Add the ability to set emulator ROM folder (#348)

Emulators now can load games with the same file extensions if you either place ROMs into the folder named as the emulator in the config file (libretro.core.list value) or any folder as you specify in the `libretro.core.list.{emulator}.folder` config param.

configs/config.yaml

@@ -125,10 +125,19 @@ emulator:
           compression: zip
       # Libretro core configuration
       #
+      # The emulator selection will happen in this order:
+      #   - based on the folder name in the folder param
+      #   - based on the folder name (core name) in the list (i.e. nes, snes)
+      #   - based on the rom names in the roms param
+      #
       # Available config params:
       #   - lib (string)
       #   - config (string)
       #   - roms ([]string)
+      #   - folder (string)
+      #       By default emulator selection is based on the folder named as cores
+      #       in the list (i.e. nes, snes) but if you specify folder param,
+      #       then it will try to load the ROM file from that folder first.
       #   - width (int) -- broken
       #   - height (int) -- broken
       #   - ratio (float)
@@ -142,11 +151,16 @@ emulator:
         pcsx:
           lib: pcsx_rearmed_libretro
           roms: [ "cue" ]
+          # example of folder override
+          folder: psx
         # MAME core requires additional manual setup, please read:
         # https://docs.libretro.com/library/fbneo/
         mame:
           lib: fbneo_libretro
           roms: [ "zip" ]
+        mame2003:
+          lib: mame2003_libretro
+          roms: [ "zip" ]
         nes:
           lib: nestopia_libretro
           roms: [ "nes" ]

pkg/config/emulator/config.go

@@ -3,6 +3,7 @@ package emulator
 import (
 	"path"
 	"path/filepath"
+	"strings"
 )
 
 type Emulator struct {
@@ -42,6 +43,7 @@ type LibretroCoreConfig struct {
 	Lib         string
 	Config      string
 	Roms        []string
+	Folder      string
 	Width       int
 	Height      int
 	Ratio       float64
@@ -64,17 +66,24 @@ func (e Emulator) GetLibretroCoreConfig(emulator string) LibretroCoreConfig {
 	return conf
 }
 
-// GetEmulatorByRom returns emulator name by its supported ROM name.
-// !to cache into an optimized data structure
-func (e Emulator) GetEmulatorByRom(rom string) string {
+// GetEmulator tries to find a suitable emulator.
+// !to remove quadratic complexity
+func (e Emulator) GetEmulator(rom string, path string) string {
+	found := ""
 	for emu, core := range e.Libretro.Cores.List {
 		for _, romName := range core.Roms {
 			if rom == romName {
-				return emu
+				found = emu
+				if p := strings.SplitN(filepath.ToSlash(path), "/", 2); len(p) > 1 {
+					folder := p[0]
+					if (folder != "" && folder == core.Folder) || folder == emu {
+						return emu
+					}
+				}
 			}
 		}
 	}
-	return ""
+	return found
 }
 
 func (e Emulator) GetSupportedExtensions() []string {

pkg/config/emulator/config_test.go

@@ -0,0 +1,52 @@
+package emulator
+
+import "testing"
+
+func TestGetEmulator(t *testing.T) {
+	tests := []struct {
+		rom      string
+		path     string
+		config   map[string]LibretroCoreConfig
+		emulator string
+	}{
+		{
+			rom:  "nes",
+			path: "test/game.nes",
+			config: map[string]LibretroCoreConfig{
+				"snes": {Roms: []string{"nes"}},
+				"nes":  {Folder: "test", Roms: []string{"nes"}},
+			},
+			emulator: "nes",
+		},
+		{
+			rom:  "nes",
+			path: "nes/game.nes",
+			config: map[string]LibretroCoreConfig{
+				"snes": {Roms: []string{"nes"}},
+				"nes":  {Roms: []string{"nes"}},
+			},
+			emulator: "nes",
+		},
+		{
+			rom:  "nes",
+			path: "test/game.nes",
+			config: map[string]LibretroCoreConfig{
+				"snes": {Roms: []string{"nes"}},
+				"nes":  {Roms: []string{"nes"}},
+			},
+			emulator: "nes",
+		},
+	}
+
+	emu := Emulator{
+		Libretro: LibretroConfig{},
+	}
+
+	for _, test := range tests {
+		emu.Libretro.Cores.List = test.config
+		em := emu.GetEmulator(test.rom, test.path)
+		if test.emulator != em {
+			t.Errorf("expected result: %v, but was %v with: %v, %v", test.emulator, em, test.rom, test.path)
+		}
+	}
+}

pkg/coordinator/useragenthandlers.go

@@ -205,6 +205,7 @@ func newGameStartCall(roomId string, data string, library games.GameLibrary) (ap
 
 	return api.GameStartCall{
 		Name: gameInfo.Name,
+		Base: gameInfo.Base,
 		Path: gameInfo.Path,
 		Type: gameInfo.Type,
 	}, nil

pkg/cws/api/coordinator.go

@@ -30,6 +30,7 @@ func (packet *GameStartRequest) From(data string) error { return from(packet, da
 
 type GameStartCall struct {
 	Name string `json:"name"`
+	Base string `json:"base"`
 	Path string `json:"path"`
 	Type string `json:"type"`
 }

pkg/games/game_library.go

@@ -74,6 +74,7 @@ type GameMetadata struct {
 	Name string
 	// the game file extension (e.g. nes, n64)
 	Type string
+	Base string
 	// the game path relative to the library base path
 	Path string
 }
@@ -126,8 +127,8 @@ func (lib *library) GetAll() []GameMetadata {
 func (lib *library) FindGameByName(name string) GameMetadata {
 	var game GameMetadata
 	if val, ok := lib.games[name]; ok {
-		val.Path = filepath.Join(lib.config.path, val.Path)
-		game = val
+		val.Base = lib.config.path
+		return val
 	}
 	return game
 }

pkg/games/game_library_test.go

@@ -1,7 +1,6 @@
 package games
 
 import (
-	"reflect"
 	"testing"
 )
 
@@ -31,7 +30,19 @@ func TestLibraryScan(t *testing.T) {
 			return meta.Name
 		})
 
-		if !reflect.DeepEqual(test.expected, list) {
+		// ^2 complexity (;
+		all := true
+		for _, expect := range test.expected {
+			found := false
+			for _, game := range list {
+				if game == expect {
+					found = true
+					break
+				}
+			}
+			all = all && found
+		}
+		if !all {
 			t.Errorf("Test fail for dir %v with %v != %v", test.directory, list, test.expected)
 		}
 	}

pkg/worker/internalhandlers.go

@@ -110,28 +110,21 @@ func (h *Handler) handleGameStart() cws.PacketHandler {
 		log.Println("Received a start request from coordinator")
 		session := h.getSession(resp.SessionID)
 		if session == nil {
-			log.Printf("Error: No session for ID: %s\n", resp.SessionID)
+			log.Printf("error: no session with id: %s", resp.SessionID)
 			return cws.EmptyPacket
 		}
 
-		peerconnection := session.peerconnection
 		// TODO: Standardize for all types of packet. Make WSPacket generic
-		startPacket := api.GameStartCall{}
-		if err := startPacket.From(resp.Data); err != nil {
+		rom := api.GameStartCall{}
+		if err := rom.From(resp.Data); err != nil {
 			return cws.EmptyPacket
 		}
-		gameMeta := games.GameMetadata{
-			Name: startPacket.Name,
-			Type: startPacket.Type,
-			Path: startPacket.Path,
-		}
-
-		room := h.startGameHandler(gameMeta, resp.RoomID, resp.PlayerIndex, peerconnection)
+		game := games.GameMetadata{Name: rom.Name, Type: rom.Type, Base: rom.Base, Path: rom.Path}
+		room := h.startGameHandler(game, resp.RoomID, resp.PlayerIndex, session.peerconnection)
 		session.RoomID = room.ID
-		// TODO: can data race
+		// TODO: can data race (and it does)
 		h.rooms[room.ID] = room
-
-		return cws.WSPacket{ID: "start", RoomID: room.ID}
+		return cws.WSPacket{ID: api.GameStart, RoomID: room.ID}
 	}
 }
 

pkg/worker/room/room.go

@@ -10,6 +10,7 @@ import (
 	"math"
 	"net"
 	"os"
+	"path/filepath"
 	"sync"
 
 	"github.com/giongto35/cloud-game/v2/pkg/config/worker"
@@ -157,8 +158,8 @@ func NewRoom(roomID string, game games.GameMetadata, onlineStorage *storage.Clie
 		// If not then load room or create room from local.
 		log.Printf("Room %s started. GameName: %s, WithGame: %t", roomID, game.Name, cfg.Encoder.WithoutGame)
 
-		// Spawn new emulator based on gameName and plug-in all channels
-		emuName := cfg.Emulator.GetEmulatorByRom(game.Type)
+		// Spawn new emulator and plug-in all channels
+		emuName := cfg.Emulator.GetEmulator(game.Type, game.Path)
 		libretroConfig := cfg.Emulator.GetLibretroCoreConfig(emuName)
 
 		if cfg.Encoder.WithoutGame {
@@ -176,7 +177,7 @@ func NewRoom(roomID string, game games.GameMetadata, onlineStorage *storage.Clie
 			room.audioChannel = audioChannel
 		}
 
-		gameMeta := room.director.LoadMeta(game.Path)
+		gameMeta := room.director.LoadMeta(filepath.Join(game.Base, game.Path))
 
 		// nwidth, nheight are the WebRTC output size
 		var nwidth, nheight int