package mpsync

import (
	"context"
	"net"
	"path/filepath"
	"testing"
	"time"

	"mc/internal/block"
	"mc/internal/logx"
	"mc/internal/netproto"
	"mc/internal/netserver"
	"mc/internal/world"
	"mc/internal/worldgen"
)

// syncHandler 测试用服务器处理器：登录 → hub.AddPlayer。
type syncHandler struct {
	hub  *Hub
	recv chan *netserver.Conn
}

func (h *syncHandler) OnConnect(c *netserver.Conn) {}
func (h *syncHandler) OnHandshake(c *netserver.Conn, hs netproto.Handshake) uint8 {
	if h.recv != nil {
		h.recv <- c
	}
	h.hub.AddPlayer(c, 8, 8)
	return 0
}
func (h *syncHandler) OnMove(c *netserver.Conn, m netproto.PlayerMove) {}
func (h *syncHandler) OnDisconnect(c *netserver.Conn)                  { h.hub.RemovePlayer(c) }

// TestLoginReceivesChunk 登录后客户端收到区块数据帧（多人同步.md §4）。
func TestLoginReceivesChunk(t *testing.T) {
	reg, err := block.Load(filepath.Join("..", "..", "assets", "config", "blocks.json"))
	if err != nil {
		t.Fatalf("加载注册表失败: %v", err)
	}
	gen, err := worldgen.New(reg, 7, 0.005, 0.01, 0.1)
	if err != nil {
		t.Fatalf("创建生成器失败: %v", err)
	}
	w, err := world.New(reg, gen, 4)
	if err != nil {
		t.Fatalf("创建世界失败: %v", err)
	}
	defer w.Close()
	deadline := time.Now().Add(15 * time.Second)
	for time.Now().Before(deadline) {
		w.Update(8, 64, 8, 8*time.Millisecond)
		if w.Block(8, 0, 8) != block.Air {
			break
		}
		time.Sleep(2 * time.Millisecond)
	}

	hub := NewHub(w, 4)
	log, _ := logx.New("", logx.LevelDebug)
	h := &syncHandler{hub: hub, recv: make(chan *netserver.Conn, 1)}
	srv := netserver.New("127.0.0.1:0", log, h)
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	if err := srv.Listen(ctx); err != nil {
		t.Fatalf("监听失败: %v", err)
	}
	nc, err := net.DialTimeout("tcp", srv.Addr(), 3*time.Second)
	if err != nil {
		t.Fatalf("拨号失败: %v", err)
	}
	defer nc.Close()

	hs := netproto.Handshake{ProtocolVersion: 1, ClientID: "同步测试"}
	_, _ = nc.Write(netproto.EncodeFrame(netproto.Frame{MsgID: netproto.MsgHandshake, Payload: hs.Encode()}))

	gotChunk := false
	buf := make([]byte, 64*1024)
	_ = nc.SetReadDeadline(time.Now().Add(5 * time.Second))
	acc := []byte{}
	for !gotChunk {
		n, err := nc.Read(buf)
		if err != nil {
			break
		}
		acc = append(acc, buf[:n]...)
		for len(acc) >= 4 {
			f, rest, err := netproto.DecodeFrame(acc)
			if err != nil {
				break
			}
			acc = rest
			if f.MsgID == netproto.MsgChunkData {
				gotChunk = true
			}
		}
	}
	if !gotChunk {
		t.Fatal("登录后未收到区块数据")
	}
}

// TestBlockChangeBroadcast 服务器权威写方块 → 客户端收到广播（多人同步.md §5）。
func TestBlockChangeBroadcast(t *testing.T) {
	reg, err := block.Load(filepath.Join("..", "..", "assets", "config", "blocks.json"))
	if err != nil {
		t.Fatalf("加载注册表失败: %v", err)
	}
	gen, err := worldgen.New(reg, 8, 0.005, 0.01, 0.1)
	if err != nil {
		t.Fatalf("创建生成器失败: %v", err)
	}
	w, err := world.New(reg, gen, 2)
	if err != nil {
		t.Fatalf("创建世界失败: %v", err)
	}
	defer w.Close()

	hub := NewHub(w, 4)
	log, _ := logx.New("", logx.LevelDebug)
	h := &syncHandler{hub: hub, recv: make(chan *netserver.Conn, 1)}
	srv := netserver.New("127.0.0.1:0", log, h)
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	if err := srv.Listen(ctx); err != nil {
		t.Fatalf("监听失败: %v", err)
	}
	nc, err := net.DialTimeout("tcp", srv.Addr(), 3*time.Second)
	if err != nil {
		t.Fatalf("拨号失败: %v", err)
	}
	defer nc.Close()
	_, _ = nc.Write(netproto.EncodeFrame(netproto.Frame{MsgID: netproto.MsgHandshake, Payload: netproto.Handshake{ProtocolVersion: 1}.Encode()}))

	// 等待服务器完成登录注册（避免广播早于 AddPlayer 执行，多人同步.md §2 时序）
	select {
	case <-h.recv:
	case <-time.After(3 * time.Second):
		t.Fatal("未完成登录注册")
	}

	torch, _ := reg.ID("torch")
	go hub.SetBlockWorld(8, 70, 8, block.NewState(torch, 0))

	buf := make([]byte, 64*1024)
	_ = nc.SetReadDeadline(time.Now().Add(5 * time.Second))
	acc := []byte{}
	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		n, err := nc.Read(buf)
		if err != nil {
			break
		}
		acc = append(acc, buf[:n]...)
		for len(acc) >= 4 {
			f, rest, err := netproto.DecodeFrame(acc)
			if err != nil {
				break
			}
			acc = rest
			if f.MsgID != netproto.MsgBlockChange {
				continue
			}
			m, err := netproto.DecodeBlockChange(f.Payload)
			if err != nil {
				t.Fatalf("解码失败: %v", err)
			}
			if m.X == 8 && m.Y == 70 && m.Z == 8 && m.BlockID == torch {
				return
			}
		}
	}
	t.Fatal("未收到方块变更广播")
}