dice-roller/main.go

package main

import (
	"flag"
	"fmt"
	"math/rand"
	"os"
	"time"
)

var (
	surfaces, modifier, diceThrows, attacks int
	advantage, disadvantage                 bool
)

func main() {

	rand.Seed(time.Now().Unix())
	ParseFlags()

	switch {
	case advantage:
		fmt.Println("Advantage")
		fmt.Println(Advantage(SimpleCast(), SimpleCast()))
	case disadvantage:
		fmt.Println("Disadvantage")
		fmt.Println(Disadvantage(SimpleCast(), SimpleCast()))
	case attacks < 1:
		fmt.Println("Attack amount cannot be below 1.")
		os.Exit(1)
	case attacks > 1:
		for i := 0; i < attacks; i++ {
			fmt.Println()
			Cast(surfaces, diceThrows, modifier)
		}
	default:
		Cast(surfaces, diceThrows, modifier)
	}
}

func ParseFlags() {
	flag.IntVar(&surfaces, "surfaces", 20, "Specify amount of die surfaces")
	flag.IntVar(&diceThrows, "throws", 1, "Specify dice diceThrows")
	flag.IntVar(&modifier, "modifier", 0, "Stat modifier")
	flag.IntVar(&attacks, "attacks", 1, "Attacks")

	flag.BoolVar(&advantage, "advantage", false, "Advantage")
	flag.BoolVar(&disadvantage, "disadvantage", false, "Disadvantage")

	flag.Parse()
}

func Cast(dieSurfaces, castAmount, modifier int) {
	var (
		casts       []int
		cast, total int
	)

	for i := 0; i < castAmount; i++ {
		cast = rand.Intn(dieSurfaces) + 1
		casts = append(casts, cast)
		total += cast
	}

	if castAmount > 1 {
		fmt.Println(casts)
	}

	if modifier != 0 {
		fmt.Println("Without modifier:", total)
		fmt.Println("With modifier:", total+modifier)
	} else {
		fmt.Println(total)
	}
}

func SimpleCast() int {
	return rand.Intn(20) + 1
}

func Advantage(x, y int) int {
	fmt.Println("x:", x)
	fmt.Println("Y:", y)
	if x > y {
		return x
	} else {
		return y
	}
}

func Disadvantage(x, y int) int {
	fmt.Println("x:", x)
	fmt.Println("Y:", y)
	if x < y {
		return x
	} else {
		return y
	}
}