//go:build linux

package transport

import (
	"net"
	"reflect"
	"testing"

	"omnisocketgo/cmd/internal/latencylog"
	"omnisocketgo/cmd/internal/protocol"
)

func TestUDPLinuxTimestampingRecordsKernelEvents(t *testing.T) {
	tests := []struct {
		name string
		msg  protocol.Message
	}{
		{
			name: "text",
			msg: protocol.Message{
				Type: protocol.MessageTypeText,
				ID:   41,
				From: "peer-a",
				To:   "peer-b",
				Body: []byte("hello over udp"),
			},
		},
		{
			name: "file",
			msg: protocol.Message{
				Type:     protocol.MessageTypeFile,
				ID:       42,
				From:     "peer-a",
				To:       "peer-b",
				FileName: "payload.bin",
				Body:     []byte{0x00, 0x01, 0x02, 0xff},
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			senderLogger := &recordingLogger{}
			receiverLogger := &recordingLogger{}

			serverAddr, err := net.ResolveUDPAddr("udp", "127.0.0.1:0")
			if err != nil {
				t.Fatalf("ResolveUDPAddr() error = %v", err)
			}
			serverRaw, err := net.ListenUDP("udp", serverAddr)
			if err != nil {
				t.Fatalf("ListenUDP() error = %v", err)
			}
			receiver, err := NewUDPConn(
				serverRaw,
				nil,
				WithUDPLogger(receiverLogger, latencylog.NodeRolePeer, "peer-b"),
			)
			if err != nil {
				_ = serverRaw.Close()
				t.Fatalf("NewUDPConn(receiver) error = %v", err)
			}
			t.Cleanup(func() { _ = receiver.Close() })

			peerRaw, err := net.DialUDP("udp", nil, serverRaw.LocalAddr().(*net.UDPAddr))
			if err != nil {
				t.Fatalf("DialUDP() error = %v", err)
			}
			sender, err := NewUDPConn(
				peerRaw,
				nil,
				WithUDPLogger(senderLogger, latencylog.NodeRolePeer, "peer-a"),
			)
			if err != nil {
				_ = peerRaw.Close()
				t.Fatalf("NewUDPConn(sender) error = %v", err)
			}
			t.Cleanup(func() { _ = sender.Close() })

			sendErr := make(chan error, 1)
			go func() {
				sendErr <- sender.Send(tt.msg)
			}()

			got, _, err := receiver.Receive()
			if err != nil {
				t.Fatalf("Receive() error = %v", err)
			}
			if err := <-sendErr; err != nil {
				t.Fatalf("Send() error = %v", err)
			}
			if !reflect.DeepEqual(got, tt.msg) {
				t.Fatalf("message mismatch: got %+v want %+v", got, tt.msg)
			}

			assertHasEvent(t, senderLogger.Events(), latencylog.EventATXSched, tt.msg.ID)
			assertHasEvent(t, senderLogger.Events(), latencylog.EventATXSoftware, tt.msg.ID)
			assertHasEvent(t, receiverLogger.Events(), latencylog.EventBRXSoftware, tt.msg.ID)
		})
	}
}

func TestUDPLinuxTimestampingDebugLoggerCapturesDatagramAndErrqueueEvents(t *testing.T) {
	debugLogger := &recordingTXTimestampDebugLogger{}
	senderLogger := &recordingLogger{}
	receiverLogger := &recordingLogger{}

	serverAddr, err := net.ResolveUDPAddr("udp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("ResolveUDPAddr() error = %v", err)
	}
	serverRaw, err := net.ListenUDP("udp", serverAddr)
	if err != nil {
		t.Fatalf("ListenUDP() error = %v", err)
	}
	receiver, err := NewUDPConn(
		serverRaw,
		nil,
		WithUDPLogger(receiverLogger, latencylog.NodeRolePeer, "peer-b"),
	)
	if err != nil {
		_ = serverRaw.Close()
		t.Fatalf("NewUDPConn(receiver) error = %v", err)
	}
	t.Cleanup(func() { _ = receiver.Close() })

	peerRaw, err := net.DialUDP("udp", nil, serverRaw.LocalAddr().(*net.UDPAddr))
	if err != nil {
		t.Fatalf("DialUDP() error = %v", err)
	}
	sender, err := NewUDPConn(
		peerRaw,
		nil,
		WithUDPLogger(senderLogger, latencylog.NodeRolePeer, "peer-a"),
		WithUDPTXTimestampDebugLogger(debugLogger),
	)
	if err != nil {
		_ = peerRaw.Close()
		t.Fatalf("NewUDPConn(sender) error = %v", err)
	}
	t.Cleanup(func() { _ = sender.Close() })

	msg := protocol.Message{
		Type: protocol.MessageTypeText,
		ID:   99,
		From: "peer-a",
		To:   "peer-b",
		Body: []byte("hello udp debug"),
	}

	sendErr := make(chan error, 1)
	go func() {
		sendErr <- sender.Send(msg)
	}()

	got, _, err := receiver.Receive()
	if err != nil {
		t.Fatalf("Receive() error = %v", err)
	}
	if err := <-sendErr; err != nil {
		t.Fatalf("Send() error = %v", err)
	}
	if !reflect.DeepEqual(got, msg) {
		t.Fatalf("message mismatch: got %+v want %+v", got, msg)
	}

	assertHasEvent(t, senderLogger.Events(), latencylog.EventATXSched, msg.ID)
	assertHasEvent(t, senderLogger.Events(), latencylog.EventATXSoftware, msg.ID)
	assertHasEvent(t, receiverLogger.Events(), latencylog.EventBRXSoftware, msg.ID)

	sendChunkRecords := debugRecordsByType(debugLogger.Records(), txTimestampDebugRecordTypeSendChunk)
	errqueueRecords := debugRecordsByType(debugLogger.Records(), txTimestampDebugRecordTypeErrqueueEvent)
	if len(sendChunkRecords) == 0 {
		t.Fatal("send_chunk debug records = 0, want at least 1")
	}
	if len(errqueueRecords) == 0 {
		t.Fatal("errqueue_event debug records = 0, want at least 1")
	}

	finalChunkRecord := sendChunkRecords[len(sendChunkRecords)-1]
	if finalChunkRecord.ExpectedTXID == nil {
		t.Fatal("final send_chunk expected_tx_id = nil, want non-nil")
	}
	finalExpectedTXID := *finalChunkRecord.ExpectedTXID

	selectedRecords := selectedErrqueueRecords(errqueueRecords)
	if len(selectedRecords) == 0 {
		t.Fatal("selected errqueue debug records = 0, want at least 1")
	}

	highestObservedID := uint32(0)
	haveHighestObservedID := false
	haveExactFinalID := false
	for _, record := range errqueueRecords {
		if record.EEData == nil {
			continue
		}
		if !haveHighestObservedID || *record.EEData > highestObservedID {
			highestObservedID = *record.EEData
			haveHighestObservedID = true
		}
		if *record.EEData == finalExpectedTXID && isBusinessTXTimestampRecord(record) {
			haveExactFinalID = true
		}
	}
	if !haveHighestObservedID {
		t.Fatal("highestObservedID missing, want at least one ee_data")
	}

	wantSelectedID := highestObservedID
	if haveExactFinalID {
		wantSelectedID = finalExpectedTXID
	}
	for _, record := range selectedRecords {
		if record.EEData == nil {
			t.Fatalf("selected record missing ee_data: %+v", record)
		}
		if *record.EEData != wantSelectedID {
			t.Fatalf("selected ee_data = %d, want %d", *record.EEData, wantSelectedID)
		}
	}

	selectedByEventName := make(map[string]int64, len(selectedRecords))
	for _, record := range selectedRecords {
		if record.TSUnixNano == nil {
			t.Fatalf("selected record missing timestamp: %+v", record)
		}
		selectedByEventName[record.EventName] = *record.TSUnixNano
	}

	senderEventsByName := make(map[string]int64)
	for _, event := range senderLogger.Events() {
		if event.MessageID != msg.ID {
			continue
		}
		if !isBusinessTXTimestampEventName(event.Event) {
			continue
		}
		senderEventsByName[event.Event] = event.TsUnixNano
	}

	for eventName, selectedTS := range selectedByEventName {
		if senderEventsByName[eventName] != selectedTS {
			t.Fatalf("sender latency event %s = %d, want %d from selected debug record", eventName, senderEventsByName[eventName], selectedTS)
		}
	}
}