<?php

namespace app\api\controller\mcp;

class Mcp extends Base
{
    // 工具定义常量
    private const ADD_FUNCTION = [
        'name' => 'add',
        'description' => '计算两个数字的和',
        'toolType' => 'function',
        'parameters' => [
                'a' => [
                    'description' => '第一个加数（必填）',
                    'example' => 10
                ],
                'b' => [
                    'description' => '第二个加数（必填）',
                    'example' => 20
                ]
        ],
        'metadata' => [
            'capability' => [
                'streaming' => false,
                'batch' => true,
                'transactional' => false
            ],
            'version' => '1.0.0',
            'vendor' => 'MyCompany',
            'protocol' => 'json-rpc-2.0'
        ]
    ];


    public function sse()
    {
        // 设置 CORS 头
        header('Access-Control-Allow-Origin: *');
        header('Access-Control-Allow-Methods: POST, OPTIONS');
        header('Access-Control-Allow-Headers: Content-Type, Authorization');

        // 处理 OPTIONS 预检请求
        if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
            http_response_code(200);
            exit;
        }

        // 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');

        // 获取原始输入
        $input = file_get_contents('php://input');
        file_put_contents('mcp_debug.log', date('Y-m-d H:i:s').' Raw input: '.$input.PHP_EOL, FILE_APPEND);

        // 解析 JSON-RPC 请求
        $request = json_decode($input, true);

        // 处理请求
        if (isset($request['method'])) {
            switch($request['method']) {
                case 'initialize':
                    $this->handleInitializeRequest($request);
                    break;
                case 'function':
                case 'tools/call': // 新增支持tools/call方法
                    $this->handleFunctionRequest($request);
                    break;
                case 'ping':
                    $this->sendJsonRpcResponse($request['id'] ?? null, ['result' => 'pong']);
                    break;
                case 'notifications/initialized':
                    $this->sendJsonRpcResponse($request['id'] ?? null, ['result' => 'success']);
                    break;
                case 'tools/list':
                    $this->sendJsonRpcResponse($request['id'] ?? null, ['tools' => [self::ADD_FUNCTION]]);
                    break;
                default:
                    $this->handleOtherRequests($request);
            }
        } else {
            $this->handleOtherRequests($request);
        }
    }

    /**
     * 处理初始化请求
     */
    private function handleInitializeRequest($request)
    {
        $id = $request['id'] ?? null;

        // 记录完整的初始化请求内容
        file_put_contents('mcp_debug.log', "Received initialize request: " . json_encode($request) . PHP_EOL, FILE_APPEND);

        // 发送初始化响应
        $this->sendJsonRpcResponse($id, [
            'capabilities' => [
                'progress' => true,
                'functions' => [self::ADD_FUNCTION]
            ],
            'serverInfo' => [
                'name' => 'Calculator Server',
                'version' => '1.0.0',
                'vendor' => 'MyCompany',
                'license' => 'MIT'
            ],
            'protocolVersion' => '2025-03-26'
        ]);
    }

    /**
     * 处理函数调用请求
     */
    public function handleFunctionRequest($request)
    {
        $id = $request['id'] ?? null;
        $function = $request['params']['function'] ?? '';
        $arguments = $request['params']['arguments'] ?? [];

//        // 恢复函数名验证
//        if ($function !== 'add') {
//            $this->sendJsonRpcResponse($id, [
//                'error' => [
//                    'code' => -32601,
//                    'message' => 'Unsupported function',
//                    'data' => "Function not found: $function"
//                ]
//            ]);
//            return;
//        }

//        // 提取参数验证为独立方法
//        $validationResult = $this->validateAddParameters($arguments, $id);
//        if ($validationResult !== true) {
//            $this->sendJsonRpcResponse($id, $validationResult);
//            return;
//        }

        // 解构参数
        $a = $arguments['a'] ?? 0;
        $b = $arguments['b'] ?? 0;

        // 发送进度通知
        $this->sendNotification('progress', ['id' => $id, 'message' => '正在计算...']);

        // 模拟处理延迟
        sleep(1);

        $result = $this->calculateAdd($a, $b);
        $this->sendJsonRpcResponse($id, [
//            'result' => [
                'operation' => 'add',
                'result' => $result,
                'expression' => "$a + $b = $result",
                'timestamp' => time()
//            ]
        ]);
    }

    /**
     * 验证加法参数
     * @param array $arguments
     * @param mixed $id
     * @return array|bool 返回true表示验证通过，否则返回错误响应数组
     */
    private function validateAddParameters(array $arguments, $id)
    {
        if (!isset($arguments['a'], $arguments['b'])) {
            return [
                'error' => [
                    'code' => -32602,
                    'message' => 'Invalid params',
                    'data' => 'Missing required parameters: a and b'
                ]
            ];
        }

        if (!is_numeric($arguments['a']) || !is_numeric($arguments['b'])) {
            return [
                'error' => [
                    'code' => -32602,
                    'message' => 'Invalid params',
                    'data' => 'Parameters must be numbers'
                ]
            ];
        }

        return true;
    }

    /**
     * 处理其他类型的请求
     */
    private function handleOtherRequests($request)
    {
        if (!$request || !isset($request['function'])) {
            $this->sendJsonRpcResponse($request['id'] ?? null, ['error' => 'Invalid request format']);
            return;
        }

        if ($request['function'] === 'add' || $request['function'] === 'tools/call') {
            $a = $request['params']['a'] ?? 0;
            $b = $request['params']['b'] ?? 0;

            if (!is_numeric($a) || !is_numeric($b)) {
                $this->sendEvent('error', 'Parameters must be numbers');
                return;
            }

            // 模拟处理延迟
            sleep(1);

            $result = $this->calculateAdd($a, $b);
            $this->sendEvent('result', [
                'operation' => 'add',
                'result' => $result,
                'expression' => "$a + $b = $result"
            ]);
        } else {
            $this->sendEvent('error', 'Unsupported function: ' . $request['function']);
        }
    }

    /**
     * 执行加法计算
     */
    private function calculateAdd(float $a, float $b): float
    {
        return $a + $b;
    }

    /**
     * 发送 JSON-RPC 响应
     */
    private function sendJsonRpcResponse($id, $resultOrError)
    {
        $response = [
            'jsonrpc' => '2.0',
            'id' => $id
        ];

        if (isset($resultOrError['error'])) {
            $response['error'] = $resultOrError['error'];
        } else {
            $response['result'] = $resultOrError;
        }

        $this->sendStreamData(json_encode($response, JSON_UNESCAPED_UNICODE));
    }

    /**
     * 发送通知（用于进度更新等）
     */
    private function sendNotification($method, $params)
    {
        $notification = [
            'jsonrpc' => '2.0',
            'method' => $method,
            'params' => $params
        ];

        $this->sendStreamData(json_encode($notification, JSON_UNESCAPED_UNICODE));
    }

    /**
     * 发送标准 SSE 事件
     */
    private function sendEvent($type, $data)
    {
        $jsonData = json_encode($data, JSON_UNESCAPED_UNICODE);
        echo "event: $type\n";
        echo "data: $jsonData\n\n";
        $this->flushBuffers();
        file_put_contents('mcp_debug.log', "Sent event: $type - $jsonData".PHP_EOL, FILE_APPEND);
    }

    /**
     * 发送流数据
     */
    private function sendStreamData(string $data)
    {
        echo "data: $data\n\n";
        $this->flushBuffers();
        file_put_contents('mcp_debug.log', "JSON-RPC Response: $data".PHP_EOL, FILE_APPEND);
    }

    /**
     * 刷新输出缓冲区
     */
    private function flushBuffers()
    {
        ob_flush();
        flush();
    }
}