From c07f862ef2d483d0140fe3113a6fe123369ec5a6 Mon Sep 17 00:00:00 2001
From: Flyinghead <raphael.jean@gmail.com>
Date: Tue, 16 May 2023 09:43:21 +0200
Subject: [PATCH] ggpo: exchange vf4 cards when starting the session

---
 core/hw/maple/maple_cfg.h    |  2 ++
 core/hw/maple/maple_devs.cpp | 52 +++++++++++++++++++++++++++++++-----
 core/network/ggpo.cpp        | 26 +++++++++++++++++-
 3 files changed, 72 insertions(+), 8 deletions(-)

diff --git a/core/hw/maple/maple_cfg.h b/core/hw/maple/maple_cfg.h
index 949080be5..ccd8b1cdd 100644
--- a/core/hw/maple/maple_cfg.h
+++ b/core/hw/maple/maple_cfg.h
@@ -108,3 +108,5 @@ void mcfg_DeserializeDevices(Deserializer& deser);
 bool maple_atomiswave_coin_chute(int slot);
 void push_vmu_screen(int bus_id, int bus_port, u8* buffer);
 void insertRfidCard(int playerNum);
+const u8 *getRfidCardData(int playerNum);
+void setRfidCardData(int playerNum, u8 *data);
diff --git a/core/hw/maple/maple_devs.cpp b/core/hw/maple/maple_devs.cpp
index edad7e409..a00dd2488 100755
--- a/core/hw/maple/maple_devs.cpp
+++ b/core/hw/maple/maple_devs.cpp
@@ -6,6 +6,7 @@
 #include "oslib/audiostream.h"
 #include "oslib/oslib.h"
 #include "hw/aica/sgc_if.h"
+#include "cfg/option.h"
 #include <zlib.h>
 #include <time.h>
 
@@ -1499,14 +1500,24 @@ struct RFIDReaderWriter : maple_base
 	void OnSetup() override
 	{
 		memset(cardData, 0, sizeof(cardData));
+		transientData = false;
 	}
 
-	std::string getCardPath() const {
-		return hostfs::getArcadeFlashPath() + "-p" + std::to_string(player_num + 1) + ".card";
-	}
-
-	bool loadCard()
+	std::string getCardPath() const
 	{
+		int playerNum;
+		if (config::GGPOEnable && !config::ActAsServer)
+			// Always load P1 card with GGPO to be consistent with P1 inputs being used
+			playerNum = 1;
+		else
+			playerNum = player_num + 1;
+		return hostfs::getArcadeFlashPath() + "-p" + std::to_string(playerNum) + ".card";
+	}
+
+	void loadCard()
+	{
+		if (transientData)
+			return;
 		std::string path = getCardPath();
 		FILE *fp = nowide::fopen(path.c_str(), "rb");
 		if (fp == nullptr)
@@ -1538,12 +1549,12 @@ struct RFIDReaderWriter : maple_base
 				WARN_LOG(NAOMI, "Truncated or empty card file: %s" ,path.c_str());
 			fclose(fp);
 		}
-
-		return true;
 	}
 
 	void saveCard() const
 	{
+		if (transientData)
+			return;
 		std::string path = getCardPath();
 		FILE *fp = nowide::fopen(path.c_str(), "wb");
 		if (fp == nullptr)
@@ -1579,10 +1590,21 @@ struct RFIDReaderWriter : maple_base
 		loadCard();
 	}
 
+	const u8 *getCardData() {
+		loadCard();
+		return cardData;
+	}
+
+	void setCardData(u8 *data) {
+		memcpy(cardData, data, sizeof(cardData));
+		transientData = true;
+	}
+
 	u8 cardData[128];
 	bool d4Seen = false;
 	bool cardInserted = false;
 	bool cardLocked = false;
+	bool transientData = false;
 };
 
 void insertRfidCard(int playerNum)
@@ -1592,6 +1614,22 @@ void insertRfidCard(int playerNum)
 		((RFIDReaderWriter *)mapleDev)->insertCard();
 }
 
+void setRfidCardData(int playerNum, u8 *data)
+{
+	maple_device *mapleDev = MapleDevices[1 + playerNum][5];
+	if (mapleDev != nullptr && mapleDev->get_device_type() == MDT_RFIDReaderWriter)
+		((RFIDReaderWriter *)mapleDev)->setCardData(data);
+}
+
+const u8 *getRfidCardData(int playerNum)
+{
+	maple_device *mapleDev = MapleDevices[1 + playerNum][5];
+	if (mapleDev != nullptr && mapleDev->get_device_type() == MDT_RFIDReaderWriter)
+		return ((RFIDReaderWriter *)mapleDev)->getCardData();
+	else
+		return nullptr;
+}
+
 maple_device* maple_Create(MapleDeviceType type)
 {
 	maple_device* rv=0;
diff --git a/core/network/ggpo.cpp b/core/network/ggpo.cpp
index 0652ae1e8..344ae1dc7 100644
--- a/core/network/ggpo.cpp
+++ b/core/network/ggpo.cpp
@@ -174,13 +174,18 @@ static_assert(BTN_TRIGGER_RIGHT < (1 << 20));
 struct GameEvent
 {
 	enum : char {
-		Chat
+		Chat,
+		VF4Card
 	} type;
 	union {
 		struct {
 			u8 playerNum;
 			char message[512 - sizeof(playerNum) - sizeof(type)];
 		} chat;
+		struct {
+			u8 playerNum;
+			u8 data[128];
+		} card;
 	} u;
 
 	constexpr static int chatMessageLen(int len) { return len - sizeof(u.chat.playerNum) - sizeof(type); }
@@ -451,6 +456,10 @@ static void on_message(u8 *msg, int len)
 			chatCallback(event->u.chat.playerNum, std::string(event->u.chat.message, GameEvent::chatMessageLen(len)));
 		break;
 
+	case GameEvent::VF4Card:
+		setRfidCardData(event->u.card.playerNum, event->u.card.data);
+		break;
+
 	default:
 		WARN_LOG(NETWORK, "Unknown app message type %d", event->type);
 		break;
@@ -817,6 +826,21 @@ std::future<bool> startNetwork()
 			getInput(state);
 		}
 #endif
+		if (active() && (settings.content.gameId == "VIRTUA FIGHTER 4 JAPAN"
+				|| settings.content.gameId == "VF4 EVOLUTION JAPAN"
+				|| settings.content.gameId == "VF4 FINAL TUNED JAPAN"))
+		{
+			// Send the local P1 card
+			const u8 *cardData = getRfidCardData(0);
+			if (cardData != nullptr)
+			{
+				GameEvent event;
+				event.type = GameEvent::VF4Card;
+				event.u.card.playerNum = config::ActAsServer ? 0 : 1;
+				memcpy(event.u.card.data, cardData, sizeof(event.u.card.data));
+				ggpo_send_message(ggpoSession, &event, sizeof(event.type) + sizeof(event.u.card), true);
+			}
+		}
 		emu.setNetworkState(active());
 		return active();
 	});