package store

import (
	"context"
	"database/sql"
)

// AllocationBindingStillValidSQL cross-checks a signed workload token's
// claims against the durable allocation record before trusting it. A
// validly-signed, unexpired token alone is not proof the allocation it names
// is still the live binding for that match/server pair -- this closes that
// gap defense-in-depth. allocations rows are append-only and never leave
// 'ALLOCATED' (see allocator_sql.go), so this is a simple existence check,
// not a state-machine walk.
const AllocationBindingStillValidSQL = `SELECT 1 FROM allocations
WHERE allocation_id = $1 AND match_id = $2 AND server_id = $3 AND state = 'ALLOCATED'`

// AllocationBindingStillValid reports whether the given (allocationID,
// matchID, serverID) triple names a real, still-allocated row. db, and every
// identifier, must be non-empty -- callers pass this an already-parsed and
// signature-verified token's claims, so empty fields here indicate a caller
// bug rather than a legitimate "not found".
func AllocationBindingStillValid(ctx context.Context, db *sql.DB, allocationID, matchID, serverID string) (bool, error) {
	if db == nil || allocationID == "" || matchID == "" || serverID == "" {
		return false, sql.ErrNoRows
	}
	var one int
	err := db.QueryRowContext(ctx, AllocationBindingStillValidSQL, allocationID, matchID, serverID).Scan(&one)
	if err == sql.ErrNoRows {
		return false, nil
	}
	if err != nil {
		return false, err
	}
	return true, nil
}