// Monster Battle -- finished version.
// Two monsters trade blows until one faints.
// Run with: go run projects/monster-battle/finished.go

package main

import (
	"fmt"
	"math/rand"
)

type monster struct {
	name   string
	hp     int
	maxHP  int
	attack int
}

// newMonster checks the numbers first. rand.Intn crashes the program if it is
// given a number below 1, so attack must be at least 1.
func newMonster(name string, hp int, attack int) (*monster, error) {
	if hp < 1 {
		return nil, fmt.Errorf("%s: hp %d is below 1", name, hp)
	}
	if attack < 1 {
		return nil, fmt.Errorf("%s: attack %d is below 1", name, attack)
	}
	return &monster{name: name, hp: hp, maxHP: hp, attack: attack}, nil
}

func (m *monster) isAlive() bool {
	return m.hp > 0
}

// hit deals random damage to other, prints the result and returns the damage.
func (m *monster) hit(other *monster) int {
	damage := rand.Intn(m.attack) + 1
	other.hp = other.hp - damage
	if other.hp < 0 {
		other.hp = 0
	}
	fmt.Printf("%s hits %s for %d. %s has %d HP left.\n", m.name, other.name, damage, other.name, other.hp)
	return damage
}

// String makes *monster satisfy fmt.Stringer.
func (m *monster) String() string {
	return fmt.Sprintf("%s: %d/%d HP", m.name, m.hp, m.maxHP)
}

func main() {
	hero, err := newMonster("Hero", 30, 8)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}

	goblin, err := newMonster("Goblin", 25, 6)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}

	dealt := map[string]int{}

	round := 1
	for hero.isAlive() && goblin.isAlive() {
		fmt.Printf("-- Round %d --\n", round)
		dealt[hero.name] += hero.hit(goblin)
		if goblin.isAlive() {
			dealt[goblin.name] += goblin.hit(hero)
		}
		round++
	}

	if hero.isAlive() {
		fmt.Println(hero.name + " wins!")
	} else {
		fmt.Println(goblin.name + " wins!")
	}

	fighters := []*monster{hero, goblin}
	for _, m := range fighters {
		fmt.Printf("%v, dealt %d damage\n", m, dealt[m.name])
	}
}