Hangman - Part 3 struct and receiver methods

hangman.go

package main

import (
	"bufio"
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"strings"
	"time"
)

var dev = flag.Bool("dev", false, "dev mode")

const (
	GAME_PLAY = iota // untyped int constants
	GAME_WIN
	GAME_LOSE
	GAME_TIMEOUT
	GAME_ERR
)

type Hangman struct {
	Entries     map[string]bool
	Placeholder []string
	chances     int
	word        string
	duration    time.Duration // game duration
	input       io.Reader
}

func get_keys(entries map[string]bool) (keys []string) {
	for k, _ := range entries {
		keys = append(keys, k)
	}
	return
}

func get_word() string {
	if *dev {
		return "elephant"
	}
	resp, err := http.Get("https://random-word-api.herokuapp.com/word?number=5")
	if err != nil {
		return "elephant"
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)

	var words []string
	err = json.Unmarshal(body, &words)
	if err != nil {
		// handle error
		return "elephant"
	}

	//fmt.Println(words)
	for _, word := range words {
		if len(word) > 4 && len(word) < 9 {
			return word
		}
	}

	return words[0]
}

func (h *Hangman) Render(status uint) {
	switch status {
	case GAME_PLAY:
		fmt.Println(h.Placeholder)                       // render the placeholder
		fmt.Printf("Chances: %d\n", h.chances)           // render the chances left
		fmt.Printf("Entries: %v\n", get_keys(h.Entries)) // show the letters or words guessed till now.
		fmt.Printf("Guess a letter or the word: ")

	case GAME_WIN:
		fmt.Println("You win!!")
	case GAME_LOSE:
		fmt.Println("You're out of chances")
		fmt.Println("Word was: ", h.word)
		fmt.Println("Game Over! Try again")

	case GAME_ERR:
		fmt.Println("Something wrong with getting input")

	case GAME_TIMEOUT:
		fmt.Println("Timedout... too bad!")
	}
}

func (h *Hangman) GetInput() (str string) {
	str = ""
	fmt.Scanln(&str)
	return
}

func get_input(input io.Reader) (str string, err error) {
	scanner := bufio.NewScanner(input)
	if scanner.Scan() { // scan one line
		str = scanner.Text()
		return
	}

	err = scanner.Err()
	return
}

func play(h *Hangman, result chan bool) {
	for {
		// evaluate a loss! If user guesses a wrong letter or the wrong word, they lose a chance.
		userInput := strings.Join(h.Placeholder, "")
		if h.chances == 0 && userInput != h.word {
			h.Render(GAME_LOSE)
			result <- false
			return
		}

		// evaluate a win!
		if userInput == h.word {
			h.Render(GAME_WIN)
			result <- true
			return
		}

		// Console display
		h.Render(GAME_PLAY)
		// Addon validation: Allow only alpha!
		// Addon validation: manage case!

		str := h.GetInput()

		// if len(str) > 2, compare the word with the str
		if len(str) > 2 {
			if str == h.word {
				h.Render(GAME_WIN)
				result <- true
				return
			} else {
				// you lose a chance
				h.Entries[str] = true
				h.chances -= 1
				continue
			}
		}

		// compare and update entries, placeholder and chances.
		_, ok := h.Entries[str]
		if ok {
			// key exists already; duplicate
			continue
		}

		h.Entries[str] = true
		// check if letter exists in the word!
		found := false
		for i, v := range h.word {
			if str == string(v) {
				h.Placeholder[i] = string(v)
				found = true
			}
		}

		if !found {
			h.chances -= 1
		}
	}
}

func main() {
	flag.Parse()

	h := Hangman{
		Entries:     map[string]bool{},
		Placeholder: []string{},
		chances:     8,
		duration:    2 * time.Minute,
	}

	h.word = get_word()

	// get length of the word len(word)
	// initialize slice with each element as "_"
	for i := 0; i < len(h.word); i++ {
		h.Placeholder = append(h.Placeholder, "_")
		//placeholder[i] = "_"
	}

	t := time.NewTimer(h.duration)
	result := make(chan bool)

	go play(&h, result)

	// Wait on either game to finish or timeout!
	select {
	case <-result:
	case <-t.C:
		h.Render(GAME_TIMEOUT)
	}
}