package stopjobsconsumer_test

import (
	"context"
	"errors"
	"io"
	"log/slog"
	"strconv"
	"sync"
	"testing"
	"time"

	"galaxy/rtmanager/internal/domain/operation"
	"galaxy/rtmanager/internal/domain/runtime"
	"galaxy/rtmanager/internal/ports"
	"galaxy/rtmanager/internal/service/startruntime"
	"galaxy/rtmanager/internal/service/stopruntime"
	"galaxy/rtmanager/internal/worker/stopjobsconsumer"

	"github.com/alicebob/miniredis/v2"
	"github.com/redis/go-redis/v9"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func silentLogger() *slog.Logger {
	return slog.New(slog.NewTextHandler(io.Discard, nil))
}

type fakeStopService struct {
	mu     sync.Mutex
	inputs []stopruntime.Input
	result stopruntime.Result
	err    error
}

func (s *fakeStopService) Handle(_ context.Context, input stopruntime.Input) (stopruntime.Result, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.inputs = append(s.inputs, input)
	return s.result, s.err
}

func (s *fakeStopService) Inputs() []stopruntime.Input {
	s.mu.Lock()
	defer s.mu.Unlock()
	out := make([]stopruntime.Input, len(s.inputs))
	copy(out, s.inputs)
	return out
}

type fakeJobResults struct {
	mu        sync.Mutex
	published []ports.JobResult
	publishErr error
}

func (s *fakeJobResults) Publish(_ context.Context, result ports.JobResult) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	if s.publishErr != nil {
		return s.publishErr
	}
	s.published = append(s.published, result)
	return nil
}

func (s *fakeJobResults) Published() []ports.JobResult {
	s.mu.Lock()
	defer s.mu.Unlock()
	out := make([]ports.JobResult, len(s.published))
	copy(out, s.published)
	return out
}

type fakeOffsetStore struct {
	mu      sync.Mutex
	offsets map[string]string
}

func newFakeOffsetStore() *fakeOffsetStore {
	return &fakeOffsetStore{offsets: map[string]string{}}
}

func (s *fakeOffsetStore) Load(_ context.Context, label string) (string, bool, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	value, ok := s.offsets[label]
	return value, ok, nil
}

func (s *fakeOffsetStore) Save(_ context.Context, label, entryID string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.offsets[label] = entryID
	return nil
}

func (s *fakeOffsetStore) Get(label string) (string, bool) {
	s.mu.Lock()
	defer s.mu.Unlock()
	value, ok := s.offsets[label]
	return value, ok
}

type harness struct {
	consumer *stopjobsconsumer.Consumer
	stops    *fakeStopService
	results  *fakeJobResults
	offsets  *fakeOffsetStore
	stream   string
	server   *miniredis.Miniredis
	client   *redis.Client
}

func newHarness(t *testing.T) *harness {
	t.Helper()
	server := miniredis.RunT(t)
	client := redis.NewClient(&redis.Options{Addr: server.Addr()})
	t.Cleanup(func() { _ = client.Close() })

	stops := &fakeStopService{}
	results := &fakeJobResults{}
	offsets := newFakeOffsetStore()
	stream := "runtime:stop_jobs"

	consumer, err := stopjobsconsumer.NewConsumer(stopjobsconsumer.Config{
		Client:       client,
		Stream:       stream,
		BlockTimeout: 50 * time.Millisecond,
		StopService:  stops,
		JobResults:   results,
		OffsetStore:  offsets,
		Logger:       silentLogger(),
	})
	require.NoError(t, err)

	return &harness{
		consumer: consumer,
		stops:    stops,
		results:  results,
		offsets:  offsets,
		stream:   stream,
		server:   server,
		client:   client,
	}
}

func stopMessage(id, gameID, reason string, requestedAtMS int64) redis.XMessage {
	return redis.XMessage{
		ID: id,
		Values: map[string]any{
			"game_id":         gameID,
			"reason":          reason,
			"requested_at_ms": strconv.FormatInt(requestedAtMS, 10),
		},
	}
}

func TestNewConsumerRejectsMissingDeps(t *testing.T) {
	server := miniredis.RunT(t)
	client := redis.NewClient(&redis.Options{Addr: server.Addr()})
	t.Cleanup(func() { _ = client.Close() })

	cases := []stopjobsconsumer.Config{
		{},
		{Client: client},
		{Client: client, Stream: "runtime:stop_jobs"},
		{Client: client, Stream: "runtime:stop_jobs", BlockTimeout: time.Second},
		{Client: client, Stream: "runtime:stop_jobs", BlockTimeout: time.Second, StopService: &fakeStopService{}},
		{Client: client, Stream: "runtime:stop_jobs", BlockTimeout: time.Second, StopService: &fakeStopService{}, JobResults: &fakeJobResults{}},
	}
	for index, cfg := range cases {
		_, err := stopjobsconsumer.NewConsumer(cfg)
		require.Errorf(t, err, "case %d should fail", index)
	}
}

func TestHandleMessageSuccessPublishesSuccessResult(t *testing.T) {
	h := newHarness(t)
	h.stops.result = stopruntime.Result{
		Record: runtime.RuntimeRecord{
			GameID:             "game-1",
			Status:             runtime.StatusStopped,
			CurrentContainerID: "c-1",
			CurrentImageRef:    "galaxy/game:1.0.0",
			EngineEndpoint:     "http://galaxy-game-game-1:8080",
		},
		Outcome: operation.OutcomeSuccess,
	}

	h.consumer.HandleMessage(context.Background(), stopMessage("100-0", "game-1", "cancelled", 1700))

	inputs := h.stops.Inputs()
	require.Len(t, inputs, 1)
	assert.Equal(t, "game-1", inputs[0].GameID)
	assert.Equal(t, stopruntime.StopReasonCancelled, inputs[0].Reason)
	assert.Equal(t, operation.OpSourceLobbyStream, inputs[0].OpSource)
	assert.Equal(t, "100-0", inputs[0].SourceRef)

	published := h.results.Published()
	require.Len(t, published, 1)
	assert.Equal(t, ports.JobResult{
		GameID:         "game-1",
		Outcome:        ports.JobOutcomeSuccess,
		ContainerID:    "c-1",
		EngineEndpoint: "http://galaxy-game-game-1:8080",
	}, published[0])
}

func TestHandleMessageFailureNotFoundPublishesFailureResult(t *testing.T) {
	h := newHarness(t)
	h.stops.result = stopruntime.Result{
		Outcome:      operation.OutcomeFailure,
		ErrorCode:    startruntime.ErrorCodeNotFound,
		ErrorMessage: "runtime record for game \"game-2\" does not exist",
	}

	h.consumer.HandleMessage(context.Background(), stopMessage("101-0", "game-2", "admin_request", 1700))

	published := h.results.Published()
	require.Len(t, published, 1)
	assert.Equal(t, ports.JobResult{
		GameID:       "game-2",
		Outcome:      ports.JobOutcomeFailure,
		ErrorCode:    "not_found",
		ErrorMessage: "runtime record for game \"game-2\" does not exist",
	}, published[0])
}

func TestHandleMessageReplayNoOpForRemovedRecordHasEmptyContainerAndEndpoint(t *testing.T) {
	h := newHarness(t)
	h.stops.result = stopruntime.Result{
		Record: runtime.RuntimeRecord{
			GameID:             "game-3",
			Status:             runtime.StatusRemoved,
			CurrentContainerID: "",
			EngineEndpoint:     "http://galaxy-game-game-3:8080",
		},
		Outcome:   operation.OutcomeSuccess,
		ErrorCode: startruntime.ErrorCodeReplayNoOp,
	}

	h.consumer.HandleMessage(context.Background(), stopMessage("102-0", "game-3", "finished", 1700))

	published := h.results.Published()
	require.Len(t, published, 1)
	assert.Equal(t, ports.JobResult{
		GameID:         "game-3",
		Outcome:        ports.JobOutcomeSuccess,
		ContainerID:    "",
		EngineEndpoint: "http://galaxy-game-game-3:8080",
		ErrorCode:      "replay_no_op",
	}, published[0])
}

func TestHandleMessageMalformedEnvelopesAreAbsorbed(t *testing.T) {
	h := newHarness(t)

	cases := []redis.XMessage{
		{ID: "200-0", Values: map[string]any{"reason": "cancelled", "requested_at_ms": "1"}},
		{ID: "200-1", Values: map[string]any{"game_id": "game-x", "requested_at_ms": "1"}},
		{ID: "200-2", Values: map[string]any{"game_id": "game-x", "reason": "  ", "requested_at_ms": "1"}},
		{ID: "200-3", Values: map[string]any{"game_id": "game-x", "reason": "not_a_known_reason", "requested_at_ms": "1"}},
		{ID: "200-4", Values: map[string]any{"game_id": "game-x", "reason": "cancelled", "requested_at_ms": "abc"}},
	}
	for _, msg := range cases {
		h.consumer.HandleMessage(context.Background(), msg)
	}

	assert.Empty(t, h.stops.Inputs(), "malformed envelopes must not reach the stop service")
	assert.Empty(t, h.results.Published(), "malformed envelopes must not produce job results")
}

func TestHandleMessagePublishFailureIsAbsorbed(t *testing.T) {
	h := newHarness(t)
	h.stops.result = stopruntime.Result{Outcome: operation.OutcomeFailure, ErrorCode: "internal_error"}
	h.results.publishErr = errors.New("redis transient")

	h.consumer.HandleMessage(context.Background(), stopMessage("300-0", "game-x", "cancelled", 1700))

	require.Len(t, h.stops.Inputs(), 1, "service still runs even when publish fails")
}

func TestHandleMessageGoLevelErrorIsAbsorbed(t *testing.T) {
	h := newHarness(t)
	h.stops.err = errors.New("nil ctx")

	h.consumer.HandleMessage(context.Background(), stopMessage("400-0", "game-y", "cancelled", 1700))

	assert.Empty(t, h.results.Published(), "go-level service errors must not surface as job results")
}

func TestRunAdvancesOffsetPerMessage(t *testing.T) {
	h := newHarness(t)
	h.stops.result = stopruntime.Result{
		Record: runtime.RuntimeRecord{
			GameID:             "game-5",
			Status:             runtime.StatusStopped,
			CurrentContainerID: "c-5",
			EngineEndpoint:     "http://galaxy-game-game-5:8080",
		},
		Outcome: operation.OutcomeSuccess,
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	done := make(chan error, 1)
	go func() { done <- h.consumer.Run(ctx) }()

	mustXAdd(t, h.client, h.stream, "game-5", "cancelled", 1)
	mustXAdd(t, h.client, h.stream, "game-5", "finished", 2)

	require.Eventually(t, func() bool {
		return len(h.results.Published()) == 2
	}, time.Second, 10*time.Millisecond, "consumer must produce one job result per envelope")

	cancel()
	require.Eventually(t, func() bool {
		select {
		case <-done:
			return true
		default:
			return false
		}
	}, time.Second, 10*time.Millisecond, "Run must exit after context cancel")

	id, ok := h.offsets.Get("stopjobs")
	require.True(t, ok, "offset must be persisted after the run loop processed messages")
	assert.NotEmpty(t, id, "offset entry id must not be empty")
}

func TestRunExitsImmediatelyOnAlreadyCancelledContext(t *testing.T) {
	h := newHarness(t)
	ctx, cancel := context.WithCancel(context.Background())
	cancel()

	err := h.consumer.Run(ctx)
	require.ErrorIs(t, err, context.Canceled)
	assert.Empty(t, h.stops.Inputs())
	assert.Empty(t, h.results.Published())
}

func mustXAdd(t *testing.T, client *redis.Client, stream, gameID, reason string, requestedAtMS int64) string {
	t.Helper()
	id, err := client.XAdd(context.Background(), &redis.XAddArgs{
		Stream: stream,
		Values: map[string]any{
			"game_id":         gameID,
			"reason":          reason,
			"requested_at_ms": strconv.FormatInt(requestedAtMS, 10),
		},
	}).Result()
	require.NoError(t, err)
	return id
}