<?php

namespace App\Controllers;

use App\Models\Config;
use App\Services\AIService;

class ChatController
{
    public static function completions(): void
    {
        $input = json_decode(file_get_contents('php://input'), true);

        $provider = $input['provider'] ?? '';
        $model = $input['model'] ?? '';
        $messages = $input['messages'] ?? [];
        $stream = $input['stream'] ?? true;
        $systemPrompt = $input['systemPrompt'] ?? '';
        $thinkingMode = $input['thinkingMode'] ?? false;

        if (!$provider || !$model || !$messages) {
            http_response_code(400);
            echo json_encode(['success' => false, 'message' => '缺少必要参数（provider、model、messages）']);
            return;
        }

        if (!is_array($messages) || empty($messages)) {
            http_response_code(400);
            echo json_encode(['success' => false, 'message' => 'messages 必须是非空数组']);
            return;
        }

        // 获取供应商配置
        $configRow = Config::getByKey('providers');
        if (!$configRow) {
            http_response_code(500);
            echo json_encode(['success' => false, 'message' => '未找到供应商配置']);
            return;
        }

        $providers = json_decode($configRow['config_value'], true);
        if (!is_array($providers)) {
            http_response_code(500);
            echo json_encode(['success' => false, 'message' => '供应商配置格式错误']);
            return;
        }

        $providerKey = $provider;
        if (!isset($providers[$providerKey])) {
            http_response_code(400);
            echo json_encode(['success' => false, 'message' => '供应商不存在: ' . $providerKey]);
            return;
        }

        $providerConfig = $providers[$providerKey];
        if (empty($providerConfig['enabled'])) {
            http_response_code(400);
            echo json_encode(['success' => false, 'message' => '供应商已禁用: ' . $providerKey]);
            return;
        }

        $models = $providerConfig['models'] ?? [];
        if (!empty($models) && !in_array($model, $models)) {
            http_response_code(400);
            echo json_encode(['success' => false, 'message' => '模型不在供应商支持列表中: ' . $model]);
            return;
        }

        // 非流式模式暂不支持
        if (!$stream) {
            http_response_code(400);
            echo json_encode(['success' => false, 'message' => '当前仅支持流式响应']);
            return;
        }

        // 设置 SSE 响应头
        header('Content-Type: text/event-stream');
        header('Cache-Control: no-cache');
        header('Connection: keep-alive');
        header('X-Accel-Buffering: no');

        // 关闭输出缓冲
        while (ob_get_level()) {
            ob_end_flush();
        }

        $options = [
            'provider' => $providerConfig,
            'systemPrompt' => $systemPrompt,
            'thinkingMode' => (bool) $thinkingMode
        ];

        try {
            AIService::streamChat($providerKey, $model, $messages, $options, function ($chunk, $type = 'content') {
                if ($type === 'thinking') {
                    self::sendSSE(['thinking' => $chunk]);
                } else {
                    self::sendSSE(['content' => $chunk]);
                }
            });

            self::sendSSE('[DONE]');
        } catch (\Throwable $e) {
            self::sendSSE(['type' => 'error', 'message' => $e->getMessage()]);
        }
    }

    private static function sendSSE($data): void
    {
        if (is_string($data)) {
            echo "data: " . $data . "\n\n";
        } else {
            echo "data: " . json_encode($data, JSON_UNESCAPED_UNICODE) . "\n\n";
        }
        flush();
    }
}