/*
 * Copyright (c) 2000, Red Hat, Inc.
 *
 *     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 2 of the License, or
 *     (at your option) any later version.
 *
 *     A copy of the GNU General Public License can be found at
 *     http://www.gnu.org/
 *
 * Written by DJ Delorie <dj@cygnus.com>
 *
 */

/* The purpose of this file is to manage internet downloads using the
   Internet Explorer version 5 DLLs.  To use this method, the user
   must already have installed and configured IE5.  This module is
   called from netio.cc, which is called from geturl.cc */

#include "win32.h"

#include "resource.h"
#include "state.h"
#include "dialog.h"
#include "msg.h"
#include "netio.h"
#include "nio-ie5.h"
#include "LogSingleton.h"
#include "setup_version.h"
#include "getopt++/StringOption.h"
#include <sstream>
#include <iomanip>

static StringOption UserAgent ("", '\0', "user-agent", IDS_HELPTEXT_USER_AGENT);

static const std::string
machine_name(USHORT machine)
{
  switch (machine)
    {
    case IMAGE_FILE_MACHINE_I386:
      return "Win32";
      break;
    case IMAGE_FILE_MACHINE_AMD64:
      return "Win64";
      break;
    case IMAGE_FILE_MACHINE_ARM64:
      return "ARM64";
      break;
    default:
      std::stringstream machine_desc;
      machine_desc << std::hex << machine;
      return machine_desc.str();
    }
}

const std::string &
determine_default_useragent(void)
{
  static std::string default_useragent;

  if (!default_useragent.empty())
    return default_useragent;

  std::stringstream os;
  os << "Windows NT " << OSMajorVersion() << "." << OSMinorVersion() << "." << OSBuildNumber();

#ifdef __x86_64__
  USHORT processMachine = IMAGE_FILE_MACHINE_AMD64;
#else
  USHORT processMachine = IMAGE_FILE_MACHINE_I386;
#endif

  USHORT nativeMachine = WowNativeMachine();

  std::string bitness;
  if (processMachine != nativeMachine)
    bitness = machine_name(processMachine) + "-on-" + machine_name(nativeMachine);
  else
    bitness = machine_name(processMachine);

  typedef LANGID (WINAPI *PFNGETTHREADUILANGUAGE)();
  PFNGETTHREADUILANGUAGE pfnGetThreadUILanguage = (PFNGETTHREADUILANGUAGE)GetProcAddress(GetModuleHandle("kernel32"), "GetThreadUILanguage");
  std::stringstream langid;
  if (pfnGetThreadUILanguage)
    {
      LANGID l = pfnGetThreadUILanguage();
      langid << std::hex << std::setw(4) << std::setfill('0') << l;
    }

  std::string symlinks = "";
  if (nt_sec.hasSymlinkCreationRights())
    symlinks.append("SymLinkPriv");
  if (is_developer_mode())
    {
      if (!symlinks.empty())
        symlinks.append("+");
      symlinks.append("UnprivilegedSymLink");
    }

  default_useragent = std::string("Cygwin-Setup/") + setup_version + " (" + os.str() + ";" + bitness + ";" + langid.str() + ";" + symlinks + ")";
  Log (LOG_BABBLE) << "User-Agent: default is \"" << default_useragent << "\"" << endLog;

  return default_useragent;
}


class Proxy
{
  int method;
  std::string host;
  int port;
  std::string hostport;  // host:port

public:
  Proxy (int method, char const *host, int port)
    : method(method),
      host(host ? host : ""),
      port(port),
      hostport(std::string(host ? host : "") + ":" + std::to_string(port))
    {};

  bool operator!= (const Proxy &o) const;

  DWORD type (void) const;
  char const *string (void) const;
};

bool Proxy::operator!= (const Proxy &o) const
{
    if (method != o.method) return true;
    if (method != IDC_NET_PROXY) return false;
    // it's only meaningful to compare host:port for method == IDC_NET_PROXY
    if (host != o.host) return true;
    if (port != o.port) return true;
    return false;
}

char const *Proxy::string(void) const
{
  if (method == IDC_NET_PROXY)
    return hostport.c_str();
  else
    return NULL;
}

DWORD Proxy::type (void) const
{
  switch (method)
    {
      case IDC_NET_PROXY: return INTERNET_OPEN_TYPE_PROXY;
      case IDC_NET_PRECONFIG: return INTERNET_OPEN_TYPE_PRECONFIG;
      default:
      case IDC_NET_DIRECT: return INTERNET_OPEN_TYPE_DIRECT;
    }
}

static HINTERNET internet = 0;
static Proxy last_proxy = Proxy(-1, "", -1);

NetIO_IE5::NetIO_IE5 (char const *url, bool cachable)
{
  int resend = 0;

  Proxy proxy = Proxy(net_method, net_proxy_host, net_proxy_port);
  if (proxy != last_proxy)
    {
      last_proxy = proxy;

      if (internet != 0)
        InternetCloseHandle(internet);
      else
        InternetAttemptConnect (0);

      const char *lpszAgent = determine_default_useragent().c_str();
      if (UserAgent.isPresent())
        {
          const std::string &user_agent = UserAgent;
          if (user_agent.length())
            {
              // override the default user agent string
              lpszAgent = user_agent.c_str();
              Log (LOG_PLAIN) << "User-Agent: header overridden to \"" << lpszAgent << "\"" << endLog;
            }
          else
            {
              // user-agent option is present, but no string is specified means
              // don't add a user-agent header
              lpszAgent = NULL;
              Log (LOG_PLAIN) << "User-Agent: header suppressed " << lpszAgent << endLog;
            }
        }

      internet = InternetOpen (lpszAgent, proxy.type(), proxy.string(), NULL, 0);
    }

  DWORD flags =
    INTERNET_FLAG_KEEP_CONNECTION |
    INTERNET_FLAG_EXISTING_CONNECT | INTERNET_FLAG_PASSIVE;

  if (!cachable) {
    flags |= INTERNET_FLAG_NO_CACHE_WRITE;
  } else {
    flags |= INTERNET_FLAG_RESYNCHRONIZE;
  }

  connection = InternetOpenUrl (internet, url, NULL, 0, flags, 0);

try_again:

  if (net_user && net_passwd)
    {
      InternetSetOption (connection, INTERNET_OPTION_USERNAME,
			 net_user, strlen (net_user));
      InternetSetOption (connection, INTERNET_OPTION_PASSWORD,
			 net_passwd, strlen (net_passwd));
    }

  if (net_proxy_user && net_proxy_passwd)
    {
      InternetSetOption (connection, INTERNET_OPTION_PROXY_USERNAME,
			 net_proxy_user, strlen (net_proxy_user));
      InternetSetOption (connection, INTERNET_OPTION_PROXY_PASSWORD,
			 net_proxy_passwd, strlen (net_proxy_passwd));
    }

  if (resend)
    if (!HttpSendRequest (connection, 0, 0, 0, 0))
      connection = 0;

  if (!connection)
    {
      DWORD e = GetLastError ();
      if (e == ERROR_INTERNET_EXTENDED_ERROR)
        {
          char buf[2000];
          DWORD e, l = sizeof (buf);
          InternetGetLastResponseInfo (&e, buf, &l);

          // show errors apart from file-not-found (e doesn't contain the
          // response code so we have to resort to looking at the message)
          if (strncmp("550", buf, 3) != 0)
            mbox (0, IDS_NIO_ERROR, MB_OK, buf);

          for (unsigned int i = 0; i < l; i++)
            if (buf[i] == '\n' or buf[i] == '\r')
              buf[i] = ' ';
          Log (LOG_PLAIN) << "connection error: " << buf << " fetching " << url << endLog;
        }
      else
        {
          Log (LOG_PLAIN) << "connection error: " << e << " fetching " << url << endLog;
        }
    }

  ULONG type = 0;
  DWORD type_s = sizeof (type);
  InternetQueryOption (connection, INTERNET_OPTION_HANDLE_TYPE,
		       &type, &type_s);

  switch (type)
    {
    case INTERNET_HANDLE_TYPE_HTTP_REQUEST:
    case INTERNET_HANDLE_TYPE_CONNECT_HTTP:
      type_s = sizeof (DWORD);
      if (HttpQueryInfo (connection,
			 HTTP_QUERY_STATUS_CODE | HTTP_QUERY_FLAG_NUMBER,
			 &type, &type_s, NULL))
	{
	  if (type != 200)
	    Log (LOG_PLAIN) << "HTTP status " << type << " fetching " << url << endLog;

	  if (type == 401)	/* authorization required */
	    {
	      flush_io ();
	      get_auth (NULL);
	      resend = 1;
	      goto try_again;
	    }
	  else if (type == 407)	/* proxy authorization required */
	    {
	      flush_io ();
	      get_proxy_auth (NULL);
	      resend = 1;
	      goto try_again;
	    }
	  else if (type >= 300)
	    {
	      InternetCloseHandle (connection);
	      connection = 0;
	      return;
	    }
	}
    }

  InternetQueryOption (connection, INTERNET_OPTION_REQUEST_FLAGS,
                       &type, &type_s);
  if (type & INTERNET_REQFLAG_FROM_CACHE)
    Log (LOG_BABBLE) << "Request for URL " << url << " satisfied from cache" << endLog;
}

void
NetIO_IE5::flush_io ()
{
  DWORD actual = 0;
  char buf[1024];
  do
    {
      InternetReadFile (connection, buf, 1024, &actual);
    }
  while (actual > 0);
}

NetIO_IE5::~NetIO_IE5 ()
{
  if (connection)
    InternetCloseHandle (connection);
}

int
NetIO_IE5::ok ()
{
  return (connection == NULL) ? 0 : 1;
}

int
NetIO_IE5::read (char *buf, int nbytes)
{
#define READ_CHUNK (64 * 1024)
  /* Read in chunks rather than the whole file at once, so we can do progress
     reporting */
  if (nbytes > READ_CHUNK)
    nbytes = READ_CHUNK;

  DWORD actual;
  if (InternetReadFile (connection, buf, nbytes, &actual))
    return actual;

  return -1;
}