package registry

import (
	"database/sql"
	"errors"
)

// MaterializeTimerRegistration preserves the identity already recorded by root.
// The caller must retain host exclusion and check its inventory revision before
// this write. Replay accepts only the exact resulting row, including ownership.
func (r *Registry) MaterializeTimerRegistration(t Timer, expected string) (*Timer, error) {
	if r.remote != nil {
		out, err := r.remote.call(nil, remoteRequest{Method: "MaterializeTimerRegistration", T: t, Expected: expected}, nil)
		return out.Timer, err
	}
	if !t.ClaimOwnership.Valid() || t.Registration == "" || t.Registration != t.ClaimRowID {
		return nil, ErrClaimOwnership
	}
	tx, err := r.sql.Begin()
	if err != nil {
		return nil, err
	}
	defer tx.Rollback()
	route, err := scanRoute(tx.QueryRow(`SELECT `+routeCols+` FROM routes WHERE host=?`, t.Host).Scan)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil, ErrClaimOwnership
		}
		return nil, err
	}
	if !route.ClaimOwnership.Valid() || route.ClaimIncarnation != t.ClaimIncarnation || route.ClaimStamp != t.ClaimStamp || route.ClaimOwner != t.ClaimOwner {
		return nil, ErrClaimOwnership
	}
	old, err := scanTimer(tx.QueryRow(`SELECT `+timerCols+` FROM timers WHERE host=? AND name=?`, t.Host, t.Name))
	switch {
	case errors.Is(err, sql.ErrNoRows):
		if expected != "" {
			return nil, ErrTimerChanged
		}
	case err != nil:
		return nil, err
	default:
		if old == t {
			if err := tx.Commit(); err != nil {
				return nil, err
			}
			return &old, nil
		}
		if old.Registration == t.Registration {
			return nil, ErrTimerChanged
		}
		if old.Kind != t.Kind {
			return nil, ErrTimerKind
		}
		if expected == "" || old.Registration != expected || old.ClaimRowID != expected || old.ClaimIncarnation != t.ClaimIncarnation || old.ClaimStamp != t.ClaimStamp || old.ClaimOwner != t.ClaimOwner {
			return nil, ErrTimerChanged
		}
		if _, err := tx.Exec(`DELETE FROM timers WHERE host=? AND name=? AND registration=? AND claim_incarnation=? AND claim_stamp=? AND claim_owner=? AND claim_row_id=?`, t.Host, t.Name, expected, t.ClaimIncarnation, t.ClaimStamp, t.ClaimOwner, expected); err != nil {
			return nil, err
		}
	}
	if _, err := tx.Exec(`INSERT INTO timers (`+timerCols+`) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)`, t.Host, t.Name, t.Kind, t.Spec, t.Path, t.NextAt, t.LastAt, t.LastStatus, t.LastMs, t.Attempts, t.CreatedAt, t.DueAt, t.Registration, t.ClaimIncarnation, t.ClaimStamp, t.ClaimOwner, t.ClaimRowID); err != nil {
		return nil, err
	}
	if err := tx.Commit(); err != nil {
		return nil, err
	}
	return &t, nil
}

// DeleteTimerOwnedRegistration cannot remove a successor or a row with a
// copied registration but another installation's ownership.
func (r *Registry) DeleteTimerOwnedRegistration(t Timer) error {
	if r.remote != nil {
		_, err := r.remote.call(nil, remoteRequest{Method: "DeleteTimerOwnedRegistration", T: t}, nil)
		return err
	}
	if !t.ClaimOwnership.Valid() || t.Registration == "" || t.Registration != t.ClaimRowID {
		return ErrClaimOwnership
	}
	res, err := r.sql.Exec(`DELETE FROM timers WHERE host=? AND name=? AND registration=? AND claim_incarnation=? AND claim_stamp=? AND claim_owner=? AND claim_row_id=?`, t.Host, t.Name, t.Registration, t.ClaimIncarnation, t.ClaimStamp, t.ClaimOwner, t.ClaimRowID)
	return timerRegistrationResult(res, err)
}