card_id/cmd/server/main.go

package main

import (
	"encoding/json"
	"log"
	"os"
	"strconv"

	"context"
	"net/http"

	"git.tuxpa.in/a/card_id/common/game"
	"git.tuxpa.in/a/card_id/common/game/card"
	"lukechampine.com/frand"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	"github.com/go-chi/render"
)

type Engine struct {
	dealer *card.Dealer

	games map[string]*game.Game
}

func main() {
	dealer, err := card.NewDealer().ReadFromRoot(os.Getenv("CARD_DATA_DIR"))
	if err != nil {
		log.Panicln(err)
	}

	e := &Engine{
		dealer: dealer,
		games:  map[string]*game.Game{},
	}

	r := chi.NewRouter()

	r.Use(middleware.RequestID)
	r.Use(middleware.Logger)
	r.Use(middleware.Recoverer)
	r.Use(middleware.URLFormat)
	r.Use(render.SetContentType(render.ContentTypeJSON))

	r.Get("/healthz", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("OK"))
	})

	r.Get("/ping", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("pong"))
	})

	// RESTy routes for "instances" resource
	r.Route("/game", func(r chi.Router) {
		//	r.Use(oauth.Authorize(os.Getenv("OAUTH_TOKEN"), nil))
		r.Post("/new", e.CreateGame)
		r.Route("/{instanceId}", func(r chi.Router) {
			r.Use(e.GameCtx)
			r.Route("/play", func(r chi.Router) {
				r.Get("/click/{cardId}", nil)
			})
			r.Route("/debug", func(r chi.Router) {
				r.Get("/info", e.GetGame)
			})
		})

	})
	port := ":3333"
	log.Println(port)
	http.ListenAndServe(port, r)
}

// GameCtx middleware is used to load an Game object from
// the URL parameters passed through as the request. In case
// the Game could not be found, we stop here and return a 404.
func (e *Engine) GameCtx(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		var instance *game.Game
		if instanceID := chi.URLParam(r, "instanceId"); instanceID != "" {
			instance = e.games[instanceID]
		}
		if instance == nil {
			render.Render(w, r, ErrNotFound)
			return
		}
		ctx := context.WithValue(r.Context(), "instance", instance)
		next.ServeHTTP(w, r.WithContext(ctx))
	})
}

func (e *Engine) CreateGame(w http.ResponseWriter, r *http.Request) {
	id := strconv.Itoa(frand.Intn(0xfff))
	e.games[id] = game.New("", e.dealer)
	w.Write([]byte(id))
	w.WriteHeader(200)
}

func (e *Engine) GetGame(w http.ResponseWriter, r *http.Request) {
	instance, ok := r.Context().Value("instance").(*game.Game)
	if !ok {
		render.Render(w, r, ErrNotFound)
		return
	}
	err := json.NewEncoder(w).Encode(instance)
	if err != nil {
		render.Render(w, r, ErrInvalidRequest(err))
		return
	}
	w.WriteHeader(200)
}

var ErrNotFound = &ErrResponse{HTTPStatusCode: 404, StatusText: "game not found."}

type ErrResponse struct {
	Err            error `json:"-"` // low-level runtime error
	HTTPStatusCode int   `json:"-"` // http response status code

	StatusText string `json:"status"`          // user-level status message
	AppCode    int64  `json:"code,omitempty"`  // application-specific error code
	ErrorText  string `json:"error,omitempty"` // application-level error message, for debugging
}

func (e *ErrResponse) Render(w http.ResponseWriter, r *http.Request) error {
	render.Status(r, e.HTTPStatusCode)
	return nil
}

func ErrInvalidRequest(err error) render.Renderer {
	return &ErrResponse{
		Err:            err,
		HTTPStatusCode: 400,
		StatusText:     "Invalid request.",
		ErrorText:      err.Error(),
	}
}

func ErrRender(err error) render.Renderer {
	return &ErrResponse{
		Err:            err,
		HTTPStatusCode: 422,
		StatusText:     "Error rendering response.",
		ErrorText:      err.Error(),
	}
}