<?php

declare(strict_types=1);

namespace App\Services\Crawler;

use App\Models\CrawlRule;
use Illuminate\Http\Client\PendingRequest;
use Illuminate\Support\Facades\Http;

class OpenAiFallbackExtractor
{
    private ?string $lastError = null;

    /**
     * @param array<string, mixed> $options
     * @return array<string, mixed>
     */
    public function extract(CrawlRule $rule, string $html, array $options = []): array
    {
        $this->lastError = null;

        $credentials = $this->resolveCredentials();
        if ($credentials === null) {
            $this->lastError = 'AI credentials not configured.';
            return [];
        }

        $ruleAiOptions = is_array($rule->extractor_config['ai'] ?? null)
            ? $rule->extractor_config['ai']
            : [];
        $mergedOptions = array_merge($ruleAiOptions, $options);

        $model = $this->resolveModel($rule->ai_model, $mergedOptions);
        $temperature = $this->resolveTemperature($mergedOptions);
        $contentMaxChars = $this->resolveContentMaxChars($mergedOptions, 12000);

        $targetSchema = $rule->target_module?->value === 'tool'
            ? 'name, summary, official_url, pricing_type, platform, language, description, logo_url'
            : 'name, summary, provider, modality, deployment_mode, context_window, price_input, price_output, description';

        $defaultUserPrompt = <<<PROMPT
从页面内容中提取结构化字段并输出 JSON。
仅返回 JSON 对象本身，不要 Markdown。
目标字段：{$targetSchema}
字段缺失时请直接省略该字段，不要输出 null。
PROMPT;

        $systemPrompt = $this->resolveSystemPrompt($mergedOptions, '你是一个精确的信息抽取引擎。');
        $userPrompt = $this->resolveUserPrompt($mergedOptions, $defaultUserPrompt);

        $content = $this->requestAiContent(
            credentials: $credentials,
            model: $model,
            temperature: $temperature,
            systemPrompt: $systemPrompt,
            userPrompt: $userPrompt,
            html: $html,
            contentMaxChars: $contentMaxChars,
            stripTags: true,
        );

        return $this->decodeJsonContent($content);
    }

    public function isConfigured(): bool
    {
        return $this->resolveCredentials() !== null;
    }

    public function lastError(): ?string
    {
        return $this->lastError;
    }

    /**
     * @param array<string, mixed> $options
     * @return array<string, mixed>
     */
    public function suggestExtractorConfig(string $targetModule, string $html, array $options = []): array
    {
        $this->lastError = null;

        $credentials = $this->resolveCredentials();
        if ($credentials === null) {
            $this->lastError = 'AI credentials not configured.';
            return [];
        }

        $targetModule = in_array($targetModule, ['tool', 'model'], true) ? $targetModule : 'tool';
        $fields = $targetModule === 'tool'
            ? ['name', 'summary', 'official_url', 'pricing_type', 'platform', 'language', 'description', 'logo_url']
            : ['name', 'summary', 'provider', 'modality', 'deployment_mode', 'context_window', 'price_input', 'price_output', 'description'];

        $defaultUserPrompt = <<<PROMPT
请根据页面 HTML 推断可复用的 XPath 抽取规则，输出格式必须是 JSON：
{
  "list_link_xpath": "...",
  "fields": {
    "name": "...",
    "summary": "..."
  }
}
要求：
1. 仅输出 JSON，不要代码块。
2. fields 至少包含 name 与 summary。
3. 只返回 XPath 字符串，不返回 CSS 选择器。
4. 如果页面看起来是详情页，list_link_xpath 返回空字符串即可。
5. 目标模块是 {$targetModule}，优先考虑字段：{$this->implodeFields($fields)}。
PROMPT;

        $model = $this->resolveModel((string) ($options['model'] ?? null), $options);
        $temperature = $this->resolveTemperature($options);
        $contentMaxChars = $this->resolveContentMaxChars($options, 16000);

        $systemPrompt = $this->resolveSystemPrompt($options, '你是 XPath 规则设计专家，擅长从 HTML 生成稳定的抽取规则。');
        $userPrompt = $this->resolveUserPrompt($options, $defaultUserPrompt);

        $content = $this->requestAiContent(
            credentials: $credentials,
            model: $model,
            temperature: $temperature,
            systemPrompt: $systemPrompt,
            userPrompt: $userPrompt,
            html: $html,
            contentMaxChars: $contentMaxChars,
            stripTags: false,
        );

        $decoded = $this->decodeJsonContent($content);
        if (! is_array($decoded)) {
            $this->lastError = $this->lastError ?: 'AI response is not valid JSON.';
            return [];
        }

        $fieldsConfig = is_array($decoded['fields'] ?? null) ? $decoded['fields'] : [];
        if ($fieldsConfig === []) {
            $this->lastError = $this->lastError ?: 'AI response does not include fields config.';
            return [];
        }

        return [
            'list_link_xpath' => is_string($decoded['list_link_xpath'] ?? null) ? $decoded['list_link_xpath'] : '',
            'fields' => $fieldsConfig,
        ];
    }

    /**
     * @return array{endpoint: string, api_key: string, wire_api: string, disable_response_storage: bool, reasoning_effort: string}|null
     */
    private function resolveCredentials(): ?array
    {
        $apiKey = (string) config('crawler.openai_compatible_key', '');
        $endpoint = $this->resolveEndpoint();

        if ($endpoint === '' || $apiKey === '') {
            return null;
        }

        return [
            'endpoint' => $endpoint,
            'api_key' => $apiKey,
            'wire_api' => $this->resolveWireApi(),
            'disable_response_storage' => (bool) config('crawler.openai_disable_response_storage', false),
            'reasoning_effort' => trim((string) config('crawler.openai_reasoning_effort', '')),
        ];
    }

    private function resolveEndpoint(): string
    {
        $configuredEndpoint = trim((string) config('crawler.openai_compatible_endpoint', ''));
        if ($configuredEndpoint !== '') {
            return $configuredEndpoint;
        }

        $baseUrl = trim((string) config('crawler.openai_compatible_base_url', ''));
        if ($baseUrl === '') {
            return '';
        }

        $baseUrl = rtrim($baseUrl, '/');

        return $this->resolveWireApi() === 'responses'
            ? $baseUrl.'/v1/responses'
            : $baseUrl.'/v1/chat/completions';
    }

    private function resolveWireApi(): string
    {
        $wireApi = strtolower(trim((string) config('crawler.openai_wire_api', 'chat_completions')));

        return $wireApi === 'responses' ? 'responses' : 'chat_completions';
    }

    /**
     * @param string|null $ruleModel
     * @param array<string, mixed> $options
     */
    private function resolveModel(?string $ruleModel, array $options): string
    {
        $model = '';

        if (is_string($options['model'] ?? null)) {
            $model = trim((string) $options['model']);
        }

        if ($model === '' && is_string($ruleModel)) {
            $model = trim($ruleModel);
        }

        if ($model === '') {
            $model = (string) config('crawler.openai_default_model', 'gpt-4o-mini');
        }

        return $model;
    }

    /**
     * @param array<string, mixed> $options
     */
    private function resolveTemperature(array $options): float
    {
        $temperature = is_numeric($options['temperature'] ?? null)
            ? (float) $options['temperature']
            : 0.0;

        return max(0.0, min(2.0, $temperature));
    }

    /**
     * @param array<string, mixed> $options
     */
    private function resolveContentMaxChars(array $options, int $default): int
    {
        $value = is_numeric($options['content_max_chars'] ?? null)
            ? (int) $options['content_max_chars']
            : $default;

        return max(500, min(50000, $value));
    }

    /**
     * @param array<string, mixed> $options
     */
    private function resolveSystemPrompt(array $options, string $default): string
    {
        $prompt = is_string($options['system_prompt'] ?? null)
            ? trim((string) $options['system_prompt'])
            : '';

        return $prompt === '' ? $default : $prompt;
    }

    /**
     * @param array<string, mixed> $options
     */
    private function resolveUserPrompt(array $options, string $default): string
    {
        $prompt = is_string($options['user_prompt'] ?? null)
            ? trim((string) $options['user_prompt'])
            : '';

        return $prompt === '' ? $default : $prompt;
    }

    private function implodeFields(array $fields): string
    {
        return implode(', ', $fields);
    }

    /**
     * @param array{endpoint: string, api_key: string, wire_api: string, disable_response_storage: bool, reasoning_effort: string} $credentials
     */
    private function requestAiContent(
        array $credentials,
        string $model,
        float $temperature,
        string $systemPrompt,
        string $userPrompt,
        string $html,
        int $contentMaxChars,
        bool $stripTags,
    ): string {
        $source = $stripTags ? strip_tags($html) : $html;
        $content = mb_substr($source, 0, $contentMaxChars);

        if ($credentials['wire_api'] === 'responses') {
            return $this->requestResponsesApi(
                credentials: $credentials,
                model: $model,
                systemPrompt: $systemPrompt,
                userPrompt: $userPrompt,
                content: $content,
            );
        }

        return $this->requestChatCompletionsApi(
            credentials: $credentials,
            model: $model,
            temperature: $temperature,
            systemPrompt: $systemPrompt,
            userPrompt: $userPrompt,
            content: $content,
        );
    }

    /**
     * @param array{endpoint: string, api_key: string, wire_api: string, disable_response_storage: bool, reasoning_effort: string} $credentials
     */
    private function requestChatCompletionsApi(
        array $credentials,
        string $model,
        float $temperature,
        string $systemPrompt,
        string $userPrompt,
        string $content,
    ): string {
        try {
            $payload = [
                'model' => $model,
                'temperature' => $temperature,
                'messages' => [
                    ['role' => 'system', 'content' => $systemPrompt],
                    ['role' => 'user', 'content' => $userPrompt."\n\n页面内容：\n".$content],
                ],
            ];

            if ($credentials['disable_response_storage']) {
                $payload['store'] = false;
            }

            if ($credentials['reasoning_effort'] !== '') {
                $payload['reasoning'] = ['effort' => $credentials['reasoning_effort']];
            }

            $response = $this->requestBuilder($credentials['api_key'])
                ->post($credentials['endpoint'], $payload);

            if (! $response->successful()) {
                $this->lastError = sprintf('AI HTTP %d: %s', $response->status(), mb_substr($response->body(), 0, 240));
                return '';
            }

            return (string) data_get($response->json(), 'choices.0.message.content', '');
        } catch (\Throwable $exception) {
            $this->lastError = $exception->getMessage();

            return '';
        }
    }

    /**
     * @param array{endpoint: string, api_key: string, wire_api: string, disable_response_storage: bool, reasoning_effort: string} $credentials
     */
    private function requestResponsesApi(
        array $credentials,
        string $model,
        string $systemPrompt,
        string $userPrompt,
        string $content,
    ): string {
        try {
            $payload = [
                'model' => $model,
                'input' => [
                    [
                        'role' => 'system',
                        'content' => [
                            ['type' => 'input_text', 'text' => $systemPrompt],
                        ],
                    ],
                    [
                        'role' => 'user',
                        'content' => [
                            ['type' => 'input_text', 'text' => $userPrompt."\n\n页面内容：\n".$content],
                        ],
                    ],
                ],
            ];

            if ($credentials['disable_response_storage']) {
                $payload['store'] = false;
            }

            if ($credentials['reasoning_effort'] !== '') {
                $payload['reasoning'] = ['effort' => $credentials['reasoning_effort']];
            }

            $response = $this->requestBuilder($credentials['api_key'])
                ->post($credentials['endpoint'], $payload);

            if (! $response->successful()) {
                $this->lastError = sprintf('AI HTTP %d: %s', $response->status(), mb_substr($response->body(), 0, 240));
                return '';
            }

            $json = $response->json();
            $outputText = (string) data_get($json, 'output_text', '');
            if ($outputText !== '') {
                return $outputText;
            }

            $output = data_get($json, 'output', []);
            if (! is_array($output)) {
                $this->lastError = 'AI output is empty.';
                return '';
            }

            $chunks = [];
            foreach ($output as $item) {
                if (! is_array($item)) {
                    continue;
                }

                $contents = $item['content'] ?? [];
                if (! is_array($contents)) {
                    continue;
                }

                foreach ($contents as $contentItem) {
                    if (! is_array($contentItem)) {
                        continue;
                    }

                    $text = (string) ($contentItem['text'] ?? '');
                    if ($text !== '') {
                        $chunks[] = $text;
                    }
                }
            }

            if ($chunks === []) {
                $this->lastError = 'AI output chunks are empty.';
                return '';
            }

            return implode("\n", $chunks);
        } catch (\Throwable $exception) {
            $this->lastError = $exception->getMessage();

            return '';
        }
    }

    private function requestBuilder(string $apiKey): PendingRequest
    {
        $aiTimeout = (int) config('crawler.ai_timeout_seconds', (int) config('crawler.request_timeout_seconds', 20));
        $request = Http::timeout(max($aiTimeout, 5))
            ->withToken($apiKey);

        if (! (bool) config('crawler.verify_ssl', true)) {
            $request = $request->withoutVerifying();
        }

        $options = [];
        if ((bool) config('crawler.force_ipv4', false)) {
            $options['force_ip_resolve'] = 'v4';
        }

        $dnsServers = trim((string) config('crawler.dns_servers', ''));
        if ($dnsServers !== '' && defined('CURLOPT_DNS_SERVERS')) {
            $options['curl'][CURLOPT_DNS_SERVERS] = $dnsServers;
        }

        if ($options !== []) {
            $request = $request->withOptions($options);
        }

        return $request;
    }

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

        $decoded = json_decode($content, true);
        if (is_array($decoded)) {
            return $decoded;
        }

        if (preg_match('/\{.*\}/s', $content, $matches) === 1) {
            $decoded = json_decode($matches[0], true);

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

        return [];
    }
}