/****************************************************************************
 Copyright (c) 2013 cocos2d-x.org
 
 http://www.cocos2d-x.org
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ****************************************************************************/

#include "Downloader.h"
#include "cocos2d.h"
#include <curl/curl.h>
#include <curl/easy.h>
#include <cstdio>
#include <cerrno>

NS_CC_EXT_BEGIN

#define LOW_SPEED_LIMIT     1L
#define LOW_SPEED_TIME      5L
#define MAX_REDIRS          2
#define DEFAULT_TIMEOUT     5
#define HTTP_CODE_SUPPORT_RESUME    206

#define TEMP_EXT            ".temp"

size_t fileWriteFunc(void *ptr, size_t size, size_t nmemb, void *userdata)
{
    FILE *fp = (FILE*)userdata;
    size_t written = fwrite(ptr, size, nmemb, fp);
    return written;
}

size_t bufferWriteFunc(void *ptr, size_t size, size_t nmemb, void *userdata)
{
    Downloader::StreamData *streamBuffer = (Downloader::StreamData *)userdata;
    size_t written = size * nmemb;
    // Avoid pointer overflow
    if (streamBuffer->offset + written <= streamBuffer->total)
    {
        memcpy(streamBuffer->buffer + streamBuffer->offset, ptr, written);
        streamBuffer->offset += written;
        return written;
    }
    else return 0;
}

// This is only for batchDownload process, will notify file succeed event in progress function
int batchDownloadProgressFunc(Downloader::ProgressData *ptr, double totalToDownload, double nowDownloaded, double totalToUpLoad, double nowUpLoaded)
{
    if (ptr->totalToDownload == 0)
    {
        ptr->totalToDownload = totalToDownload;
    }
    
    if (ptr->downloaded != nowDownloaded)
    {
        ptr->downloaded = nowDownloaded;
        
        Downloader::ProgressData data = *ptr;
        
        if (nowDownloaded == totalToDownload)
        {
            Director::getInstance()->getScheduler()->performFunctionInCocosThread([=]{
                if (!data.downloader.expired())
                {
                    std::shared_ptr<Downloader> downloader = data.downloader.lock();
                
                    auto progressCB = downloader->getProgressCallback();
                    if (progressCB != nullptr)
                    {
                        progressCB(totalToDownload, nowDownloaded, data.url, data.customId);
                    }
                    auto successCB = downloader->getSuccessCallback();
                    if (successCB != nullptr)
                    {
                        successCB(data.url, data.path + data.name, data.customId);
                    }
                }
            });
        }
        else
        {
            Director::getInstance()->getScheduler()->performFunctionInCocosThread([=]{
                if (!data.downloader.expired())
                {
                    std::shared_ptr<Downloader> downloader = data.downloader.lock();
                
                    auto callback = downloader->getProgressCallback();
                    if (callback != nullptr)
                    {
                        callback(totalToDownload, nowDownloaded, data.url, data.customId);
                    }
                }
            });
        }
    }
    
    return 0;
}

// Compare to batchDownloadProgressFunc, this only handles progress information notification
int downloadProgressFunc(Downloader::ProgressData *ptr, double totalToDownload, double nowDownloaded, double totalToUpLoad, double nowUpLoaded)
{
    if (ptr->totalToDownload == 0)
    {
        ptr->totalToDownload = totalToDownload;
    }
    
    if (ptr->downloaded != nowDownloaded)
    {
        ptr->downloaded = nowDownloaded;
        Downloader::ProgressData data = *ptr;
        
        Director::getInstance()->getScheduler()->performFunctionInCocosThread([=]{
            if (!data.downloader.expired())
            {
                std::shared_ptr<Downloader> downloader = data.downloader.lock();
                
                auto callback = downloader->getProgressCallback();
                if (callback != nullptr)
                {
                    callback(totalToDownload, nowDownloaded, data.url, data.customId);
                }
            }
        });
    }
    
    return 0;
}

Downloader::Downloader()
: _connectionTimeout(DEFAULT_TIMEOUT)
, _onError(nullptr)
, _onProgress(nullptr)
, _onSuccess(nullptr)
, _supportResuming(false)
{
    _fileUtils = FileUtils::getInstance();
}

Downloader::~Downloader()
{
}

int Downloader::getConnectionTimeout()
{
    return _connectionTimeout;
}

void Downloader::setConnectionTimeout(int timeout)
{
    if (timeout >= 0)
        _connectionTimeout = timeout;
}

void Downloader::notifyError(ErrorCode code, const std::string &msg/* ="" */, const std::string &customId/* ="" */, int curle_code/* = CURLE_OK*/, int curlm_code/* = CURLM_OK*/)
{
    std::weak_ptr<Downloader> ptr = shared_from_this();
    Director::getInstance()->getScheduler()->performFunctionInCocosThread([=]{
        if (!ptr.expired())
        {
            std::shared_ptr<Downloader> downloader = ptr.lock();
            if (downloader->_onError != nullptr)
            {
                Error err;
                err.code = code;
                err.curle_code = curle_code;
                err.curlm_code = curlm_code;
                err.message = msg;
                err.customId = customId;
                downloader->_onError(err);
            }
        }
    });
}

void Downloader::notifyError(const std::string &msg, int curlm_code, const std::string &customId/* = ""*/)
{
    notifyError(ErrorCode::CURL_MULTI_ERROR, msg, customId, CURLE_OK, curlm_code);
}

void Downloader::notifyError(const std::string &msg, const std::string &customId, int curle_code)
{
    notifyError(ErrorCode::CURL_EASY_ERROR, msg, customId, curle_code);
}

std::string Downloader::getFileNameFromUrl(const std::string &srcUrl)
{
    // Find file name and file extension
    std::string filename;
    unsigned long found = srcUrl.find_last_of("/\\");
    if (found != std::string::npos)
        filename = srcUrl.substr(found+1);
    return filename;
}

void Downloader::clearBatchDownloadData()
{
    while (_progDatas.size() != 0) {
        delete _progDatas.back();
        _progDatas.pop_back();
    }
    
    while (_files.size() != 0) {
        delete _files.back();
        _files.pop_back();
    }
}

void Downloader::prepareDownload(const std::string &srcUrl, const std::string &storagePath, const std::string &customId, bool resumeDownload, FileDescriptor *fDesc, ProgressData *pData)
{
    std::shared_ptr<Downloader> downloader = shared_from_this();
    pData->customId = customId;
    pData->url = srcUrl;
    pData->downloader = downloader;
    pData->downloaded = 0;
    pData->totalToDownload = 0;
    
    fDesc->fp = nullptr;
    fDesc->curl = nullptr;
    
    Error err;
    err.customId = customId;
    
    // Asserts
    // Find file name and file extension
    unsigned long found = storagePath.find_last_of("/\\");
    if (found != std::string::npos)
    {
        pData->name = storagePath.substr(found+1);
        pData->path = storagePath.substr(0, found+1);
    }
    else
    {
        err.code = ErrorCode::INVALID_URL;
        err.message = "Invalid url or filename not exist error: " + srcUrl;
        if (this->_onError) this->_onError(err);
        return;
    }
    
    // Create a file to save file.
    const std::string outFileName = storagePath + TEMP_EXT;
    if (_supportResuming && resumeDownload && _fileUtils->isFileExist(outFileName))
    {
        fDesc->fp = fopen(outFileName.c_str(), "ab");
    }
    else
    {
        fDesc->fp = fopen(outFileName.c_str(), "wb");
    }
    if (!fDesc->fp)
    {
        err.code = ErrorCode::CREATE_FILE;
        err.message = StringUtils::format("Can not create file %s: errno %d", outFileName.c_str(), errno);
        if (this->_onError) this->_onError(err);
    }
}

bool Downloader::prepareHeader(void *curl, const std::string &srcUrl) const
{
    curl_easy_setopt(curl, CURLOPT_URL, srcUrl.c_str());
    curl_easy_setopt(curl, CURLOPT_HEADER, 1);
    curl_easy_setopt(curl, CURLOPT_NOBODY, 1);
    if (curl_easy_perform(curl) == CURLE_OK)
        return true;
    else
        return false;
}

long Downloader::getContentSize(const std::string &srcUrl) const
{
    double contentLength = -1;
    CURL *header = curl_easy_init();
    if (prepareHeader(header, srcUrl))
    {
        curl_easy_getinfo(header, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &contentLength);
    }
    curl_easy_cleanup(header);
    
    return contentLength;
}

void Downloader::downloadToBufferAsync(const std::string &srcUrl, unsigned char *buffer, const long &size, const std::string &customId/* = ""*/)
{
    if (buffer != nullptr)
    {
        std::shared_ptr<Downloader> downloader = shared_from_this();
        ProgressData pData;
        pData.customId = customId;
        pData.url = srcUrl;
        pData.downloader = downloader;
        pData.downloaded = 0;
        pData.totalToDownload = 0;
        
        StreamData streamBuffer;
        streamBuffer.buffer = buffer;
        streamBuffer.total = size;
        streamBuffer.offset = 0;
        
        auto t = std::thread(&Downloader::downloadToBuffer, this, srcUrl, customId, streamBuffer, pData);
        t.detach();
    }
}

void Downloader::downloadToBufferSync(const std::string &srcUrl, unsigned char *buffer, const long &size, const std::string &customId/* = ""*/)
{
    if (buffer != nullptr)
    {
        std::shared_ptr<Downloader> downloader = shared_from_this();
        ProgressData pData;
        pData.customId = customId;
        pData.url = srcUrl;
        pData.downloader = downloader;
        pData.downloaded = 0;
        pData.totalToDownload = 0;
        
        StreamData streamBuffer;
        streamBuffer.buffer = buffer;
        streamBuffer.total = size;
        streamBuffer.offset = 0;
        
        downloadToBuffer(srcUrl, customId, streamBuffer, pData);
    }
}

void Downloader::downloadToBuffer(const std::string &srcUrl, const std::string &customId, const StreamData &buffer, const ProgressData &data)
{
    std::weak_ptr<Downloader> ptr = shared_from_this();
    CURL *curl = curl_easy_init();
    if (!curl)
    {
        this->notifyError(ErrorCode::CURL_EASY_ERROR, "Can not init curl with curl_easy_init", customId);
        return;
    }
    
    // Download pacakge
    curl_easy_setopt(curl, CURLOPT_URL, srcUrl.c_str());
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, bufferWriteFunc);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &buffer);
    curl_easy_setopt(curl, CURLOPT_NOPROGRESS, false);
    curl_easy_setopt(curl, CURLOPT_PROGRESSFUNCTION, downloadProgressFunc);
    curl_easy_setopt(curl, CURLOPT_PROGRESSDATA, &data);
    curl_easy_setopt(curl, CURLOPT_FAILONERROR, true);
    if (_connectionTimeout) curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, _connectionTimeout);
    curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1L);
    curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, LOW_SPEED_LIMIT);
    curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, LOW_SPEED_TIME);
    
    CURLcode res = curl_easy_perform(curl);
    if (res != CURLE_OK)
    {
        _fileUtils->removeFile(data.path + data.name + TEMP_EXT);
        std::string msg = StringUtils::format("Unable to download file: [curl error]%s", curl_easy_strerror(res));
        this->notifyError(msg, customId, res);
    }
    
    curl_easy_cleanup(curl);
    
    Director::getInstance()->getScheduler()->performFunctionInCocosThread([=]{
        if (!ptr.expired())
        {
            std::shared_ptr<Downloader> downloader = ptr.lock();
            
            auto successCB = downloader->getSuccessCallback();
            if (successCB != nullptr)
            {
                successCB(data.url, "", data.customId);
            }
        }
    });
}

void Downloader::downloadAsync(const std::string &srcUrl, const std::string &storagePath, const std::string &customId/* = ""*/)
{
    FileDescriptor fDesc;
    ProgressData pData;
    prepareDownload(srcUrl, storagePath, customId, false, &fDesc, &pData);
    if (fDesc.fp != NULL)
    {
        auto t = std::thread(&Downloader::download, this, srcUrl, customId, fDesc, pData);
        t.detach();
    }
}

void Downloader::downloadSync(const std::string &srcUrl, const std::string &storagePath, const std::string &customId/* = ""*/)
{
    FileDescriptor fDesc;
    ProgressData pData;
    prepareDownload(srcUrl, storagePath, customId, false, &fDesc, &pData);
    if (fDesc.fp != NULL)
    {
        download(srcUrl, customId, fDesc, pData);
    }
}

void Downloader::download(const std::string &srcUrl, const std::string &customId, const FileDescriptor &fDesc, const ProgressData &data)
{
    std::weak_ptr<Downloader> ptr = shared_from_this();
    CURL *curl = curl_easy_init();
    if (!curl)
    {
        this->notifyError(ErrorCode::CURL_EASY_ERROR, "Can not init curl with curl_easy_init", customId);
        return;
    }
    
    // Download pacakge
    curl_easy_setopt(curl, CURLOPT_URL, srcUrl.c_str());
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fileWriteFunc);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, fDesc.fp);
    curl_easy_setopt(curl, CURLOPT_NOPROGRESS, false);
    curl_easy_setopt(curl, CURLOPT_PROGRESSFUNCTION, downloadProgressFunc);
    curl_easy_setopt(curl, CURLOPT_PROGRESSDATA, &data);
    curl_easy_setopt(curl, CURLOPT_FAILONERROR, true);
    if (_connectionTimeout) curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, _connectionTimeout);
    curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1L);
    curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, LOW_SPEED_LIMIT);
    curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, LOW_SPEED_TIME);
    
    CURLcode res = curl_easy_perform(curl);
    if (res != CURLE_OK)
    {
        _fileUtils->removeFile(data.path + data.name + TEMP_EXT);
        std::string msg = StringUtils::format("Unable to download file: [curl error]%s", curl_easy_strerror(res));
        this->notifyError(msg, customId, res);
    }
    
    fclose(fDesc.fp);
    curl_easy_cleanup(curl);
    
    // This can only be done after fclose
    if (res == CURLE_OK)
    {
        _fileUtils->renameFile(data.path, data.name + TEMP_EXT, data.name);
        
        Director::getInstance()->getScheduler()->performFunctionInCocosThread([=]{
            if (!ptr.expired())
            {
                std::shared_ptr<Downloader> downloader = ptr.lock();
                
                auto successCB = downloader->getSuccessCallback();
                if (successCB != nullptr)
                {
                    successCB(data.url, data.path + data.name, data.customId);
                }
            }
        });
    }
}

void Downloader::batchDownloadAsync(const DownloadUnits &units, const std::string &batchId/* = ""*/)
{
    auto t = std::thread(&Downloader::batchDownloadSync, this, units, batchId);
    t.detach();
}

void Downloader::batchDownloadSync(const DownloadUnits &units, const std::string &batchId/* = ""*/)
{
    if (units.size() == 0)
    {
        return;
    }
    // Make sure downloader won't be released
    std::weak_ptr<Downloader> ptr = shared_from_this();
    
    // Test server download resuming support with the first unit
    _supportResuming = false;
    CURL *header = curl_easy_init();
    // Make a resume request
    curl_easy_setopt(header, CURLOPT_RESUME_FROM_LARGE, 0);
    if (prepareHeader(header, units.begin()->second.srcUrl))
    {
        long responseCode;
        curl_easy_getinfo(header, CURLINFO_RESPONSE_CODE, &responseCode);
        if (responseCode == HTTP_CODE_SUPPORT_RESUME)
        {
            _supportResuming = true;
        }
    }
    curl_easy_cleanup(header);
    
    int count = 0;
    DownloadUnits group;
    for (auto it = units.cbegin(); it != units.cend(); ++it, ++count)
    {
        if (count == FOPEN_MAX)
        {
            groupBatchDownload(group);
            group.clear();
            count = 0;
        }
        const std::string &key = it->first;
        const DownloadUnit &unit = it->second;
        group.emplace(key, unit);
    }
    if (group.size() > 0)
    {
        groupBatchDownload(group);
    }
    
    Director::getInstance()->getScheduler()->performFunctionInCocosThread([ptr, batchId]{
        if (!ptr.expired()) {
            std::shared_ptr<Downloader> downloader = ptr.lock();
            auto callback = downloader->getSuccessCallback();
            if (callback != nullptr)
            {
                callback("", "", batchId);
            }
        }
    });
    _supportResuming = false;
}

void Downloader::groupBatchDownload(const DownloadUnits &units)
{
    CURLM* multi_handle = curl_multi_init();
    int still_running = 0;
    
    for (auto it = units.cbegin(); it != units.cend(); ++it)
    {
        DownloadUnit unit = it->second;
        std::string srcUrl = unit.srcUrl;
        std::string storagePath = unit.storagePath;
        std::string customId = unit.customId;
        
        FileDescriptor *fDesc = new FileDescriptor();
        ProgressData *data = new ProgressData();
        prepareDownload(srcUrl, storagePath, customId, unit.resumeDownload, fDesc, data);
        
        if (fDesc->fp != NULL)
        {
            CURL* curl = curl_easy_init();
            curl_easy_setopt(curl, CURLOPT_URL, srcUrl.c_str());
            curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fileWriteFunc);
            curl_easy_setopt(curl, CURLOPT_WRITEDATA, fDesc->fp);
            curl_easy_setopt(curl, CURLOPT_NOPROGRESS, false);
            curl_easy_setopt(curl, CURLOPT_PROGRESSFUNCTION, batchDownloadProgressFunc);
            curl_easy_setopt(curl, CURLOPT_PROGRESSDATA, data);
            curl_easy_setopt(curl, CURLOPT_FAILONERROR, true);
            if (_connectionTimeout) curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, _connectionTimeout);
            curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1L);
            curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, LOW_SPEED_LIMIT);
            curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, LOW_SPEED_TIME);
            curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, true);
            curl_easy_setopt(curl, CURLOPT_MAXREDIRS, MAX_REDIRS);
            
            // Resuming download support
            if (_supportResuming && unit.resumeDownload)
            {
                // Check already downloaded size for current download unit
                long size = _fileUtils->getFileSize(storagePath + TEMP_EXT);
                if (size != -1)
                {
                    curl_easy_setopt(curl, CURLOPT_RESUME_FROM_LARGE, size);
                }
            }
            fDesc->curl = curl;
            
            CURLMcode code = curl_multi_add_handle(multi_handle, curl);
            if (code != CURLM_OK)
            {
                // Avoid memory leak
                fclose(fDesc->fp);
                delete data;
                delete fDesc;
                std::string msg = StringUtils::format("Unable to add curl handler for %s: [curl error]%s", customId.c_str(), curl_multi_strerror(code));
                this->notifyError(msg, code, customId);
            }
            else
            {
                // Add to list for tracking
                _progDatas.push_back(data);
                _files.push_back(fDesc);
            }
        }
    }
    
    // Query multi perform
    CURLMcode curlm_code = CURLM_CALL_MULTI_PERFORM;
    while(CURLM_CALL_MULTI_PERFORM == curlm_code) {
        curlm_code = curl_multi_perform(multi_handle, &still_running);
    }
    if (curlm_code != CURLM_OK) {
        std::string msg = StringUtils::format("Unable to continue the download process: [curl error]%s", curl_multi_strerror(curlm_code));
        this->notifyError(msg, curlm_code);
    }
    else
    {
        bool failed = false;
        while (still_running > 0 && !failed)
        {
            // set a suitable timeout to play around with
            struct timeval select_tv;
            long curl_timeo = -1;
            select_tv.tv_sec = 1;
            select_tv.tv_usec = 0;
            
            curl_multi_timeout(multi_handle, &curl_timeo);
            if(curl_timeo >= 0) {
                select_tv.tv_sec = curl_timeo / 1000;
                if(select_tv.tv_sec > 1)
                    select_tv.tv_sec = 1;
                else
                    select_tv.tv_usec = (curl_timeo % 1000) * 1000;
            }
            
            int rc;
            fd_set fdread;
            fd_set fdwrite;
            fd_set fdexcep;
            int maxfd = -1;
            FD_ZERO(&fdread);
            FD_ZERO(&fdwrite);
            FD_ZERO(&fdexcep);
            curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
            rc = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &select_tv);
            
            switch(rc)
            {
                case -1:
                    failed = true;
                    break;
                case 0:
                default:
                    curlm_code = CURLM_CALL_MULTI_PERFORM;
                    while(CURLM_CALL_MULTI_PERFORM == curlm_code) {
                        curlm_code = curl_multi_perform(multi_handle, &still_running);
                    }
                    if (curlm_code != CURLM_OK) {
                        std::string msg = StringUtils::format("Unable to continue the download process: [curl error]%s", curl_multi_strerror(curlm_code));
                        this->notifyError(msg, curlm_code);
                    }
                    break;
            }
        }
    }
    
    // Clean up and close files
    curl_multi_cleanup(multi_handle);
    for (auto it = _files.begin(); it != _files.end(); ++it)
    {
        FILE *f = (*it)->fp;
        fclose(f);
        auto single = (*it)->curl;
        curl_multi_remove_handle(multi_handle, single);
        curl_easy_cleanup(single);
    }
    
    // Check unfinished files and notify errors, succeed files will be renamed from temporary file name to real name
    for (auto it = _progDatas.begin(); it != _progDatas.end(); ++it) {
        ProgressData *data = *it;
        if (data->downloaded < data->totalToDownload || data->totalToDownload == 0)
        {
            this->notifyError(ErrorCode::NETWORK, "Unable to download file", data->customId);
        }
        else
        {
            _fileUtils->renameFile(data->path, data->name + TEMP_EXT, data->name);
        }
    }
    
    clearBatchDownloadData();
}

NS_CC_EXT_END