package diplomail_test

import (
	"context"
	"database/sql"
	"errors"
	"net/url"
	"sync"
	"testing"
	"time"

	"galaxy/backend/internal/config"
	"galaxy/backend/internal/diplomail"
	backendpg "galaxy/backend/internal/postgres"
	pgshared "galaxy/postgres"

	"github.com/google/uuid"
	testcontainers "github.com/testcontainers/testcontainers-go"
	tcpostgres "github.com/testcontainers/testcontainers-go/modules/postgres"
	"github.com/testcontainers/testcontainers-go/wait"
)

const (
	testImage     = "postgres:16-alpine"
	testUser      = "galaxy"
	testPassword  = "galaxy"
	testDatabase  = "galaxy_backend"
	testSchema    = "backend"
	testStartup   = 90 * time.Second
	testOpTimeout = 10 * time.Second
)

// startPostgres mirrors the harness used by `lobby_e2e_test.go`. It
// spins up a postgres:16-alpine container, applies the embedded
// migrations, and returns a ready-to-use `*sql.DB`. The container is
// torn down via t.Cleanup.
func startPostgres(t *testing.T) *sql.DB {
	t.Helper()
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
	t.Cleanup(cancel)

	pgContainer, err := tcpostgres.Run(ctx, testImage,
		tcpostgres.WithDatabase(testDatabase),
		tcpostgres.WithUsername(testUser),
		tcpostgres.WithPassword(testPassword),
		testcontainers.WithWaitStrategy(
			wait.ForLog("database system is ready to accept connections").
				WithOccurrence(2).
				WithStartupTimeout(testStartup),
		),
	)
	if err != nil {
		t.Skipf("postgres testcontainer unavailable, skipping: %v", err)
	}
	t.Cleanup(func() {
		if termErr := testcontainers.TerminateContainer(pgContainer); termErr != nil {
			t.Errorf("terminate postgres container: %v", termErr)
		}
	})

	baseDSN, err := pgContainer.ConnectionString(ctx, "sslmode=disable")
	if err != nil {
		t.Fatalf("connection string: %v", err)
	}
	scopedDSN, err := dsnWithSearchPath(baseDSN, testSchema)
	if err != nil {
		t.Fatalf("scope dsn: %v", err)
	}
	cfg := pgshared.DefaultConfig()
	cfg.PrimaryDSN = scopedDSN
	cfg.OperationTimeout = testOpTimeout
	db, err := pgshared.OpenPrimary(ctx, cfg, backendpg.NoObservabilityOptions()...)
	if err != nil {
		t.Fatalf("open primary: %v", err)
	}
	t.Cleanup(func() {
		if err := db.Close(); err != nil {
			t.Errorf("close db: %v", err)
		}
	})
	if err := pgshared.Ping(ctx, db, cfg.OperationTimeout); err != nil {
		t.Fatalf("ping: %v", err)
	}
	if err := backendpg.ApplyMigrations(ctx, db); err != nil {
		t.Fatalf("apply migrations: %v", err)
	}
	return db
}

func dsnWithSearchPath(baseDSN, schema string) (string, error) {
	parsed, err := url.Parse(baseDSN)
	if err != nil {
		return "", err
	}
	values := parsed.Query()
	values.Set("search_path", schema)
	if values.Get("sslmode") == "" {
		values.Set("sslmode", "disable")
	}
	parsed.RawQuery = values.Encode()
	return parsed.String(), nil
}

// recordingPublisher captures every emitted DiplomailNotification so
// the test can assert push fan-out without booting the real
// notification pipeline.
type recordingPublisher struct {
	mu       sync.Mutex
	captured []diplomail.DiplomailNotification
}

func (p *recordingPublisher) PublishDiplomailEvent(_ context.Context, ev diplomail.DiplomailNotification) error {
	p.mu.Lock()
	defer p.mu.Unlock()
	p.captured = append(p.captured, ev)
	return nil
}

func (p *recordingPublisher) snapshot() []diplomail.DiplomailNotification {
	p.mu.Lock()
	defer p.mu.Unlock()
	out := make([]diplomail.DiplomailNotification, len(p.captured))
	copy(out, p.captured)
	return out
}

// staticMembershipLookup serves an in-memory fixture. The test seeds
// memberships up-front and the lookup is keyed on (gameID, userID).
type staticMembershipLookup struct {
	rows map[[2]uuid.UUID]diplomail.ActiveMembership
}

func (l *staticMembershipLookup) GetActiveMembership(_ context.Context, gameID, userID uuid.UUID) (diplomail.ActiveMembership, error) {
	if l == nil || l.rows == nil {
		return diplomail.ActiveMembership{}, diplomail.ErrNotFound
	}
	row, ok := l.rows[[2]uuid.UUID{gameID, userID}]
	if !ok {
		return diplomail.ActiveMembership{}, diplomail.ErrNotFound
	}
	return row, nil
}

// seedAccount inserts a minimal accounts row so memberships and mail
// recipient FKs are satisfiable.
func seedAccount(t *testing.T, db *sql.DB, userID uuid.UUID) {
	t.Helper()
	_, err := db.ExecContext(context.Background(), `
		INSERT INTO backend.accounts (
			user_id, email, user_name, preferred_language, time_zone
		) VALUES ($1, $2, $3, 'en', 'UTC')
	`, userID, userID.String()+"@test.local", "user-"+userID.String()[:8])
	if err != nil {
		t.Fatalf("seed account %s: %v", userID, err)
	}
}

// seedGame inserts a minimal games row so the diplomail_messages.game_id
// FK is satisfiable.
func seedGame(t *testing.T, db *sql.DB, gameID uuid.UUID, name string) {
	t.Helper()
	_, err := db.ExecContext(context.Background(), `
		INSERT INTO backend.games (
			game_id, visibility, status, game_name,
			min_players, max_players, start_gap_hours, start_gap_players,
			enrollment_ends_at, turn_schedule, target_engine_version,
			runtime_snapshot
		) VALUES (
			$1, 'private', 'enrollment_open', $2,
			1, 4, 1, 1,
			now() + interval '1 day', '0 0 * * *', '1.0.0',
			'{}'::jsonb
		)
	`, gameID, name)
	if err != nil {
		t.Fatalf("seed game %s: %v", gameID, err)
	}
}

func TestDiplomailPersonalFlow(t *testing.T) {
	db := startPostgres(t)
	ctx := context.Background()

	gameID := uuid.New()
	sender := uuid.New()
	recipient := uuid.New()
	other := uuid.New()
	seedAccount(t, db, sender)
	seedAccount(t, db, recipient)
	seedAccount(t, db, other)
	seedGame(t, db, gameID, "Stage A Test Game")

	lookup := &staticMembershipLookup{
		rows: map[[2]uuid.UUID]diplomail.ActiveMembership{
			{gameID, sender}: {
				UserID: sender, GameID: gameID, GameName: "Stage A Test Game",
				UserName: "sender", RaceName: "Senders",
			},
			{gameID, recipient}: {
				UserID: recipient, GameID: gameID, GameName: "Stage A Test Game",
				UserName: "recipient", RaceName: "Receivers",
			},
		},
	}
	publisher := &recordingPublisher{}

	svc := diplomail.NewService(diplomail.Deps{
		Store:        diplomail.NewStore(db),
		Memberships:  lookup,
		Notification: publisher,
		Config: config.DiplomailConfig{
			MaxBodyBytes:    4096,
			MaxSubjectBytes: 256,
		},
	})

	// 1. SendPersonal happy path.
	msg, rcpt, err := svc.SendPersonal(ctx, diplomail.SendPersonalInput{
		GameID:          gameID,
		SenderUserID:    sender,
		RecipientUserID: recipient,
		Subject:         "Trade proposal",
		Body:            "Care to talk gas mining?",
		SenderIP:        "203.0.113.4",
	})
	if err != nil {
		t.Fatalf("send personal: %v", err)
	}
	if msg.Kind != diplomail.KindPersonal {
		t.Fatalf("kind = %q, want personal", msg.Kind)
	}
	if rcpt.UserID != recipient {
		t.Fatalf("recipient.UserID = %s, want %s", rcpt.UserID, recipient)
	}
	if rcpt.ReadAt != nil {
		t.Fatalf("freshly sent message should be unread, read_at=%v", rcpt.ReadAt)
	}
	if got := publisher.snapshot(); len(got) != 1 {
		t.Fatalf("publisher captured %d events, want 1", len(got))
	} else if got[0].Recipient != recipient {
		t.Fatalf("push recipient = %s, want %s", got[0].Recipient, recipient)
	}

	// 2. ListInbox shows the message for the recipient.
	inbox, err := svc.ListInbox(ctx, gameID, recipient)
	if err != nil {
		t.Fatalf("list inbox: %v", err)
	}
	if len(inbox) != 1 || inbox[0].MessageID != msg.MessageID {
		t.Fatalf("inbox = %+v, want one matching entry", inbox)
	}

	// 3. ListSent surfaces the message for the sender.
	sent, err := svc.ListSent(ctx, gameID, sender)
	if err != nil {
		t.Fatalf("list sent: %v", err)
	}
	if len(sent) != 1 || sent[0].MessageID != msg.MessageID {
		t.Fatalf("sent = %+v, want one matching entry", sent)
	}

	// 4. Non-recipient reads are 404.
	if _, err := svc.GetMessage(ctx, other, msg.MessageID); !errors.Is(err, diplomail.ErrNotFound) {
		t.Fatalf("non-recipient get: %v, want ErrNotFound", err)
	}

	// 5. Delete before read is a conflict.
	if _, err := svc.DeleteMessage(ctx, recipient, msg.MessageID); !errors.Is(err, diplomail.ErrConflict) {
		t.Fatalf("delete before read: %v, want ErrConflict", err)
	}

	// 6. MarkRead sets read_at; second call is a no-op.
	read, err := svc.MarkRead(ctx, recipient, msg.MessageID)
	if err != nil {
		t.Fatalf("mark read: %v", err)
	}
	if read.ReadAt == nil {
		t.Fatalf("mark read returned no read_at")
	}
	again, err := svc.MarkRead(ctx, recipient, msg.MessageID)
	if err != nil {
		t.Fatalf("mark read idempotent: %v", err)
	}
	if !again.ReadAt.Equal(*read.ReadAt) {
		t.Fatalf("mark read idempotent shifted read_at: %v -> %v", read.ReadAt, again.ReadAt)
	}

	// 7. Unread counts go to zero after the read.
	counts, err := svc.UnreadCountsForUser(ctx, recipient)
	if err != nil {
		t.Fatalf("unread counts: %v", err)
	}
	if len(counts) != 0 {
		t.Fatalf("unread counts = %+v, want empty after read", counts)
	}

	// 8. Soft delete now succeeds.
	deleted, err := svc.DeleteMessage(ctx, recipient, msg.MessageID)
	if err != nil {
		t.Fatalf("delete after read: %v", err)
	}
	if deleted.DeletedAt == nil {
		t.Fatalf("delete after read returned no deleted_at")
	}

	// 9. Inbox now excludes the soft-deleted message.
	inbox, err = svc.ListInbox(ctx, gameID, recipient)
	if err != nil {
		t.Fatalf("list inbox after delete: %v", err)
	}
	if len(inbox) != 0 {
		t.Fatalf("inbox after delete = %+v, want empty", inbox)
	}
}

func TestDiplomailRejectsNonActiveSender(t *testing.T) {
	db := startPostgres(t)
	ctx := context.Background()

	gameID := uuid.New()
	sender := uuid.New()
	recipient := uuid.New()
	seedAccount(t, db, sender)
	seedAccount(t, db, recipient)
	seedGame(t, db, gameID, "Solo Test Game")

	// Only the recipient is on the active roster.
	lookup := &staticMembershipLookup{
		rows: map[[2]uuid.UUID]diplomail.ActiveMembership{
			{gameID, recipient}: {
				UserID: recipient, GameID: gameID, GameName: "Solo Test Game",
				UserName: "recipient", RaceName: "Receivers",
			},
		},
	}

	svc := diplomail.NewService(diplomail.Deps{
		Store:       diplomail.NewStore(db),
		Memberships: lookup,
		Config: config.DiplomailConfig{
			MaxBodyBytes:    4096,
			MaxSubjectBytes: 256,
		},
	})

	_, _, err := svc.SendPersonal(ctx, diplomail.SendPersonalInput{
		GameID:          gameID,
		SenderUserID:    sender,
		RecipientUserID: recipient,
		Subject:         "Hi",
		Body:            "Trade?",
	})
	if !errors.Is(err, diplomail.ErrForbidden) {
		t.Fatalf("send from non-member: %v, want ErrForbidden", err)
	}
}

func TestDiplomailRejectsOverlongBody(t *testing.T) {
	db := startPostgres(t)
	ctx := context.Background()

	gameID := uuid.New()
	sender := uuid.New()
	recipient := uuid.New()
	seedAccount(t, db, sender)
	seedAccount(t, db, recipient)
	seedGame(t, db, gameID, "Length Test Game")

	lookup := &staticMembershipLookup{
		rows: map[[2]uuid.UUID]diplomail.ActiveMembership{
			{gameID, sender}: {
				UserID: sender, GameID: gameID, GameName: "Length Test Game",
				UserName: "sender", RaceName: "Senders",
			},
			{gameID, recipient}: {
				UserID: recipient, GameID: gameID, GameName: "Length Test Game",
				UserName: "recipient", RaceName: "Receivers",
			},
		},
	}

	svc := diplomail.NewService(diplomail.Deps{
		Store:       diplomail.NewStore(db),
		Memberships: lookup,
		Config: config.DiplomailConfig{
			MaxBodyBytes:    32,
			MaxSubjectBytes: 256,
		},
	})

	bigBody := make([]byte, 64)
	for i := range bigBody {
		bigBody[i] = 'a'
	}
	_, _, err := svc.SendPersonal(ctx, diplomail.SendPersonalInput{
		GameID:          gameID,
		SenderUserID:    sender,
		RecipientUserID: recipient,
		Body:            string(bigBody),
	})
	if !errors.Is(err, diplomail.ErrInvalidInput) {
		t.Fatalf("send overlong: %v, want ErrInvalidInput", err)
	}
}