// 文件: Core\CmdClients\CommandDispatcher.cs

using MessagePack;
using Newtonsoft.Json.Linq;
using SHH.Contracts;
using System.Text;

namespace SHH.CameraService;

public class CommandDispatcher
{
    // 1. 注入路由表
    private readonly Dictionary<string, ICommandHandler> _handlers;

    // 2. 定义回执事件 (ACK闭环的核心)
    public event Action<CommandResult>? OnResponseReady;

    // 3. 构造函数：注入所有 Handler
    public CommandDispatcher(IEnumerable<ICommandHandler> handlers)
    {
        // 将注入的 Handler 转换为字典，Key = ActionName (e.g. "SyncCamera")
        _handlers = handlers.ToDictionary(h => h.ActionName, h => h, StringComparer.OrdinalIgnoreCase);
    }

    public async Task DispatchAsync(string protocol, byte[] data)
    {
        try
        {
            // 只处理 COMMAND 协议
            if (protocol != ProtocolHeaders.Command) return;

            // 反序列化信封
            var envelope = MessagePackSerializer.Deserialize<CommandPayload>(data);
            if (envelope == null) return;

            string cmdCode = envelope.CmdCode; // e.g. "SyncCamera"
            Console.WriteLine($"[分发] 收到指令: {cmdCode} (ID: {envelope.RequestId})");

            bool isSuccess = true;
            string message = "OK";

            // --- 路由匹配逻辑 ---
            if (_handlers.TryGetValue(cmdCode, out var handler))
            {
                try
                {
                    // 数据适配：你的 Handler 需要 JToken
                    // 如果 envelope.JsonParams 是空的，传个空对象防止报错
                    var jsonStr = string.IsNullOrEmpty(envelope.JsonParams) ? "{}" : envelope.JsonParams;
                    var token = JToken.Parse(jsonStr);

                    // ★★★ 核心：调用 SyncCameraHandler.ExecuteAsync ★★★
                    await handler.ExecuteAsync(token);

                    message = $"Executed {cmdCode}";
                }
                catch (Exception ex)
                {
                    isSuccess = false;
                    message = $"Handler Error: {ex.Message}";
                    Console.WriteLine($"[业务异常] {message}");
                }
            }
            else
            {
                isSuccess = false;
                message = $"No handler found for {cmdCode}";
                Console.WriteLine($"[警告] {message}");
            }

            // --- ACK 闭环逻辑 ---
            if (envelope.RequireAck)
            {
                var result = new CommandResult
                {
                    Protocol = ProtocolHeaders.CommandResult,
                    RequestId = envelope.RequestId, // 必须带回 ID
                    Success = isSuccess,
                    Message = message,
                    Timestamp = DateTime.Now.Ticks
                };
                // 触发事件
                OnResponseReady?.Invoke(result);
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"[Dispatcher] 致命错误: {ex.Message}");
        }
    }
}