package interrupt

import (
	"fmt"
	"os"
	"os/signal"
	"syscall"
)

// Cleaner type referes to a function with no inputs that returns an error
type Cleaner func() error

var cleaners []Cleaner
var active = false

// RegisterCleaner is responsible for regisreting a cleaner function. When a function is registered, the Signal watcher is started in a goroutine.
func RegisterCleaner(f ...Cleaner) {
	for _, fn := range f {
		cleaners = append(cleaners, fn)
		if !active {
			active = true
			go func() {
				ch := make(chan os.Signal, 1)
				signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM, os.Interrupt)
				<-ch
				// Prevent un-terminated ^C character in terminal
				fmt.Println()
				clean()
				os.Exit(1)
			}()
		}
	}
}

// Clean invokes all registered cleanup functions
func clean() {
	fmt.Println("Cleaning")
	for _, f := range cleaners {
		_ = f()
	}
	cleaners = []Cleaner{}
}