package redisstate

import (
	"encoding/json"
	"fmt"
)

// registeredRecord stores the strict Redis JSON shape of one registered
// race name. The canonical key is stored only as the Redis key suffix and
// is not duplicated inside the blob.
type registeredRecord struct {
	UserID         string `json:"user_id"`
	RaceName       string `json:"race_name"`
	SourceGameID   string `json:"source_game_id"`
	RegisteredAtMS int64  `json:"registered_at_ms"`
}

// reservationStatusReserved marks a per-game race name reservation that
// has not yet been promoted by capability evaluation.
const reservationStatusReserved = "reserved"

// reservationStatusPending marks a reservation that has been promoted to
// pending_registration by the capability evaluator at game_finished.
const reservationStatusPending = "pending_registration"

// reservationRecord stores the strict Redis JSON shape of one per-game
// race name reservation. The game_id and canonical key are carried by the
// Redis key suffix; the blob never duplicates them.
type reservationRecord struct {
	UserID          string `json:"user_id"`
	RaceName        string `json:"race_name"`
	ReservedAtMS    int64  `json:"reserved_at_ms"`
	Status          string `json:"status"`
	EligibleUntilMS *int64 `json:"eligible_until_ms,omitempty"`
}

// canonicalLookupRecord stores the eager canonical-lookup cache entry
// used by Check to return availability without scanning the authoritative
// keys. GameID is populated only for reservation and pending_registration
// kinds; it is omitted for registered bindings.
type canonicalLookupRecord struct {
	Kind         string `json:"kind"`
	HolderUserID string `json:"holder_user_id"`
	GameID       string `json:"game_id,omitempty"`
}

// marshalRegisteredRecord encodes record into the strict Redis JSON shape
// used for registered race names.
func marshalRegisteredRecord(record registeredRecord) ([]byte, error) {
	payload, err := json.Marshal(record)
	if err != nil {
		return nil, fmt.Errorf("marshal redis registered race name record: %w", err)
	}

	return payload, nil
}

// unmarshalRegisteredRecord decodes payload from the strict Redis JSON
// shape used for registered race names.
func unmarshalRegisteredRecord(payload []byte) (registeredRecord, error) {
	var record registeredRecord
	if err := decodeStrictJSON("decode redis registered race name record", payload, &record); err != nil {
		return registeredRecord{}, err
	}

	return record, nil
}

// marshalReservationRecord encodes record into the strict Redis JSON
// shape used for per-game race name reservations.
func marshalReservationRecord(record reservationRecord) ([]byte, error) {
	payload, err := json.Marshal(record)
	if err != nil {
		return nil, fmt.Errorf("marshal redis race name reservation record: %w", err)
	}

	return payload, nil
}

// unmarshalReservationRecord decodes payload from the strict Redis JSON
// shape used for per-game race name reservations.
func unmarshalReservationRecord(payload []byte) (reservationRecord, error) {
	var record reservationRecord
	if err := decodeStrictJSON("decode redis race name reservation record", payload, &record); err != nil {
		return reservationRecord{}, err
	}

	return record, nil
}

// marshalCanonicalLookupRecord encodes record into the strict Redis JSON
// shape used for canonical-lookup cache entries.
func marshalCanonicalLookupRecord(record canonicalLookupRecord) ([]byte, error) {
	payload, err := json.Marshal(record)
	if err != nil {
		return nil, fmt.Errorf("marshal redis race name canonical lookup record: %w", err)
	}

	return payload, nil
}

// unmarshalCanonicalLookupRecord decodes payload from the strict Redis
// JSON shape used for canonical-lookup cache entries.
func unmarshalCanonicalLookupRecord(payload []byte) (canonicalLookupRecord, error) {
	var record canonicalLookupRecord
	if err := decodeStrictJSON("decode redis race name canonical lookup record", payload, &record); err != nil {
		return canonicalLookupRecord{}, err
	}

	return record, nil
}