// Package racenamedir implements the PostgreSQL-backed adapter for
// `ports.RaceNameDirectory`.
//
// One row in the `race_names` table backs one of three bindings on a
// canonical key: a registered name (one per canonical_key, immutable
// holder), a per-game reservation, or a pending_registration created by a
// capable game finish. The composite primary key (canonical_key, game_id)
// matches the existing two-tier semantics, where the same user may hold
// reservations on the same canonical key across multiple active games.
// Registered rows store game_id = '' and keep the source game in
// source_game_id, so the per-canonical uniqueness rule reduces to a
// partial UNIQUE index. Cross-user collisions on canonical_key are
// arbitrated by serialising every write transaction with
// pg_advisory_xact_lock(hashtextextended(canonical_key, 0)).
//
// PG_PLAN.md §6B introduces this adapter; see
// `galaxy/lobby/docs/postgres-migration.md` for the full decision record.
package racenamedir

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"strings"
	"time"

	"galaxy/lobby/internal/adapters/postgres/internal/sqlx"
	pgtable "galaxy/lobby/internal/adapters/postgres/jet/lobby/table"
	"galaxy/lobby/internal/domain/common"
	"galaxy/lobby/internal/domain/racename"
	"galaxy/lobby/internal/ports"

	pg "github.com/go-jet/jet/v2/postgres"
)

// Binding kind values stored verbatim in `race_names.binding_kind`. They
// equal the corresponding `ports.Kind*` constants so adapter methods can
// surface them at the port boundary without translation.
const (
	bindingRegistered  = ports.KindRegistered          // "registered"
	bindingReservation = ports.KindReservation         // "reservation"
	bindingPending     = ports.KindPendingRegistration // "pending_registration"
)

// registeredGameID is the sentinel value stored in the (canonical_key,
// game_id) primary key for binding_kind = 'registered' rows. The actual
// source game is kept in source_game_id; the empty `game_id` keeps
// registered rows distinct from per-game reservations under the same
// canonical_key.
const registeredGameID = ""

// Config configures one PostgreSQL-backed Race Name Directory adapter.
// The adapter does not own the underlying *sql.DB lifecycle: the caller
// (typically the service runtime) opens, instruments, migrates, and
// closes the pool.
type Config struct {
	// DB is the connection pool the directory uses for every query.
	DB *sql.DB

	// OperationTimeout bounds one operation. Read-only methods derive a
	// single context from it; write methods reuse the same bound across
	// the BEGIN ... COMMIT transaction.
	OperationTimeout time.Duration

	// Policy supplies the canonical-key derivation and ValidateName
	// rules; the adapter owns no race-name policy of its own.
	Policy *racename.Policy

	// Clock supplies wall-clock time used to stamp reserved_at_ms,
	// registered_at_ms and the cutoff passed to
	// ExpirePendingRegistrations.Defaults to time.Now when nil.
	Clock func() time.Time
}

// Directory persists Race Name Directory bindings in PostgreSQL.
type Directory struct {
	db               *sql.DB
	operationTimeout time.Duration
	policy           *racename.Policy
	nowFn            func() time.Time
}

// New constructs one PostgreSQL-backed Race Name Directory from cfg.
func New(cfg Config) (*Directory, error) {
	if cfg.DB == nil {
		return nil, errors.New("new postgres race name directory: db must not be nil")
	}
	if cfg.OperationTimeout <= 0 {
		return nil, errors.New("new postgres race name directory: operation timeout must be positive")
	}
	if cfg.Policy == nil {
		return nil, errors.New("new postgres race name directory: policy must not be nil")
	}
	nowFn := cfg.Clock
	if nowFn == nil {
		nowFn = time.Now
	}
	return &Directory{
		db:               cfg.DB,
		operationTimeout: cfg.OperationTimeout,
		policy:           cfg.Policy,
		nowFn:            nowFn,
	}, nil
}

// Canonicalize returns the canonical uniqueness key for raceName as a
// plain string. Validation failures map to ports.ErrInvalidName.
func (directory *Directory) Canonicalize(raceName string) (string, error) {
	if directory == nil {
		return "", errors.New("canonicalize race name: nil directory")
	}
	canonical, err := directory.policy.Canonicalize(raceName)
	if err != nil {
		return "", fmt.Errorf("canonicalize race name: %w", ports.ErrInvalidName)
	}
	return canonical.String(), nil
}

// Check reports whether raceName is taken for actorUserID. A concurrent
// Reserve may race against the result; service code that needs atomicity
// must rely on Reserve returning ErrNameTaken instead of pre-checking.
func (directory *Directory) Check(
	ctx context.Context,
	raceName, actorUserID string,
) (ports.Availability, error) {
	if directory == nil {
		return ports.Availability{}, errors.New("check race name: nil directory")
	}
	actor, err := normalizeNonEmpty(actorUserID, "check race name", "actor user id")
	if err != nil {
		return ports.Availability{}, err
	}
	canonical, err := directory.policy.Canonicalize(raceName)
	if err != nil {
		return ports.Availability{}, fmt.Errorf("check race name: %w", ports.ErrInvalidName)
	}

	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "check race name", directory.operationTimeout)
	if err != nil {
		return ports.Availability{}, err
	}
	defer cancel()

	stmt := pg.SELECT(
		pgtable.RaceNames.HolderUserID,
		pgtable.RaceNames.BindingKind,
	).FROM(pgtable.RaceNames).
		WHERE(pgtable.RaceNames.CanonicalKey.EQ(pg.String(canonical.String())))

	query, args := stmt.Sql()
	rows, err := directory.db.QueryContext(operationCtx, query, args...)
	if err != nil {
		return ports.Availability{}, fmt.Errorf("check race name: %w", err)
	}
	defer rows.Close()

	var (
		bestHolder string
		bestKind   string
		bestRank   int
	)
	for rows.Next() {
		var holder, kind string
		if err := rows.Scan(&holder, &kind); err != nil {
			return ports.Availability{}, fmt.Errorf("check race name: scan: %w", err)
		}
		rank := bindingPriority(kind)
		if bestKind == "" || rank < bestRank {
			bestHolder = holder
			bestKind = kind
			bestRank = rank
		}
	}
	if err := rows.Err(); err != nil {
		return ports.Availability{}, fmt.Errorf("check race name: %w", err)
	}
	if bestKind == "" {
		return ports.Availability{}, nil
	}
	return ports.Availability{
		Taken:        bestHolder != actor,
		HolderUserID: bestHolder,
		Kind:         bestKind,
	}, nil
}

// Reserve claims raceName for (gameID, userID). Repeating the call with
// the same tuple is idempotent; cross-user collisions on the canonical
// key surface ports.ErrNameTaken.
func (directory *Directory) Reserve(
	ctx context.Context,
	gameID, userID, raceName string,
) error {
	if directory == nil {
		return errors.New("reserve race name: nil directory")
	}
	game, err := normalizeGameID(gameID, "reserve race name")
	if err != nil {
		return err
	}
	user, err := normalizeNonEmpty(userID, "reserve race name", "user id")
	if err != nil {
		return err
	}
	displayName, err := racename.ValidateName(raceName)
	if err != nil {
		return fmt.Errorf("reserve race name: %w", ports.ErrInvalidName)
	}
	canonical, err := directory.policy.Canonical(displayName)
	if err != nil {
		return fmt.Errorf("reserve race name: %w", ports.ErrInvalidName)
	}

	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "reserve race name", directory.operationTimeout)
	if err != nil {
		return err
	}
	defer cancel()

	reservedAtMs := directory.nowFn().UTC().UnixMilli()
	return directory.withCanonicalLock(operationCtx, canonical, "reserve race name", func(tx *sql.Tx) error {
		existing, err := loadByCanonicalTx(operationCtx, tx, canonical)
		if err != nil {
			return fmt.Errorf("reserve race name: %w", err)
		}
		for _, r := range existing {
			if r.holderUserID != user {
				return ports.ErrNameTaken
			}
		}
		// Same-user idempotency: a row already at this PK means the
		// holder already binds this canonical for this game (whether as
		// reservation or pending_registration). Skip the INSERT.
		for _, r := range existing {
			if r.gameID == game.String() {
				return nil
			}
		}
		stmt := pgtable.RaceNames.INSERT(
			pgtable.RaceNames.CanonicalKey,
			pgtable.RaceNames.GameID,
			pgtable.RaceNames.HolderUserID,
			pgtable.RaceNames.RaceName,
			pgtable.RaceNames.BindingKind,
			pgtable.RaceNames.SourceGameID,
			pgtable.RaceNames.ReservedAtMs,
		).VALUES(
			canonical.String(),
			game.String(),
			user,
			displayName,
			bindingReservation,
			game.String(),
			reservedAtMs,
		)
		query, args := stmt.Sql()
		if _, err := tx.ExecContext(operationCtx, query, args...); err != nil {
			return fmt.Errorf("reserve race name: %w", err)
		}
		return nil
	})
}

// ReleaseReservation removes the reservation held by userID for raceName
// in gameID. Missing reservation, mismatched holder, and invalid raceName
// all resolve to a silent no-op per the port contract.
func (directory *Directory) ReleaseReservation(
	ctx context.Context,
	gameID, userID, raceName string,
) error {
	if directory == nil {
		return errors.New("release race name reservation: nil directory")
	}
	game, err := normalizeGameID(gameID, "release race name reservation")
	if err != nil {
		return err
	}
	user, err := normalizeNonEmpty(userID, "release race name reservation", "user id")
	if err != nil {
		return err
	}
	canonical, err := directory.policy.Canonicalize(raceName)
	if err != nil {
		// Invalid name is a silent no-op per the port contract.
		if ctxErr := contextAlive(ctx); ctxErr != nil {
			return ctxErr
		}
		return nil
	}

	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "release race name reservation", directory.operationTimeout)
	if err != nil {
		return err
	}
	defer cancel()

	return directory.withCanonicalLock(operationCtx, canonical, "release race name reservation", func(tx *sql.Tx) error {
		stmt := pgtable.RaceNames.DELETE().WHERE(pg.AND(
			pgtable.RaceNames.CanonicalKey.EQ(pg.String(canonical.String())),
			pgtable.RaceNames.GameID.EQ(pg.String(game.String())),
			pgtable.RaceNames.HolderUserID.EQ(pg.String(user)),
		))
		query, args := stmt.Sql()
		if _, err := tx.ExecContext(operationCtx, query, args...); err != nil {
			return fmt.Errorf("release race name reservation: %w", err)
		}
		return nil
	})
}

// MarkPendingRegistration promotes the reservation for (gameID, userID)
// on raceName's canonical key to pending_registration status.
func (directory *Directory) MarkPendingRegistration(
	ctx context.Context,
	gameID, userID, raceName string,
	eligibleUntil time.Time,
) error {
	if directory == nil {
		return errors.New("mark pending race name registration: nil directory")
	}
	game, err := normalizeGameID(gameID, "mark pending race name registration")
	if err != nil {
		return err
	}
	user, err := normalizeNonEmpty(userID, "mark pending race name registration", "user id")
	if err != nil {
		return err
	}
	if eligibleUntil.IsZero() {
		return fmt.Errorf("mark pending race name registration: eligible until must be set")
	}
	displayName, err := racename.ValidateName(raceName)
	if err != nil {
		return fmt.Errorf("mark pending race name registration: %w", ports.ErrInvalidName)
	}
	canonical, err := directory.policy.Canonical(displayName)
	if err != nil {
		return fmt.Errorf("mark pending race name registration: %w", ports.ErrInvalidName)
	}

	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "mark pending race name registration", directory.operationTimeout)
	if err != nil {
		return err
	}
	defer cancel()

	eligibleUntilMs := eligibleUntil.UTC().UnixMilli()
	return directory.withCanonicalLock(operationCtx, canonical, "mark pending race name registration", func(tx *sql.Tx) error {
		existing, err := loadByCanonicalTx(operationCtx, tx, canonical)
		if err != nil {
			return fmt.Errorf("mark pending race name registration: %w", err)
		}
		var target *raceNameRow
		for index, candidate := range existing {
			if candidate.gameID == game.String() && candidate.holderUserID == user {
				target = &existing[index]
				break
			}
		}
		if target == nil {
			return fmt.Errorf("mark pending race name registration: reservation missing for game %q user %q", game, user)
		}
		switch target.bindingKind {
		case bindingPending:
			if target.eligibleUntilMs == nil || *target.eligibleUntilMs != eligibleUntilMs {
				return fmt.Errorf("mark pending race name registration: %w", ports.ErrInvalidName)
			}
			return nil
		case bindingReservation:
			// promote
		default:
			return fmt.Errorf("mark pending race name registration: reservation missing for game %q user %q", game, user)
		}

		stmt := pgtable.RaceNames.UPDATE(
			pgtable.RaceNames.BindingKind,
			pgtable.RaceNames.RaceName,
			pgtable.RaceNames.EligibleUntilMs,
		).SET(
			bindingPending,
			displayName,
			eligibleUntilMs,
		).WHERE(pg.AND(
			pgtable.RaceNames.CanonicalKey.EQ(pg.String(canonical.String())),
			pgtable.RaceNames.GameID.EQ(pg.String(game.String())),
		))
		query, args := stmt.Sql()
		if _, err := tx.ExecContext(operationCtx, query, args...); err != nil {
			return fmt.Errorf("mark pending race name registration: %w", err)
		}
		return nil
	})
}

// ExpirePendingRegistrations releases every pending registration whose
// eligible_until_ms is at or before now. Each released entry is returned
// so callers can emit telemetry; running the method twice over the same
// state returns an empty slice the second time.
func (directory *Directory) ExpirePendingRegistrations(
	ctx context.Context,
	now time.Time,
) ([]ports.ExpiredPending, error) {
	if directory == nil {
		return nil, errors.New("expire pending race name registrations: nil directory")
	}

	cutoff := now.UTC().UnixMilli()

	scanCtx, cancel, err := sqlx.WithTimeout(ctx, "expire pending race name registrations", directory.operationTimeout)
	if err != nil {
		return nil, err
	}
	defer cancel()

	stmt := pg.SELECT(
		pgtable.RaceNames.CanonicalKey,
		pgtable.RaceNames.GameID,
	).FROM(pgtable.RaceNames).WHERE(pg.AND(
		pgtable.RaceNames.BindingKind.EQ(pg.String(bindingPending)),
		pgtable.RaceNames.EligibleUntilMs.LT_EQ(pg.Int(cutoff)),
	))
	query, args := stmt.Sql()
	rows, err := directory.db.QueryContext(scanCtx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("expire pending race name registrations: %w", err)
	}
	type candidate struct {
		canonical racename.CanonicalKey
		gameID    string
	}
	var candidates []candidate
	for rows.Next() {
		var canonicalKey, gameID string
		if err := rows.Scan(&canonicalKey, &gameID); err != nil {
			rows.Close()
			return nil, fmt.Errorf("expire pending race name registrations: scan: %w", err)
		}
		candidates = append(candidates, candidate{
			canonical: racename.CanonicalKey(canonicalKey),
			gameID:    gameID,
		})
	}
	if err := rows.Close(); err != nil {
		return nil, fmt.Errorf("expire pending race name registrations: %w", err)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("expire pending race name registrations: %w", err)
	}
	if len(candidates) == 0 {
		return nil, nil
	}

	expired := make([]ports.ExpiredPending, 0, len(candidates))
	for _, cand := range candidates {
		entry, released, err := directory.expireOne(ctx, cand.canonical, cand.gameID, cutoff)
		if err != nil {
			return nil, fmt.Errorf("expire pending race name registrations: %w", err)
		}
		if released {
			expired = append(expired, entry)
		}
	}
	return expired, nil
}

// expireOne re-reads the candidate row under an advisory lock, deletes it
// when still pending and at-or-before cutoff, and returns the matching
// ExpiredPending entry. Concurrent transitions (Register, ReleaseReservation,
// or a refreshed eligible_until_ms) cause expireOne to skip the row.
func (directory *Directory) expireOne(
	ctx context.Context,
	canonical racename.CanonicalKey,
	gameID string,
	cutoff int64,
) (ports.ExpiredPending, bool, error) {
	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "expire pending race name registrations", directory.operationTimeout)
	if err != nil {
		return ports.ExpiredPending{}, false, err
	}
	defer cancel()

	var (
		entry    ports.ExpiredPending
		released bool
	)
	err = directory.withCanonicalLock(operationCtx, canonical, "expire pending race name registrations", func(tx *sql.Tx) error {
		row, found, err := loadOneByPKTx(operationCtx, tx, canonical, gameID)
		if err != nil {
			return err
		}
		if !found {
			return nil
		}
		if row.bindingKind != bindingPending {
			return nil
		}
		if row.eligibleUntilMs == nil || *row.eligibleUntilMs > cutoff {
			return nil
		}
		stmt := pgtable.RaceNames.DELETE().WHERE(pg.AND(
			pgtable.RaceNames.CanonicalKey.EQ(pg.String(canonical.String())),
			pgtable.RaceNames.GameID.EQ(pg.String(gameID)),
		))
		query, args := stmt.Sql()
		if _, err := tx.ExecContext(operationCtx, query, args...); err != nil {
			return err
		}
		entry = ports.ExpiredPending{
			CanonicalKey:    canonical.String(),
			RaceName:        row.raceName,
			GameID:          gameID,
			UserID:          row.holderUserID,
			EligibleUntilMs: *row.eligibleUntilMs,
		}
		released = true
		return nil
	})
	if err != nil {
		return ports.ExpiredPending{}, false, err
	}
	return entry, released, nil
}

// Register converts the pending registration identified by (gameID,
// userID) on raceName's canonical key into a registered race name.
func (directory *Directory) Register(
	ctx context.Context,
	gameID, userID, raceName string,
) error {
	if directory == nil {
		return errors.New("register race name: nil directory")
	}
	game, err := normalizeGameID(gameID, "register race name")
	if err != nil {
		return err
	}
	user, err := normalizeNonEmpty(userID, "register race name", "user id")
	if err != nil {
		return err
	}
	displayName, err := racename.ValidateName(raceName)
	if err != nil {
		return fmt.Errorf("register race name: %w", ports.ErrInvalidName)
	}
	canonical, err := directory.policy.Canonical(displayName)
	if err != nil {
		return fmt.Errorf("register race name: %w", ports.ErrInvalidName)
	}

	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "register race name", directory.operationTimeout)
	if err != nil {
		return err
	}
	defer cancel()

	nowMs := directory.nowFn().UTC().UnixMilli()
	return directory.withCanonicalLock(operationCtx, canonical, "register race name", func(tx *sql.Tx) error {
		existing, err := loadByCanonicalTx(operationCtx, tx, canonical)
		if err != nil {
			return fmt.Errorf("register race name: %w", err)
		}
		// Already registered: idempotent for the same holder, ErrNameTaken
		// for any other user.
		for _, r := range existing {
			if r.bindingKind == bindingRegistered {
				if r.holderUserID == user {
					return nil
				}
				return ports.ErrNameTaken
			}
		}
		var pending *raceNameRow
		for index, r := range existing {
			if r.gameID == game.String() && r.holderUserID == user && r.bindingKind == bindingPending {
				pending = &existing[index]
				break
			}
		}
		if pending == nil {
			return ports.ErrPendingMissing
		}
		if pending.eligibleUntilMs == nil || *pending.eligibleUntilMs <= nowMs {
			return ports.ErrPendingExpired
		}

		del := pgtable.RaceNames.DELETE().WHERE(pg.AND(
			pgtable.RaceNames.CanonicalKey.EQ(pg.String(canonical.String())),
			pgtable.RaceNames.GameID.EQ(pg.String(game.String())),
		))
		delQuery, delArgs := del.Sql()
		if _, err := tx.ExecContext(operationCtx, delQuery, delArgs...); err != nil {
			return fmt.Errorf("register race name: %w", err)
		}
		ins := pgtable.RaceNames.INSERT(
			pgtable.RaceNames.CanonicalKey,
			pgtable.RaceNames.GameID,
			pgtable.RaceNames.HolderUserID,
			pgtable.RaceNames.RaceName,
			pgtable.RaceNames.BindingKind,
			pgtable.RaceNames.SourceGameID,
			pgtable.RaceNames.ReservedAtMs,
			pgtable.RaceNames.RegisteredAtMs,
		).VALUES(
			canonical.String(),
			registeredGameID,
			user,
			pending.raceName,
			bindingRegistered,
			game.String(),
			pending.reservedAtMs,
			nowMs,
		)
		insQuery, insArgs := ins.Sql()
		if _, err := tx.ExecContext(operationCtx, insQuery, insArgs...); err != nil {
			return fmt.Errorf("register race name: %w", err)
		}
		return nil
	})
}

// ListRegistered returns every registered race name owned by userID.
func (directory *Directory) ListRegistered(
	ctx context.Context,
	userID string,
) ([]ports.RegisteredName, error) {
	if directory == nil {
		return nil, errors.New("list registered race names: nil directory")
	}
	user, err := normalizeNonEmpty(userID, "list registered race names", "user id")
	if err != nil {
		return nil, err
	}

	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "list registered race names", directory.operationTimeout)
	if err != nil {
		return nil, err
	}
	defer cancel()

	stmt := pg.SELECT(
		pgtable.RaceNames.CanonicalKey,
		pgtable.RaceNames.RaceName,
		pgtable.RaceNames.SourceGameID,
		pgtable.RaceNames.RegisteredAtMs,
	).FROM(pgtable.RaceNames).WHERE(pg.AND(
		pgtable.RaceNames.HolderUserID.EQ(pg.String(user)),
		pgtable.RaceNames.BindingKind.EQ(pg.String(bindingRegistered)),
	))

	query, args := stmt.Sql()
	rows, err := directory.db.QueryContext(operationCtx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("list registered race names: %w", err)
	}
	defer rows.Close()
	var out []ports.RegisteredName
	for rows.Next() {
		var (
			canonical    string
			raceName     string
			sourceGameID string
			regAt        sql.NullInt64
		)
		if err := rows.Scan(&canonical, &raceName, &sourceGameID, &regAt); err != nil {
			return nil, fmt.Errorf("list registered race names: scan: %w", err)
		}
		var regAtMs int64
		if regAt.Valid {
			regAtMs = regAt.Int64
		}
		out = append(out, ports.RegisteredName{
			CanonicalKey:   canonical,
			RaceName:       raceName,
			SourceGameID:   sourceGameID,
			RegisteredAtMs: regAtMs,
		})
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("list registered race names: %w", err)
	}
	return out, nil
}

// ListReservations returns every active reservation owned by userID
// whose status has not yet been promoted to pending_registration.
func (directory *Directory) ListReservations(
	ctx context.Context,
	userID string,
) ([]ports.Reservation, error) {
	if directory == nil {
		return nil, errors.New("list race name reservations: nil directory")
	}
	user, err := normalizeNonEmpty(userID, "list race name reservations", "user id")
	if err != nil {
		return nil, err
	}

	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "list race name reservations", directory.operationTimeout)
	if err != nil {
		return nil, err
	}
	defer cancel()

	stmt := pg.SELECT(
		pgtable.RaceNames.CanonicalKey,
		pgtable.RaceNames.RaceName,
		pgtable.RaceNames.GameID,
		pgtable.RaceNames.ReservedAtMs,
	).FROM(pgtable.RaceNames).WHERE(pg.AND(
		pgtable.RaceNames.HolderUserID.EQ(pg.String(user)),
		pgtable.RaceNames.BindingKind.EQ(pg.String(bindingReservation)),
	))

	query, args := stmt.Sql()
	rows, err := directory.db.QueryContext(operationCtx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("list race name reservations: %w", err)
	}
	defer rows.Close()
	var out []ports.Reservation
	for rows.Next() {
		var (
			canonical    string
			raceName     string
			gameID       string
			reservedAtMs int64
		)
		if err := rows.Scan(&canonical, &raceName, &gameID, &reservedAtMs); err != nil {
			return nil, fmt.Errorf("list race name reservations: scan: %w", err)
		}
		out = append(out, ports.Reservation{
			CanonicalKey: canonical,
			RaceName:     raceName,
			GameID:       gameID,
			ReservedAtMs: reservedAtMs,
		})
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("list race name reservations: %w", err)
	}
	return out, nil
}

// ListPendingRegistrations returns every pending registration owned by
// userID.
func (directory *Directory) ListPendingRegistrations(
	ctx context.Context,
	userID string,
) ([]ports.PendingRegistration, error) {
	if directory == nil {
		return nil, errors.New("list pending race name registrations: nil directory")
	}
	user, err := normalizeNonEmpty(userID, "list pending race name registrations", "user id")
	if err != nil {
		return nil, err
	}

	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "list pending race name registrations", directory.operationTimeout)
	if err != nil {
		return nil, err
	}
	defer cancel()

	stmt := pg.SELECT(
		pgtable.RaceNames.CanonicalKey,
		pgtable.RaceNames.RaceName,
		pgtable.RaceNames.GameID,
		pgtable.RaceNames.ReservedAtMs,
		pgtable.RaceNames.EligibleUntilMs,
	).FROM(pgtable.RaceNames).WHERE(pg.AND(
		pgtable.RaceNames.HolderUserID.EQ(pg.String(user)),
		pgtable.RaceNames.BindingKind.EQ(pg.String(bindingPending)),
	))

	query, args := stmt.Sql()
	rows, err := directory.db.QueryContext(operationCtx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("list pending race name registrations: %w", err)
	}
	defer rows.Close()
	var out []ports.PendingRegistration
	for rows.Next() {
		var (
			canonical    string
			raceName     string
			gameID       string
			reservedAtMs int64
			eligibleAt   sql.NullInt64
		)
		if err := rows.Scan(&canonical, &raceName, &gameID, &reservedAtMs, &eligibleAt); err != nil {
			return nil, fmt.Errorf("list pending race name registrations: scan: %w", err)
		}
		var eligibleAtMs int64
		if eligibleAt.Valid {
			eligibleAtMs = eligibleAt.Int64
		}
		out = append(out, ports.PendingRegistration{
			CanonicalKey:    canonical,
			RaceName:        raceName,
			GameID:          gameID,
			ReservedAtMs:    reservedAtMs,
			EligibleUntilMs: eligibleAtMs,
		})
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("list pending race name registrations: %w", err)
	}
	return out, nil
}

// ReleaseAllByUser atomically clears every binding owned by userID. The
// user-lifecycle consumer invokes the method on permanent_blocked and
// deleted events, so concurrent writes by the same user cannot race
// (the user is permanently disabled by the time the cascade runs).
func (directory *Directory) ReleaseAllByUser(
	ctx context.Context,
	userID string,
) error {
	if directory == nil {
		return errors.New("release all race names by user: nil directory")
	}
	user, err := normalizeNonEmpty(userID, "release all race names by user", "user id")
	if err != nil {
		return err
	}

	operationCtx, cancel, err := sqlx.WithTimeout(ctx, "release all race names by user", directory.operationTimeout)
	if err != nil {
		return err
	}
	defer cancel()

	stmt := pgtable.RaceNames.DELETE().
		WHERE(pgtable.RaceNames.HolderUserID.EQ(pg.String(user)))
	query, args := stmt.Sql()
	if _, err := directory.db.ExecContext(operationCtx, query, args...); err != nil {
		return fmt.Errorf("release all race names by user: %w", err)
	}
	return nil
}

// raceNameRow mirrors one race_names row in adapter-internal code so
// transactional methods can read the row state under an advisory lock and
// branch without re-deriving column ordering at every call site.
type raceNameRow struct {
	canonicalKey    string
	gameID          string
	holderUserID    string
	raceName        string
	bindingKind     string
	sourceGameID    string
	reservedAtMs    int64
	eligibleUntilMs *int64
	registeredAtMs  *int64
}

// raceNameAllColumns is the column list scanRow expects in order.
var raceNameAllColumns = pg.ColumnList{
	pgtable.RaceNames.CanonicalKey,
	pgtable.RaceNames.GameID,
	pgtable.RaceNames.HolderUserID,
	pgtable.RaceNames.RaceName,
	pgtable.RaceNames.BindingKind,
	pgtable.RaceNames.SourceGameID,
	pgtable.RaceNames.ReservedAtMs,
	pgtable.RaceNames.EligibleUntilMs,
	pgtable.RaceNames.RegisteredAtMs,
}

func scanRow(scanner interface{ Scan(...any) error }) (raceNameRow, error) {
	var (
		row        raceNameRow
		eligible   sql.NullInt64
		registered sql.NullInt64
	)
	if err := scanner.Scan(
		&row.canonicalKey,
		&row.gameID,
		&row.holderUserID,
		&row.raceName,
		&row.bindingKind,
		&row.sourceGameID,
		&row.reservedAtMs,
		&eligible,
		&registered,
	); err != nil {
		return raceNameRow{}, err
	}
	if eligible.Valid {
		v := eligible.Int64
		row.eligibleUntilMs = &v
	}
	if registered.Valid {
		v := registered.Int64
		row.registeredAtMs = &v
	}
	return row, nil
}

// loadByCanonicalTx returns every race_names row for canonical_key.
func loadByCanonicalTx(
	ctx context.Context,
	tx *sql.Tx,
	canonical racename.CanonicalKey,
) ([]raceNameRow, error) {
	stmt := pg.SELECT(raceNameAllColumns).
		FROM(pgtable.RaceNames).
		WHERE(pgtable.RaceNames.CanonicalKey.EQ(pg.String(canonical.String())))
	query, args := stmt.Sql()
	rows, err := tx.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []raceNameRow
	for rows.Next() {
		row, err := scanRow(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, row)
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	return out, nil
}

// loadOneByPKTx loads one row by its (canonical_key, game_id) primary
// key. The returned bool is false when no row matches.
func loadOneByPKTx(
	ctx context.Context,
	tx *sql.Tx,
	canonical racename.CanonicalKey,
	gameID string,
) (raceNameRow, bool, error) {
	stmt := pg.SELECT(raceNameAllColumns).
		FROM(pgtable.RaceNames).
		WHERE(pg.AND(
			pgtable.RaceNames.CanonicalKey.EQ(pg.String(canonical.String())),
			pgtable.RaceNames.GameID.EQ(pg.String(gameID)),
		))
	query, args := stmt.Sql()
	row := tx.QueryRowContext(ctx, query, args...)
	out, err := scanRow(row)
	if sqlx.IsNoRows(err) {
		return raceNameRow{}, false, nil
	}
	if err != nil {
		return raceNameRow{}, false, err
	}
	return out, true, nil
}

// withCanonicalLock runs op inside a transaction guarded by
// pg_advisory_xact_lock(hashtextextended(canonical_key, 0)). The lock is
// released when the transaction terminates (commit or rollback).
func (directory *Directory) withCanonicalLock(
	ctx context.Context,
	canonical racename.CanonicalKey,
	operation string,
	op func(tx *sql.Tx) error,
) error {
	tx, err := directory.db.BeginTx(ctx, nil)
	if err != nil {
		return fmt.Errorf("%s: begin tx: %w", operation, err)
	}
	committed := false
	defer func() {
		if !committed {
			_ = tx.Rollback()
		}
	}()
	if _, err := tx.ExecContext(ctx, "SELECT pg_advisory_xact_lock(hashtextextended($1, 0))", canonical.String()); err != nil {
		return fmt.Errorf("%s: advisory lock: %w", operation, err)
	}
	if err := op(tx); err != nil {
		return err
	}
	if err := tx.Commit(); err != nil {
		return fmt.Errorf("%s: commit: %w", operation, err)
	}
	committed = true
	return nil
}

// bindingPriority maps a binding_kind value to a priority rank where
// lower numbers mean a stronger binding (registered > pending > reservation).
func bindingPriority(kind string) int {
	switch kind {
	case bindingRegistered:
		return 1
	case bindingPending:
		return 2
	case bindingReservation:
		return 3
	default:
		return 99
	}
}

// normalizeNonEmpty trims value and rejects empty results with an error
// that mentions operation and field for traceability.
func normalizeNonEmpty(value, operation, field string) (string, error) {
	trimmed := strings.TrimSpace(value)
	if trimmed == "" {
		return "", fmt.Errorf("%s: %s must not be empty", operation, field)
	}
	return trimmed, nil
}

// normalizeGameID trims value and converts it into a typed common.GameID,
// rejecting empty input through normalizeNonEmpty.
func normalizeGameID(value, operation string) (common.GameID, error) {
	trimmed, err := normalizeNonEmpty(value, operation, "game id")
	if err != nil {
		return "", err
	}
	return common.GameID(trimmed), nil
}

// contextAlive surfaces ctx cancellation through a stable error path even
// when the calling method is a defensive no-op for invalid input. The
// shared port test suite expects every method to honour cancellation
// regardless of preceding validation.
func contextAlive(ctx context.Context) error {
	if ctx == nil {
		return errors.New("nil context")
	}
	if err := ctx.Err(); err != nil {
		return err
	}
	return nil
}

// Ensure *Directory satisfies the ports.RaceNameDirectory interface at
// compile time.
var _ ports.RaceNameDirectory = (*Directory)(nil)