using Google.Protobuf;
using Grpc.Net.Client;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using SHH.Contracts.Grpc;

namespace SHH.CameraService;

/// <summary>
/// gRPC 视频流发送工作者
/// 职责：监听特定的 StreamTarget 队列，建立 gRPC 客户端流并持续推送图片
/// </summary>
public class GrpcSenderWorker : BackgroundService
{
    private readonly StreamTarget _target;
    private readonly ILogger<GrpcSenderWorker> _logger;
    private readonly string _grpcUrl;

    public GrpcSenderWorker(StreamTarget target, ILogger<GrpcSenderWorker> logger)
    {
        _target = target;
        _logger = logger;

        // 自动适配地址：将配置的 tcp://localhost:9001 转换为 http://localhost:9001
        // 并且严格使用你验证成功的 localhost
        _grpcUrl = _target.Config.Endpoint.Replace("tcp://", "http://");
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        _logger.LogInformation($"[gRPC Worker] 启动。目标: {_target.Config.Name}, 地址: {_grpcUrl}");

        while (!stoppingToken.IsCancellationRequested)
        {
            try
            {
                // 1. 建立通道
                using var channel = GrpcChannel.ForAddress(_grpcUrl);
                var client = new GatewayProvider.GatewayProviderClient(channel);

                // 2. 开启客户端流 (UploadVideoStream 是在 proto 中定义的)
                using var call = client.UploadVideoStream(cancellationToken: stoppingToken);

                _logger.LogInformation($"[gRPC Worker] 已开启视频推送流: {_target.Config.Name}");

                // 3. 核心搬运循环：从内存队列 (Channel) 读取数据
                await foreach (var payload in _target.Channel.Reader.ReadAllAsync(stoppingToken))
                {
                    // 将业务 DTO 转换为 gRPC 原生 Request
                    var request = new VideoFrameRequest
                    {
                        CameraId = payload.CameraId ?? "Unknown",
                        CaptureTimestamp = payload.CaptureTimestamp,
                        OriginalWidth = payload.OriginalWidth,
                        OriginalHeight = payload.OriginalHeight,
                        HasOriginalImage = payload.HasOriginalImage,
                        HasTargetImage = payload.HasTargetImage,

                        // ★ 核心：将 byte[] 转换为 gRPC 的 ByteString (高性能)
                        OriginalImageBytes = payload.OriginalImageBytes != null
                            ? ByteString.CopyFrom(payload.OriginalImageBytes)
                            : ByteString.Empty,

                        TargetImageBytes = payload.TargetImageBytes != null
                            ? ByteString.CopyFrom(payload.TargetImageBytes)
                            : ByteString.Empty
                    };

                    // 处理诊断信息 map<string, string>
                    if (payload.Diagnostics != null)
                    {
                        foreach (var kv in payload.Diagnostics)
                        {
                            request.Diagnostics.Add(kv.Key, kv.Value?.ToString() ?? "");
                        }
                    }

                    // 4. 发送至 AiVideo
                    await call.RequestStream.WriteAsync(request);
                }

                // 正常结束流
                await call.RequestStream.CompleteAsync();
            }
            catch (OperationCanceledException) { break; }
            catch (Exception ex)
            {
                _logger.LogError($"[gRPC Worker] 推送链路异常，5秒后重连: {ex.Message}");
                await Task.Delay(5000, stoppingToken);
            }
        }
    }
}