<?php

declare(strict_types=1);

namespace WordPress\CloudflareWorkersAiProvider\Diagnostics;

use WordPress\CloudflareWorkersAiProvider\Routing\TaskContext;

use function WordPress\CloudflareWorkersAiProvider\get_account_id;
use function WordPress\CloudflareWorkersAiProvider\get_plugin_settings;

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

/**
 * The last failed requests to Cloudflare (Workers AI, AI Gateway, Vectorize, Turnstile) and to a
 * Qdrant server, for Help and the diagnostics report.
 *
 * Every request goes through the WordPress HTTP API, so one hook sees them all. A request
 * blocked before it leaves (the AI plugin's connector approval) is caught too. Kept: when, the
 * feature, the service, the address path with the account ID replaced, the model, the HTTP
 * status, Cloudflare's error code and message, its request ID (cf-ray) and how long it took.
 * Never kept: tokens, prompts, answers, or any content. At most 100, for 7 days.
 */
final class ErrorLog
{
    public const OPTION = 'aipcf_recent_errors';

    private const MAX = 100;

    private const KEEP = 7 * DAY_IN_SECONDS;

    /** @var array<string, float> url => microtime the request started */
    private static array $started = [];

    public static function boot(): void
    {
        add_filter('pre_http_request', [self::class, 'start'], 1, 3);
        add_filter('pre_http_request', [self::class, 'blocked'], PHP_INT_MAX, 3);
        add_action('http_api_debug', [self::class, 'capture'], 10, 5);
    }

    /**
     * @param mixed                $pre
     * @param array<string, mixed> $args
     * @return mixed
     */
    public static function start($pre, $args, $url)
    {
        if (is_string($url) && self::service($url) !== '') {
            self::$started[$url] = microtime(true);
        }
        return $pre;
    }

    /**
     * A request another plugin stopped before it left (it never reaches http_api_debug).
     *
     * @param mixed                $pre
     * @param array<string, mixed> $args
     * @return mixed
     */
    public static function blocked($pre, $args, $url)
    {
        if ($pre instanceof \WP_Error && is_string($url) && self::service($url) !== '') {
            self::capture($pre, 'response', '', is_array($args) ? $args : [], $url);
        }
        return $pre;
    }

    /**
     * @param array<string, mixed>|\WP_Error $response
     * @param array<string, mixed>           $args
     */
    public static function capture($response, $context, $class, $args, $url): void
    {
        if ($context !== 'response' || !is_string($url)) {
            return;
        }
        $service = self::service($url);
        if ($service === '') {
            return;
        }
        $status = is_wp_error($response) ? 0 : (int) wp_remote_retrieve_response_code($response);
        $ms     = isset(self::$started[$url]) ? (int) round((microtime(true) - self::$started[$url]) * 1000) : 0;
        unset(self::$started[$url]);
        if (!is_wp_error($response) && $status < 400) {
            return;
        }

        $code    = '';
        $message = '';
        $ray     = '';
        if (is_wp_error($response)) {
            $code    = (string) $response->get_error_code();
            $message = $response->get_error_message();
        } else {
            $ray  = (string) wp_remote_retrieve_header($response, 'cf-ray');
            $body = json_decode((string) wp_remote_retrieve_body($response), true);
            if (is_array($body) && isset($body['errors'][0]) && is_array($body['errors'][0])) {
                $code    = (string) ($body['errors'][0]['code'] ?? '');
                $message = (string) ($body['errors'][0]['message'] ?? '');
            } elseif (is_array($body) && isset($body['status']['error'])) {
                $message = (string) $body['status']['error']; // Qdrant
            }
        }

        self::record([
            'time'    => time(),
            'feature' => TaskContext::current(),
            'service' => $service,
            'path'    => self::path($url),
            'model'   => self::model($url, $args),
            'status'  => $status,
            'code'    => mb_substr($code, 0, 60),
            'message' => mb_substr(Redact::text($message), 0, 200),
            'ray'     => mb_substr($ray, 0, 40),
            'ms'      => $ms,
        ]);
    }

    /**
     * @param array{time: int, feature: string, service: string, path: string, model: string, status: int, code: string, message: string, ray: string, ms: int} $entry
     */
    public static function record(array $entry): void
    {
        $all   = self::all();
        array_unshift($all, $entry);
        $since = time() - self::KEEP;
        $all   = array_values(array_filter($all, static fn(array $e): bool => (int) ($e['time'] ?? 0) >= $since));
        update_option(self::OPTION, array_slice($all, 0, self::MAX), false);
    }

    /**
     * Newest first.
     *
     * @return list<array{time: int, feature: string, service: string, path: string, model: string, status: int, code: string, message: string, ray: string, ms: int}>
     */
    public static function all(): array
    {
        $all = get_option(self::OPTION, []);
        return is_array($all) ? array_values(array_filter($all, 'is_array')) : [];
    }

    public static function countSince(int $seconds): int
    {
        $since = time() - $seconds;
        return count(array_filter(self::all(), static fn(array $e): bool => (int) ($e['time'] ?? 0) >= $since));
    }

    public static function clear(): void
    {
        delete_option(self::OPTION);
    }

    /**
     * Which service a URL belongs to, or '' for one this log does not watch.
     */
    public static function service(string $url): string
    {
        $host = strtolower((string) wp_parse_url($url, PHP_URL_HOST));
        if ($host === 'gateway.ai.cloudflare.com') {
            return 'gateway';
        }
        if ($host === 'challenges.cloudflare.com') {
            return 'turnstile';
        }
        if ($host === 'api.cloudflare.com') {
            return strpos($url, '/vectorize/') !== false ? 'vectorize' : 'workers-ai';
        }
        $qdrant = (string) (get_plugin_settings()['qdrant_url'] ?? '');
        if ($qdrant !== '' && strpos($url, untrailingslashit($qdrant)) === 0) {
            return 'qdrant';
        }
        return '';
    }

    /**
     * The address path, without the host, the query or the account ID.
     */
    public static function path(string $url): string
    {
        $path    = (string) wp_parse_url($url, PHP_URL_PATH);
        $account = get_account_id();
        if ($account !== '') {
            $path = str_replace($account, '{account}', $path);
        }
        return (string) preg_replace('#/accounts/[0-9a-f]{32}#i', '/accounts/{account}', $path);
    }

    /**
     * The model a request was for: in the path (/ai/run/@cf/...) or in the JSON body.
     *
     * @param array<string, mixed> $args
     */
    private static function model(string $url, array $args): string
    {
        if (preg_match('#/ai/run/(@[^?]+)#', $url, $m)) {
            return mb_substr($m[1], 0, 100);
        }
        $body = isset($args['body']) && is_string($args['body']) ? json_decode($args['body'], true) : null;
        return is_array($body) && isset($body['model']) && is_string($body['model']) ? mb_substr($body['model'], 0, 100) : '';
    }
}