roll.go

// Copy from game/entropy/models/roll.go
package main

import (
	"fmt"
	"math/rand"
	"strconv"
	"strings"
)

type Rolls struct {
	dieValue int
	nbDice   int
	rolls    []bonus
	extra    []int
}

func (r Rolls) String() string {
	var out string

	rs := make([]string, 0, len(r.rolls))
	for _, v := range r.rolls {
		s := strconv.Itoa(v.Value)
		if v.Type != "" {
			s += " (" + v.Type + ")"
		}
		rs = append(rs, s)
	}

	out += strings.Join(rs, " + ")
	out += " = " + strconv.FormatInt(int64(r.Total()), 10)
	return out
}

func (r Rolls) Total() int {
	var total int
	for _, v := range r.rolls {
		total += int(v.Value)
	}
	return total
}

// TODO: refactor/rename/cleanup
type bonus struct {
	Value int
	Type  string
}

func (r *Rolls) Extra(b bonus) *Rolls {
	if b.Value == 0 {
		return r
	}

	r.extra = append(r.extra, b.Value)
	r.rolls = append(r.rolls, b)

	return r
}

func roll(dice, n int) *Rolls {
	var rolls []bonus
	var all int

	for i := 0; i < n; i++ {
		roll := 1 + rand.Intn(dice)
		all += roll
	}

	rolls = append(rolls, bonus{Value: all, Type: fmt.Sprintf("%dd%d", n, dice)})

	return &Rolls{
		dieValue: dice,
		nbDice:   n,
		rolls:    rolls,
	}
}

func d4(n int) *Rolls {
	return roll(4, n)
}

func d6(n int) *Rolls {
	return roll(6, n)
}

func d8(n int) *Rolls {
	return roll(8, n)
}

func d12(n int) *Rolls {
	return roll(12, n)
}

func d20(n int) *Rolls {
	return roll(20, n)
}