package release

import (
	"errors"
	"os"
)

// RecordCreation is called only inside root's first-registration transaction,
// after root proves the installation is new. Existing history is preserved.
func (h *RootHistory) RecordCreation(b HistoryBinding, installation string) error {
	if !b.valid() || installation == "" || len(installation) > 4096 {
		return os.ErrPermission
	}
	_, err := h.read(b)
	if err == nil {
		return nil
	}
	if !errors.Is(err, os.ErrNotExist) {
		return err
	}
	return h.write(historyRecord{Schema: 1, Binding: b, Revision: 1, Creation: installation, Fresh: true,
		Programs: historyPrograms{Revision: 1, Complete: true}, Refusals: historyRefusals{Revision: 1, Complete: true}})
}

func (h *RootHistory) FreshInstallation(b HistoryBinding, installation string) (bool, error) {
	r, err := h.read(b)
	if err != nil {
		return false, err
	}
	return installation != "" && r.Creation == installation && r.Fresh, nil
}

func (h *RootHistory) ConsumeCreation(b HistoryBinding) error {
	r, err := h.read(b)
	if errors.Is(err, os.ErrNotExist) {
		return nil
	}
	if err != nil {
		return err
	}
	if !r.Fresh {
		return nil
	}
	if r.Revision == ^uint64(0) {
		return os.ErrPermission
	}
	r.Revision++
	r.Fresh = false
	return h.write(r)
}