package gopackagebase

import (
	"context"
	"log"
	"os"
	"os/signal"
)

func InitSignalHandler() (context.Context, func()) {
	// Setup some initial context for gracefully killing the program
	// with system interrupt signals like ctrl+c
	// https://pace.dev/blog/2020/02/17/repond-to-ctrl-c-interrupt-signals-gracefully-with-context-in-golang-by-mat-ryer.html
	ctx := context.Background()
	ctx, cancel := context.WithCancel(ctx)
	signalChan := make(chan os.Signal, 1)
	signal.Notify(signalChan, os.Interrupt)

	// Start a goroutine to listen for signal interrupts
	go func() {
		select {
		case <-signalChan:
			// Graceful exit on ctrl+c
			log.Printf("Attempting to exit gracefully...\n")
			cancel()
		case <-ctx.Done():
		}
		<-signalChan // Hard exit on second ctrl+c
		log.Printf("Hard kill\n")
		os.Exit(2)
	}()

	// Return a new cancel function that also sends the stop signal.
	killFunc := func() {
		signal.Stop(signalChan)
		cancel()
	}

	return ctx, killFunc
}