// Copyright Epic Games, Inc. All Rights Reserved.

#include "httpclientcpr.h"

#include <zencore/compactbinary.h>
#include <zencore/compactbinarybuilder.h>
#include <zencore/compactbinarypackage.h>
#include <zencore/compactbinaryutil.h>
#include <zencore/compress.h>
#include <zencore/iobuffer.h>
#include <zencore/iohash.h>
#include <zencore/session.h>
#include <zencore/stream.h>
#include <zenhttp/packageformat.h>

namespace zen {

HttpClientBase*
CreateCprHttpClient(std::string_view BaseUri, const HttpClientSettings& ConnectionSettings)
{
	return new CprHttpClient(BaseUri, ConnectionSettings);
}

static std::atomic<uint32_t> HttpClientRequestIdCounter{0};

// If we want to support different HTTP client implementations then we'll need to make this more abstract

HttpClientError::ResponseClass
HttpClientError::GetResponseClass() const
{
	if ((cpr::ErrorCode)m_Error != cpr::ErrorCode::OK)
	{
		switch ((cpr::ErrorCode)m_Error)
		{
			case cpr::ErrorCode::CONNECTION_FAILURE:
				return ResponseClass::kHttpCantConnectError;
			case cpr::ErrorCode::HOST_RESOLUTION_FAILURE:
			case cpr::ErrorCode::PROXY_RESOLUTION_FAILURE:
				return ResponseClass::kHttpNoHost;
			case cpr::ErrorCode::INTERNAL_ERROR:
			case cpr::ErrorCode::NETWORK_RECEIVE_ERROR:
			case cpr::ErrorCode::NETWORK_SEND_FAILURE:
			case cpr::ErrorCode::OPERATION_TIMEDOUT:
				return ResponseClass::kHttpTimeout;
			case cpr::ErrorCode::SSL_CONNECT_ERROR:
			case cpr::ErrorCode::SSL_LOCAL_CERTIFICATE_ERROR:
			case cpr::ErrorCode::SSL_REMOTE_CERTIFICATE_ERROR:
			case cpr::ErrorCode::SSL_CACERT_ERROR:
			case cpr::ErrorCode::GENERIC_SSL_ERROR:
				return ResponseClass::kHttpSLLError;
			default:
				return ResponseClass::kHttpOtherClientError;
		}
	}
	else if (IsHttpSuccessCode(m_ResponseCode))
	{
		return ResponseClass::kSuccess;
	}
	else
	{
		switch (m_ResponseCode)
		{
			case HttpResponseCode::Unauthorized:
				return ResponseClass::kHttpUnauthorized;
			case HttpResponseCode::NotFound:
				return ResponseClass::kHttpNotFound;
			case HttpResponseCode::Forbidden:
				return ResponseClass::kHttpForbidden;
			case HttpResponseCode::Conflict:
				return ResponseClass::kHttpConflict;
			case HttpResponseCode::InternalServerError:
				return ResponseClass::kHttpInternalServerError;
			case HttpResponseCode::ServiceUnavailable:
				return ResponseClass::kHttpServiceUnavailable;
			case HttpResponseCode::BadGateway:
				return ResponseClass::kHttpBadGateway;
			case HttpResponseCode::GatewayTimeout:
				return ResponseClass::kHttpGatewayTimeout;
			default:
				if (m_ResponseCode >= HttpResponseCode::InternalServerError)
				{
					return ResponseClass::kHttpOtherServerError;
				}
				else
				{
					return ResponseClass::kHttpOtherClientError;
				}
		}
	}
}

//////////////////////////////////////////////////////////////////////////
//
// CPR helpers

static cpr::Body
AsCprBody(const CbObject& Obj)
{
	return cpr::Body((const char*)Obj.GetBuffer().GetData(), Obj.GetBuffer().GetSize());
}

static cpr::Body
AsCprBody(const IoBuffer& Obj)
{
	return cpr::Body((const char*)Obj.GetData(), Obj.GetSize());
}

//////////////////////////////////////////////////////////////////////////

static HttpClient::Response
ResponseWithPayload(std::string_view SessionId, cpr::Response& HttpResponse, const HttpResponseCode WorkResponseCode, IoBuffer&& Payload)
{
	// This ends up doing a memcpy, would be good to get rid of it by streaming results
	// into buffer directly
	IoBuffer ResponseBuffer = Payload ? std::move(Payload) : IoBuffer(IoBuffer::Clone, HttpResponse.text.data(), HttpResponse.text.size());

	if (auto It = HttpResponse.header.find("Content-Type"); It != HttpResponse.header.end())
	{
		const HttpContentType ContentType = ParseContentType(It->second);

		ResponseBuffer.SetContentType(ContentType);
	}

	if (!IsHttpSuccessCode(WorkResponseCode) && WorkResponseCode != HttpResponseCode::NotFound)
	{
		ZEN_WARN("HttpClient request failed (session: {}): {}", SessionId, HttpResponse);
	}

	return HttpClient::Response{.StatusCode		 = WorkResponseCode,
								.ResponsePayload = std::move(ResponseBuffer),
								.Header			 = HttpClient::KeyValueMap(HttpResponse.header.begin(), HttpResponse.header.end()),
								.UploadedBytes	 = gsl::narrow<int64_t>(HttpResponse.uploaded_bytes),
								.DownloadedBytes = gsl::narrow<int64_t>(HttpResponse.downloaded_bytes),
								.ElapsedSeconds	 = HttpResponse.elapsed};
}

static HttpClient::Response
CommonResponse(std::string_view SessionId, cpr::Response&& HttpResponse, IoBuffer&& Payload = {})
{
	const HttpResponseCode WorkResponseCode = HttpResponseCode(HttpResponse.status_code);
	if (HttpResponse.error)
	{
		if (HttpResponse.error.code != cpr::ErrorCode::OPERATION_TIMEDOUT &&
			HttpResponse.error.code != cpr::ErrorCode::CONNECTION_FAILURE && HttpResponse.error.code != cpr::ErrorCode::REQUEST_CANCELLED)
		{
			ZEN_WARN("HttpClient client failure (session: {}): {}", SessionId, HttpResponse);
		}

		// Client side failure code
		return HttpClient::Response{
			.StatusCode		 = WorkResponseCode,
			.ResponsePayload = IoBufferBuilder::MakeCloneFromMemory(HttpResponse.text.data(), HttpResponse.text.size()),
			.Header			 = HttpClient::KeyValueMap(HttpResponse.header.begin(), HttpResponse.header.end()),
			.UploadedBytes	 = gsl::narrow<int64_t>(HttpResponse.uploaded_bytes),
			.DownloadedBytes = gsl::narrow<int64_t>(HttpResponse.downloaded_bytes),
			.ElapsedSeconds	 = HttpResponse.elapsed,
			.Error			 = HttpClient::ErrorContext{.ErrorCode	  = gsl::narrow<int>(HttpResponse.error.code),
														.ErrorMessage = HttpResponse.error.message}};
	}

	if (WorkResponseCode == HttpResponseCode::NoContent || (HttpResponse.text.empty() && !Payload))
	{
		return HttpClient::Response{.StatusCode		 = WorkResponseCode,
									.Header			 = HttpClient::KeyValueMap(HttpResponse.header.begin(), HttpResponse.header.end()),
									.UploadedBytes	 = gsl::narrow<int64_t>(HttpResponse.uploaded_bytes),
									.DownloadedBytes = gsl::narrow<int64_t>(HttpResponse.downloaded_bytes),
									.ElapsedSeconds	 = HttpResponse.elapsed};
	}
	else
	{
		return ResponseWithPayload(
			SessionId,
			HttpResponse,
			WorkResponseCode,
			Payload ? std::move(Payload) : IoBufferBuilder::MakeCloneFromMemory(HttpResponse.text.data(), HttpResponse.text.size()));
	}
}

static bool
ShouldRetry(const cpr::Response& Response)
{
	switch (Response.error.code)
	{
		case cpr::ErrorCode::OK:
			break;
		case cpr::ErrorCode::INTERNAL_ERROR:
		case cpr::ErrorCode::NETWORK_RECEIVE_ERROR:
		case cpr::ErrorCode::NETWORK_SEND_FAILURE:
		case cpr::ErrorCode::OPERATION_TIMEDOUT:
			return true;
		default:
			return false;
	}
	switch ((HttpResponseCode)Response.status_code)
	{
		case HttpResponseCode::RequestTimeout:
		case HttpResponseCode::TooManyRequests:
		case HttpResponseCode::InternalServerError:
		case HttpResponseCode::BadGateway:
		case HttpResponseCode::ServiceUnavailable:
		case HttpResponseCode::GatewayTimeout:
			return true;
		default:
			return false;
	}
};

static bool
ValidatePayload(cpr::Response& Response, std::unique_ptr<detail::TempPayloadFile>& PayloadFile)
{
	ZEN_TRACE_CPU("ValidatePayload");
	IoBuffer ResponseBuffer = (Response.text.empty() && PayloadFile) ? PayloadFile->BorrowIoBuffer()
																	 : IoBuffer(IoBuffer::Wrap, Response.text.data(), Response.text.size());

	if (auto ContentLength = Response.header.find("Content-Length"); ContentLength != Response.header.end())
	{
		std::optional<uint64_t> ExpectedContentSize = ParseInt<uint64_t>(ContentLength->second);
		if (!ExpectedContentSize.has_value())
		{
			Response.error =
				cpr::Error(/*CURLE_READ_ERROR*/ 26, fmt::format("Can not parse Content-Length header. Value: '{}'", ContentLength->second));
			return false;
		}
		if (ExpectedContentSize.value() != ResponseBuffer.GetSize())
		{
			Response.error = cpr::Error(
				/*CURLE_READ_ERROR*/ 26,
				fmt::format("Payload size {} does not match Content-Length {}", ResponseBuffer.GetSize(), ContentLength->second));
			return false;
		}
	}

	if (Response.status_code == (long)HttpResponseCode::PartialContent)
	{
		return true;
	}

	if (auto JupiterHash = Response.header.find("X-Jupiter-IoHash"); JupiterHash != Response.header.end())
	{
		IoHash ExpectedPayloadHash;
		if (IoHash::TryParse(JupiterHash->second, ExpectedPayloadHash))
		{
			IoHash PayloadHash = IoHash::HashBuffer(ResponseBuffer);
			if (PayloadHash != ExpectedPayloadHash)
			{
				Response.error = cpr::Error(/*CURLE_READ_ERROR*/ 26,
											fmt::format("Payload hash {} does not match X-Jupiter-IoHash {}",
														PayloadHash.ToHexString(),
														ExpectedPayloadHash.ToHexString()));
				return false;
			}
		}
	}

	if (auto ContentType = Response.header.find("Content-Type"); ContentType != Response.header.end())
	{
		if (ContentType->second == "application/x-ue-comp")
		{
			IoHash	 RawHash;
			uint64_t RawSize;
			if (CompressedBuffer::ValidateCompressedHeader(ResponseBuffer, RawHash, RawSize))
			{
				return true;
			}
			else
			{
				Response.error = cpr::Error(/*CURLE_READ_ERROR*/ 26, "Compressed binary failed validation");
				return false;
			}
		}
		if (ContentType->second == "application/x-ue-cb")
		{
			if (CbValidateError Error = ValidateCompactBinary(ResponseBuffer.GetView(), CbValidateMode::Default);
				Error == CbValidateError::None)
			{
				return true;
			}
			else
			{
				Response.error = cpr::Error(/*CURLE_READ_ERROR*/ 26, fmt::format("Compact binary failed validation: {}", ToString(Error)));
				return false;
			}
		}
	}

	return true;
}

static cpr::Response
DoWithRetry(
	std::string_view							 SessionId,
	std::function<cpr::Response()>&&			 Func,
	uint8_t										 RetryCount,
	std::function<bool(cpr::Response& Result)>&& Validate = [](cpr::Response&) { return true; })
{
	uint8_t		  Attempt = 0;
	cpr::Response Result  = Func();
	while (Attempt < RetryCount)
	{
		if (!ShouldRetry(Result))
		{
			if (Result.error || !IsHttpSuccessCode(Result.status_code))
			{
				break;
			}
			if (Validate(Result))
			{
				break;
			}
		}
		Sleep(100 * (Attempt + 1));
		Attempt++;
		ZEN_INFO("{} Attempt {}/{}", CommonResponse(SessionId, std::move(Result)).ErrorMessage("Retry"), Attempt, RetryCount + 1);
		Result = Func();
	}
	return Result;
}

static cpr::Response
DoWithRetry(std::string_view						  SessionId,
			std::function<cpr::Response()>&&		  Func,
			std::unique_ptr<detail::TempPayloadFile>& PayloadFile,
			uint8_t									  RetryCount)
{
	uint8_t		  Attempt = 0;
	cpr::Response Result  = Func();
	while (Attempt < RetryCount)
	{
		if (!ShouldRetry(Result))
		{
			if (Result.error || !IsHttpSuccessCode(Result.status_code))
			{
				break;
			}
			if (ValidatePayload(Result, PayloadFile))
			{
				break;
			}
		}
		Sleep(100 * (Attempt + 1));
		Attempt++;
		ZEN_INFO("{} Attempt {}/{}", CommonResponse(SessionId, std::move(Result)).ErrorMessage("Retry"), Attempt, RetryCount + 1);
		Result = Func();
	}
	return Result;
}

static std::pair<std::string, std::string>
HeaderContentType(ZenContentType ContentType)
{
	return std::make_pair("Content-Type", std::string(MapContentTypeToString(ContentType)));
}

//////////////////////////////////////////////////////////////////////////

CprHttpClient::CprHttpClient(std::string_view BaseUri, const HttpClientSettings& Connectionsettings)
: HttpClientBase(BaseUri, Connectionsettings)
{
}

CprHttpClient::~CprHttpClient()
{
	ZEN_TRACE_CPU("CprHttpClient::~CprHttpClient");
	m_SessionLock.WithExclusiveLock([&] {
		for (auto CprSession : m_Sessions)
		{
			delete CprSession;
		}
		m_Sessions.clear();
	});
}

//////////////////////////////////////////////////////////////////////////

CprHttpClient::Session
CprHttpClient::AllocSession(const std::string_view				 BaseUrl,
							const std::string_view				 ResourcePath,
							const HttpClientSettings&			 ConnectionSettings,
							const KeyValueMap&					 AdditionalHeader,
							const KeyValueMap&					 Parameters,
							const std::string_view				 SessionId,
							std::optional<HttpClientAccessToken> AccessToken)
{
	ZEN_TRACE_CPU("CprHttpClient::AllocSession");
	cpr::Session* CprSession = nullptr;
	m_SessionLock.WithExclusiveLock([&] {
		if (!m_Sessions.empty())
		{
			CprSession = m_Sessions.back();
			m_Sessions.pop_back();
		}
	});

	if (CprSession == nullptr)
	{
		CprSession = new cpr::Session();
		CprSession->SetConnectTimeout(ConnectionSettings.ConnectTimeout);
		CprSession->SetTimeout(ConnectionSettings.Timeout);
		if (ConnectionSettings.AssumeHttp2)
		{
			CprSession->SetHttpVersion(cpr::HttpVersion{cpr::HttpVersionCode::VERSION_2_0_PRIOR_KNOWLEDGE});
		}
	}

	if (!AdditionalHeader->empty())
	{
		CprSession->SetHeader(cpr::Header(AdditionalHeader->begin(), AdditionalHeader->end()));
	}
	if (!SessionId.empty())
	{
		CprSession->UpdateHeader({{"UE-Session", std::string(SessionId)}});
	}
	if (AccessToken)
	{
		CprSession->UpdateHeader({{"Authorization", AccessToken->Value}});
	}
	if (!Parameters->empty())
	{
		cpr::Parameters Tmp;
		for (auto It = Parameters->begin(); It != Parameters->end(); It++)
		{
			Tmp.Add({It->first, It->second});
		}
		CprSession->SetParameters(Tmp);
	}
	else
	{
		CprSession->SetParameters({});
	}

	ExtendableStringBuilder<128> UrlBuffer;
	UrlBuffer << BaseUrl << ResourcePath;
	CprSession->SetUrl(UrlBuffer.c_str());

	return Session(this, CprSession);
}

void
CprHttpClient::ReleaseSession(cpr::Session* CprSession)
{
	ZEN_TRACE_CPU("CprHttpClient::ReleaseSession");
	CprSession->SetUrl({});
	CprSession->SetHeader({});
	CprSession->SetBody({});
	m_SessionLock.WithExclusiveLock([&] { m_Sessions.push_back(CprSession); });
}

CprHttpClient::Response
CprHttpClient::TransactPackage(std::string_view Url, CbPackage Package, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::TransactPackage");

	Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());

	// First, list of offered chunks for filtering on the server end

	std::vector<IoHash>			  AttachmentsToSend;
	std::span<const CbAttachment> Attachments = Package.GetAttachments();

	const uint32_t RequestId	   = ++HttpClientRequestIdCounter;
	auto		   RequestIdString = fmt::to_string(RequestId);

	if (Attachments.empty() == false)
	{
		CbObjectWriter Writer;
		Writer.BeginArray("offer");

		for (const CbAttachment& Attachment : Attachments)
		{
			Writer.AddHash(Attachment.GetHash());
		}

		Writer.EndArray();

		BinaryWriter MemWriter;
		Writer.Save(MemWriter);

		Sess->UpdateHeader({HeaderContentType(HttpContentType::kCbPackageOffer), {"UE-Request", RequestIdString}});
		Sess->SetBody(cpr::Body{(const char*)MemWriter.Data(), MemWriter.Size()});

		cpr::Response FilterResponse = Sess.Post();

		if (FilterResponse.status_code == 200)
		{
			IoBuffer		ResponseBuffer(IoBuffer::Wrap, FilterResponse.text.data(), FilterResponse.text.size());
			CbValidateError ValidationError = CbValidateError::None;
			if (CbObject ResponseObject = ValidateAndReadCompactBinaryObject(std::move(ResponseBuffer), ValidationError);
				ValidationError == CbValidateError::None)
			{
				for (CbFieldView& Entry : ResponseObject["need"])
				{
					ZEN_ASSERT(Entry.IsHash());
					AttachmentsToSend.push_back(Entry.AsHash());
				}
			}
		}
	}

	// Prepare package for send

	CbPackage SendPackage;
	SendPackage.SetObject(Package.GetObject(), Package.GetObjectHash());

	for (const IoHash& AttachmentCid : AttachmentsToSend)
	{
		const CbAttachment* Attachment = Package.FindAttachment(AttachmentCid);

		if (Attachment)
		{
			SendPackage.AddAttachment(*Attachment);
		}
		else
		{
			// This should be an error -- server asked to have something we can't find
		}
	}

	// Transmit package payload

	CompositeBuffer Message		= FormatPackageMessageBuffer(SendPackage);
	SharedBuffer	FlatMessage = Message.Flatten();

	Sess->UpdateHeader({HeaderContentType(HttpContentType::kCbPackage), {"UE-Request", RequestIdString}});
	Sess->SetBody(cpr::Body{(const char*)FlatMessage.GetData(), FlatMessage.GetSize()});

	cpr::Response FilterResponse = Sess.Post();

	if (!IsHttpSuccessCode(FilterResponse.status_code))
	{
		return {.StatusCode = HttpResponseCode(FilterResponse.status_code)};
	}

	IoBuffer ResponseBuffer(IoBuffer::Clone, FilterResponse.text.data(), FilterResponse.text.size());

	if (auto It = FilterResponse.header.find("Content-Type"); It != FilterResponse.header.end())
	{
		HttpContentType ContentType = ParseContentType(It->second);

		ResponseBuffer.SetContentType(ContentType);
	}

	return {.StatusCode = HttpResponseCode(FilterResponse.status_code), .ResponsePayload = ResponseBuffer};
}

//////////////////////////////////////////////////////////////////////////
//
// Standard HTTP verbs
//

CprHttpClient::Response
CprHttpClient::Put(std::string_view Url, const IoBuffer& Payload, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::Put");

	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());
				Sess->SetBody(AsCprBody(Payload));
				Sess->UpdateHeader({HeaderContentType(Payload.GetContentType())});
				return Sess.Put();
			},
			m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Put(std::string_view Url, const KeyValueMap& Parameters)
{
	ZEN_TRACE_CPU("CprHttpClient::Put");

	return CommonResponse(m_SessionId,
						  DoWithRetry(
							  m_SessionId,
							  [&]() {
								  Session Sess = AllocSession(m_BaseUri,
															  Url,
															  m_ConnectionSettings,
															  {{"Content-Length", "0"}},
															  Parameters,
															  m_SessionId,
															  GetAccessToken());
								  return Sess.Put();
							  },
							  m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Get(std::string_view Url, const KeyValueMap& AdditionalHeader, const KeyValueMap& Parameters)
{
	ZEN_TRACE_CPU("CprHttpClient::Get");
	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess =
					AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, Parameters, m_SessionId, GetAccessToken());
				return Sess.Get();
			},
			m_ConnectionSettings.RetryCount,
			[](cpr::Response& Result) {
				std::unique_ptr<detail::TempPayloadFile> NoTempFile;
				return ValidatePayload(Result, NoTempFile);
			}));
}

CprHttpClient::Response
CprHttpClient::Head(std::string_view Url, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::Head");

	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());
				return Sess.Head();
			},
			m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Delete(std::string_view Url, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::Delete");

	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());
				return Sess.Delete();
			},
			m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Post(std::string_view Url, const KeyValueMap& AdditionalHeader, const KeyValueMap& Parameters)
{
	ZEN_TRACE_CPU("CprHttpClient::PostNoPayload");

	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess =
					AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, Parameters, m_SessionId, GetAccessToken());
				return Sess.Post();
			},
			m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Post(std::string_view Url, const IoBuffer& Payload, const KeyValueMap& AdditionalHeader)
{
	return Post(Url, Payload, Payload.GetContentType(), AdditionalHeader);
}

CprHttpClient::Response
CprHttpClient::Post(std::string_view Url, const IoBuffer& Payload, ZenContentType ContentType, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::PostWithPayload");

	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());
				Sess->UpdateHeader({HeaderContentType(ContentType)});

				IoBufferFileReference FileRef = {nullptr, 0, 0};
				if (Payload.GetFileReference(FileRef))
				{
					uint64_t					   Offset = 0;
					detail::BufferedReadFileStream Buffer(FileRef.FileHandle, FileRef.FileChunkOffset, FileRef.FileChunkSize, 512u * 1024u);
					auto						   ReadCallback = [&Payload, &Offset, &Buffer](char* buffer, size_t& size, intptr_t) {
						  size = Min<size_t>(size, Payload.GetSize() - Offset);
						  Buffer.Read(buffer, size);
						  Offset += size;
						  return true;
					};
					return Sess.Post(cpr::ReadCallback(gsl::narrow<cpr::cpr_off_t>(Payload.GetSize()), ReadCallback));
				}
				Sess->SetBody(AsCprBody(Payload));
				return Sess.Post();
			},
			m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Post(std::string_view Url, CbObject Payload, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::PostObjectPayload");

	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());

				Sess->SetBody(AsCprBody(Payload));
				Sess->UpdateHeader({HeaderContentType(ZenContentType::kCbObject)});
				return Sess.Post();
			},
			m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Post(std::string_view Url, CbPackage Pkg, const KeyValueMap& AdditionalHeader)
{
	return Post(Url, zen::FormatPackageMessageBuffer(Pkg), ZenContentType::kCbPackage, AdditionalHeader);
}

CprHttpClient::Response
CprHttpClient::Post(std::string_view Url, const CompositeBuffer& Payload, ZenContentType ContentType, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::Post");

	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());
				Sess->UpdateHeader({HeaderContentType(ContentType)});

				detail::CompositeBufferReadStream Reader(Payload, 512u * 1024u);
				auto							  ReadCallback = [&Reader](char* buffer, size_t& size, intptr_t) {
					 size = Reader.Read(buffer, size);
					 return true;
				};
				return Sess.Post(cpr::ReadCallback(gsl::narrow<cpr::cpr_off_t>(Payload.GetSize()), ReadCallback));
			},
			m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Upload(std::string_view Url, const IoBuffer& Payload, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::Upload");

	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());
				Sess->UpdateHeader({HeaderContentType(Payload.GetContentType())});

				IoBufferFileReference FileRef = {nullptr, 0, 0};
				if (Payload.GetFileReference(FileRef))
				{
					uint64_t					   Offset = 0;
					detail::BufferedReadFileStream Buffer(FileRef.FileHandle, FileRef.FileChunkOffset, FileRef.FileChunkSize, 512u * 1024u);
					auto						   ReadCallback = [&Payload, &Offset, &Buffer](char* buffer, size_t& size, intptr_t) {
						  size = Min<size_t>(size, Payload.GetSize() - Offset);
						  Buffer.Read(buffer, size);
						  Offset += size;
						  return true;
					};
					return Sess.Put(cpr::ReadCallback(gsl::narrow<cpr::cpr_off_t>(Payload.GetSize()), ReadCallback));
				}
				Sess->SetBody(AsCprBody(Payload));
				return Sess.Put();
			},
			m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Upload(std::string_view Url, const CompositeBuffer& Payload, ZenContentType ContentType, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::Upload");

	return CommonResponse(
		m_SessionId,
		DoWithRetry(
			m_SessionId,
			[&]() {
				Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());
				Sess->UpdateHeader({HeaderContentType(ContentType)});

				detail::CompositeBufferReadStream Reader(Payload, 512u * 1024u);
				auto							  ReadCallback = [&Reader](char* buffer, size_t& size, intptr_t) {
					 size = Reader.Read(buffer, size);
					 return true;
				};
				return Sess.Put(cpr::ReadCallback(gsl::narrow<cpr::cpr_off_t>(Payload.GetSize()), ReadCallback));
			},
			m_ConnectionSettings.RetryCount));
}

CprHttpClient::Response
CprHttpClient::Download(std::string_view Url, const std::filesystem::path& TempFolderPath, const KeyValueMap& AdditionalHeader)
{
	ZEN_TRACE_CPU("CprHttpClient::Download");

	std::string								 PayloadString;
	std::unique_ptr<detail::TempPayloadFile> PayloadFile;
	cpr::Response							 Response = DoWithRetry(
		   m_SessionId,
		   [&]() {
			   auto GetHeader = [&](std::string header) -> std::pair<std::string, std::string> {
				   size_t DelimiterPos = header.find(':');
				   if (DelimiterPos != std::string::npos)
				   {
					   std::string		  Key = header.substr(0, DelimiterPos);
					   constexpr AsciiSet WhitespaceCharacters(" \v\f\t\r\n");
					   Key = AsciiSet::TrimSuffixWith(Key, WhitespaceCharacters);
					   Key = AsciiSet::TrimPrefixWith(Key, WhitespaceCharacters);

					   std::string Value = header.substr(DelimiterPos + 1);
					   Value			 = AsciiSet::TrimSuffixWith(Value, WhitespaceCharacters);
					   Value			 = AsciiSet::TrimPrefixWith(Value, WhitespaceCharacters);

					   return std::make_pair(Key, Value);
				   }
				   return std::make_pair(header, "");
			   };

			   auto DownloadCallback = [&](std::string data, intptr_t) {
				   if (PayloadFile)
				   {
					   ZEN_ASSERT(PayloadString.empty());
					   std::error_code Ec = PayloadFile->Write(data);
					   if (Ec)
					   {
						   ZEN_WARN("Failed to write to temp file in '{}' for HttpClient::Download. Reason: {}",
									TempFolderPath.string(),
									Ec.message());
						   return false;
					   }
				   }
				   else
				   {
					   PayloadString.append(data);
				   }
				   return true;
			   };

			   uint64_t RequestedContentLength = (uint64_t)-1;
			   if (auto RangeIt = AdditionalHeader.Entries.find("Range"); RangeIt != AdditionalHeader.Entries.end())
			   {
				   if (RangeIt->second.starts_with("bytes"))
				   {
					   size_t RangeStartPos = RangeIt->second.find('=', 5);
					   if (RangeStartPos != std::string::npos)
					   {
						   RangeStartPos++;
						   size_t RangeSplitPos = RangeIt->second.find('-', RangeStartPos);
						   if (RangeSplitPos != std::string::npos)
						   {
							   std::optional<size_t> RequestedRangeStart =
								   ParseInt<size_t>(RangeIt->second.substr(RangeStartPos, RangeSplitPos - RangeStartPos));
							   std::optional<size_t> RequestedRangeEnd = ParseInt<size_t>(RangeIt->second.substr(RangeStartPos + 1));
							   if (RequestedRangeStart.has_value() && RequestedRangeEnd.has_value())
							   {
								   RequestedContentLength = RequestedRangeEnd.value() - 1;
							   }
						   }
					   }
				   }
			   }

			   cpr::Response Response;
			   {
				   std::vector<std::pair<std::string, std::string>> ReceivedHeaders;
				   auto												HeaderCallback = [&](std::string header, intptr_t) {
					   std::pair<std::string, std::string> Header = GetHeader(header);
					   if (Header.first == "Content-Length"sv)
					   {
						   std::optional<size_t> ContentLength = ParseInt<size_t>(Header.second);
						   if (ContentLength.has_value())
						   {
							   if (ContentLength.value() > 1024 * 1024)
							   {
								   PayloadFile = std::make_unique<detail::TempPayloadFile>();
								   std::error_code Ec = PayloadFile->Open(TempFolderPath, ContentLength.value());
								   if (Ec)
								   {
									   ZEN_WARN("Failed to create temp file in '{}' for HttpClient::Download. Reason: {}",
												TempFolderPath.string(),
												Ec.message());
									   PayloadFile.reset();
								   }
							   }
							   else
							   {
								   PayloadString.reserve(ContentLength.value());
							   }
						   }
					   }
					   if (!Header.first.empty())
					   {
						   ReceivedHeaders.emplace_back(std::move(Header));
					   }
					   return 1;
				   };

				   Session Sess = AllocSession(m_BaseUri, Url, m_ConnectionSettings, AdditionalHeader, {}, m_SessionId, GetAccessToken());
				   Response = Sess.Download(cpr::WriteCallback{DownloadCallback}, cpr::HeaderCallback{HeaderCallback});
				   for (const std::pair<std::string, std::string>& H : ReceivedHeaders)
				   {
					   Response.header.insert_or_assign(H.first, H.second);
				   }
			   }
			   if (m_ConnectionSettings.AllowResume)
			   {
				   auto SupportsRanges = [](const cpr::Response& Response) -> bool {
					   if (Response.header.find("Content-Range") != Response.header.end())
					   {
						   return true;
					   }
					   if (auto It = Response.header.find("Accept-Ranges"); It != Response.header.end())
					   {
						   return It->second == "bytes"sv;
					   }
					   return false;
				   };

				   auto ShouldResume = [&SupportsRanges](const cpr::Response& Response) -> bool {
					   if (ShouldRetry(Response))
					   {
						   return SupportsRanges(Response);
					   }
					   return false;
				   };

				   if (ShouldResume(Response))
				   {
					   auto It = Response.header.find("Content-Length");
					   if (It != Response.header.end())
					   {
						   std::vector<std::pair<std::string, std::string>> ReceivedHeaders;

						   auto HeaderCallback = [&](std::string header, intptr_t) {
							   std::pair<std::string, std::string> Header = GetHeader(header);
							   if (!Header.first.empty())
							   {
								   ReceivedHeaders.emplace_back(std::move(Header));
							   }

							   if (Header.first == "Content-Range"sv)
							   {
								   if (Header.second.starts_with("bytes "sv))
								   {
									   size_t RangeStartEnd = Header.second.find('-', 6);
									   if (RangeStartEnd != std::string::npos)
									   {
										   const auto Start = ParseInt<uint64_t>(Header.second.substr(6, RangeStartEnd - 6));
										   if (Start)
										   {
											   uint64_t DownloadedSize = PayloadFile ? PayloadFile->GetSize() : PayloadString.length();
											   if (Start.value() == DownloadedSize)
											   {
												   return 1;
											   }
											   else if (Start.value() > DownloadedSize)
											   {
												   return 0;
											   }
											   if (PayloadFile)
											   {
												   PayloadFile->ResetWritePos(Start.value());
											   }
											   else
											   {
												   PayloadString = PayloadString.substr(0, Start.value());
											   }
											   return 1;
										   }
									   }
								   }
								   return 0;
							   }
							   return 1;
						   };

						   KeyValueMap HeadersWithRange(AdditionalHeader);
						   do
						   {
							   uint64_t DownloadedSize = PayloadFile ? PayloadFile->GetSize() : PayloadString.length();

							   uint64_t ContentLength = RequestedContentLength;
							   if (ContentLength == uint64_t(-1))
							   {
								   if (auto ParsedContentLength = ParseInt<int64_t>(It->second); ParsedContentLength.has_value())
								   {
									   ContentLength = ParsedContentLength.value();
								   }
							   }

							   std::string Range = fmt::format("bytes={}-{}", DownloadedSize, DownloadedSize + ContentLength - 1);
							   if (auto RangeIt = HeadersWithRange.Entries.find("Range"); RangeIt != HeadersWithRange.Entries.end())
							   {
								   if (RangeIt->second == Range)
								   {
									   // If we didn't make any progress, abort
									   break;
								   }
							   }
							   HeadersWithRange.Entries.insert_or_assign("Range", Range);

							   Session Sess =
								   AllocSession(m_BaseUri, Url, m_ConnectionSettings, HeadersWithRange, {}, m_SessionId, GetAccessToken());
							   Response = Sess.Download(cpr::WriteCallback{DownloadCallback}, cpr::HeaderCallback{HeaderCallback});
							   for (const std::pair<std::string, std::string>& H : ReceivedHeaders)
							   {
								   Response.header.insert_or_assign(H.first, H.second);
							   }
							   ReceivedHeaders.clear();
						   } while (ShouldResume(Response));
					   }
				   }
			   }

			   if (!PayloadString.empty())
			   {
				   Response.text = std::move(PayloadString);
			   }
			   return Response;
		   },
		   PayloadFile,
		   m_ConnectionSettings.RetryCount);

	return CommonResponse(m_SessionId, std::move(Response), PayloadFile ? PayloadFile->DetachToIoBuffer() : IoBuffer{});
}

}  // namespace zen