Step 2: Integrate Rivet

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/GameModeBase.h"

#include "RivetClient.h"
#include "RivetPlayer.h"

#include "MyProjectGameMode.generated.h"

UCLASS(minimalapi)
class AMyProjectGameMode : public AGameModeBase
{
	GENERATED_BODY()

public:
	AMyProjectGameMode();

	/** Map of player IDs to the associated Rivet player information. */
	UPROPERTY()
	TArray<URivetPlayer*> RivetPlayers;

	UPROPERTY()
	FString RivetToken;

	UPROPERTY()
	URivetClient* Rivet;

	void InitGame(const FString& MapName, const FString& Options, FString& ErrorMessage) override;
	APlayerController* Login(UPlayer* NewPlayer, ENetRole InRemoteRole, const FString& Portal, const FString& Options, const FUniqueNetIdRepl& UniqueId, FString& ErrorMessage) override;
	void Logout(AController* Exiting) override;
};

#include "MyProjectGameMode.h"
#include "MyProjectCharacter.h"
#include "UObject/ConstructorHelpers.h"
#include "GameFramework/GameSession.h"
#include "GameFramework/PlayerState.h"
#include "GenericPlatform/GenericPlatformMisc.h"
#include "Kismet/GameplayStatics.h" 

#include "MatchmakerPlayersConnected.h"
#include "MatchmakerPlayersDisconnected.h"
#include "MatchmakerLobbiesReady.h"

AMyProjectGameMode::AMyProjectGameMode()
{
	Rivet = NewObject<URivetClient>();

	// set default pawn class to our Blueprinted character
	static ConstructorHelpers::FClassFinder<APawn> PlayerPawnBPClass(TEXT("/Game/ThirdPerson/Blueprints/BP_ThirdPersonCharacter"));
	if (PlayerPawnBPClass.Class != NULL)
	{
		DefaultPawnClass = PlayerPawnBPClass.Class;
	}
}

void AMyProjectGameMode::InitGame(const FString& MapName, const FString& Options, FString& ErrorMessage)
{
	Super::InitGame(MapName, Options, ErrorMessage);

	// Set lobby as ready
	FMatchmakerLobbiesReadyRequest Req;
	FMatchmakerLobbiesReadyDelegate OnSuccess;
	FRivetHttpRequestFailDelegate OnFailure;
	Rivet->MatchmakerLobbiesReady(Req, OnSuccess, OnFailure);
}

APlayerController* AMyProjectGameMode::Login(UPlayer *NewPlayer, ENetRole InRemoteRole, const FString &Portal, const FString &Options, const FUniqueNetIdRepl &UniqueId, FString &ErrorMessage)
{
	UE_LOG(LogTemp, Warning, TEXT("Login: %s"), *Options);
	
	// Read player token option
	auto PlayerToken = UGameplayStatics::ParseOption(Options, "PlayerToken");
	if (PlayerToken.IsEmpty())
	{
		ErrorMessage = TEXT("No PlayerToken option provided");
		return nullptr;
	}
	UE_LOG(LogTemp, Warning, TEXT("Palyer token: %s"), *PlayerToken);
	
	// Create player
	auto PlayerController = Super::Login(NewPlayer, InRemoteRole, Portal, Options, UniqueId, ErrorMessage);
	if (!ErrorMessage.IsEmpty()) {
		UE_LOG(LogTemp, Warning, TEXT("Error connecting player: %s"), *ErrorMessage);
		return nullptr;
	}

	// Save the Rivet player information
	auto RivetPlayer = NewObject<URivetPlayer>();
	RivetPlayer->PlayerId = PlayerController->PlayerState->GetPlayerId();
	RivetPlayer->PlayerController = PlayerController;
	RivetPlayer->PlayerToken = PlayerToken;
	RivetPlayers.Add(RivetPlayer);

	// Send connection request
	FMatchmakerPlayersConnectedRequest Req;
	Req.PlayerToken = PlayerToken;

	FMatchmakerPlayersConnectedDelegate OnSuccess;
	OnSuccess.BindDynamic(RivetPlayer, &URivetPlayer::OnPlayerConnectedSuccess);
	
	FRivetHttpRequestFailDelegate OnFailure;
	OnFailure.BindDynamic(RivetPlayer, &URivetPlayer::OnPlayerConnectedFailure);

	Rivet->MatchmakerPlayersConnected(Req, OnSuccess, OnFailure);

	return PlayerController;
}

void AMyProjectGameMode::Logout(AController *Exiting)
{
	auto PlayerId = Exiting->PlayerState->GetPlayerId();
	auto RivetPlayer = *RivetPlayers.FindByPredicate([&](auto X) { return X->PlayerId == PlayerId; });
	if (RivetPlayer == nullptr) {
		UE_LOG(LogTemp, Error, TEXT("Could not find RivetPlayer to disconnect for player %d"), PlayerId);
		return;
	}

	UE_LOG(LogTemp, Error, TEXT("Logging out player: %d %s"), PlayerId, *RivetPlayer->PlayerToken);

	// Send connection request
	FMatchmakerPlayersDisconnectedRequest Req;
	Req.PlayerToken = RivetPlayer->PlayerToken;

	FMatchmakerPlayersDisconnectedDelegate OnSuccess;
	OnSuccess.BindDynamic(RivetPlayer, &URivetPlayer::OnPlayerDisconnectedSuccess);
	
	FRivetHttpRequestFailDelegate OnFailure;
	OnFailure.BindDynamic(RivetPlayer, &URivetPlayer::OnPlayerDisconnectedFailure);

	Rivet->MatchmakerPlayersDisconnected(Req, OnSuccess, OnFailure);
}