// Copyright Istio Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package cmd

import (
	"context"
	"flag"
	"fmt"
	"os"
	"os/signal"
	"syscall"

	"github.com/spf13/cobra"
	"github.com/spf13/pflag"

	"istio.io/istio/pkg/log"
)

// WaitSignal awaits for SIGINT or SIGTERM and closes the channel
func WaitSignal(stop chan struct{}) {
	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
	<-sigs
	close(stop)
	_ = log.Sync()
}

// WaitSignalFunc awaits for SIGINT or SIGTERM and calls the cancel function
func WaitSignalFunc(cancel context.CancelCauseFunc) {
	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
	sig := <-sigs
	cancel(fmt.Errorf("received signal: %v", sig.String()))
	_ = log.Sync()
}

// AddFlags adds all command line flags to the given command.
func AddFlags(rootCmd *cobra.Command) {
	rootCmd.PersistentFlags().AddGoFlagSet(flag.CommandLine)
}

// PrintFlags logs the flags in the flagset
func PrintFlags(flags *pflag.FlagSet) {
	flags.VisitAll(func(flag *pflag.Flag) {
		log.Infof("FLAG: --%s=%q", flag.Name, flag.Value)
	})
}
