box-o-sand/conway/web.go

package conway

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"image/png"
	"log"
	"math/rand"
	"net/http"
	"net/url"
	"strconv"
	"time"
)

type WebGameParams struct {
	Random bool
	Height int
	Width  int
	Xmul   int
	Ymul   int
}

type WebGameState struct {
	State *GameState `json:"state"`
	Img   string     `json:"img"`
}

var jQueryMinJs = []byte("")

func init() {
	rand.Seed(time.Now().UTC().UnixNano())
	jqmin, err := base64.StdEncoding.DecodeString(JQUERY_MIN_JS)
	if err != nil {
		log.Fatal("Failed to decode internal jquery.min.js")
	}
	jQueryMinJs = append(jQueryMinJs, jqmin...)
}

func NewWebGameParams(q url.Values) *WebGameParams {
	params := &WebGameParams{
		Height: 50,
		Width:  50,
		Xmul:   10,
		Ymul:   10,
	}

	if len(q.Get("random")) > 0 {
		params.Random = true
	}

	h := q.Get("h")
	if len(h) > 0 {
		if i, err := strconv.Atoi(h); err == nil {
			params.Height = i
		}
	}

	w := q.Get("w")
	if len(w) > 0 {
		if i, err := strconv.Atoi(w); err == nil {
			params.Width = i
		}
	}

	xm := q.Get("xm")
	if len(xm) > 0 {
		if i, err := strconv.Atoi(xm); err == nil {
			params.Xmul = i
		}
	}

	ym := q.Get("ym")
	if len(ym) > 0 {
		if i, err := strconv.Atoi(ym); err == nil {
			params.Ymul = i
		}
	}

	return params
}

func handle405(method, uri string, w http.ResponseWriter) {
	w.Header().Set("Content-Type", "text/plain")
	w.WriteHeader(http.StatusMethodNotAllowed)
	w.Write([]byte(fmt.Sprintf("Nope.  %v not allowed at %v\n", method, uri)))
}

func handle500(err error, w http.ResponseWriter) {
	log.Println("ERROR:", err)
	w.Header().Set("Content-Type", "text/plain")
	w.WriteHeader(http.StatusInternalServerError)
	w.Write([]byte(fmt.Sprintf("We exploded!: %v\n", err)))
}

func HandleWebGameRoot(w http.ResponseWriter, req *http.Request) {
	if req.Method != "GET" {
		handle405(req.Method, req.RequestURI, w)
		return
	}

	w.Header().Set("Content-Type", "text/html")
	w.WriteHeader(http.StatusOK)
	w.Write([]byte(GAME_OF_LIFE_INDEX_HTML))
	return
}

func HandleWebGameStatic(w http.ResponseWriter, req *http.Request) {
	if req.Method != "GET" {
		handle405(req.Method, req.RequestURI, w)
		return
	}

	if req.URL.Path == "/static/normalize.css" {
		w.Header().Set("Content-Type", "text/css")
		w.WriteHeader(http.StatusOK)
		w.Write([]byte(NORMALIZE_CSS))
		return
	}

	if req.URL.Path == "/static/jquery.min.js" {
		w.Header().Set("Content-Type", "text/javascript")
		w.WriteHeader(http.StatusOK)
		w.Write(jQueryMinJs)
		return
	}

	w.Header().Set("Content-Type", "text/plain")
	w.WriteHeader(http.StatusNotFound)
	w.Write([]byte(fmt.Sprintf("Don't have: %v\n", req.URL.Path)))
}

func HandleWebGameState(w http.ResponseWriter, req *http.Request) {
	if req.Method != "GET" {
		handle405(req.Method, req.RequestURI, w)
		return
	}

	q := req.URL.Query()
	params := NewWebGameParams(q)

	if params.Random {
		game := NewGameOfLife(params.Height, params.Width)
		err := game.ImportRandomState()
		if err != nil {
			handle500(err, w)
			return
		}

		img, err := game.Image(params.Xmul, params.Ymul)

		if err != nil {
			handle500(err, w)
			return
		}

		log.Println("Serving random state image.")

		var pngBuf bytes.Buffer
		err = png.Encode(&pngBuf, img)
		if err != nil {
			handle500(err, w)
		}

		imgB64 := base64.StdEncoding.EncodeToString(pngBuf.Bytes())
		webGameState := &WebGameState{State: game.State, Img: imgB64}
		wgsJson, err := json.Marshal(webGameState)

		if err != nil {
			handle500(err, w)
		}

		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		w.Write(wgsJson)

		return
	}

	rawState := q.Get("s")
	if len(rawState) < 1 {
		w.Header().Set("Content-Type", "text/plain")
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Missing query param \"s\".\n"))
		return
	}

	//state := &GameState{}
	//err := json.Unmarshal([]byte(rawState), state)
	//if err != nil {
	//w.Header().Set("Content-Type", "text/plain")
	//w.WriteHeader(http.StatusBadRequest)
	//w.Write([]byte(fmt.Sprintf("Invalid query param \"s\": %v\n", err)))
	//return
	//}

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	w.Write([]byte(`{"state":null,"img":""}`))
	return
}

func RunWebGame(address string, height, width, sleepMs int, mutate bool) (int, error) {
	http.HandleFunc("/", HandleWebGameRoot)
	http.HandleFunc("/state", HandleWebGameState)
	http.HandleFunc("/static/", HandleWebGameStatic)

	fmt.Printf("Serving on %v\n", address)
	err := http.ListenAndServe(address, nil)
	if err != nil {
		return 1, err
	}
	return 0, nil
}