package main

import (
	"fmt"

	"gitty.informatik.hs-mannheim.de/steger/pr3-code/go/04-design-pattern/patterns"
)

type Counter struct {
	patterns.Subject
	Count int
}

func NewCounter() Counter {
	return Counter{patterns.NewSubject(), 0}
}

func (c *Counter) Inc() {
	c.Count++
	c.Notify()
}

func (c *Counter) Dec() {
	c.Count--
	c.Notify()
}

type CountPrinter struct {
	counter *Counter
}

func (cp *CountPrinter) Update() {
	fmt.Println("count updated to ", cp.counter.Count)
}

type CounterHistory struct {
	counter *Counter
	history []int
}

func (ch *CounterHistory) Update() {
	ch.history = append(ch.history, ch.counter.Count)
}

func main() {
	counter := NewCounter()

	history := CounterHistory{&counter, []int{}}
	counter.Register(&history)

	printer := CountPrinter{&counter}
	counter.Register(&printer)
	printerRegistered := true

	var input string
	for {
		fmt.Print("Enter a command (+: increment, -: decrement, q: quit): ")
		fmt.Scanln(&input)

		if len(input) != 1 {
			fmt.Println("Please enter a single character.")
			continue
		}

		switch input[0] {
		case '+':
			counter.Inc()
		case '-':
			counter.Dec()
		case 'p':
			if printerRegistered {
				counter.Unregister(&printer)
			} else {
				counter.Register(&printer)
			}
			printerRegistered = !printerRegistered
		case 'q':
			fmt.Println("Exiting...")
			fmt.Println(history.history)
			return
		default:
			fmt.Println("Unknown command. Use '+', '-', or 'q'.")
		}
	}
}