// ================================================================================================
// DTFluxRequestManager.cpp - Implémentation du gestionnaire de requêtes
// ================================================================================================

#include "DTFluxQueuedManager.h"

#include "DTFluxAsyncParser.h"
#include "DTFluxNetworkModule.h"
#include "Struct/DTFluxServerResponseStruct.h"
#include "Struct/DTFluxRequestStructs.h"
#include "JsonObjectConverter.h"

bool FDTFluxTrackedRequest::HasTimedOut() const
{
	if (State != EDTFluxRequestState::Pending && State != EDTFluxRequestState::Sent)
		return false;
	return (FDateTime::Now() - CreatedAt).GetTotalSeconds() > Config.TimeoutSeconds;
}

bool FDTFluxTrackedRequest::CanRetry() const
{
	return CurrentRetries < Config.MaxRetries &&
		(State == EDTFluxRequestState::Failed || State == EDTFluxRequestState::TimedOut);
}


float FDTFluxTrackedRequest::GetRetryDelay() const
{
	return FMath::Pow(Config.RetryBackoffMultiplier, CurrentRetries);
}

bool FDTFluxTrackedRequest::Matches(EDTFluxApiDataType InType, int32 InContestId, int32 InStageId,
                                    int32 InSplitId) const
{
	return RequestType == InType && ContestId == InContestId && StageId == InStageId && SplitId == InSplitId;
}


void FDTFluxTrackedRequest::SetRawResponse(const FString& RawData)
{
	RawResponseData = RawData;
	ParsedResponse.Reset();
	bIsResponseParsed = false;
}

FString FDTFluxTrackedRequest::Serialize() const
{
	FString JSONString;
	switch (RequestType)
	{
	case EDTFluxApiDataType::RaceData:
		{
			FDTFluxRaceDataRequest RaceData;
			FJsonObjectConverter::UStructToJsonObjectString(RaceData, JSONString);
			break;
		}
	case EDTFluxApiDataType::TeamList:
		{
			const FDTFluxTeamListRequest TeamList;
			FJsonObjectConverter::UStructToJsonObjectString(TeamList, JSONString);
			break;
		}
	case EDTFluxApiDataType::ContestRanking:
		{
			FDTFluxContestRankingRequest ContestRanking(ContestId);
			FJsonObjectConverter::UStructToJsonObjectString(ContestRanking, JSONString);
			break;
		}
	case EDTFluxApiDataType::StageRanking:
		{
			FDTFluxStageRankingRequest StageRanking(ContestId, StageId);
			FJsonObjectConverter::UStructToJsonObjectString(StageRanking, JSONString);
			break;
		}
	case EDTFluxApiDataType::SplitRanking:
		{
			FDTFluxSplitRankingRequest SplitRanking(ContestId, StageId, SplitId);
			FJsonObjectConverter::UStructToJsonObjectString(SplitRanking, JSONString);
			break;
		}
	default:
		JSONString = "";
		break;
	}
	return JSONString;
}

FDTFluxQueuedRequestManager::FDTFluxQueuedRequestManager()
{
	AsyncParser = MakeUnique<FDTFluxAsyncParser>();
	UE_LOG(logDTFluxNetwork, Verbose, TEXT("RequestManager created"));
}

FDTFluxQueuedRequestManager::~FDTFluxQueuedRequestManager()
{
	Shutdown();
	UE_LOG(logDTFluxNetwork, Verbose, TEXT("RequestManager destroyed"));
}

void FDTFluxQueuedRequestManager::Initialize(const FDTFluxRequestConfig& InDefaultConfig)
{
	if (bIsInitialized.load())
	{
		UE_LOG(logDTFluxNetwork, Warning, TEXT("RequestManager already initialized"));
		return;
	}

	DefaultConfig = InDefaultConfig;
	bIsInitialized.store(true);

	UE_LOG(logDTFluxNetwork, Log, TEXT("RequestManager initialized with timeout=%.1fs"),
	       DefaultConfig.TimeoutSeconds);
}

void FDTFluxQueuedRequestManager::Shutdown()
{
	if (!bIsInitialized.load())
		return;

	bIsInitialized.store(false);
	// Nettoyer toutes les données
	{
		FScopeLock RequestsLock_Local(&RequestsLock);
		FScopeLock CallbacksLock_Local(&CallbacksLock);

		AllRequests.Empty();
		SuccessCallbacks.Empty();
		ErrorCallbacks.Empty();
	}

	UE_LOG(logDTFluxNetwork, Log, TEXT("RequestManager shutdown"));
}

FGuid FDTFluxQueuedRequestManager::CreateTrackedRequest(
	EDTFluxApiDataType RequestType,
	int32 ContestId,
	int32 StageId,
	int32 SplitId,
	const FDTFluxRequestConfig& CustomConfig)
{
	if (!bIsInitialized.load())
	{
		UE_LOG(logDTFluxNetwork, Error, TEXT("RequestManager not initialized"));
		return FGuid();
	}
	// Create new request
	auto NewRequest = MakeShared<FDTFluxTrackedRequest>();
	NewRequest->RequestType = RequestType;
	NewRequest->ContestId = ContestId;
	NewRequest->StageId = StageId;
	NewRequest->SplitId = SplitId;
	NewRequest->Config = (CustomConfig.TimeoutSeconds > 0) ? CustomConfig : DefaultConfig;

	FGuid RequestId = NewRequest->RequestId;

	{
		FScopeLock Lock(&RequestsLock);
		AllRequests.Add(RequestId, NewRequest);
		TotalRequests++;
	}
	UE_LOG(logDTFluxNetwork, Log, TEXT("Created tracked request %s: Type=%s, Contest=%d, Stage=%d, Split=%d"),
	       *RequestId.ToString(), *UEnum::GetValueAsString(RequestType), ContestId, StageId, SplitId);
	return RequestId;
}

FGuid FDTFluxQueuedRequestManager::CreateTrackedRequestWithCallbacks(
	EDTFluxApiDataType RequestType,
	int32 ContestId,
	int32 StageId,
	int32 SplitId,
	FOnDTFluxRequestSuccess OnSuccess,
	FOnDTFluxRequestError OnError,
	const FDTFluxRequestConfig& CustomConfig)
{
	FGuid RequestId = CreateTrackedRequest(RequestType, ContestId, StageId, SplitId, CustomConfig);

	if (RequestId.IsValid())
	{
		FScopeLock Lock(&CallbacksLock);

		if (OnSuccess.IsBound())
		{
			SuccessCallbacks.Add(RequestId, OnSuccess);
		}
		if (OnError.IsBound())
		{
			ErrorCallbacks.Add(RequestId, OnError);
		}
	}

	return RequestId;
}

bool FDTFluxQueuedRequestManager::MarkRequestAsSent(const FGuid& RequestId)
{
	FScopeLock Lock(&RequestsLock);

	if (TSharedPtr<FDTFluxTrackedRequest>* RequestPtr = AllRequests.Find(RequestId))
	{
		TSharedPtr<FDTFluxTrackedRequest> Request = *RequestPtr;
		Request->SentAt = FDateTime::Now();
		Request->LastAttemptTime = FDateTime::Now();
		ChangeRequestState(Request, EDTFluxRequestState::Sent);
		return true;
	}

	return false;
}

bool FDTFluxQueuedRequestManager::CompleteRequest(const FGuid& RequestId, const FString& RawResponseData,
                                                  bool bUseAsyncParsing)
{
	UE_LOG(logDTFluxNetwork, Log, TEXT("FDTFluxQueuedRequestManager::CompleteRequest() %s"), *RequestId.ToString());
	TSharedPtr<FDTFluxTrackedRequest> Request;
	{
		FScopeLock Lock(&RequestsLock);
		if (TSharedPtr<FDTFluxTrackedRequest>* RequestPtr = AllRequests.Find(RequestId))
		{
			Request = *RequestPtr;
		}
	}
	if (!Request.IsValid())
	{
		UE_LOG(logDTFluxNetwork, Warning, TEXT("Request %s not found"), *RequestId.ToString());
		return false;
	}

	// Store RawResponse
	Request->SetRawResponse(RawResponseData);
	Request->CompletedAt = FDateTime::Now();
	UE_LOG(logDTFluxNetwork, Log, TEXT("Request %s completed at %s"), *RequestId.ToString(),
	       *Request->CompletedAt.ToString());
	// Decide to parse based upon config
	bool bHasCallbacks = false;
	{
		FScopeLock Lock(&CallbacksLock);
		bHasCallbacks = SuccessCallbacks.Contains(RequestId) || ErrorCallbacks.Contains(RequestId);
	}

	if (bHasCallbacks && bUseAsyncParsing && !RawResponseData.IsEmpty())
	{
		UE_LOG(logDTFluxNetwork, Log,
		       TEXT("Request %s [bHasCallbacks=%s], [bUseAsyncParsing=%s], [bIsRawResponseEmpty=%s]"),
		       *RequestId.ToString(),
		       bHasCallbacks ? TEXT("true") : TEXT("false"), bUseAsyncParsing ? TEXT("true") : TEXT("false"),
		       RawResponseData.IsEmpty() ? TEXT("true") : TEXT("false"));

		// Async parsing for Cb
		FOnParsingCompleted OnCompleted = FOnParsingCompleted::CreateRaw(
			this, &FDTFluxQueuedRequestManager::OnParsingCompleted
		);

		FOnParsingFailed OnFailed = FOnParsingFailed::CreateRaw(
			this, &FDTFluxQueuedRequestManager::OnParsingFailed
		);
		// Maybe send to parser in another place
		AsyncParser->ParseResponseAsync(RequestId, RawResponseData, OnCompleted, OnFailed);
		UE_LOG(logDTFluxNetwork, Verbose, TEXT("Started async parsing for request %s"), *RequestId.ToString());
		return true;
	}
	else
	{
		UE_LOG(logDTFluxNetwork, Warning, TEXT("request %s completed without sync"), *RequestId.ToString());
		// Compléter immédiatement sans parsing ou avec parsing sync
		EDTFluxRequestState NewState = EDTFluxRequestState::Completed;
		ChangeRequestState(Request, NewState);
		// Déclencher les callbacks avec les données brutes
		TriggerCallbacks(*Request);
		CleanupCallbacks(RequestId);
		return true;
	}
}

/**
 * @todo Check protocol errors ???
 * @param RequestId 
 * @param ErrorMessage 
 * @return 
 */
bool FDTFluxQueuedRequestManager::FailRequest(const FGuid& RequestId, const FString& ErrorMessage)
{
	TSharedPtr<FDTFluxTrackedRequest> Request;

	{
		FScopeLock Lock(&RequestsLock);
		if (TSharedPtr<FDTFluxTrackedRequest>* RequestPtr = AllRequests.Find(RequestId))
		{
			Request = *RequestPtr;
		}
	}

	if (!Request.IsValid())
	{
		return false;
	}

	Request->LastErrorMessage = ErrorMessage;
	ChangeRequestState(Request, EDTFluxRequestState::Failed);

	TriggerCallbacks(*Request);
	CleanupCallbacks(RequestId);

	UE_LOG(logDTFluxNetwork, Error, TEXT("Failed request %s: %s"), *RequestId.ToString(), *ErrorMessage);
	return true;
}

bool FDTFluxQueuedRequestManager::RetryRequest(const FGuid& RequestId)
{
	TSharedPtr<FDTFluxTrackedRequest> Request;

	{
		FScopeLock Lock(&RequestsLock);
		if (TSharedPtr<FDTFluxTrackedRequest>* RequestPtr = AllRequests.Find(RequestId))
		{
			Request = *RequestPtr;
		}
	}

	if (!Request.IsValid() || !Request->CanRetry())
	{
		return false;
	}

	Request->CurrentRetries++;
	Request->LastAttemptTime = FDateTime::Now();
	ChangeRequestState(Request, EDTFluxRequestState::Retrying);

	UE_LOG(logDTFluxNetwork, Log, TEXT("Retrying request %s (attempt %d/%d)"),
	       *RequestId.ToString(), Request->CurrentRetries, Request->Config.MaxRetries);

	return true;
}

bool FDTFluxQueuedRequestManager::FindPendingRequest(
	FGuid& OutRequestId,
	EDTFluxApiDataType RequestType,
	int32 ContestId,
	int32 StageId,
	int32 SplitId) const
{
	FScopeLock Lock(&RequestsLock);

	for (const auto& [RequestId, Request] : AllRequests)
	{
		if ((Request->State == EDTFluxRequestState::Pending || Request->State == EDTFluxRequestState::Sent) &&
			Request->Matches(RequestType, ContestId, StageId, SplitId))
		{
			OutRequestId = RequestId;
			return true;
		}
	}

	return false;
}

// === ACCESSEURS ===

bool FDTFluxQueuedRequestManager::GetRequest(const FGuid& RequestId, FDTFluxTrackedRequest& OutRequest) const
{
	FScopeLock Lock(&RequestsLock);

	if (const TSharedPtr<FDTFluxTrackedRequest>* RequestPtr = AllRequests.Find(RequestId))
	{
		OutRequest = **RequestPtr;
		return true;
	}

	return false;
}

const FDTFluxTrackedRequest* FDTFluxQueuedRequestManager::GetRequestPtr(const FGuid& RequestId) const
{
	FScopeLock Lock(&RequestsLock);

	if (const TSharedPtr<FDTFluxTrackedRequest>* RequestPtr = AllRequests.Find(RequestId))
	{
		return RequestPtr->Get();
	}

	return nullptr;
}

TArray<FDTFluxTrackedRequest> FDTFluxQueuedRequestManager::GetRequestsByState(EDTFluxRequestState State) const
{
	FScopeLock Lock(&RequestsLock);

	TArray<FDTFluxTrackedRequest> Results;

	for (const auto& [RequestId, Request] : AllRequests)
	{
		if (Request->State == State)
		{
			Results.Add(*Request);
		}
	}

	return Results;
}

int32 FDTFluxQueuedRequestManager::GetRequestCount(EDTFluxRequestState State) const
{
	FScopeLock Lock(&RequestsLock);

	int32 Count = 0;

	for (const auto& [RequestId, Request] : AllRequests)
	{
		if (Request->State == State)
		{
			Count++;
		}
	}

	return Count;
}

FDTFluxQueuedRequestManager::FRequestStatistics FDTFluxQueuedRequestManager::GetStatistics() const
{
	FScopeLock RequestsLock_Local(&RequestsLock);
	FScopeLock MetricsLock_Local(&MetricsLock);

	FRequestStatistics Stats;

	for (const auto& [RequestId, Request] : AllRequests)
	{
		switch (Request->State)
		{
		case EDTFluxRequestState::Pending:
		case EDTFluxRequestState::Sent:
		case EDTFluxRequestState::Retrying:
			Stats.Pending++;
			break;
		case EDTFluxRequestState::Completed:
			Stats.Completed++;
			break;
		case EDTFluxRequestState::Failed:
		case EDTFluxRequestState::TimedOut:
			Stats.Failed++;
			break;
		}
	}

	Stats.TotalRequests = TotalRequests;
	return Stats;
}

// === NETTOYAGE ===
int32 FDTFluxQueuedRequestManager::CleanupCompletedRequests(float OlderThanSeconds)
{
	FScopeLock Lock(&RequestsLock);

	TArray<FGuid> OldRequests;
	const FDateTime Threshold = FDateTime::Now() - FTimespan::FromSeconds(OlderThanSeconds);

	for (const auto& [RequestId, Request] : AllRequests)
	{
		if ((Request->State == EDTFluxRequestState::Completed || Request->State == EDTFluxRequestState::Failed ||
			Request->State == EDTFluxRequestState::TimedOut) && Request->CompletedAt < Threshold)
		{
			OldRequests.Add(RequestId);
		}
	}

	for (const FGuid& RequestId : OldRequests)
	{
		AllRequests.Remove(RequestId);
	}

	return OldRequests.Num();
}

void FDTFluxQueuedRequestManager::ClearAllRequests()
{
	FScopeLock RequestsLock_Local(&RequestsLock);
	FScopeLock CallbacksLock_Local(&CallbacksLock);

	AllRequests.Empty();
	SuccessCallbacks.Empty();
	ErrorCallbacks.Empty();

	UE_LOG(logDTFluxNetwork, Log, TEXT("Cleared all requests"));
}

void FDTFluxQueuedRequestManager::Tick(float DeltaTime)
{
	if (!bIsInitialized.load())
		return;

	// Mise à jour des timers
	TimeSinceLastTimeoutCheck += DeltaTime;
	TimeSinceLastRetryCheck += DeltaTime;

	// Vérifier les timeouts
	if (TimeSinceLastTimeoutCheck >= TimeoutCheckInterval)
	{
		ProcessTimeouts();
		TimeSinceLastTimeoutCheck = 0.0f;
	}

	// Vérifier les retries
	if (TimeSinceLastRetryCheck >= RetryCheckInterval)
	{
		ProcessRetries();
		TimeSinceLastRetryCheck = 0.0f;
	}
}

void FDTFluxQueuedRequestManager::ChangeRequestState(TSharedPtr<FDTFluxTrackedRequest> Request,
                                                     EDTFluxRequestState NewState)
{
	if (!Request.IsValid())
		return;

	const EDTFluxRequestState OldState = Request->State;
	Request->State = NewState;

	// Déclencher l'événement de changement d'état
	OnRequestStateChanged.Broadcast(Request->RequestId, NewState);

	UE_LOG(logDTFluxNetwork, VeryVerbose, TEXT("DTFluxQueuedRequestManager: Request %s state changed from %s to %s"),
	       *Request->RequestId.ToString(),
	       *UEnum::GetValueAsString(OldState),
	       *UEnum::GetValueAsString(NewState));
}

void FDTFluxQueuedRequestManager::ProcessTimeouts()
{
	FScopeLock Lock(&RequestsLock);

	TArray<TSharedPtr<FDTFluxTrackedRequest>> TimedOutRequests;

	for (const auto& Pair : AllRequests)
	{
		const auto& Request = Pair.Value;
		if (Request->HasTimedOut())
		{
			TimedOutRequests.Add(Request);
		}
	}

	for (const auto& Request : TimedOutRequests)
	{
		Request->LastErrorMessage = FString::Printf(
			TEXT("Request timed out after %.1f seconds"), Request->Config.TimeoutSeconds);

		if (Request->CanRetry())
		{
			Request->CurrentRetries++;
			ChangeRequestState(Request, EDTFluxRequestState::Retrying);
		}
		else
		{
			ChangeRequestState(Request, EDTFluxRequestState::TimedOut);
			TriggerCallbacks(*Request);
			OnRequestFailed.Broadcast(*Request);
		}
	}
}

void FDTFluxQueuedRequestManager::ProcessRetries()
{
	FScopeLock Lock(&RequestsLock);

	const FDateTime Now = FDateTime::Now();
	TArray<TSharedPtr<FDTFluxTrackedRequest>> ReadyToRetry;

	for (const auto& Pair : AllRequests)
	{
		const auto& Request = Pair.Value;
		if (Request->State == EDTFluxRequestState::Retrying)
		{
			const float ElapsedSinceLastAttempt = (Now - Request->LastAttemptTime).GetTotalSeconds();
			if (ElapsedSinceLastAttempt >= Request->GetRetryDelay())
			{
				ReadyToRetry.Add(Request);
			}
		}
	}

	for (const auto& Request : ReadyToRetry)
	{
		Request->LastAttemptTime = Now;
		ChangeRequestState(Request, EDTFluxRequestState::Pending);
	}
}

void FDTFluxQueuedRequestManager::TriggerCallbacks(const FDTFluxTrackedRequest& Request)
{
	FScopeLock Lock(&CallbacksLock);

	if (Request.State == EDTFluxRequestState::Completed)
	{
		// Success Cb
		const FOnDTFluxRequestSuccess* SuccessCallback = SuccessCallbacks.Find(Request.RequestId);
		if (SuccessCallback && SuccessCallback->IsBound())
		{
			SuccessCallback->Execute(Request);
		}
	}
	else if (Request.State == EDTFluxRequestState::Failed || Request.State == EDTFluxRequestState::TimedOut)
	{
		// Error Cb
		const FOnDTFluxRequestError* ErrorCallback = ErrorCallbacks.Find(Request.RequestId);
		if (ErrorCallback && ErrorCallback->IsBound())
		{
			ErrorCallback->Execute(Request, Request.LastErrorMessage);
		}
	}
}

void FDTFluxQueuedRequestManager::CleanupCallbacks(const FGuid& RequestId)
{
	FScopeLock Lock(&CallbacksLock);
	SuccessCallbacks.Remove(RequestId);
	ErrorCallbacks.Remove(RequestId);
}

void FDTFluxQueuedRequestManager::OnParsingCompleted(const FGuid& RequestId,
                                                     TSharedPtr<FDTFluxServerResponse> ParsedResponse, bool bSuccess)
{
	UE_LOG(logDTFluxNetwork, Log, TEXT("FDTFluxQueuedRequestManager::OnParsingCompleted() request %s"),
	       *RequestId.ToString())
	TSharedPtr<FDTFluxTrackedRequest> Request;
	{
		FScopeLock Lock(&RequestsLock);

		auto* RequestPtr = AllRequests.Find(RequestId);
		if (!RequestPtr || !RequestPtr->IsValid())
		{
			UE_LOG(logDTFluxNetwork, Error,
			       TEXT(
				       "DTFluxQueuedRequestManager::OnParsingCompleted() RequestId%s [InvalidRequestId=%s], [RequestPtrValid=%s]"
			       ),
			       *RequestId.ToString(), RequestPtr ? TEXT("true") : TEXT("false"),
			       RequestPtr->IsValid() ? TEXT("true") : TEXT("false"));
			return;
		}

		Request = *RequestPtr;
	}

	if (bSuccess && ParsedResponse.IsValid())
	{
		Request->ParsedResponse = ParsedResponse;
		Request->bIsResponseParsed = true;
		EDTFluxRequestState NewState = EDTFluxRequestState::Completed;

		ChangeRequestState(Request, NewState);
		UE_LOG(logDTFluxNetwork, Log,
		       TEXT("DTFluxQueuedRequestManager: Async parsing completed for request %s"),
		       *RequestId.ToString());
	}
	else
	{
		Request->LastErrorMessage = TEXT("Async parsing failed");
		ChangeRequestState(Request, EDTFluxRequestState::Failed);

		UE_LOG(logDTFluxNetwork, Error, TEXT("Async parsing failed for request %s"), *RequestId.ToString());
	}
	TriggerCallbacks(*Request);
	CleanupCallbacks(RequestId);
}

void FDTFluxQueuedRequestManager::OnParsingFailed(const FGuid& RequestId, const FString& ErrorMessage)
{
	UE_LOG(logDTFluxNetwork, Error, TEXT("DTFluxQueuedRequestManager: Async parsing failed for request %s: %s"),
	       *RequestId.ToString(),
	       *ErrorMessage);
	FailRequest(RequestId, FString::Printf(TEXT("Parsing failed: %s"), *ErrorMessage));
}