package netserver

import (
	"context"
	"net"
	"testing"
	"time"

	"mc/internal/logx"
	"mc/internal/netproto"
)

// testHandler 记录回调的测试处理器。
type testHandler struct {
	logins   chan netproto.Handshake
	moves    chan netproto.PlayerMove
	connects chan uint64
}

func newTestHandler() *testHandler {
	return &testHandler{
		logins:   make(chan netproto.Handshake, 8),
		moves:    make(chan netproto.PlayerMove, 8),
		connects: make(chan uint64, 8),
	}
}

func (h *testHandler) OnConnect(c *Conn) { h.connects <- c.ID() }
func (h *testHandler) OnHandshake(c *Conn, hs netproto.Handshake) uint8 {
	h.logins <- hs
	return 0
}
func (h *testHandler) OnMove(c *Conn, m netproto.PlayerMove) { h.moves <- m }
func (h *testHandler) OnDisconnect(c *Conn)                  {}

// startServer 启动测试服务器。
func startServer(t *testing.T) (*Server, *testHandler, context.CancelFunc) {
	t.Helper()
	log, err := logx.New("", logx.LevelDebug) // 仅 stderr（避免临时文件句柄）
	if err != nil {
		t.Fatalf("创建日志失败: %v", err)
	}
	h := newTestHandler()
	s := New("127.0.0.1:0", log, h)
	ctx, cancel := context.WithCancel(context.Background())
	if err := s.Listen(ctx); err != nil {
		t.Fatalf("监听失败: %v", err)
	}
	t.Cleanup(func() {
		cancel()
		time.Sleep(20 * time.Millisecond)
	})
	return s, h, cancel
}

// dial 建立客户端连接。
func dial(t *testing.T, addr string) net.Conn {
	t.Helper()
	c, err := net.DialTimeout("tcp", addr, 3*time.Second)
	if err != nil {
		t.Fatalf("拨号失败: %v", err)
	}
	t.Cleanup(func() { _ = c.Close() })
	return c
}

// TestHandshakeFlow 握手 → 登录响应 → 心跳回显全链路（网络协议.md §4）。
func TestHandshakeFlow(t *testing.T) {
	s, h, _ := startServer(t)
	nc := dial(t, s.Addr())

	// 发送握手
	hs := netproto.Handshake{ProtocolVersion: 1, ClientID: "测试客户端"}
	_, err := nc.Write(netproto.EncodeFrame(netproto.Frame{MsgID: netproto.MsgHandshake, Payload: hs.Encode()}))
	if err != nil {
		t.Fatalf("发送握手失败: %v", err)
	}
	select {
	case got := <-h.logins:
		if got != hs {
			t.Fatalf("握手内容不一致: %+v", got)
		}
	case <-time.After(3 * time.Second):
		t.Fatal("未收到握手回调")
	}

	// 读登录响应帧
	_ = nc.SetReadDeadline(time.Now().Add(3 * time.Second))
	buf := make([]byte, 256)
	n, err := nc.Read(buf)
	if err != nil {
		t.Fatalf("读登录响应失败: %v", err)
	}
	f, _, err := netproto.DecodeFrame(buf[:n])
	if err != nil || f.MsgID != netproto.MsgLoginResponse {
		t.Fatalf("登录响应异常: %+v err=%v", f, err)
	}
	if len(f.Payload) != 1 || f.Payload[0] != 0 {
		t.Fatalf("登录结果应为 0（成功），实际 %v", f.Payload)
	}

	// 心跳回显
	_, _ = nc.Write(netproto.EncodeFrame(netproto.Frame{MsgID: netproto.MsgHeartbeat, Payload: []byte{7}}))
	n, _ = nc.Read(buf)
	f, _, _ = netproto.DecodeFrame(buf[:n])
	if f.MsgID != netproto.MsgHeartbeat || len(f.Payload) != 1 || f.Payload[0] != 7 {
		t.Fatalf("心跳回显异常: %+v", f)
	}
}

// TestMoveBroadcast 移动消息分发。
func TestMoveBroadcast(t *testing.T) {
	s, h, _ := startServer(t)
	nc := dial(t, s.Addr())
	m := netproto.PlayerMove{X: 1.5, Y: 64, Z: -2, Yaw: 0.5, Pitch: 0, OnGround: true}
	_, _ = nc.Write(netproto.EncodeFrame(netproto.Frame{MsgID: netproto.MsgPlayerMove, Payload: m.Encode()}))
	select {
	case got := <-h.moves:
		if got != m {
			t.Fatalf("移动数据不一致: %+v", got)
		}
	case <-time.After(3 * time.Second):
		t.Fatal("未收到移动回调")
	}
	_ = s.Count() // 连接计数可用
}