<?php

namespace WooOrderCart\Monitoring;

use WP_REST_Request;
use WP_REST_Response;

class CheckoutMollieFailureProbe {
    private static $instance = null;

    /**
     * @var array<int,array<string,mixed>>
     */
    private $request_context_by_order = [];

    public static function instance(): self {
        if ( null === self::$instance ) {
            self::$instance = new self();
        }

        return self::$instance;
    }

    private function __construct() {
        if ( ! CheckoutTraceConfig::is_enabled() ) {
            return;
        }

        add_action( 'mollie-payments-for-woocommerce_create_payment', [ $this, 'capture_create_payment' ], 10, 2 );
        add_filter( 'mollie-payments-for-woocommerce_return_url', [ $this, 'capture_return_url' ], 10, 2 );
        add_filter( 'mollie-payments-for-woocommerce_webhook_url', [ $this, 'capture_webhook_url' ], 10, 2 );
        add_filter( 'rest_request_after_callbacks', [ $this, 'capture_checkout_failure_details' ], 20, 3 );
    }

    /**
     * @param array<string,mixed> $data
     * @param mixed               $order
     */
    public function capture_create_payment( $data, $order ): void {
        $order_id = $this->resolve_order_id( $order );

        if ( $order_id <= 0 ) {
            return;
        }

        $gateway_id = $this->resolve_gateway_id( $order );
        if ( ! $this->is_mollie_gateway( $gateway_id ) ) {
            return;
        }

        $entry = $this->get_request_context( $order_id );
        $entry['order_id'] = $order_id;
        $entry['gateway_id'] = $gateway_id;
        $entry['payment_request_type'] = $this->resolve_request_type( $data );
        $entry['request_method'] = sanitize_key( (string) ( $data['method'] ?? '' ) );
        $entry['request_locale'] = sanitize_text_field( (string) ( $data['locale'] ?? '' ) );
        $entry['payment_keys'] = $this->sanitize_keys( is_array( $data['payment'] ?? null ) ? array_keys( $data['payment'] ) : [] );
        $entry['has_card_token'] = ! empty( $data['payment']['cardToken'] );
        $entry['line_count'] = is_array( $data['lines'] ?? null ) ? count( $data['lines'] ) : 0;

        if ( isset( $data['redirectUrl'] ) ) {
            $entry['redirect_url'] = (string) $data['redirectUrl'];
        }

        if ( isset( $data['webhookUrl'] ) ) {
            $entry['webhook_url'] = (string) $data['webhookUrl'];
        }

        $this->request_context_by_order[ $order_id ] = $entry;
    }

    /**
     * @param mixed $order
     */
    public function capture_return_url( string $return_url, $order ): string {
        $order_id = $this->resolve_order_id( $order );

        if ( $order_id > 0 ) {
            $entry = $this->get_request_context( $order_id );
            $entry['redirect_url'] = $return_url;
            $entry['gateway_id'] = $this->resolve_gateway_id( $order );
            $this->request_context_by_order[ $order_id ] = $entry;
        }

        return $return_url;
    }

    /**
     * @param mixed $order
     */
    public function capture_webhook_url( string $webhook_url, $order ): string {
        $order_id = $this->resolve_order_id( $order );

        if ( $order_id > 0 ) {
            $entry = $this->get_request_context( $order_id );
            $entry['webhook_url'] = $webhook_url;
            $entry['gateway_id'] = $this->resolve_gateway_id( $order );
            $this->request_context_by_order[ $order_id ] = $entry;
        }

        return $webhook_url;
    }

    /**
     * @param mixed            $response
     * @param array<int,mixed> $handler
     * @return mixed
     */
    public function capture_checkout_failure_details( $response, array $handler, WP_REST_Request $request ) {
        if ( ! $this->is_store_checkout_request( $request ) ) {
            return $response;
        }

        $trace_id = $this->get_trace_id( $request );
        if ( '' === $trace_id ) {
            return $response;
        }

        $status_code = 200;
        if ( is_wp_error( $response ) ) {
            $status_code = 400;
        } elseif ( $response instanceof WP_REST_Response ) {
            $status_code = (int) $response->get_status();
        }

        $gateway_id = sanitize_key( (string) $request->get_param( 'payment_method' ) );

        if ( $status_code < 400 || ! $this->is_mollie_gateway( $gateway_id ) ) {
            return $response;
        }

        $failure_summary = $this->build_failure_summary( $gateway_id );
        $message = (string) ( $failure_summary['message'] ?? '' );

        CheckoutTraceService::record(
            [
                'traceId' => $trace_id,
                'event' => 'mollie_failure_probe',
                'step' => 'review',
                'status' => 'error',
                'origin' => 'backend',
                'gatewayId' => $gateway_id,
                'message' => $message,
                'context' => [
                    'order_id' => (int) ( $failure_summary['order_id'] ?? 0 ),
                    'payment_request_type' => sanitize_key( (string) ( $failure_summary['payment_request_type'] ?? '' ) ),
                    'request_method' => sanitize_key( (string) ( $failure_summary['request_method'] ?? '' ) ),
                    'request_locale' => sanitize_text_field( (string) ( $failure_summary['request_locale'] ?? '' ) ),
                    'has_card_token' => ! empty( $failure_summary['has_card_token'] ),
                    'redirect_url_host' => sanitize_text_field( (string) ( $failure_summary['redirect_url_host'] ?? '' ) ),
                    'redirect_url_scheme' => sanitize_key( (string) ( $failure_summary['redirect_url_scheme'] ?? '' ) ),
                    'webhook_url_host' => sanitize_text_field( (string) ( $failure_summary['webhook_url_host'] ?? '' ) ),
                    'webhook_url_scheme' => sanitize_key( (string) ( $failure_summary['webhook_url_scheme'] ?? '' ) ),
                    'webhook_is_local' => ! empty( $failure_summary['is_local'] ),
                    'webhook_uses_https' => ! empty( $failure_summary['uses_https'] ),
                    'likely_failure_reason' => sanitize_key( (string) ( $failure_summary['reason'] ?? '' ) ),
                    'api_error_field' => sanitize_key( (string) ( $failure_summary['field'] ?? '' ) ),
                    'api_error_status' => (int) ( $failure_summary['status'] ?? 0 ),
                    'mollie_log_excerpt' => is_array( $failure_summary['excerpt'] ?? null ) ? $failure_summary['excerpt'] : [],
                ],
            ]
        );

        return $response;
    }

    /**
     * @return array<string,mixed>
     */
    public function get_failure_summary( string $gateway_id ): array {
        return $this->build_failure_summary( sanitize_key( $gateway_id ) );
    }

    /**
     * @return array<string,mixed>
     */
    private function resolve_failed_order_context( string $gateway_id ): array {
        $matching = [];

        foreach ( $this->request_context_by_order as $order_id => $context ) {
            if ( sanitize_key( (string) ( $context['gateway_id'] ?? '' ) ) !== $gateway_id ) {
                continue;
            }

            $matching[ $order_id ] = $context;
        }

        if ( [] === $matching ) {
            return [];
        }

        end( $matching );

        $latest = current( $matching );

        return is_array( $latest ) ? $latest : [];
    }

    /**
     * @return array<string,mixed>
     */
    private function probe_mollie_log( int $order_id ): array {
        $log_file = $this->resolve_mollie_log_file();

        if ( '' === $log_file || ! is_readable( $log_file ) ) {
            return [];
        }

        $tail_lines = $this->read_log_tail_lines( $log_file, 120 );
        $excerpt = [];

        foreach ( array_reverse( $tail_lines ) as $line ) {
            $normalized = html_entity_decode( wp_strip_all_tags( (string) $line ), ENT_QUOTES, 'UTF-8' );
            $normalized = trim( preg_replace( '/\s+/', ' ', $normalized ) );

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

            if ( $order_id > 0 && false === strpos( $normalized, (string) $order_id ) && false === stripos( $normalized, 'webhook url' ) && false === stripos( $normalized, 'Error executing API call' ) ) {
                continue;
            }

            $excerpt[] = sanitize_text_field( $normalized );

            if ( count( $excerpt ) >= 4 ) {
                break;
            }
        }

        $excerpt = array_reverse( $excerpt );
        $joined = implode( ' | ', $excerpt );

        return [
            'status' => $this->parse_api_status( $joined ),
            'field' => $this->parse_api_field( $joined ),
            'reason' => $this->parse_failure_reason( $joined ),
            'excerpt' => $excerpt,
        ];
    }

    private function resolve_mollie_log_file(): string {
        if ( is_callable( [ '\Automattic\WooCommerce\Utilities\LoggingUtil', 'get_log_directory' ] ) ) {
            // Respect Woo's configured directory without creating it during diagnostics.
            $log_dir = \Automattic\WooCommerce\Utilities\LoggingUtil::get_log_directory( false );
        } else {
            // WooCommerce versions before the logging utility expose the resolved path here.
            $log_dir = defined( 'WC_LOG_DIR' ) ? (string) WC_LOG_DIR : '';
        }

        if ( '' === $log_dir || ! is_dir( $log_dir ) ) {
            return '';
        }

        $matches = glob( trailingslashit( $log_dir ) . 'mollie-payments-for-woocommerce-*.log' );
        $matches = is_array( $matches ) ? array_values( array_filter( $matches, 'is_file' ) ) : [];

        if ( [] === $matches ) {
            return '';
        }

        usort(
            $matches,
            static function ( string $left, string $right ): int {
                return filemtime( $right ) <=> filemtime( $left );
            }
        );

        return (string) $matches[0];
    }

    /**
     * @return array<int,string>
     */
    private function read_log_tail_lines( string $log_file, int $max_lines ): array {
        $size = filesize( $log_file );

        if ( false === $size || $size <= 0 ) {
            return [];
        }

        $offset = max( 0, $size - 65536 );
        // Read a bounded tail, even when the provider log has grown very large.
        $buffer = file_get_contents( $log_file, false, null, $offset, 65536 );

        if ( false === $buffer ) {
            return [];
        }

        $lines = preg_split( "/\r\n|\n|\r/", $buffer );

        if ( ! is_array( $lines ) ) {
            return [];
        }

        return array_values( array_slice( $lines, -1 * absint( $max_lines ) ) );
    }

    /**
     * @param mixed $order
     */
    private function resolve_order_id( $order ): int {
        if ( is_object( $order ) && method_exists( $order, 'get_id' ) ) {
            return (int) $order->get_id();
        }

        return 0;
    }

    /**
     * @param mixed $order
     */
    private function resolve_gateway_id( $order ): string {
        if ( is_object( $order ) && method_exists( $order, 'get_payment_method' ) ) {
            return sanitize_key( (string) $order->get_payment_method() );
        }

        return '';
    }

    private function is_mollie_gateway( string $gateway_id ): bool {
        return 0 === strpos( $gateway_id, 'mollie_wc_gateway_' );
    }

    /**
     * @param array<string,mixed> $data
     */
    private function resolve_request_type( array $data ): string {
        if ( isset( $data['orderNumber'] ) || isset( $data['lines'] ) ) {
            return 'order';
        }

        return 'payment';
    }

    /**
     * @param array<int|string> $keys
     * @return array<int,string>
     */
    private function sanitize_keys( array $keys ): array {
        $sanitized = [];

        foreach ( array_slice( $keys, 0, 8 ) as $key ) {
            $key = sanitize_key( (string) $key );

            if ( '' !== $key ) {
                $sanitized[] = $key;
            }
        }

        return array_values( array_unique( $sanitized ) );
    }

    /**
     * @return array<string,mixed>
     */
    private function summarize_url( string $url ): array {
        if ( '' === $url ) {
            return [];
        }

        $host = (string) wp_parse_url( $url, PHP_URL_HOST );
        $scheme = (string) wp_parse_url( $url, PHP_URL_SCHEME );

        return [
            'host' => $host,
            'scheme' => $scheme,
            'is_local' => $this->is_local_host_value( $host ),
        ];
    }

    private function is_local_host_value( string $host ): bool {
        $host = strtolower( $host );

        if ( '' === $host ) {
            return false;
        }

        return in_array( $host, [ 'localhost', '127.0.0.1', '::1' ], true )
            || '.local' === substr( $host, -6 );
    }

    private function parse_api_status( string $message ): int {
        if ( preg_match( '/API call \\((\\d+):/i', $message, $matches ) ) {
            return (int) $matches[1];
        }

        return 0;
    }

    private function parse_api_field( string $message ): string {
        if ( preg_match( '/Field:\\s*([A-Za-z0-9_]+)/i', $message, $matches ) ) {
            return (string) $matches[1];
        }

        return '';
    }

    private function parse_failure_reason( string $message ): string {
        $message = strtolower( $message );

        if ( false !== strpos( $message, 'webhook url is invalid because it is unreachable' ) ) {
            return 'webhook_url_unreachable';
        }

        if ( false !== strpos( $message, 'webhook url is invalid' ) ) {
            return 'webhook_url_invalid';
        }

        if ( false !== strpos( $message, 'invalid phone number' ) ) {
            return 'invalid_phone_number';
        }

        if ( false !== strpos( $message, 'suspected fraud' ) ) {
            return 'fraud_rejection';
        }

        return '';
    }

    /**
     * @return array<string,mixed>
     */
    private function get_request_context( int $order_id ): array {
        $existing = $this->request_context_by_order[ $order_id ] ?? [];

        return is_array( $existing ) ? $existing : [];
    }

    /**
     * @return array<string,mixed>
     */
    private function build_failure_summary( string $gateway_id ): array {
        if ( ! $this->is_mollie_gateway( $gateway_id ) ) {
            return [];
        }

        $order_context = $this->resolve_failed_order_context( $gateway_id );
        $order_id = (int) ( $order_context['order_id'] ?? 0 );
        $log_probe = $this->probe_mollie_log( $order_id );
        $redirect_summary = $this->summarize_url( (string) ( $order_context['redirect_url'] ?? '' ) );
        $webhook_summary = $this->summarize_url( (string) ( $order_context['webhook_url'] ?? '' ) );

        return [
            'gateway_id' => $gateway_id,
            'order_id' => $order_id,
            'payment_request_type' => sanitize_key( (string) ( $order_context['payment_request_type'] ?? '' ) ),
            'request_method' => sanitize_key( (string) ( $order_context['request_method'] ?? '' ) ),
            'request_locale' => sanitize_text_field( (string) ( $order_context['request_locale'] ?? '' ) ),
            'has_card_token' => ! empty( $order_context['has_card_token'] ),
            'redirect_url_host' => sanitize_text_field( (string) ( $redirect_summary['host'] ?? '' ) ),
            'redirect_url_scheme' => sanitize_key( (string) ( $redirect_summary['scheme'] ?? '' ) ),
            'webhook_url_host' => sanitize_text_field( (string) ( $webhook_summary['host'] ?? '' ) ),
            'webhook_url_scheme' => sanitize_key( (string) ( $webhook_summary['scheme'] ?? '' ) ),
            'is_local' => ! empty( $webhook_summary['is_local'] ),
            'uses_https' => 'https' === ( $webhook_summary['scheme'] ?? '' ),
            'reason' => sanitize_key( (string) ( $log_probe['reason'] ?? '' ) ),
            'field' => sanitize_key( (string) ( $log_probe['field'] ?? '' ) ),
            'status' => (int) ( $log_probe['status'] ?? 0 ),
            'excerpt' => is_array( $log_probe['excerpt'] ?? null ) ? $log_probe['excerpt'] : [],
            'message' => $this->build_failure_message( $log_probe ),
        ];
    }

    private function build_failure_message( array $log_probe ): string {
        $reason = sanitize_key( (string) ( $log_probe['reason'] ?? '' ) );
        $field = sanitize_key( (string) ( $log_probe['field'] ?? '' ) );
        $status = (int) ( $log_probe['status'] ?? 0 );
        $excerpt = is_array( $log_probe['excerpt'] ?? null ) ? $log_probe['excerpt'] : [];

        if ( '' !== $reason ) {
            return trim( sprintf( '%s%s%s', $reason, $field ? ' (' . $field . ')' : '', $status > 0 ? ' [' . $status . ']' : '' ) );
        }

        if ( ! empty( $excerpt ) ) {
            return (string) $excerpt[ count( $excerpt ) - 1 ];
        }

        return 'mollie_failure_probe';
    }

    private function is_store_checkout_request( WP_REST_Request $request ): bool {
        if ( 'POST' !== strtoupper( $request->get_method() ) ) {
            return false;
        }

        return in_array( $request->get_route(), [ '/wc/store/v1/checkout', '/wc/store/v1/checkout-order' ], true );
    }

    private function get_trace_id( ?WP_REST_Request $request = null ): string {
        $trace_id = '';

        if ( $request instanceof WP_REST_Request ) {
            $trace_id = (string) $request->get_header( 'X-IPS-Checkout-Trace' );
        }

        if ( '' === $trace_id ) {
            $trace_id = isset( $_SERVER['HTTP_X_IPS_CHECKOUT_TRACE'] ) ? sanitize_key( wp_unslash( $_SERVER['HTTP_X_IPS_CHECKOUT_TRACE'] ) ) : '';
        }

        return sanitize_key( $trace_id );
    }
}