package app

import (
	"encoding/json"
	"fmt"
	"os"
	"strings"
	"time"
)

func saveRoutesClearCache() (routesClearCacheMeta, error) {
	if err := os.MkdirAll(stateDir, 0o755); err != nil {
		return routesClearCacheMeta{}, err
	}

	routes, err := readCurrentRoutesTableLines()
	if err != nil {
		return routesClearCacheMeta{}, err
	}
	if err := writeLinesFile(routesCacheRT, routes); err != nil {
		return routesClearCacheMeta{}, err
	}

	var warns []string

	ipCount, err := snapshotNftSetToFile("agvpn4", routesCacheIPs)
	if err != nil {
		warns = append(warns, fmt.Sprintf("agvpn4 snapshot failed: %v", err))
		_ = cacheCopyOrEmpty(stateDir+"/last-ips.txt", routesCacheIPs)
		ipCount = len(readNonEmptyLines(routesCacheIPs))
	}

	dynIPCount, err := snapshotNftSetToFile("agvpn_dyn4", routesCacheDyn)
	if err != nil {
		warns = append(warns, fmt.Sprintf("agvpn_dyn4 snapshot failed: %v", err))
		_ = os.WriteFile(routesCacheDyn, []byte{}, 0o644)
		dynIPCount = 0
	}

	if err := cacheCopyOrEmpty(stateDir+"/last-ips-map.txt", routesCacheMap); err != nil {
		warns = append(warns, fmt.Sprintf("last-ips-map cache copy failed: %v", err))
	}
	if err := cacheCopyOrEmpty(lastIPsMapDirect, routesCacheMapD); err != nil {
		warns = append(warns, fmt.Sprintf("last-ips-map-direct cache copy failed: %v", err))
	}
	if err := cacheCopyOrEmpty(lastIPsMapDyn, routesCacheMapW); err != nil {
		warns = append(warns, fmt.Sprintf("last-ips-map-wildcard cache copy failed: %v", err))
	}

	meta := routesClearCacheMeta{
		CreatedAt:  time.Now().UTC().Format(time.RFC3339),
		Iface:      detectIfaceFromRoutes(routes),
		RouteCount: len(routes),
		IPCount:    ipCount,
		DynIPCount: dynIPCount,
		HasIPMap:   fileExists(routesCacheMap),
	}

	data, err := json.MarshalIndent(meta, "", "  ")
	if err != nil {
		return routesClearCacheMeta{}, err
	}
	if err := os.WriteFile(routesCacheMeta, data, 0o644); err != nil {
		return routesClearCacheMeta{}, err
	}
	if len(warns) > 0 {
		return meta, fmt.Errorf("%s", strings.Join(warns, "; "))
	}
	return meta, nil
}