package userapi

import "context"

// AccountObserver is told when an account is deactivated, after the
// account itself has been dealt with. The roomserver's side of a
// deactivation — leaving every room — is done through it, because nothing
// in this package knows about rooms.
//
// Like DeviceObserver it runs on the request path and must not fail the
// deactivation: the account is already deactivated when it is called.
type AccountObserver interface {
	AccountDeactivated(ctx context.Context, localpart string)
}

// SetAccountObserver connects the observer. It is a setter for the same
// reason SetDeviceObserver is: the roomserver is built after the userapi.
func (a *API) SetAccountObserver(o AccountObserver) { a.accounts = o }

// DeactivateAccount deactivates an account: what both the user's own
// POST /account/deactivate and the admin API's deactivation do.
//
// The order is deliberate. The flag goes first, so that every token the
// account still holds stops working at once, before anything slower runs;
// the profile is erased next, so that the leave events the observer sends
// into the user's rooms already carry no name or avatar; the devices go
// after that, taking their keys and pushers with them through the device
// observer; and the rooms are left last.
//
// The name stays taken. A deactivated account cannot be registered again,
// because a new user with the old user's ID would inherit everything other
// servers and clients remember about the old one.
func (a *API) DeactivateAccount(ctx context.Context, localpart string, erase bool) error {
	if err := a.store.SetDeactivated(ctx, localpart, true); err != nil {
		return err
	}
	if erase {
		if err := a.store.SetDisplayName(ctx, localpart, ""); err != nil {
			return err
		}
		if err := a.store.SetAvatarURL(ctx, localpart, ""); err != nil {
			return err
		}
	}
	if err := a.DeleteAllDevices(ctx, localpart); err != nil {
		return err
	}
	if a.accounts != nil {
		a.accounts.AccountDeactivated(ctx, localpart)
	}
	a.log.Info("deactivated account", "user_id", a.UserID(localpart), "erase", erase)
	return nil
}

// ReactivateAccount clears the deactivated flag, for the admin API. It
// gives back nothing a deactivation took — the rooms are left and the
// devices gone — only the ability to log in again.
func (a *API) ReactivateAccount(ctx context.Context, localpart string) error {
	if err := a.store.SetDeactivated(ctx, localpart, false); err != nil {
		return err
	}
	a.log.Info("reactivated account", "user_id", a.UserID(localpart))
	return nil
}

// ChangePassword sets a new password and, when logoutDevices is set, logs
// out every device of the user except keepDeviceID (empty keeps none).
//
// A user changing their own password keeps the session they changed it
// from; an admin resetting one keeps none, since whoever is locked out of
// the account may be the one holding the sessions.
func (a *API) ChangePassword(ctx context.Context, localpart, password string, logoutDevices bool, keepDeviceID string) error {
	if err := a.SetPassword(ctx, localpart, password); err != nil {
		return err
	}
	if !logoutDevices {
		return nil
	}
	if keepDeviceID == "" {
		return a.DeleteAllDevices(ctx, localpart)
	}
	devices, err := a.store.Devices(ctx, localpart)
	if err != nil {
		return err
	}
	others := make([]string, 0, len(devices))
	for _, d := range devices {
		if d.ID != keepDeviceID {
			others = append(others, d.ID)
		}
	}
	return a.DeleteDevices(ctx, localpart, others)
}