.
     *
     * @since 7.0.0
     */
    private ResponseFactoryInterface $response_factory;

    /**
     * Stream factory instance.
     *
     * @since 7.0.0
     */
    private StreamFactoryInterface $stream_factory;

    /**
     * Constructor.
     *
     * @since 7.0.0
     *
     * @param ResponseFactoryInterface $response_factory PSR-17 Response factory.
     * @param StreamFactoryInterface   $stream_factory   PSR-17 Stream factory.
     */
    public function __construct( ResponseFactoryInterface $response_factory, StreamFactoryInterface $stream_factory ) {
        $this->response_factory = $response_factory;
        $this->stream_factory   = $stream_factory;
    }

    /**
     * Sends a PSR-7 request and returns a PSR-7 response.
     *
     * @since 7.0.0
     *
     * @param RequestInterface $request The PSR-7 request.
     * @return ResponseInterface The PSR-7 response.
     *
     * @throws NetworkException If the WordPress HTTP request fails.
     */
    public function sendRequest( RequestInterface $request ): ResponseInterface {
        $args = $this->prepare_wp_args( $request );
        $url  = (string) $request->getUri();

        $response = wp_safe_remote_request( $url, $args );

        if ( is_wp_error( $response ) ) {
            $message = sprintf(
                /* translators: 1: HTTP method (e.g. GET, POST). 2: Request URL. 3: Error message. */
                __( 'Network error occurred while sending %1$s request to %2$s: %3$s' ),
                $request->getMethod(),
                $url,
                $response->get_error_message()
            );
            throw new NetworkException( $message ); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped
        }

        return $this->create_psr_response( $response );
    }

    /**
     * Sends a PSR-7 request with transport options and returns a PSR-7 response.
     *
     * @since 7.0.0
     *
     * @param RequestInterface $request The PSR-7 request.
     * @param RequestOptions   $options Transport options for the request.
     * @return ResponseInterface The PSR-7 response.
     *
     * @throws NetworkException If the WordPress HTTP request fails.
     */
    public function sendRequestWithOptions( RequestInterface $request, RequestOptions $options ): ResponseInterface {
        $args = $this->prepare_wp_args( $request, $options );
        $url  = (string) $request->getUri();

        $response = wp_safe_remote_request( $url, $args );

        if ( is_wp_error( $response ) ) {
            $message = sprintf(
                /* translators: 1: Request URL. 2: Error message. */
                __( 'Network error occurred while sending request to %1$s: %2$s' ),
                $url,
                $response->get_error_message()
            );

            throw new NetworkException(
                $message, // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped
                $response->get_error_code() ? (int) $response->get_error_code() : 0
            );
        }

        return $this->create_psr_response( $response );
    }

    /**
     * Prepares WordPress HTTP API arguments from a PSR-7 request.
     *
     * @since 7.0.0
     *
     * @param RequestInterface    $request The PSR-7 request.
     * @param RequestOptions|null $options Optional transport options for the request.
     * @return array<string, mixed> WordPress HTTP API arguments.
     */
    private function prepare_wp_args( RequestInterface $request, ?RequestOptions $options = null ): array {
        $args = array(
            'method'      => $request->getMethod(),
            'headers'     => $this->prepare_headers( $request ),
            'body'        => $this->prepare_body( $request ),
            'httpversion' => $request->getProtocolVersion(),
            'blocking'    => true,
        );

        if ( null !== $options ) {
            if ( null !== $options->getTimeout() ) {
                $args['timeout'] = $options->getTimeout();
            }

            if ( null !== $options->getMaxRedirects() ) {
                $args['redirection'] = $options->getMaxRedirects();
            }
        }

        return $args;
    }

    /**
     * Prepares headers for WordPress HTTP API.
     *
     * @since 7.0.0
     *
     * @param RequestInterface $request The PSR-7 request.
     * @return array<string, string> Headers array for WordPress HTTP API.
     */
    private function prepare_headers( RequestInterface $request ): array {
        $headers = array();

        foreach ( $request->getHeaders() as $name => $values ) {
            $headers[ (string) $name ] = implode( ', ', $values );
        }

        return $headers;
    }

    /**
     * Prepares request body for WordPress HTTP API.
     *
     * @since 7.0.0
     *
     * @param RequestInterface $request The PSR-7 request.
     * @return string|null The request body.
     */
    private function prepare_body( RequestInterface $request ): ?string {
        $body = $request->getBody();

        if ( $body->getSize() === 0 ) {
            return null;
        }

        if ( $body->isSeekable() ) {
            $body->rewind();
        }

        return (string) $body;
    }

    /**
     * Creates a PSR-7 response from a WordPress HTTP response.
     *
     * @since 7.0.0
     *
     * @param array<string, mixed> $wp_response WordPress HTTP API response array.
     * @return ResponseInterface PSR-7 response.
     */
    private function create_psr_response( array $wp_response ): ResponseInterface {
        $status_code   = wp_remote_retrieve_response_code( $wp_response );
        $reason_phrase = wp_remote_retrieve_response_message( $wp_response );
        $headers       = wp_remote_retrieve_headers( $wp_response );
        $body          = wp_remote_retrieve_body( $wp_response );

        $response = $this->response_factory->createResponse( (int) $status_code, $reason_phrase );

        if ( $headers instanceof WP_HTTP_Requests_Response ) {
            $headers = $headers->get_headers();
        }

        if ( is_array( $headers ) || $headers instanceof Traversable ) {
            foreach ( $headers as $name => $value ) {
                $response = $response->withHeader( $name, $value );
            }
        }

        if ( ! empty( $body ) ) {
            $stream   = $this->stream_factory->createStream( $body );
            $response = $response->withBody( $stream );
        }

        return $response;
    }
}