From d19b3f71fa9130d7c231bef8f6a7e449db54c532 Mon Sep 17 00:00:00 2001
From: Stephen McQuay <stephen@mcquay.me>
Date: Fri, 18 Oct 2013 20:48:22 -0700
Subject: [PATCH] added ability to autovivify games in debug mode

---
 control.go  |  8 +-------
 game.go     | 32 ++++++++++++++++++++++++++++++++
 main.go     |  7 +------
 protocol.go |  6 ++----
 4 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/control.go b/control.go
index 5be4c46..009d1fa 100644
--- a/control.go
+++ b/control.go
@@ -18,13 +18,7 @@ func (h JsonHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 func startGame(w http.ResponseWriter, req *http.Request) {
 	log.Println("asked to create a game")
 	new_game_name := idg.Hash()
-
-	_g := NewGame(new_game_name, *width, *height)
-	go _g.run()
-
-	games.Lock()
-	games.m[new_game_name] = _g
-	games.Unlock()
+	games.getOrCreate(new_game_name)
 
 	game_json := struct {
 		Id string `json:"id"`
diff --git a/game.go b/game.go
index 7d2525e..ba3b7ec 100644
--- a/game.go
+++ b/game.go
@@ -2,8 +2,10 @@ package main
 
 import (
 	v "bitbucket.org/hackerbots/vector"
+	"errors"
 	"log"
 	"sort"
+	"sync"
 	"time"
 )
 
@@ -37,6 +39,36 @@ type Scanner struct {
 	Stats    Stats     `json:"stats"`
 }
 
+type MapLock struct {
+	m map[string]*game
+	sync.RWMutex
+}
+
+func (ml *MapLock) getOrCreate(id string) (*game, error) {
+	ml.Lock()
+	g, ok := games.m[id]
+	ml.Unlock()
+
+	if ok {
+		return g, nil
+	}
+
+	if !*debug {
+		return nil, errors.New("game not found")
+	}
+
+	new_game_name := idg.Hash()
+
+	_g := NewGame(id, *width, *height)
+	go _g.run()
+
+	ml.Lock()
+	ml.m[new_game_name] = _g
+	ml.Unlock()
+
+	return _g, nil
+}
+
 type game struct {
 	id            string
 	players       map[*player]bool
diff --git a/main.go b/main.go
index 05cfbe0..06a3789 100644
--- a/main.go
+++ b/main.go
@@ -8,7 +8,6 @@ import (
 	"net/http"
 	"os"
 	"runtime/pprof"
-	"sync"
 	"time"
 )
 
@@ -18,16 +17,12 @@ var verbose = flag.Bool("verbose", false, "")
 var width = flag.Float64("width", 800, "width of field")
 var height = flag.Float64("height", 550, "height of field")
 var profile = flag.String("pprof", "", "if specified will run with pprof")
+var debug = flag.Bool("debug", false, "automatically create games if they don't exist")
 
 var delta float64
 
 var idg *IdGenerator
 
-type MapLock struct {
-	m map[string]*game
-	sync.RWMutex
-}
-
 // This is the main, global collection of games
 var games MapLock
 
diff --git a/protocol.go b/protocol.go
index ef84673..4e531ef 100644
--- a/protocol.go
+++ b/protocol.go
@@ -99,11 +99,9 @@ func addPlayer(ws *websocket.Conn) {
 		return
 	}
 
-	games.Lock()
-	game, ok := games.m[gid.Id]
-	games.Unlock()
+	game, err := games.getOrCreate(gid.Id)
 
-	if !ok {
+	if err != nil {
 		log.Printf("ERROR: game %s not found", gid.Id)
 		websocket.JSON.Send(ws, NewFailure("game 404"))
 		return