package store

import (
	"context"
	"database/sql"
)

// AllocationBindingByAllocationIDSQL resolves the durable match_id/server_id
// pairing for an allocation_id. A signed workload token only ever names
// allocation_id (see workload/signed_token.go for why match_id/server_id
// aren't embedded in the token itself); this is what lets WorkloadVerify
// return a binding whose match_id/server_id came from the durable allocator
// record, not from anything the caller supplied. allocations rows are
// append-only and never leave 'ALLOCATED' (see allocator_sql.go), so this is
// a simple existence lookup, not a state-machine walk.
const AllocationBindingByAllocationIDSQL = `SELECT match_id, server_id FROM allocations
WHERE allocation_id = $1 AND state = 'ALLOCATED'`

// AllocationBindingByAllocationID returns the (matchID, serverID) durably
// recorded for allocationID, and false if no such allocated row exists. db
// and allocationID must be non-empty -- callers pass this an
// already-parsed and signature-verified token's claims, so an empty
// allocationID here indicates a caller bug rather than a legitimate
// "not found".
func AllocationBindingByAllocationID(ctx context.Context, db *sql.DB, allocationID string) (matchID, serverID string, ok bool, err error) {
	if db == nil || allocationID == "" {
		return "", "", false, sql.ErrNoRows
	}
	err = db.QueryRowContext(ctx, AllocationBindingByAllocationIDSQL, allocationID).Scan(&matchID, &serverID)
	if err == sql.ErrNoRows {
		return "", "", false, nil
	}
	if err != nil {
		return "", "", false, err
	}
	return matchID, serverID, true, nil
}