package startgame_test

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

	"galaxy/lobby/internal/adapters/gameinmem"
	"galaxy/lobby/internal/adapters/mocks"
	"galaxy/lobby/internal/domain/common"
	"galaxy/lobby/internal/domain/engineimage"
	"galaxy/lobby/internal/domain/game"
	"galaxy/lobby/internal/ports"
	"galaxy/lobby/internal/service/shared"
	"galaxy/lobby/internal/service/startgame"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"go.uber.org/mock/gomock"
)

const testImageTemplate = "registry.example.com/galaxy/game:{engine_version}"

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

func fixedClock(at time.Time) func() time.Time {
	return func() time.Time { return at }
}

func newReadyGame(t *testing.T, gameType game.GameType, ownerID string) (game.Game, time.Time) {
	t.Helper()
	now := time.Date(2026, 4, 25, 12, 0, 0, 0, time.UTC)
	record, err := game.New(game.NewGameInput{
		GameID:              common.GameID("game-1"),
		GameName:            "test game",
		GameType:            gameType,
		OwnerUserID:         ownerID,
		MinPlayers:          4,
		MaxPlayers:          8,
		StartGapHours:       12,
		StartGapPlayers:     2,
		EnrollmentEndsAt:    now.Add(24 * time.Hour),
		TurnSchedule:        "0 18 * * *",
		TargetEngineVersion: "v1.0.0",
		Now:                 now,
	})
	require.NoError(t, err)
	record.Status = game.StatusReadyToStart
	return record, now
}

// runtimeRec captures every PublishStartJob/PublishStopJob call so tests
// can assert which jobs ran. Per-test error injection sets startErr.
type runtimeRec struct {
	mu        sync.Mutex
	startIDs  []string
	startRefs []string
	stopIDs   []string
	stopReas  []ports.StopReason
	startErr  error
}

func (r *runtimeRec) recordStart(_ context.Context, gameID, imageRef string) error {
	r.mu.Lock()
	defer r.mu.Unlock()
	if r.startErr != nil {
		return r.startErr
	}
	r.startIDs = append(r.startIDs, gameID)
	r.startRefs = append(r.startRefs, imageRef)
	return nil
}

func (r *runtimeRec) recordStop(_ context.Context, gameID string, reason ports.StopReason) error {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.stopIDs = append(r.stopIDs, gameID)
	r.stopReas = append(r.stopReas, reason)
	return nil
}

func (r *runtimeRec) startJobs() []string {
	r.mu.Lock()
	defer r.mu.Unlock()
	return append([]string(nil), r.startIDs...)
}

func (r *runtimeRec) startImageRefs() []string {
	r.mu.Lock()
	defer r.mu.Unlock()
	return append([]string(nil), r.startRefs...)
}

func (r *runtimeRec) stopJobs() []string {
	r.mu.Lock()
	defer r.mu.Unlock()
	return append([]string(nil), r.stopIDs...)
}

func newRuntimeMock(t *testing.T, rec *runtimeRec) *mocks.MockRuntimeManager {
	t.Helper()
	m := mocks.NewMockRuntimeManager(gomock.NewController(t))
	m.EXPECT().PublishStartJob(gomock.Any(), gomock.Any(), gomock.Any()).
		DoAndReturn(rec.recordStart).AnyTimes()
	m.EXPECT().PublishStopJob(gomock.Any(), gomock.Any(), gomock.Any()).
		DoAndReturn(rec.recordStop).AnyTimes()
	return m
}

type fixture struct {
	games   *gameinmem.Store
	rec     *runtimeRec
	runtime *mocks.MockRuntimeManager
	service *startgame.Service
	now     time.Time
}

func newFixture(t *testing.T, record game.Game, now time.Time) *fixture {
	t.Helper()
	games := gameinmem.NewStore()
	require.NoError(t, games.Save(context.Background(), record))
	rec := &runtimeRec{}
	runtime := newRuntimeMock(t, rec)
	resolver, err := engineimage.NewResolver(testImageTemplate)
	require.NoError(t, err)
	service, err := startgame.NewService(startgame.Dependencies{
		Games:          games,
		RuntimeManager: runtime,
		ImageResolver:  resolver,
		Clock:          fixedClock(now.Add(time.Hour)),
		Logger:         silentLogger(),
	})
	require.NoError(t, err)
	return &fixture{games: games, rec: rec, runtime: runtime, service: service, now: now}
}

func TestNewServiceRejectsMissingDeps(t *testing.T) {
	resolver, err := engineimage.NewResolver(testImageTemplate)
	require.NoError(t, err)

	rec := &runtimeRec{}
	runtime := newRuntimeMock(t, rec)

	_, err = startgame.NewService(startgame.Dependencies{
		RuntimeManager: runtime,
		ImageResolver:  resolver,
	})
	require.Error(t, err)

	_, err = startgame.NewService(startgame.Dependencies{
		Games:         gameinmem.NewStore(),
		ImageResolver: resolver,
	})
	require.Error(t, err)

	_, err = startgame.NewService(startgame.Dependencies{
		Games:          gameinmem.NewStore(),
		RuntimeManager: runtime,
	})
	require.Error(t, err)
}

func TestStartGamePublicAdminHappyPath(t *testing.T) {
	record, now := newReadyGame(t, game.GameTypePublic, "")
	f := newFixture(t, record, now)

	updated, err := f.service.Handle(context.Background(), startgame.Input{
		Actor:  shared.NewAdminActor(),
		GameID: record.GameID,
	})
	require.NoError(t, err)
	assert.Equal(t, game.StatusStarting, updated.Status)
	assert.Equal(t, []string{record.GameID.String()}, f.rec.startJobs())
	assert.Equal(t,
		[]string{"registry.example.com/galaxy/game:" + record.TargetEngineVersion},
		f.rec.startImageRefs(),
		"resolved image_ref must propagate to publisher",
	)
	assert.Empty(t, f.rec.stopJobs())
}

func TestStartGamePrivateOwnerHappyPath(t *testing.T) {
	record, now := newReadyGame(t, game.GameTypePrivate, "user-owner")
	f := newFixture(t, record, now)

	updated, err := f.service.Handle(context.Background(), startgame.Input{
		Actor:  shared.NewUserActor("user-owner"),
		GameID: record.GameID,
	})
	require.NoError(t, err)
	assert.Equal(t, game.StatusStarting, updated.Status)
	assert.Equal(t, []string{record.GameID.String()}, f.rec.startJobs())
}

func TestStartGameRejectsNonOwnerUser(t *testing.T) {
	record, now := newReadyGame(t, game.GameTypePrivate, "user-owner")
	f := newFixture(t, record, now)

	_, err := f.service.Handle(context.Background(), startgame.Input{
		Actor:  shared.NewUserActor("user-other"),
		GameID: record.GameID,
	})
	require.ErrorIs(t, err, shared.ErrForbidden)
	assert.Empty(t, f.rec.startJobs(), "no start job published on forbidden")

	stored, err := f.games.Get(context.Background(), record.GameID)
	require.NoError(t, err)
	assert.Equal(t, game.StatusReadyToStart, stored.Status, "status must remain ready_to_start")
}

func TestStartGameRejectsPublicUserActor(t *testing.T) {
	record, now := newReadyGame(t, game.GameTypePublic, "")
	f := newFixture(t, record, now)

	_, err := f.service.Handle(context.Background(), startgame.Input{
		Actor:  shared.NewUserActor("user-1"),
		GameID: record.GameID,
	})
	require.ErrorIs(t, err, shared.ErrForbidden)
}

func TestStartGameRejectsWrongStatus(t *testing.T) {
	record, now := newReadyGame(t, game.GameTypePublic, "")
	record.Status = game.StatusEnrollmentOpen
	f := newFixture(t, record, now)

	_, err := f.service.Handle(context.Background(), startgame.Input{
		Actor:  shared.NewAdminActor(),
		GameID: record.GameID,
	})
	require.ErrorIs(t, err, game.ErrConflict)
	assert.Empty(t, f.rec.startJobs())
}

func TestStartGameRejectsCASLossOnRecentTransition(t *testing.T) {
	record, now := newReadyGame(t, game.GameTypePublic, "")
	f := newFixture(t, record, now)

	// Concurrent start: simulate someone moved status to starting.
	require.NoError(t, f.games.UpdateStatus(context.Background(), ports.UpdateStatusInput{
		GameID:       record.GameID,
		ExpectedFrom: game.StatusReadyToStart,
		To:           game.StatusStarting,
		Trigger:      game.TriggerCommand,
		At:           now.Add(time.Minute),
	}))

	_, err := f.service.Handle(context.Background(), startgame.Input{
		Actor:  shared.NewAdminActor(),
		GameID: record.GameID,
	})
	require.ErrorIs(t, err, game.ErrConflict)
	assert.Empty(t, f.rec.startJobs())
}

func TestStartGamePublishFailureSurfacesUnavailable(t *testing.T) {
	record, now := newReadyGame(t, game.GameTypePublic, "")
	f := newFixture(t, record, now)
	f.rec.startErr = errors.New("redis down")

	_, err := f.service.Handle(context.Background(), startgame.Input{
		Actor:  shared.NewAdminActor(),
		GameID: record.GameID,
	})
	require.Error(t, err)
	assert.ErrorIs(t, err, shared.ErrServiceUnavailable)

	stored, err := f.games.Get(context.Background(), record.GameID)
	require.NoError(t, err)
	assert.Equal(t, game.StatusStarting, stored.Status,
		"status remains starting; runtime worker resolves orphan via job result")
}

func TestStartGameRejectsMissingRecord(t *testing.T) {
	games := gameinmem.NewStore()
	rec := &runtimeRec{}
	runtime := newRuntimeMock(t, rec)
	resolver, err := engineimage.NewResolver(testImageTemplate)
	require.NoError(t, err)
	service, err := startgame.NewService(startgame.Dependencies{
		Games:          games,
		RuntimeManager: runtime,
		ImageResolver:  resolver,
		Clock:          fixedClock(time.Now().UTC()),
		Logger:         silentLogger(),
	})
	require.NoError(t, err)

	_, err = service.Handle(context.Background(), startgame.Input{
		Actor:  shared.NewAdminActor(),
		GameID: common.GameID("game-missing"),
	})
	require.ErrorIs(t, err, game.ErrNotFound)
}