package global

import (
	"context"
	"os"
	"runtime"
	runtimeDebug "runtime/debug"

	B "github.com/sagernet/sing-box"
	"github.com/sagernet/sing-box/common/urltest"
	"github.com/sagernet/sing-box/experimental/libbox"
	"github.com/sagernet/sing-box/option"
	E "github.com/sagernet/sing/common/exceptions"
	"github.com/sagernet/sing/service"
	"github.com/sagernet/sing/service/filemanager"
	"github.com/sagernet/sing/service/pause"
)

var (
	sWorkingPath string
	sTempPath    string
	sUserID      int
	sGroupID     int
)

func Setup(basePath string, workingPath string, tempPath string) {
	tcpConn := runtime.GOOS == "windows" //TODO add TVOS
	libbox.Setup(basePath, workingPath, tempPath, tcpConn)
	sWorkingPath = workingPath
	os.Chdir(sWorkingPath)
	sTempPath = tempPath
	sUserID = os.Getuid()
	sGroupID = os.Getgid()
}

func NewService(options option.Options) (*libbox.BoxService, error) {
	runtimeDebug.FreeOSMemory()
	ctx, cancel := context.WithCancel(context.Background())
	ctx = filemanager.WithDefault(ctx, sWorkingPath, sTempPath, sUserID, sGroupID)
	urlTestHistoryStorage := urltest.NewHistoryStorage()
	ctx = service.ContextWithPtr(ctx, urlTestHistoryStorage)
	instance, err := B.New(B.Options{
		Context: ctx,
		Options: options,
	})
	if err != nil {
		cancel()
		return nil, E.Cause(err, "create service")
	}
	runtimeDebug.FreeOSMemory()
	service := libbox.NewBoxService(
		ctx,
		cancel,
		instance,
		service.FromContext[pause.Manager](ctx),
		urlTestHistoryStorage,
	)
	return &service, nil
}

func parseConfig(configContent string) (option.Options, error) {
	var options option.Options
	err := options.UnmarshalJSON([]byte(configContent))
	if err != nil {
		return option.Options{}, E.Cause(err, "decode config")
	}
	return options, nil
}