package network

import (
	"errors"
	"fmt"
	"io/fs"
	"isle/daemon/daecommon"
	"isle/jsonutil"
	"isle/toolkit"
	"path/filepath"
)

// loadStoreConfig writes the given NetworkConfig to the networkStateDir if the
// config is non-nil. If the config is nil then a config is read from
// networkStateDir, returning the zero value if no config was previously
// stored.
func loadStoreConfig(
	networkStateDir toolkit.Dir, config *daecommon.NetworkConfig,
) (
	daecommon.NetworkConfig, error,
) {
	path := filepath.Join(networkStateDir.Path, "config.json")

	if config == nil {
		config = new(daecommon.NetworkConfig)
		err := jsonutil.LoadFile(&config, path)
		if err != nil && !errors.Is(err, fs.ErrNotExist) {
			return daecommon.NetworkConfig{}, fmt.Errorf(
				"loading %q: %w", path, err,
			)
		}
		return *config, nil
	}

	if err := jsonutil.WriteFile(*config, path, 0600); err != nil {
		return daecommon.NetworkConfig{}, fmt.Errorf(
			"writing to %q: %w", path, err,
		)
	}

	return *config, nil
}