package redeeminvite_test

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

	"galaxy/lobby/internal/adapters/gameinmem"
	"galaxy/lobby/internal/adapters/gapactivationinmem"
	"galaxy/lobby/internal/adapters/inviteinmem"
	"galaxy/lobby/internal/adapters/membershipinmem"
	"galaxy/lobby/internal/adapters/mocks"
	"galaxy/lobby/internal/adapters/racenameinmem"
	"galaxy/lobby/internal/domain/common"
	"galaxy/lobby/internal/domain/game"
	"galaxy/lobby/internal/domain/invite"
	"galaxy/lobby/internal/domain/membership"
	"galaxy/lobby/internal/ports"
	"galaxy/lobby/internal/service/redeeminvite"
	"galaxy/lobby/internal/service/shared"
	"galaxy/notificationintent"

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

type intentRec struct {
	mu        sync.Mutex
	published []notificationintent.Intent
	err       error
}

func (r *intentRec) record(_ context.Context, intent notificationintent.Intent) (string, error) {
	r.mu.Lock()
	defer r.mu.Unlock()
	if r.err != nil {
		return "", r.err
	}
	r.published = append(r.published, intent)
	return "1", nil
}

func (r *intentRec) snapshot() []notificationintent.Intent {
	r.mu.Lock()
	defer r.mu.Unlock()
	return append([]notificationintent.Intent(nil), r.published...)
}

func (r *intentRec) setErr(err error) {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.err = err
}

type userRec struct {
	mu       sync.Mutex
	elig     map[string]ports.Eligibility
	failures map[string]error
}

func (r *userRec) record(_ context.Context, userID string) (ports.Eligibility, error) {
	r.mu.Lock()
	defer r.mu.Unlock()
	if err, ok := r.failures[userID]; ok {
		return ports.Eligibility{}, err
	}
	if e, ok := r.elig[userID]; ok {
		return e, nil
	}
	return ports.Eligibility{Exists: false}, nil
}

func (r *userRec) setEligibility(userID string, e ports.Eligibility) {
	r.mu.Lock()
	defer r.mu.Unlock()
	if r.elig == nil {
		r.elig = make(map[string]ports.Eligibility)
	}
	r.elig[userID] = e
}

func (r *userRec) setFailure(userID string, err error) {
	r.mu.Lock()
	defer r.mu.Unlock()
	if r.failures == nil {
		r.failures = make(map[string]error)
	}
	r.failures[userID] = err
}

func newIntentMock(t *testing.T, rec *intentRec) *mocks.MockIntentPublisher {
	t.Helper()
	m := mocks.NewMockIntentPublisher(gomock.NewController(t))
	m.EXPECT().Publish(gomock.Any(), gomock.Any()).DoAndReturn(rec.record).AnyTimes()
	return m
}

func newUserMock(t *testing.T, rec *userRec) *mocks.MockUserService {
	t.Helper()
	m := mocks.NewMockUserService(gomock.NewController(t))
	m.EXPECT().GetEligibility(gomock.Any(), gomock.Any()).DoAndReturn(rec.record).AnyTimes()
	return m
}

const (
	ownerUserID   = "user-owner"
	inviteeUserID = "user-invitee"
	defaultRace   = "VoidRunner"
)

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 } }

type fixedIDs struct {
	membershipID common.MembershipID
}

func (f fixedIDs) NewGameID() (common.GameID, error)               { return "", errors.New("not used") }
func (f fixedIDs) NewApplicationID() (common.ApplicationID, error) { return "", errors.New("not used") }
func (f fixedIDs) NewInviteID() (common.InviteID, error)           { return "", errors.New("not used") }
func (f fixedIDs) NewMembershipID() (common.MembershipID, error)   { return f.membershipID, nil }

type fixture struct {
	now         time.Time
	games       *gameinmem.Store
	invites     *inviteinmem.Store
	memberships *membershipinmem.Store
	directory   *racenameinmem.Directory
	users       *userRec
	usersMock   *mocks.MockUserService
	gapStore    *gapactivationinmem.Store
	intents     *intentRec
	intentsMock *mocks.MockIntentPublisher
	ids         fixedIDs
	game        game.Game
}

func newFixture(t *testing.T, maxPlayers, gapPlayers int) *fixture {
	t.Helper()
	now := time.Date(2026, 4, 25, 10, 0, 0, 0, time.UTC)
	dir, err := racenameinmem.NewDirectory(racenameinmem.WithClock(fixedClock(now)))
	require.NoError(t, err)
	games := gameinmem.NewStore()
	invites := inviteinmem.NewStore()
	memberships := membershipinmem.NewStore()

	gameRecord, err := game.New(game.NewGameInput{
		GameID:              "game-private",
		GameName:            "Friends Only",
		GameType:            game.GameTypePrivate,
		OwnerUserID:         ownerUserID,
		MinPlayers:          2,
		MaxPlayers:          maxPlayers,
		StartGapHours:       2,
		StartGapPlayers:     gapPlayers,
		EnrollmentEndsAt:    now.Add(24 * time.Hour),
		TurnSchedule:        "0 */6 * * *",
		TargetEngineVersion: "1.0.0",
		Now:                 now,
	})
	require.NoError(t, err)
	gameRecord.Status = game.StatusEnrollmentOpen
	require.NoError(t, games.Save(context.Background(), gameRecord))

	users := &userRec{}
	activeEligibility := ports.Eligibility{
		Exists:               true,
		CanLogin:             true,
		CanCreatePrivateGame: true,
		CanManagePrivateGame: true,
		CanJoinGame:          true,
		CanUpdateProfile:     true,
	}
	users.setEligibility(ownerUserID, activeEligibility)
	users.setEligibility(inviteeUserID, activeEligibility)

	intents := &intentRec{}
	return &fixture{
		now:         now,
		games:       games,
		invites:     invites,
		memberships: memberships,
		directory:   dir,
		users:       users,
		usersMock:   newUserMock(t, users),
		gapStore:    gapactivationinmem.NewStore(),
		intents:     intents,
		intentsMock: newIntentMock(t, intents),
		ids:         fixedIDs{membershipID: "membership-fixed"},
		game:        gameRecord,
	}
}

func newService(t *testing.T, f *fixture) *redeeminvite.Service {
	t.Helper()
	svc, err := redeeminvite.NewService(redeeminvite.Dependencies{
		Games:       f.games,
		Invites:     f.invites,
		Memberships: f.memberships,
		Directory:   f.directory,
		Users:       f.usersMock,
		GapStore:    f.gapStore,
		Intents:     f.intentsMock,
		IDs:         f.ids,
		Clock:       fixedClock(f.now),
		Logger:      silentLogger(),
	})
	require.NoError(t, err)
	return svc
}

func seedCreatedInvite(t *testing.T, f *fixture, inviteID common.InviteID, invitee string) invite.Invite {
	t.Helper()
	inv, err := invite.New(invite.NewInviteInput{
		InviteID:      inviteID,
		GameID:        f.game.GameID,
		InviterUserID: ownerUserID,
		InviteeUserID: invitee,
		Now:           f.now,
		ExpiresAt:     f.game.EnrollmentEndsAt,
	})
	require.NoError(t, err)
	require.NoError(t, f.invites.Save(context.Background(), inv))
	return inv
}

func defaultInput(f *fixture, inv invite.Invite) redeeminvite.Input {
	return redeeminvite.Input{
		Actor:    shared.NewUserActor(inviteeUserID),
		GameID:   f.game.GameID,
		InviteID: inv.InviteID,
		RaceName: defaultRace,
	}
}

func TestRedeemHappyPath(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	svc := newService(t, f)

	got, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.NoError(t, err)
	assert.Equal(t, common.MembershipID("membership-fixed"), got.MembershipID)
	assert.Equal(t, defaultRace, got.RaceName)
	assert.Equal(t, "voidrunner", got.CanonicalKey)
	assert.Equal(t, membership.StatusActive, got.Status)
	assert.Equal(t, f.now, got.JoinedAt)
	assert.Equal(t, inviteeUserID, got.UserID)

	updated, err := f.invites.Get(context.Background(), inv.InviteID)
	require.NoError(t, err)
	assert.Equal(t, invite.StatusRedeemed, updated.Status)
	assert.Equal(t, defaultRace, updated.RaceName)
	require.NotNil(t, updated.DecidedAt)

	avail, err := f.directory.Check(context.Background(), defaultRace, "user-other")
	require.NoError(t, err)
	assert.True(t, avail.Taken)
	assert.Equal(t, inviteeUserID, avail.HolderUserID)

	intents := f.intents.snapshot()
	require.Len(t, intents, 1)
	assert.Equal(t, notificationintent.NotificationTypeLobbyInviteRedeemed, intents[0].NotificationType)
	assert.Equal(t, []string{ownerUserID}, intents[0].RecipientUserIDs)
	assert.Contains(t, intents[0].PayloadJSON, `"invitee_name":"`+defaultRace+`"`)

	assert.False(t, f.gapStore.WasActivated(f.game.GameID))
}

func TestRedeemRejectsInviterPermanentBlock(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	f.users.setEligibility(ownerUserID, ports.Eligibility{
		Exists:           true,
		PermanentBlocked: true,
	})
	svc := newService(t, f)

	_, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.ErrorIs(t, err, shared.ErrSubjectNotFound)

	updated, err := f.invites.Get(context.Background(), inv.InviteID)
	require.NoError(t, err)
	assert.Equal(t, invite.StatusCreated, updated.Status, "invite must remain unchanged on aborted redeem")
}

func TestRedeemRejectsInviteePermanentBlock(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	f.users.setEligibility(inviteeUserID, ports.Eligibility{
		Exists:           true,
		PermanentBlocked: true,
	})
	svc := newService(t, f)

	_, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.ErrorIs(t, err, shared.ErrSubjectNotFound)
}

func TestRedeemRejectsDeletedInviter(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	f.users.setEligibility(ownerUserID, ports.Eligibility{Exists: false})
	svc := newService(t, f)

	_, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.ErrorIs(t, err, shared.ErrSubjectNotFound)
}

func TestRedeemSurfacesUserServiceTransportFailure(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	f.users.setFailure(ownerUserID, ports.ErrUserServiceUnavailable)
	svc := newService(t, f)

	_, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.ErrorIs(t, err, shared.ErrServiceUnavailable)
}

func TestRedeemActivatesGapAtMaxPlayers(t *testing.T) {
	t.Parallel()
	// max=2, gap=1; pre-seed 1 active member. Redeem pushes count to 2 (== max).
	f := newFixture(t, 2, 1)
	preexisting, err := membership.New(membership.NewMembershipInput{
		MembershipID: "membership-pre",
		GameID:       f.game.GameID,
		UserID:       "user-pre",
		RaceName:     "PriorMember",
		CanonicalKey: "priormember",
		Now:          f.now,
	})
	require.NoError(t, err)
	require.NoError(t, f.memberships.Save(context.Background(), preexisting))

	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	svc := newService(t, f)

	_, err = svc.Handle(context.Background(), defaultInput(f, inv))
	require.NoError(t, err)
	assert.True(t, f.gapStore.WasActivated(f.game.GameID))
	assert.Equal(t, f.now, f.gapStore.ActivatedAt(f.game.GameID))
}

func TestRedeemDoesNotActivateGapBelowMax(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	svc := newService(t, f)

	_, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.NoError(t, err)
	assert.False(t, f.gapStore.WasActivated(f.game.GameID))
}

func TestRedeemAdminActorForbidden(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	svc := newService(t, f)

	in := defaultInput(f, inv)
	in.Actor = shared.NewAdminActor()

	_, err := svc.Handle(context.Background(), in)
	require.ErrorIs(t, err, shared.ErrForbidden)
}

func TestRedeemNonInviteeForbidden(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	svc := newService(t, f)

	in := defaultInput(f, inv)
	in.Actor = shared.NewUserActor("user-impostor")

	_, err := svc.Handle(context.Background(), in)
	require.ErrorIs(t, err, shared.ErrForbidden)
}

func TestRedeemInviteNotFound(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	svc := newService(t, f)

	_, err := svc.Handle(context.Background(), redeeminvite.Input{
		Actor:    shared.NewUserActor(inviteeUserID),
		GameID:   f.game.GameID,
		InviteID: "invite-missing",
		RaceName: defaultRace,
	})
	require.ErrorIs(t, err, invite.ErrNotFound)
}

func TestRedeemCrossGameInviteNotFound(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	svc := newService(t, f)

	in := defaultInput(f, inv)
	in.GameID = "game-other"

	_, err := svc.Handle(context.Background(), in)
	require.ErrorIs(t, err, invite.ErrNotFound)
}

func TestRedeemAlreadyRedeemedConflict(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	require.NoError(t, f.invites.UpdateStatus(context.Background(), ports.UpdateInviteStatusInput{
		InviteID:     inv.InviteID,
		ExpectedFrom: invite.StatusCreated,
		To:           invite.StatusDeclined,
		At:           f.now,
	}))

	svc := newService(t, f)
	_, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.ErrorIs(t, err, invite.ErrConflict)
}

func TestRedeemGameNotEnrollmentOpenConflict(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)

	rec, err := f.games.Get(context.Background(), f.game.GameID)
	require.NoError(t, err)
	rec.Status = game.StatusReadyToStart
	require.NoError(t, f.games.Save(context.Background(), rec))

	svc := newService(t, f)
	_, err = svc.Handle(context.Background(), defaultInput(f, inv))
	require.ErrorIs(t, err, game.ErrConflict)
}

func TestRedeemRosterFullConflict(t *testing.T) {
	t.Parallel()
	// Capacity = max(2) + gap(1) = 3; seed 3 active members.
	f := newFixture(t, 2, 1)
	for i := range 3 {
		member, err := membership.New(membership.NewMembershipInput{
			MembershipID: common.MembershipID("membership-seed-" + string(rune('a'+i))),
			GameID:       f.game.GameID,
			UserID:       "seed-user-" + string(rune('a'+i)),
			RaceName:     "Seed " + string(rune('A'+i)),
			CanonicalKey: "seed" + string(rune('a'+i)),
			Now:          f.now,
		})
		require.NoError(t, err)
		require.NoError(t, f.memberships.Save(context.Background(), member))
	}
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	svc := newService(t, f)

	_, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.ErrorIs(t, err, game.ErrConflict)
}

func TestRedeemNameTakenByAnotherUser(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	require.NoError(t, f.directory.Reserve(context.Background(), "game-other", "user-other", defaultRace))
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	svc := newService(t, f)

	_, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.ErrorIs(t, err, ports.ErrNameTaken)
}

func TestRedeemInvalidRaceName(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	svc := newService(t, f)

	in := defaultInput(f, inv)
	in.RaceName = "   "

	_, err := svc.Handle(context.Background(), in)
	require.ErrorIs(t, err, ports.ErrInvalidName)
}

// redeemCASStub wraps inviteinmem.Store but injects ErrConflict on the next
// UpdateStatus call so we can observe the rollback path.
type redeemCASStub struct {
	*inviteinmem.Store
	failNext bool
}

func (s *redeemCASStub) UpdateStatus(ctx context.Context, input ports.UpdateInviteStatusInput) error {
	if s.failNext {
		s.failNext = false
		return invite.ErrConflict
	}
	return s.Store.UpdateStatus(ctx, input)
}

func TestRedeemCASConflictReleasesReservation(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)

	cas := &redeemCASStub{Store: f.invites, failNext: true}
	svc, err := redeeminvite.NewService(redeeminvite.Dependencies{
		Games:       f.games,
		Invites:     cas,
		Memberships: f.memberships,
		Directory:   f.directory,
		Users:       f.usersMock,
		GapStore:    f.gapStore,
		Intents:     f.intentsMock,
		IDs:         f.ids,
		Clock:       fixedClock(f.now),
		Logger:      silentLogger(),
	})
	require.NoError(t, err)

	_, err = svc.Handle(context.Background(), defaultInput(f, inv))
	require.ErrorIs(t, err, invite.ErrConflict)

	avail, err := f.directory.Check(context.Background(), defaultRace, "user-other")
	require.NoError(t, err)
	assert.False(t, avail.Taken, "reservation must be released after CAS failure")
	assert.Empty(t, avail.HolderUserID)
}

func TestRedeemPublishFailureDoesNotRollback(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	inv := seedCreatedInvite(t, f, "invite-1", inviteeUserID)
	f.intents.setErr(errors.New("publish failed"))

	svc := newService(t, f)
	got, err := svc.Handle(context.Background(), defaultInput(f, inv))
	require.NoError(t, err)
	assert.Equal(t, common.MembershipID("membership-fixed"), got.MembershipID)

	updated, err := f.invites.Get(context.Background(), inv.InviteID)
	require.NoError(t, err)
	assert.Equal(t, invite.StatusRedeemed, updated.Status)
}