package provision

import (
	"fmt"
	"time"
)

// MoveRollbackLossRebind moves a lost target's reference from a declaration
// whose claim CAS never landed (its signed loss record conflicted) to a
// fresh declaration (§7.10, claim Plan 10 J4 B1). Legal only from lost with
// exactly oldRef; the phase, Dirty and the rollback id are kept, so the
// rollback the first declaration decided stands. The caller proves oldRef
// is this move's conflicted declaration and binds newRef in its signed
// intent. The same newRef again is a replay; anything else is a conflict.
func MoveRollbackLossRebind(g MoveGuard, oldRef, newRef string, now time.Time) func(*Record) error {
	return func(rec *Record) error {
		if oldRef == "" || newRef == "" || oldRef == newRef || now.IsZero() {
			return fmt.Errorf("provision: malformed loss declaration")
		}
		rb, err := rollingBack(g, rec)
		if err != nil {
			return err
		}
		switch {
		case rb.TargetPhase == RbTargetLost && rb.LossRef == newRef:
			return nil
		case rb.TargetPhase == RbTargetLost && rb.LossRef == oldRef:
		default:
			return fmt.Errorf("%w: another loss is recorded for this target", ErrMoveConflict)
		}
		t := now.UTC()
		rb.LossRef, rb.LostAt = newRef, &t
		return nil
	}
}