package createinvite_test

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

	"galaxy/lobby/internal/adapters/gameinmem"
	"galaxy/lobby/internal/adapters/inviteinmem"
	"galaxy/lobby/internal/adapters/membershipinmem"
	"galaxy/lobby/internal/adapters/mocks"
	"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/createinvite"
	"galaxy/lobby/internal/service/shared"
	"galaxy/notificationintent"

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

// intentRec captures every Publish call so tests can assert on the
// resulting intent. Per-test error injection sets err.
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
}

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
}

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

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 {
	inviteID common.InviteID
}

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 f.inviteID, nil }
func (f fixedIDs) NewMembershipID() (common.MembershipID, error)   { return "", errors.New("not used") }

type fixture struct {
	now         time.Time
	games       *gameinmem.Store
	invites     *inviteinmem.Store
	memberships *membershipinmem.Store
	intentRec   *intentRec
	intents     *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)
	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))

	rec := &intentRec{}
	return &fixture{
		now:         now,
		games:       games,
		invites:     invites,
		memberships: memberships,
		intentRec:   rec,
		ids:         fixedIDs{inviteID: "invite-fixed"},
		game:        gameRecord,
	}
}

func newService(t *testing.T, f *fixture) *createinvite.Service {
	t.Helper()
	if f.intents == nil {
		f.intents = newIntentMock(t, f.intentRec)
	}
	svc, err := createinvite.NewService(createinvite.Dependencies{
		Games:       f.games,
		Invites:     f.invites,
		Memberships: f.memberships,
		Intents:     f.intents,
		IDs:         f.ids,
		Clock:       fixedClock(f.now),
		Logger:      silentLogger(),
	})
	require.NoError(t, err)
	return svc
}

func defaultInput(f *fixture) createinvite.Input {
	return createinvite.Input{
		Actor:         shared.NewUserActor(ownerUserID),
		GameID:        f.game.GameID,
		InviteeUserID: inviteeUserID,
	}
}

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

	got, err := svc.Handle(context.Background(), defaultInput(f))
	require.NoError(t, err)
	assert.Equal(t, common.InviteID("invite-fixed"), got.InviteID)
	assert.Equal(t, ownerUserID, got.InviterUserID)
	assert.Equal(t, inviteeUserID, got.InviteeUserID)
	assert.Equal(t, invite.StatusCreated, got.Status)
	assert.Equal(t, f.now, got.CreatedAt)
	assert.Equal(t, f.game.EnrollmentEndsAt, got.ExpiresAt)
	assert.Empty(t, got.RaceName)

	intents := f.intentRec.snapshot()
	require.Len(t, intents, 1)
	assert.Equal(t, notificationintent.NotificationTypeLobbyInviteCreated, intents[0].NotificationType)
	assert.Equal(t, []string{inviteeUserID}, intents[0].RecipientUserIDs)
}

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

	input := defaultInput(f)
	input.Actor = shared.NewAdminActor()

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

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

	input := defaultInput(f)
	input.Actor = shared.NewUserActor("user-impostor")

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

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

	publicGame, err := game.New(game.NewGameInput{
		GameID:              "game-public",
		GameName:            "Open",
		GameType:            game.GameTypePublic,
		MinPlayers:          2,
		MaxPlayers:          4,
		StartGapHours:       2,
		StartGapPlayers:     1,
		EnrollmentEndsAt:    f.now.Add(24 * time.Hour),
		TurnSchedule:        "0 */6 * * *",
		TargetEngineVersion: "1.0.0",
		Now:                 f.now,
	})
	require.NoError(t, err)
	publicGame.Status = game.StatusEnrollmentOpen
	require.NoError(t, f.games.Save(context.Background(), publicGame))

	svc := newService(t, f)
	input := defaultInput(f)
	input.GameID = publicGame.GameID

	_, err = svc.Handle(context.Background(), input)
	require.ErrorIs(t, err, game.ErrConflict)
}

func TestHandleWrongStatusConflict(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	rec, err := f.games.Get(context.Background(), f.game.GameID)
	require.NoError(t, err)
	rec.Status = game.StatusDraft
	require.NoError(t, f.games.Save(context.Background(), rec))

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

func TestHandleRosterFullConflict(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))
	}

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

func TestHandleDuplicateActiveInviteConflict(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	existing, err := invite.New(invite.NewInviteInput{
		InviteID:      "invite-existing",
		GameID:        f.game.GameID,
		InviterUserID: ownerUserID,
		InviteeUserID: inviteeUserID,
		Now:           f.now,
		ExpiresAt:     f.game.EnrollmentEndsAt,
	})
	require.NoError(t, err)
	require.NoError(t, f.invites.Save(context.Background(), existing))

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

func TestHandleDeclinedInviteAllowsReinvite(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	declined, err := invite.New(invite.NewInviteInput{
		InviteID:      "invite-declined",
		GameID:        f.game.GameID,
		InviterUserID: ownerUserID,
		InviteeUserID: inviteeUserID,
		Now:           f.now.Add(-time.Hour),
		ExpiresAt:     f.game.EnrollmentEndsAt,
	})
	require.NoError(t, err)
	require.NoError(t, f.invites.Save(context.Background(), declined))
	require.NoError(t, f.invites.UpdateStatus(context.Background(), ports.UpdateInviteStatusInput{
		InviteID:     declined.InviteID,
		ExpectedFrom: invite.StatusCreated,
		To:           invite.StatusDeclined,
		At:           f.now,
	}))

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

func TestHandleActiveMembershipBlocksInvite(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	member, err := membership.New(membership.NewMembershipInput{
		MembershipID: "membership-existing",
		GameID:       f.game.GameID,
		UserID:       inviteeUserID,
		RaceName:     "AlreadyMember",
		CanonicalKey: "alreadymember",
		Now:          f.now,
	})
	require.NoError(t, err)
	require.NoError(t, f.memberships.Save(context.Background(), member))

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

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

	input := defaultInput(f)
	input.InviteeUserID = ownerUserID

	_, err := svc.Handle(context.Background(), input)
	// invite.New refuses inviter == invitee with a validation error.
	require.Error(t, err)
}

func TestHandleInviterNameUsesActiveMembershipRaceName(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	ownerMember, err := membership.New(membership.NewMembershipInput{
		MembershipID: "membership-owner",
		GameID:       f.game.GameID,
		UserID:       ownerUserID,
		RaceName:     "OwnerRace",
		CanonicalKey: "ownerrace",
		Now:          f.now,
	})
	require.NoError(t, err)
	require.NoError(t, f.memberships.Save(context.Background(), ownerMember))

	svc := newService(t, f)
	_, err = svc.Handle(context.Background(), defaultInput(f))
	require.NoError(t, err)

	intents := f.intentRec.snapshot()
	require.Len(t, intents, 1)
	assert.Contains(t, intents[0].PayloadJSON, `"inviter_name":"OwnerRace"`)
}

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

	_, err := svc.Handle(context.Background(), defaultInput(f))
	require.NoError(t, err)

	intents := f.intentRec.snapshot()
	require.Len(t, intents, 1)
	assert.Contains(t, intents[0].PayloadJSON, `"inviter_name":"`+ownerUserID+`"`)
}

func TestHandlePublishFailureDoesNotRollback(t *testing.T) {
	t.Parallel()
	f := newFixture(t, 4, 1)
	f.intentRec.setErr(errors.New("publish failed"))
	svc := newService(t, f)

	got, err := svc.Handle(context.Background(), defaultInput(f))
	require.NoError(t, err)
	assert.Equal(t, common.InviteID("invite-fixed"), got.InviteID)

	stored, err := f.invites.Get(context.Background(), got.InviteID)
	require.NoError(t, err)
	assert.Equal(t, invite.StatusCreated, stored.Status)
}

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

	input := defaultInput(f)
	input.GameID = "game-missing"
	_, err := svc.Handle(context.Background(), input)
	require.ErrorIs(t, err, game.ErrNotFound)
}