// Copyright 2014 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

// Package utils contains internal helper functions for go-ethereum commands.
package utils

import (
	"context"
	"fmt"
	"io"
	"os"
	"os/signal"
	"runtime"
	"syscall"

	"github.com/spf13/cobra"
	"github.com/urfave/cli"

	"github.com/ledgerwatch/erigon/internal/debug"
	"github.com/ledgerwatch/erigon/log"
	"github.com/ledgerwatch/erigon/node"
)

// Fatalf formats a message to standard error and exits the program.
// The message is also printed to standard output if standard error
// is redirected to a different file.
func Fatalf(format string, args ...interface{}) {
	w := io.MultiWriter(os.Stdout, os.Stderr)
	if runtime.GOOS == "windows" {
		// The SameFile check below doesn't work on Windows.
		// stdout is unlikely to get redirected though, so just print there.
		w = os.Stdout
	} else {
		outf, _ := os.Stdout.Stat()
		errf, _ := os.Stderr.Stat()
		if outf != nil && errf != nil && os.SameFile(outf, errf) {
			w = os.Stderr
		}
	}
	fmt.Fprintf(w, "Fatal: "+format+"\n", args...)
	os.Exit(1)
}

func StartNode(stack *node.Node) {
	if err := stack.Start(); err != nil {
		Fatalf("Error starting protocol stack: %v", err)
	}
	go func() {
		sigc := make(chan os.Signal, 1)
		signal.Notify(sigc, syscall.SIGINT, syscall.SIGTERM)
		defer signal.Stop(sigc)

		<-sigc
		log.Info("Got interrupt, shutting down...")
		go stack.Close()
		for i := 10; i > 0; i-- {
			<-sigc
			if i > 1 {
				log.Warn("Already shutting down, interrupt more to panic.", "times", i-1)
			}
		}
		debug.Exit() // ensure trace and CPU profile data is flushed.
		debug.LoudPanic("boom")
	}()
}

func SetupCobra(cmd *cobra.Command) error {
	return debug.SetupCobra(cmd)
}

func StopDebug() {
	debug.Exit()
}

func SetupUrfave(ctx *cli.Context) error {
	return debug.Setup(ctx)
}

func RootContext() (context.Context, context.CancelFunc) {
	ctx, cancel := context.WithCancel(context.Background())
	go func() {
		defer cancel()

		ch := make(chan os.Signal, 1)
		defer close(ch)

		signal.Notify(ch, os.Interrupt, syscall.SIGTERM)
		defer signal.Stop(ch)

		select {
		case sig := <-ch:
			log.Info("Got interrupt, shutting down...", "sig", sig)
		case <-ctx.Done():
		}
	}()
	return ctx, cancel
}