/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#define FORBIDDEN_SYMBOL_ALLOW_ALL

#include <curl/curl.h>
#include "backends/networking/curl/networkreadstream.h"
#include "backends/networking/curl/connectionmanager.h"
#include "base/version.h"
#include "common/debug.h"

namespace Networking {

size_t NetworkReadStream::curlDataCallback(char *d, size_t n, size_t l, void *p) {
	NetworkReadStream *stream = (NetworkReadStream *)p;
	if (stream)
		return stream->_backingStream.write(d, n * l);
	return 0;
}

size_t NetworkReadStream::curlReadDataCallback(char *d, size_t n, size_t l, void *p) {
	NetworkReadStream *stream = (NetworkReadStream *)p;
	if (stream)
		return stream->fillWithSendingContents(d, n * l);
	return 0;
}

size_t NetworkReadStream::curlHeadersCallback(char *d, size_t n, size_t l, void *p) {
	NetworkReadStream *stream = (NetworkReadStream *)p;
	if (stream)
		return stream->addResponseHeaders(d, n * l);
	return 0;
}

static int curlProgressCallback(void *p, curl_off_t dltotal, curl_off_t dlnow, curl_off_t ultotal, curl_off_t ulnow) {
	NetworkReadStream *stream = (NetworkReadStream *)p;
	if (stream)
		stream->setProgress(dlnow, dltotal);
	return 0;
}

int NetworkReadStream::curlProgressCallbackOlder(void *p, double dltotal, double dlnow, double ultotal, double ulnow) {
	// for libcurl older than 7.32.0 (CURLOPT_PROGRESSFUNCTION)
	return curlProgressCallback(p, (curl_off_t)dltotal, (curl_off_t)dlnow, (curl_off_t)ultotal, (curl_off_t)ulnow);
}

void NetworkReadStream::resetStream() {
	_eos = _requestComplete = false;
	if (!_errorBuffer)
		_errorBuffer = (char *)calloc(CURL_ERROR_SIZE, 1);
	_sendingContentsBuffer = nullptr;
	_sendingContentsSize = _sendingContentsPos = 0;
	_progressDownloaded = _progressTotal = 0;
	_bufferCopy = nullptr;
}

void NetworkReadStream::initCurl(const char *url, curl_slist *headersList) {
	resetStream();

	_easy = curl_easy_init();
	curl_easy_setopt(_easy, CURLOPT_WRITEFUNCTION, curlDataCallback);
	curl_easy_setopt(_easy, CURLOPT_WRITEDATA, this); //so callback can call us
	curl_easy_setopt(_easy, CURLOPT_PRIVATE, this); //so ConnectionManager can call us when request is complete
	curl_easy_setopt(_easy, CURLOPT_HEADER, 0L);
	curl_easy_setopt(_easy, CURLOPT_HEADERDATA, this);
	curl_easy_setopt(_easy, CURLOPT_HEADERFUNCTION, curlHeadersCallback);
	curl_easy_setopt(_easy, CURLOPT_URL, url);
	curl_easy_setopt(_easy, CURLOPT_ERRORBUFFER, _errorBuffer);
	curl_easy_setopt(_easy, CURLOPT_VERBOSE, 0L);
	curl_easy_setopt(_easy, CURLOPT_FOLLOWLOCATION, 1L); //probably it's OK to have it always on
	curl_easy_setopt(_easy, CURLOPT_HTTPHEADER, headersList);
	curl_easy_setopt(_easy, CURLOPT_USERAGENT, gScummVMFullVersion);
	curl_easy_setopt(_easy, CURLOPT_NOPROGRESS, 0L);
	curl_easy_setopt(_easy, CURLOPT_PROGRESSFUNCTION, curlProgressCallbackOlder);
	curl_easy_setopt(_easy, CURLOPT_PROGRESSDATA, this);
#if defined NINTENDO_SWITCH || defined ANDROID_PLAIN_PORT || defined PSP2
	curl_easy_setopt(_easy, CURLOPT_SSL_VERIFYPEER, 0);
#endif

	const char *caCertPath = ConnMan.getCaCertPath();
	if (caCertPath) {
		curl_easy_setopt(_easy, CURLOPT_CAINFO, caCertPath);
	}

#if LIBCURL_VERSION_NUM >= 0x072000
	// CURLOPT_XFERINFOFUNCTION introduced in libcurl 7.32.0
	// CURLOPT_PROGRESSFUNCTION is used as a backup plan in case older version is used
	curl_easy_setopt(_easy, CURLOPT_XFERINFOFUNCTION, curlProgressCallback);
	curl_easy_setopt(_easy, CURLOPT_XFERINFODATA, this);
#endif

#if LIBCURL_VERSION_NUM >= 0x071900
	// Added in libcurl 7.25.0
	if (_keepAlive) {
		curl_easy_setopt(_easy, CURLOPT_TCP_KEEPALIVE, 1L);
		curl_easy_setopt(_easy, CURLOPT_TCP_KEEPIDLE, _keepAliveIdle);
		curl_easy_setopt(_easy, CURLOPT_TCP_KEEPINTVL, _keepAliveInterval);
	}
#endif
}

bool NetworkReadStream::reuseCurl(const char *url, curl_slist *headersList) {
	if (!_keepAlive) {
		warning("NetworkReadStream: Can't reuse curl handle (was not setup as keep-alive)");
		return false;
	}

	resetStream();

	curl_easy_setopt(_easy, CURLOPT_URL, url);
	curl_easy_setopt(_easy, CURLOPT_HTTPHEADER, headersList);
	curl_easy_setopt(_easy, CURLOPT_USERAGENT, gScummVMFullVersion); // in case headersList rewrites it

	return true;
}

void NetworkReadStream::setupBufferContents(const byte *buffer, uint32 bufferSize, bool uploading, bool usingPatch, bool post) {
	if (uploading) {
		curl_easy_setopt(_easy, CURLOPT_UPLOAD, 1L);
		curl_easy_setopt(_easy, CURLOPT_READDATA, this);
		curl_easy_setopt(_easy, CURLOPT_READFUNCTION, curlReadDataCallback);
		_sendingContentsBuffer = buffer;
		_sendingContentsSize = bufferSize;
	} else if (usingPatch) {
		curl_easy_setopt(_easy, CURLOPT_CUSTOMREQUEST, "PATCH");
	} else {
		if (post || bufferSize != 0) {
			curl_easy_setopt(_easy, CURLOPT_POSTFIELDSIZE, bufferSize);
#if LIBCURL_VERSION_NUM >= 0x071101
			// CURLOPT_COPYPOSTFIELDS available since curl 7.17.1
			curl_easy_setopt(_easy, CURLOPT_COPYPOSTFIELDS, buffer);
#else
			_bufferCopy = (byte*)malloc(bufferSize);
			memcpy(_bufferCopy, buffer, bufferSize);
			curl_easy_setopt(_easy, CURLOPT_POSTFIELDS, _bufferCopy);
#endif
		}
	}
	ConnMan.registerEasyHandle(_easy);
}

void NetworkReadStream::setupFormMultipart(Common::HashMap<Common::String, Common::String> formFields, Common::HashMap<Common::String, Common::String> formFiles) {
	// set POST multipart upload form fields/files
	struct curl_httppost *formpost = nullptr;
	struct curl_httppost *lastptr = nullptr;

	for (Common::HashMap<Common::String, Common::String>::iterator i = formFields.begin(); i != formFields.end(); ++i) {
		CURLFORMcode code = curl_formadd(
			&formpost,
			&lastptr,
			CURLFORM_COPYNAME, i->_key.c_str(),
			CURLFORM_COPYCONTENTS, i->_value.c_str(),
			CURLFORM_END
		);

		if (code != CURL_FORMADD_OK)
			warning("NetworkReadStream: field curl_formadd('%s') failed", i->_key.c_str());
	}

	for (Common::HashMap<Common::String, Common::String>::iterator i = formFiles.begin(); i != formFiles.end(); ++i) {
		CURLFORMcode code = curl_formadd(
			&formpost,
			&lastptr,
			CURLFORM_COPYNAME, i->_key.c_str(),
			CURLFORM_FILE, i->_value.c_str(),
			CURLFORM_END
		);

		if (code != CURL_FORMADD_OK)
			warning("NetworkReadStream: file curl_formadd('%s') failed", i->_key.c_str());
	}

	curl_easy_setopt(_easy, CURLOPT_HTTPPOST, formpost);
	ConnMan.registerEasyHandle(_easy);
}

NetworkReadStream::NetworkReadStream(const char *url, curl_slist *headersList, Common::String postFields, bool uploading, bool usingPatch, bool keepAlive, long keepAliveIdle, long keepAliveInterval):
		_backingStream(DisposeAfterUse::YES), _keepAlive(keepAlive), _keepAliveIdle(keepAliveIdle), _keepAliveInterval(keepAliveInterval), _errorBuffer(nullptr), _errorCode(CURLE_OK) {
	initCurl(url, headersList);
	setupBufferContents((const byte *)postFields.c_str(), postFields.size(), uploading, usingPatch, false);
}

NetworkReadStream::NetworkReadStream(const char *url, curl_slist *headersList, Common::HashMap<Common::String, Common::String> formFields, Common::HashMap<Common::String, Common::String> formFiles, bool keepAlive, long keepAliveIdle, long keepAliveInterval):
		_backingStream(DisposeAfterUse::YES), _keepAlive(keepAlive), _keepAliveIdle(keepAliveIdle), _keepAliveInterval(keepAliveInterval), _errorBuffer(nullptr), _errorCode(CURLE_OK) {
	initCurl(url, headersList);
	setupFormMultipart(formFields, formFiles);
}

NetworkReadStream::NetworkReadStream(const char *url, curl_slist *headersList, const byte *buffer, uint32 bufferSize, bool uploading, bool usingPatch, bool post, bool keepAlive, long keepAliveIdle, long keepAliveInterval):
		_backingStream(DisposeAfterUse::YES), _keepAlive(keepAlive), _keepAliveIdle(keepAliveIdle), _keepAliveInterval(keepAliveInterval), _errorBuffer(nullptr), _errorCode(CURLE_OK) {
	initCurl(url, headersList);
	setupBufferContents(buffer, bufferSize, uploading, usingPatch, post);
}

bool NetworkReadStream::reuse(const char *url, curl_slist *headersList, Common::String postFields, bool uploading, bool usingPatch) {
	if (!reuseCurl(url, headersList))
		return false;

	_backingStream = Common::MemoryReadWriteStream(DisposeAfterUse::YES);
	setupBufferContents((const byte *)postFields.c_str(), postFields.size(), uploading, usingPatch, false);
	return true;
}

bool NetworkReadStream::reuse(const char *url, curl_slist *headersList, Common::HashMap<Common::String, Common::String> formFields, Common::HashMap<Common::String, Common::String> formFiles) {
	if (!reuseCurl(url, headersList))
		return false;

	_backingStream = Common::MemoryReadWriteStream(DisposeAfterUse::YES);
	setupFormMultipart(formFields, formFiles);
	return true;
}

bool NetworkReadStream::reuse(const char *url, curl_slist *headersList, const byte *buffer, uint32 bufferSize, bool uploading, bool usingPatch, bool post) {
	if (!reuseCurl(url, headersList))
		return false;

	_backingStream = Common::MemoryReadWriteStream(DisposeAfterUse::YES);
	setupBufferContents(buffer, bufferSize, uploading, usingPatch, post);
	return true;
}

NetworkReadStream::~NetworkReadStream() {
	if (_easy)
		curl_easy_cleanup(_easy);
	free(_bufferCopy);
	free(_errorBuffer);
}

bool NetworkReadStream::eos() const {
	return _eos;
}

uint32 NetworkReadStream::read(void *dataPtr, uint32 dataSize) {
	uint32 actuallyRead = _backingStream.read(dataPtr, dataSize);

	if (actuallyRead == 0) {
		if (_requestComplete)
			_eos = true;
		return 0;
	}

	return actuallyRead;
}

void NetworkReadStream::finished(uint32 errorCode) {
	_requestComplete = true;

	char *url = nullptr;
	curl_easy_getinfo(_easy, CURLINFO_EFFECTIVE_URL, &url);

	_errorCode = errorCode;

	if (_errorCode == CURLE_OK) {
		debug(9, "NetworkReadStream: %s - Request succeeded", url);
	} else {
		warning("NetworkReadStream: %s - Request failed (%d - %s)", url, _errorCode, getError());
	}
}

bool NetworkReadStream::hasError() const {
	return _errorCode != CURLE_OK;
}

const char *NetworkReadStream::getError() const {
	return strlen(_errorBuffer) ? _errorBuffer : curl_easy_strerror((CURLcode)_errorCode);
}

long NetworkReadStream::httpResponseCode() const {
	long responseCode = -1;
	if (_easy)
		curl_easy_getinfo(_easy, CURLINFO_RESPONSE_CODE, &responseCode);
	return responseCode;
}

Common::String NetworkReadStream::currentLocation() const {
	Common::String result = "";
	if (_easy) {
		char *pointer;
		curl_easy_getinfo(_easy, CURLINFO_EFFECTIVE_URL, &pointer);
		result = Common::String(pointer);
	}
	return result;
}

Common::String NetworkReadStream::responseHeaders() const {
	return _responseHeaders;
}

Common::HashMap<Common::String, Common::String> NetworkReadStream::responseHeadersMap() const {
	// HTTP headers are described at RFC 2616: https://datatracker.ietf.org/doc/html/rfc2616#section-4.2
	// this implementation tries to follow it, but for simplicity it does not support multi-line header values

	Common::HashMap<Common::String, Common::String> headers;
	Common::String headerName, headerValue, trailingWhitespace;
	char c;
	bool readingName = true;

	for (uint i = 0; i < _responseHeaders.size(); ++i) {
		c = _responseHeaders[i];

		if (readingName) {
			if (c == ' ' || c == '\r' || c == '\n' || c == '\t') {
				// header names should not contain any whitespace, this is invalid
				// ignore what's been before
				headerName = "";
				continue;
			}
			if (c == ':') {
				if (!headerName.empty()) {
					readingName = false;
				}
				continue;
			}
			headerName += c;
			continue;
		}

		// reading value:
		if (c == ' ' || c == '\t') {
			if (headerValue.empty()) {
				// skip leading whitespace
				continue;
			} else {
				// accumulate trailing whitespace
				trailingWhitespace += c;
				continue;
			}
		}

		if (c == '\r' || c == '\n') {
			// not sure if RFC allows empty values, we'll ignore such
			if (!headerName.empty() && !headerValue.empty()) {
				// add header value
				// RFC allows header with the same name to be sent multiple times
				// and requires it to be equivalent of just listing all header values separated with comma
				// so if header already was met, we'll add new value to the old one
				headerName.toLowercase();
				if (headers.contains(headerName)) {
					headers[headerName] += "," + headerValue;
				} else {
					headers[headerName] = headerValue;
				}
			}

			headerName = "";
			headerValue = "";
			trailingWhitespace = "";
			readingName = true;
			continue;
		}

		// if we meet non-whitespace character, turns out those "trailing" whitespace characters were not so trailing
		headerValue += trailingWhitespace;
		trailingWhitespace = "";
		headerValue += c;
	}

	return headers;
}

uint32 NetworkReadStream::fillWithSendingContents(char *bufferToFill, uint32 maxSize) {
	uint32 sendSize = _sendingContentsSize - _sendingContentsPos;
	if (sendSize > maxSize)
		sendSize = maxSize;
	for (uint32 i = 0; i < sendSize; ++i) {
		bufferToFill[i] = _sendingContentsBuffer[_sendingContentsPos + i];
	}
	_sendingContentsPos += sendSize;
	return sendSize;
}

uint32 NetworkReadStream::addResponseHeaders(char *buffer, uint32 bufferSize) {
	_responseHeaders += Common::String(buffer, bufferSize);
	return bufferSize;
}

double NetworkReadStream::getProgress() const {
	if (_progressTotal < 1)
		return 0;
	return (double)_progressDownloaded / (double)_progressTotal;
}

void NetworkReadStream::setProgress(uint64 downloaded, uint64 total) {
	_progressDownloaded = downloaded;
	_progressTotal = total;
}

} // End of namespace Cloud
