/*
 * barrier -- mouse and keyboard sharing utility
 * Copyright (C) 2014-2016 Symless Ltd.
 *
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file LICENSE that should have accompanied this file.
 *
 * This package 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/>.
 */

#include "arch/win32/ArchInternetWindows.h"
#include "arch/win32/XArchWindows.h"
#include "arch/Arch.h"
#include "base/String.h"
#include "common/Version.h"

#include <sstream>
#include <Wininet.h>
#include <Shlwapi.h>

struct WinINetUrl {
    std::string m_scheme;
    std::string m_host;
    std::string m_path;
    INTERNET_PORT        m_port;
    DWORD                m_flags;
};

class WinINetRequest {
public:
    WinINetRequest(const std::string& url);
    ~WinINetRequest();

    std::string send();
    void                openSession();
    void                connect();
    void                openRequest();

private:
    HINTERNET            m_session;
    HINTERNET            m_connect;
    HINTERNET            m_request;
    WinINetUrl            m_url;
    bool                m_used;
};

//
// ArchInternetWindows
//

std::string ArchInternetWindows::get(const std::string& url)
{
    WinINetRequest request(url);
    return request.send();
}

std::string ArchInternetWindows::urlEncode(const std::string& url)
{
    TCHAR buffer[1024];
    DWORD bufferSize = sizeof(buffer);

    if (UrlEscape(url.c_str(), buffer, &bufferSize, URL_ESCAPE_UNSAFE) != S_OK) {
        throw XArch(new XArchEvalWindows());
    }

    std::string result(buffer);

    // the win32 url encoding functions are pretty useless (to us) and only
    // escape "unsafe" chars, but not + or =, so we need to replace these
    // manually (and probably many other chars).
    barrier::string::findReplaceAll(result, "+", "%2B");
    barrier::string::findReplaceAll(result, "=", "%3D");

    return result;
}

//
// WinINetRequest
//

static WinINetUrl parseUrl(const std::string& url);

WinINetRequest::WinINetRequest(const std::string& url) :
    m_session(NULL),
    m_connect(NULL),
    m_request(NULL),
    m_used(false),
    m_url(parseUrl(url))
{
}

WinINetRequest::~WinINetRequest()
{
    if (m_request != NULL) {
        InternetCloseHandle(m_request);
    }

    if (m_connect != NULL) {
        InternetCloseHandle(m_connect);
    }

    if (m_session != NULL) {
        InternetCloseHandle(m_session);
    }
}

std::string WinINetRequest::send()
{
    if (m_used) {
        throw XArch("class is one time use.");
    }
    m_used = true;

    openSession();
    connect();
    openRequest();

    std::string headers("Content-Type: text/html");
    if (!HttpSendRequest(m_request, headers.c_str(), (DWORD)headers.length(), NULL, NULL)) {
        throw XArch(new XArchEvalWindows());
    }

    std::stringstream result;
    CHAR buffer[1025];
    DWORD read = 0;

    while (InternetReadFile(m_request, buffer, sizeof(buffer) - 1, &read) && (read != 0)) {
        buffer[read] = 0;
        result << buffer;
        read = 0;
    }

    return result.str();
}

void WinINetRequest::openSession()
{
    std::stringstream userAgent;
    userAgent << "Barrier ";
    userAgent << kVersion;

    m_session = InternetOpen(
        userAgent.str().c_str(),
        INTERNET_OPEN_TYPE_PRECONFIG,
        NULL,
        NULL,
        NULL);

    if (m_session == NULL) {
        throw XArch(new XArchEvalWindows());
    }
}

void
WinINetRequest::connect()
{
    m_connect = InternetConnect(
        m_session,
        m_url.m_host.c_str(),
        m_url.m_port,
        NULL,
        NULL,
        INTERNET_SERVICE_HTTP,
        NULL,
        NULL);

    if (m_connect == NULL) {
        throw XArch(new XArchEvalWindows());
    }
}

void
WinINetRequest::openRequest()
{
    m_request = HttpOpenRequest(
        m_connect,
        "GET",
        m_url.m_path.c_str(),
        HTTP_VERSION,
        NULL,
        NULL,
        m_url.m_flags,
        NULL);

    if (m_request == NULL) {
        throw XArch(new XArchEvalWindows());
    }
}

// nb: i tried to use InternetCrackUrl here, but couldn't quite get that to
// work. here's some (less robust) code to split the url into components.
// this works fine with simple urls, but doesn't consider the full url spec.
static WinINetUrl parseUrl(const std::string& url)
{
    WinINetUrl parsed;

    size_t schemeEnd = url.find("://");
    size_t hostEnd = url.find('/', schemeEnd + 3);

    parsed.m_scheme = url.substr(0, schemeEnd);
    parsed.m_host = url.substr(schemeEnd + 3, hostEnd - (schemeEnd + 3));
    parsed.m_path = url.substr(hostEnd);

    parsed.m_port = INTERNET_DEFAULT_HTTP_PORT;
    parsed.m_flags = 0;

    if (parsed.m_scheme.find("https") != std::string::npos) {
        parsed.m_port = INTERNET_DEFAULT_HTTPS_PORT;
        parsed.m_flags = INTERNET_FLAG_SECURE;
    }

    return parsed;
}