package gameserver

import (
	"bytes"
	"encoding/binary"
	"math"
	"net"
	"testing"
	"time"

	"ananta-ps/internal/config"
	"ananta-ps/pkg/protocol"
)

func TestWeatherAndTimeUseActualClientContracts(t *testing.T) {
	srv := New(&config.Config{}, "")
	conn := &recordingConn{}
	srv.sessions["test"] = &Session{conn: conn}
	if err := srv.SetWorldWeather(3); err != nil {
		t.Fatal(err)
	}
	f, err := protocol.ReadFrame(conn, nil)
	if err != nil {
		t.Fatal(err)
	}
	pkt := protocol.ParseRpcPacket(f.Payload)
	if pkt.MethodID != 68712141 || !bytes.Equal(pkt.Body, []byte{3, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0}) {
		t.Fatalf("weather contract: %+v", pkt)
	}
	if err := srv.SetWorldTimeOfDay(12.5); err != nil {
		t.Fatal(err)
	}
	f, err = protocol.ReadFrame(conn, nil)
	if err != nil {
		t.Fatal(err)
	}
	pkt = protocol.ParseRpcPacket(f.Payload)
	if pkt.MethodID != 68337673 || len(pkt.Body) != 22 || binary.LittleEndian.Uint32(pkt.Body[4:8]) != 45000 || pkt.Body[8] != 1 {
		t.Fatalf("time contract: %+v", pkt)
	}
	for _, hour := range []float32{-1, 24, float32(math.NaN()), float32(math.Inf(1))} {
		if err := srv.SetWorldTimeOfDay(hour); err == nil {
			t.Fatalf("invalid hour: %v", hour)
		}
	}
	if conn.Len() != 0 {
		t.Fatal("invalid time emitted a packet")
	}
}

func TestAdminRejectsInvalidTeleport(t *testing.T) {
	srv := New(&config.Config{}, "")
	conn := &recordingConn{}
	srv.sessions["test"] = &Session{conn: conn, posX: 123}
	for _, cmd := range []string{"tp garbage 0 0", "tp NaN 0 0", "tp 0 +Inf 0"} {
		if _, err := srv.GetAdminBridge().ExecuteCommand(cmd); err == nil {
			t.Fatalf("accepted %s", cmd)
		}
	}
	if conn.Len() != 0 || srv.sessions["test"].posX != 123 {
		t.Fatal("invalid command changed position")
	}
}

type recordingConn struct{ bytes.Buffer }

func (c *recordingConn) Close() error                     { return nil }
func (c *recordingConn) LocalAddr() net.Addr              { return &net.TCPAddr{} }
func (c *recordingConn) RemoteAddr() net.Addr             { return &net.TCPAddr{} }
func (c *recordingConn) SetDeadline(time.Time) error      { return nil }
func (c *recordingConn) SetReadDeadline(time.Time) error  { return nil }
func (c *recordingConn) SetWriteDeadline(time.Time) error { return nil }

func TestDispatchContractFallbackAndPacketKinds(t *testing.T) {
	srv := New(&config.Config{}, "")
	conn := &recordingConn{}
	sess := &Session{conn: conn}
	// An unimplemented RPC returning bool needs one byte, not an empty OK.
	if err := srv.dispatch(sess, &protocol.RpcPacket{Kind: protocol.PacketKindInvoke, MethodID: 67709054, InvokeID: 12}); err != nil {
		t.Fatal(err)
	}
	f, err := protocol.ReadFrame(conn, nil)
	if err != nil {
		t.Fatal(err)
	}
	pkt := protocol.ParseRpcPacket(f.Payload)
	if pkt.Kind != protocol.PacketKindReturn || pkt.InvokeID != 12 || !bytes.Equal(pkt.Body, []byte{0}) {
		t.Fatalf("bad bool fallback: %+v", pkt)
	}
	for _, kind := range []protocol.RpcPacketKind{protocol.PacketKindReturn, protocol.PacketKindUnknown} {
		if err := srv.dispatch(sess, &protocol.RpcPacket{Kind: kind, MethodID: protocol.MethodAskSwitchSpirit}); err != nil {
			t.Fatal(err)
		}
		if conn.Len() != 0 {
			t.Fatal("dispatched a return or malformed packet as a request")
		}
	}
	if err := sess.ReturnEmptyOk(0, protocol.MethodLoginGame); err != nil {
		t.Fatal(err)
	}
	if conn.Len() != 0 {
		t.Fatal("unsolicited return for a notification")
	}
	// Fabricated old AskMoveStart collided with a real client ID; it must not move state.
	if err := srv.dispatch(sess, &protocol.RpcPacket{Kind: protocol.PacketKindNotify, MethodID: 68412852}); err != nil {
		t.Fatal(err)
	}
	if conn.Len() != 0 {
		t.Fatal("invented route still active")
	}
}

func TestHangupAndActualMovementContract(t *testing.T) {
	srv := New(&config.Config{}, "")
	sess := &Session{conn: &recordingConn{}, unitId: 9}
	for _, tc := range []struct {
		id     uint32
		paused bool
	}{{63842476, true}, {63910160, false}} {
		if err := srv.dispatch(sess, &protocol.RpcPacket{Kind: protocol.PacketKindInvoke, MethodID: tc.id, InvokeID: 1}); err != nil {
			t.Fatal(err)
		}
		if sess.hangup.Load() != tc.paused {
			t.Fatal("hangup state not updated")
		}
	}
	body := protocol.NewUxWriter().U8(0xff).Int7(1).U64(9).F32(1).F32(2).F32(3).F32(0).F32(90).F32(0).Bytes()
	if err := srv.dispatch(sess, &protocol.RpcPacket{Kind: protocol.PacketKindNotify, MethodID: 67543012, Body: body}); err != nil {
		t.Fatal(err)
	}
	if sess.posX != 1 || sess.posY != 2 || sess.posZ != 3 || sess.facing != 90 {
		t.Fatal("actual movement contract not applied")
	}
	if err := srv.dispatch(sess, &protocol.RpcPacket{Kind: protocol.PacketKindNotify, MethodID: 67543012, Body: body[:15]}); err == nil {
		t.Fatal("truncated position accepted")
	}
	if sess.posX != 1 || sess.posY != 2 {
		t.Fatal("partial position update")
	}
}

func TestTeleportIncludesNullableTail(t *testing.T) {
	conn := &recordingConn{}
	sess := &Session{conn: conn, unitId: 9}
	if err := sess.Teleport(1, 2, 3, 90); err != nil {
		t.Fatal(err)
	}
	f, err := protocol.ReadFrame(conn, nil)
	if err != nil {
		t.Fatal(err)
	}
	pkt := protocol.ParseRpcPacket(f.Payload)
	if pkt.MethodID != 68030312 || len(pkt.Body) != 29 || !bytes.Equal(pkt.Body[24:], []byte{0, 0, 6, 0, 0}) {
		t.Fatalf("invalid position contract: %+v", pkt)
	}
}

func TestStopClosesIdleHandshakeConnections(t *testing.T) {
	srv := New(&config.Config{Network: config.NetworkConfig{BindHost: "127.0.0.1"}}, "")
	if err := srv.Start(); err != nil {
		t.Fatal(err)
	}
	conn, err := net.DialTimeout("tcp", srv.ln.Addr().String(), time.Second)
	if err != nil {
		t.Fatal(err)
	}
	defer conn.Close()
	// Wait for the server to own the socket before stopping.
	deadline := time.Now().Add(time.Second)
	for {
		srv.mu.RLock()
		n := len(srv.connections)
		srv.mu.RUnlock()
		if n == 1 {
			break
		}
		if time.Now().After(deadline) {
			t.Fatal("connection not accepted")
		}
		time.Sleep(time.Millisecond)
	}
	done := make(chan struct{})
	go func() { srv.Stop(); close(done) }()
	select {
	case <-done:
	case <-time.After(time.Second):
		t.Fatal("Stop blocked on idle handshake")
	}
	conn.SetReadDeadline(time.Now().Add(time.Second))
	if _, err := conn.Read(make([]byte, 1)); err == nil {
		t.Fatal("idle connection survived Stop")
	}
}