package forwarder

import (
	"testing"

	"google.golang.org/protobuf/encoding/protojson"

	"cursor/gen/agentv1"
)

func TestCheckpointBlobSyncPublishesCheckpointAfterAcknowledgements(t *testing.T) {
	service, stream, projection := testCheckpointBlobProjection(t)
	if err := service.queueCheckpointProjection(stream, projection, nil); err != nil {
		t.Fatalf("queueCheckpointProjection() error = %v", err)
	}
	events := readCheckpointTestEvents(t, service, stream)
	if len(events) != len(projection.Blobs) {
		t.Fatalf("events before ACK = %d, want %d Blob writes", len(events), len(projection.Blobs))
	}
	for _, event := range events {
		if event.Message.GetKvServerMessage().GetSetBlobArgs() == nil {
			t.Fatalf("event before ACK = %#v, want set_blob_args", event.Message)
		}
	}

	acknowledgeCheckpointBlobs(t, service, stream)
	events = readCheckpointTestEvents(t, service, stream)
	checkpoint := events[len(events)-1].Message.GetConversationCheckpointUpdate()
	if checkpoint == nil || len(checkpoint.GetTurns()) != 1 {
		t.Fatalf("last event checkpoint = %#v, want one Blob-backed turn", checkpoint)
	}
}

func TestCheckpointBlobSyncPublishesCheckpointBeforeSuccessfulTerminal(t *testing.T) {
	service, stream, projection := testCheckpointBlobProjection(t)
	completion := &pendingTurnCompletion{
		RequestID: stream.RequestID,
		Usage:     turnUsageSnapshot{InputTokens: 11, OutputTokens: 7},
	}
	if err := service.queueCheckpointProjection(stream, projection, completion); err != nil {
		t.Fatalf("queueCheckpointProjection() error = %v", err)
	}
	acknowledgeCheckpointBlobs(t, service, stream)

	events := readCheckpointTestEvents(t, service, stream)
	checkpointIndex, turnEndedIndex, endIndex := -1, -1, -1
	for index, event := range events {
		switch {
		case event.Message.GetConversationCheckpointUpdate() != nil:
			checkpointIndex = index
		case event.Message.GetInteractionUpdate().GetTurnEnded() != nil:
			turnEndedIndex = index
		case event.End:
			endIndex = index
		}
	}
	if checkpointIndex < 0 || turnEndedIndex <= checkpointIndex || endIndex <= turnEndedIndex {
		t.Fatalf("terminal order checkpoint=%d turn_ended=%d end=%d", checkpointIndex, turnEndedIndex, endIndex)
	}
}

func TestCheckpointBlobTimeoutDoesNotFailSuccessfulTurn(t *testing.T) {
	service, stream, projection := testCheckpointBlobProjection(t)
	completion := &pendingTurnCompletion{
		RequestID: stream.RequestID,
		Usage:     turnUsageSnapshot{InputTokens: 11, OutputTokens: 7},
	}
	if err := service.queueCheckpointProjection(stream, projection, completion); err != nil {
		t.Fatalf("queueCheckpointProjection() error = %v", err)
	}
	if err := service.handleCheckpointBlobTimeout(stream); err != nil {
		t.Fatalf("handleCheckpointBlobTimeout() error = %v", err)
	}

	events := readCheckpointTestEvents(t, service, stream)
	var checkpoint, turnEnded, successfulEnd bool
	for _, event := range events {
		checkpoint = checkpoint || event.Message.GetConversationCheckpointUpdate() != nil
		turnEnded = turnEnded || event.Message.GetInteractionUpdate().GetTurnEnded() != nil
		successfulEnd = successfulEnd || event.End && event.TerminalErrorCode == ""
	}
	if checkpoint || !turnEnded || !successfulEnd {
		t.Fatalf("timeout events checkpoint=%v turn_ended=%v successful_end=%v", checkpoint, turnEnded, successfulEnd)
	}
}

func TestCancellationDiscardsPendingCheckpointAndIgnoresLateAcknowledgements(t *testing.T) {
	service, stream, projection := testCheckpointBlobProjection(t)
	if err := service.queueCheckpointProjection(stream, projection, nil); err != nil {
		t.Fatalf("queueCheckpointProjection() error = %v", err)
	}
	stream.mu.Lock()
	requestIDs := make([]uint32, 0, len(stream.PendingCheckpointBlobWrites))
	for requestID := range stream.PendingCheckpointBlobWrites {
		requestIDs = append(requestIDs, requestID)
	}
	stream.mu.Unlock()
	if err := service.handleCancelIntent(InboundIntent{
		Kind:         "cancel",
		RequestID:    stream.RequestID,
		CancelReason: "user stopped",
	}); err != nil {
		t.Fatalf("handleCancelIntent() error = %v", err)
	}
	for _, requestID := range requestIDs {
		if err := service.handleCheckpointBlobResult(stream, &agentv1.KvClientMessage{
			Id: requestID,
			Message: &agentv1.KvClientMessage_SetBlobResult{
				SetBlobResult: &agentv1.SetBlobResult{},
			},
		}); err != nil {
			t.Fatalf("late ACK %d error = %v", requestID, err)
		}
	}

	events := readCheckpointTestEvents(t, service, stream)
	var checkpoint, canceledEnd bool
	for _, event := range events {
		checkpoint = checkpoint || event.Message.GetConversationCheckpointUpdate() != nil
		canceledEnd = canceledEnd || event.End && event.TerminalErrorCode == "canceled"
	}
	stream.mu.Lock()
	pending := stream.PendingCheckpoint
	stream.mu.Unlock()
	if checkpoint || !canceledEnd || pending != nil {
		t.Fatalf("cancel events checkpoint=%v canceled_end=%v pending=%v", checkpoint, canceledEnd, pending != nil)
	}
}

func testCheckpointBlobProjection(t *testing.T) (*Service, *ActiveStream, *CheckpointProjection) {
	t.Helper()
	broker := NewStreamBroker()
	service := &Service{
		store:     NewConversationFileStore(t.TempDir()),
		projector: NewHistoryProjector(),
		broker:    broker,
	}
	stream, err := broker.OpenStream(
		"request-1", "conversation-1", 1, "default", "default",
		agentv1.AgentMode_AGENT_MODE_AGENT, "hello",
	)
	if err != nil {
		t.Fatalf("OpenStream() error = %v", err)
	}
	conversation := &ConversationFile{
		ConversationID:        "conversation-1",
		RootConversationID:    "conversation-1",
		Mode:                  "agent",
		NextTurnSeq:           2,
		NextEntrySeq:          3,
		TokenDetailsMaxTokens: projectedConversationMaxTokens,
		Entries: []HistoryEntry{
			testCheckpointUserEntry(t),
			newAssistantTextEntry(1, "request-1", "hi", "", ""),
		},
	}
	projection, err := service.projector.ProjectCheckpointProjection(conversation)
	if err != nil {
		t.Fatalf("ProjectCheckpointProjection() error = %v", err)
	}
	if err := service.replaceCheckpointConversation(stream, conversation); err != nil {
		t.Fatalf("replaceCheckpointConversation() error = %v", err)
	}
	return service, stream, projection
}

func testCheckpointUserEntry(t *testing.T) HistoryEntry {
	t.Helper()
	payload, err := protojson.Marshal(&agentv1.UserMessage{Text: "hello", MessageId: "message-1"})
	if err != nil {
		t.Fatalf("marshal user message: %v", err)
	}
	return HistoryEntry{Seq: 1, TurnSeq: 1, RequestID: "request-1", Role: "user", Kind: "user_message", Payload: payload}
}

func acknowledgeCheckpointBlobs(t *testing.T, service *Service, stream *ActiveStream) {
	t.Helper()
	for {
		stream.mu.Lock()
		requestIDs := make([]uint32, 0, len(stream.PendingCheckpointBlobWrites))
		for requestID := range stream.PendingCheckpointBlobWrites {
			requestIDs = append(requestIDs, requestID)
		}
		stream.mu.Unlock()
		if len(requestIDs) == 0 {
			return
		}
		for _, requestID := range requestIDs {
			if err := service.handleCheckpointBlobResult(stream, &agentv1.KvClientMessage{
				Id: requestID,
				Message: &agentv1.KvClientMessage_SetBlobResult{
					SetBlobResult: &agentv1.SetBlobResult{},
				},
			}); err != nil {
				t.Fatalf("handleCheckpointBlobResult(%d) error = %v", requestID, err)
			}
		}
	}
}

func readCheckpointTestEvents(t *testing.T, service *Service, stream *ActiveStream) []StreamEvent {
	t.Helper()
	events, err := service.broker.ReadFromCursor(stream.RequestID, 0)
	if err != nil {
		t.Fatalf("ReadFromCursor() error = %v", err)
	}
	return events
}