/*
 * HTTPConnection.cpp
 *****************************************************************************
 * Copyright (C) 2014-2015 - VideoLAN and VLC Authors
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include "HTTPConnection.hpp"
#include "ConnectionParams.hpp"
#include "AuthStorage.hpp"
#include "Transport.hpp"
#include "../tools/Helper.h"

#include <cstdio>
#include <sstream>
#include <algorithm>
#include <vlc_stream.h>

using namespace adaptive::http;

AbstractConnection::AbstractConnection(vlc_object_t *p_object_)
{
    p_object = p_object_;
    available = true;
    bytesRead = 0;
    contentLength = 0;
}

AbstractConnection::~AbstractConnection()
{

}

bool AbstractConnection::prepare(const ConnectionParams &params_)
{
    if (!available)
        return false;
    params = params_;
    available = false;
    return true;
}

size_t AbstractConnection::getContentLength() const
{
    return contentLength;
}

const std::string & AbstractConnection::getContentType() const
{
    return contentType;
}

HTTPConnection::HTTPConnection(vlc_object_t *p_object_, AuthStorage *auth,
                               Transport *socket_, const ConnectionParams &proxy)
    : AbstractConnection( p_object_ )
{
    transport = socket_;
    char *psz_useragent = var_InheritString(p_object_, "http-user-agent");
    useragent = psz_useragent ? std::string(psz_useragent) : std::string("");
    free(psz_useragent);
    char *psz_referer = var_InheritString(p_object_, "http-referrer");
    referer = psz_referer ? std::string(psz_referer) : std::string("");
    free(psz_referer);
    std::replace_if(useragent.begin(), useragent.end(), [](const char &c){return !::isprint(c);}, ' ');
    std::replace_if(referer.begin(), referer.end(), [](const char &c){return !::isprint(c);}, ' ');
    queryOk = false;
    retries = 0;
    authStorage = auth;
    connectionClose = false;
    chunked = false;
    chunked_eof = false;
    chunkLength = 0;
    proxyparams = proxy;
}

HTTPConnection::~HTTPConnection()
{
    delete transport;
}

bool HTTPConnection::canReuse(const ConnectionParams &params_) const
{
    if( !available || params_.usesAccess() )
        return false;

    char *psz_proxy_url = vlc_getProxyUrl(params_.getUrl().c_str());
    if(psz_proxy_url)
    {
        ConnectionParams proxy(psz_proxy_url);
        free(psz_proxy_url);
        return (proxyparams.getHostname() == proxy.getHostname() &&
                proxyparams.getScheme() == proxy.getScheme() &&
                proxyparams.getPort() == proxy.getPort());
    }
    else return (params.getHostname() == params_.getHostname() &&
                 params.getScheme() == params_.getScheme() &&
                 params.getPort() == params_.getPort());
}

bool HTTPConnection::connect()
{
    if(proxyparams.getHostname().empty())
        return transport->connect(p_object, params.getHostname().c_str(),
                                         params.getPort());
    else
        return transport->connect(p_object, proxyparams.getHostname().c_str(),
                                         proxyparams.getPort());
}

bool HTTPConnection::connected() const
{
    return transport->connected();
}

void HTTPConnection::disconnect()
{
    queryOk = false;
    bytesRead = 0;
    contentLength = 0;
    connectionClose = false;
    chunked = false;
    chunkLength = 0;
    bytesRange = BytesRange();
    contentType = std::string();
    transport->disconnect();
}

RequestStatus HTTPConnection::request(const std::string &path,
                                      const BytesRange &range)
{
    queryOk = false;
    chunked = false;
    chunked_eof = false;
    chunkLength = 0;

    /* Set new path for this query */
    params.setPath(path);
    locationparams = ConnectionParams();

    msg_Dbg(p_object, "Retrieving %s @%zu", params.getUrl().c_str(),
                       range.isValid() ? range.getStartByte() : 0);

    std::string querypath;
    if(!proxyparams.getHostname().empty())
    {
        msg_Dbg(p_object, "Using proxy %s", proxyparams.getUrl().c_str());
        querypath = params.getUrl();
    }
    else querypath = path;

    if(!connected() && ( params.getHostname().empty() || !connect() ))
        return RequestStatus::GenericError;

    bytesRange = range;
    if(range.isValid() && range.getEndByte() > 0)
        contentLength = range.getEndByte() - range.getStartByte() + 1;

    std::string header = buildRequestHeader(querypath);
    if(connectionClose)
        header.append("Connection: close\r\n");
    header.append("\r\n");

    if(!send( header ))
    {
        transport->disconnect();
        if(!connectionClose)
        {
            /* server closed connection pipeline after last req. need new */
            connectionClose = true;
            return request(path, range);
        }
        return RequestStatus::GenericError;
    }

    RequestStatus status = parseReply();
    if(status == RequestStatus::Success)
    {
        queryOk = true;
    }
    else if(status == RequestStatus::Redirection)
    {
        transport->disconnect();
    }
    else if(status == RequestStatus::GenericError)
    {
        transport->disconnect();
        if(!connectionClose)
        {
            connectionClose = true;
            return request(path, range);
        }
    }

    return status;
}

ssize_t HTTPConnection::read(void *p_buffer, size_t len)
{
    if( !connected() ||
       (!queryOk && bytesRead == 0) )
        return VLC_EGENERIC;

    if(len == 0)
        return VLC_SUCCESS;

    queryOk = false;

    const size_t toRead = (contentLength) ? contentLength - bytesRead : len;
    if (toRead == 0)
        return VLC_SUCCESS;

    if(len > toRead)
        len = toRead;

    ssize_t ret = ( chunked ) ? readChunk(p_buffer, len)
                              : transport->read(p_buffer, len);
    if(ret >= 0)
        bytesRead += ret;

    if(ret < 0 || (size_t)ret < len || /* set EOF */
       (contentLength == bytesRead && connectionClose))
    {
        transport->disconnect();
        return ret;
    }

    return ret;
}

bool HTTPConnection::send(const std::string &data)
{
    return send(data.c_str(), data.length());
}

bool HTTPConnection::send(const void *buf, size_t size)
{
    return transport->send(buf, size);
}

RequestStatus HTTPConnection::parseReply()
{
    std::string statusline = readLine();

    if(statusline.empty())
        return RequestStatus::GenericError;

    if (statusline.compare(0, 9, "HTTP/1.1 ")!=0)
    {
        if(statusline.compare(0, 9, "HTTP/1.0 ")!=0)
            return RequestStatus::NotFound;
        else
            connectionClose = true;
    }

    std::istringstream ss(statusline.substr(9));
    ss.imbue(std::locale("C"));
    int replycode;
    ss >> replycode;

    std::string lines;
    for( ;; )
    {
        std::string l = readLine();
        if(l.empty())
            break;
        lines.append(l);

        size_t split = lines.find_first_of(':');
        if(split != std::string::npos)
        {
            size_t value = lines.find_first_not_of(' ', split + 1);
            if(value == std::string::npos)
                value = lines.length();
            onHeader(lines.substr(0, split), lines.substr(value));
            lines = std::string();
        }
    }

    if((replycode == 301 || replycode == 302 || replycode == 307 || replycode == 308) &&
       !locationparams.getUrl().empty())
    {
        msg_Info(p_object, "%d redirection to %s", replycode, locationparams.getUrl().c_str());
        if(locationparams.isLocal() && !params.isLocal())
        {
            msg_Err(p_object, "redirection to local rejected");
            return RequestStatus::GenericError;
        }
        return RequestStatus::Redirection;
    }
    else if (replycode != 200 && replycode != 206)
    {
        msg_Err(p_object, "Failed reading %s: %s", params.getUrl().c_str(), statusline.c_str());
        return RequestStatus::NotFound;
    }

    return RequestStatus::Success;
}

ssize_t HTTPConnection::readChunk(void *p_buffer, size_t len)
{
    size_t copied = 0;

    for( ; copied < len && !chunked_eof; )
    {
        /* adapted from access/http/chunked.c */
        if(chunkLength == 0)
        {
            std::string line = readLine();
            int end;
            if (std::sscanf(line.c_str(), "%zx%n", &chunkLength, &end) < 1
                    || (line[end] != '\0' && line[end] != ';' /* ignore extension(s) */))
                return -1;
        }

        if(chunkLength > 0)
        {
            size_t toread = len - copied;
            if(toread > chunkLength)
                toread = chunkLength;

            ssize_t in = transport->read(&((uint8_t*)p_buffer)[copied], toread);
            if(in < 0)
            {
                return (copied == 0) ? in : copied;
            }
            else if((size_t)in < toread)
            {
               return copied + in;
            }
            copied += in;
            chunkLength -= in;
        }
        else chunked_eof = true;

        if(chunkLength == 0)
        {
            char crlf[2];
            ssize_t in = transport->read(&crlf, 2);
            if(in < 2 || memcmp(crlf, "\r\n", 2))
                return (copied == 0) ? -1 : copied;
        }
    }

    return copied;
}

std::string HTTPConnection::readLine()
{
    return transport->readline();
}

void HTTPConnection::setUsed( bool b )
{
    available = !b;
    if(available)
    {
        if(!connectionClose && contentLength == bytesRead && (!chunked || chunked_eof))
        {
            queryOk = false;
            bytesRead = 0;
            contentLength = 0;
            bytesRange = BytesRange();
        }
        else  /* We can't resend request if we haven't finished reading */
            disconnect();
    }
}

void HTTPConnection::onHeader(const std::string &key,
                              const std::string &value)
{
    if(Helper::icaseEquals(key, "Content-Length"))
    {
        std::istringstream ss(value);
        ss.imbue(std::locale("C"));
        size_t length;
        ss >> length;
        contentLength = length;
    }
    else if (Helper::icaseEquals(key, "Connection") &&
             Helper::icaseEquals(value, "close"))
    {
        connectionClose = true;
    }
    else if (Helper::icaseEquals(key, "Transfer-Encoding") &&
             Helper::icaseEquals(value, "chunked"))
    {
        chunked = true;
    }
    else if(Helper::icaseEquals(key, "Content-Type"))
    {
        contentType = value;
    }
    else if(Helper::icaseEquals(key, "Location"))
    {
        locationparams = ConnectionParams();
        ConnectionParams loc = ConnectionParams( value );
        if(loc.getScheme().empty())
        {
            locationparams = params;
            locationparams.setPath(loc.getPath());
        }
        else locationparams = loc;
    }
    else if(Helper::icaseEquals(key, "Set-Cookie") && authStorage)
    {
        authStorage->addCookie( value, params );
    }
}

std::string HTTPConnection::buildRequestHeader(const std::string &path) const
{
    std::stringstream req;
    req.imbue(std::locale("C"));
    req << "GET " << path << " HTTP/1.1\r\n";
    if((params.getScheme() == "http" && params.getPort() != 80) ||
            (params.getScheme() == "https" && params.getPort() != 443))
    {
        req << "Host: " << params.getHostname() << ":" << params.getPort() << "\r\n";
    }
    else
    {
        req << "Host: " << params.getHostname() << "\r\n";
    }
    if(authStorage)
    {
        std::string cookie = authStorage->getCookie(params,
                                                    params.getScheme() == "https" ||
                                                    params.getPort() == 443);
        if(!cookie.empty())
            req << "Cookie: " << cookie << "\r\n";
    }
    req << "Cache-Control: no-cache" << "\r\n";
    if(!useragent.empty())
        req << "User-Agent: " << useragent << "\r\n";
    if(!referer.empty())
        req << "Referer: " << referer << "\r\n";
    req << extraRequestHeaders();
    return req.str();
}

std::string HTTPConnection::extraRequestHeaders() const
{
    std::stringstream ss;
    ss.imbue(std::locale("C"));
    if(bytesRange.isValid())
    {
        ss << "Range: bytes=" << bytesRange.getStartByte() << "-";
        if(bytesRange.getEndByte())
            ss << bytesRange.getEndByte();
        ss << "\r\n";
    }
    return ss.str();
}

const ConnectionParams & HTTPConnection::getRedirection() const
{
    return locationparams;
}

StreamUrlConnection::StreamUrlConnection(vlc_object_t *p_object)
    : AbstractConnection(p_object)
{
    p_streamurl = nullptr;
    bytesRead = 0;
    contentLength = 0;
}

StreamUrlConnection::~StreamUrlConnection()
{
    reset();
}

void StreamUrlConnection::reset()
{
    if(p_streamurl)
        vlc_stream_Delete(p_streamurl);
    p_streamurl = nullptr;
    bytesRead = 0;
    contentLength = 0;
    contentType = std::string();
    bytesRange = BytesRange();
}

bool StreamUrlConnection::canReuse(const ConnectionParams &params_) const
{
    if( !available || !params_.usesAccess() )
        return false;
    return (params.getHostname() == params_.getHostname() &&
            params.getScheme() == params_.getScheme() &&
            params.getPort() == params_.getPort());
}

RequestStatus StreamUrlConnection::request(const std::string &path,
                                           const BytesRange &range)
{
    reset();

    /* Set new path for this query */
    params.setPath(path);

    msg_Dbg(p_object, "Retrieving %s @%zu", params.getUrl().c_str(),
                      range.isValid() ? range.getStartByte() : 0);

    p_streamurl = vlc_stream_NewURL(p_object, params.getUrl().c_str());
    if(!p_streamurl)
        return RequestStatus::GenericError;

    char *psz_type = stream_ContentType(p_streamurl);
    if(psz_type)
    {
        contentType = std::string(psz_type);
        free(psz_type);
    }

    stream_t *p_chain = vlc_stream_FilterNew( p_streamurl, "inflate" );
    if( p_chain )
        p_streamurl = p_chain;

    if(range.isValid() && range.getEndByte() > 0)
    {
        if(vlc_stream_Seek(p_streamurl, range.getStartByte()) != VLC_SUCCESS)
        {
            vlc_stream_Delete(p_streamurl);
            return RequestStatus::GenericError;
        }
        bytesRange = range;
        contentLength = range.getEndByte() - range.getStartByte() + 1;
    }

    int64_t i_size = stream_Size(p_streamurl);
    if(i_size > -1)
    {
        if(!range.isValid() || contentLength > (size_t) i_size)
            contentLength = (size_t) i_size;
    }
    return RequestStatus::Success;
}

ssize_t StreamUrlConnection::read(void *p_buffer, size_t len)
{
    if( !p_streamurl )
        return VLC_EGENERIC;

    if(len == 0)
        return VLC_SUCCESS;

    const size_t toRead = (contentLength) ? contentLength - bytesRead : len;
    if (toRead == 0)
        return VLC_SUCCESS;

    if(len > toRead)
        len = toRead;

    ssize_t ret = vlc_stream_Read(p_streamurl, p_buffer, len);
    if(ret >= 0)
        bytesRead += ret;

    if(ret < 0 || (size_t)ret < len || /* set EOF */
       contentLength == bytesRead )
    {
        reset();
        return ret;
    }

    return ret;
}

void StreamUrlConnection::setUsed( bool b )
{
    available = !b;
    if(available && contentLength == bytesRead)
       reset();
}

NativeConnectionFactory::NativeConnectionFactory( AuthStorage *auth )
    : AbstractConnectionFactory()
{
    authStorage = auth;
}

NativeConnectionFactory::~NativeConnectionFactory()
{
}

AbstractConnection * NativeConnectionFactory::createConnection(vlc_object_t *p_object,
                                                         const ConnectionParams &params)
{
    if(params.usesAccess() ||
       (params.getScheme() != "http" && params.getScheme() != "https") ||
       params.getHostname().empty())
        return nullptr;

    ConnectionParams proxy;

    std::string scheme;
    char *psz_proxy_url = vlc_getProxyUrl(params.getUrl().c_str());
    if(psz_proxy_url)
    {
        proxy = ConnectionParams(psz_proxy_url);
        free(psz_proxy_url);
        scheme = proxy.getScheme();
    }
    else scheme = params.getScheme();

    Transport *socket = new (std::nothrow) Transport(params.getScheme() == "https");
    if(!socket)
        return nullptr;

    HTTPConnection *conn = new (std::nothrow)
            HTTPConnection(p_object, authStorage, socket, proxy);
    if(!conn)
    {
        delete socket;
        return nullptr;
    }

    return conn;
}

StreamUrlConnectionFactory::StreamUrlConnectionFactory()
    : AbstractConnectionFactory()
{

}

AbstractConnection * StreamUrlConnectionFactory::createConnection(vlc_object_t *p_object,
                                                                  const ConnectionParams &)
{
    return new (std::nothrow) StreamUrlConnection(p_object);
}