package app

import (
	"encoding/json"
	"os"
	"path/filepath"
	"time"
)

func loadTransportInterfacesState() transportInterfacesState {
	st := transportInterfacesState{Version: transportStateVersion}
	data, err := os.ReadFile(transportInterfacesStatePath)
	if err != nil {
		norm, _ := normalizeTransportInterfacesState(st, nil)
		_ = saveTransportInterfacesState(norm)
		return norm
	}
	if err := json.Unmarshal(data, &st); err != nil {
		st = transportInterfacesState{Version: transportStateVersion}
	}
	if st.Version == 0 {
		st.Version = transportStateVersion
	}
	if st.Items == nil {
		st.Items = nil
	}
	norm, changed := normalizeTransportInterfacesState(st, nil)
	if changed {
		_ = saveTransportInterfacesState(norm)
	}
	return norm
}

func saveTransportInterfacesState(st transportInterfacesState) error {
	norm, _ := normalizeTransportInterfacesState(st, nil)
	st = norm
	st.Version = transportStateVersion
	st.UpdatedAt = time.Now().UTC().Format(time.RFC3339)

	data, err := json.MarshalIndent(st, "", "  ")
	if err != nil {
		return err
	}
	if err := os.MkdirAll(filepath.Dir(transportInterfacesStatePath), 0o755); err != nil {
		return err
	}
	tmp := transportInterfacesStatePath + ".tmp"
	if err := os.WriteFile(tmp, data, 0o644); err != nil {
		return err
	}
	return os.Rename(tmp, transportInterfacesStatePath)
}