/*! @file
    
    @id $Id$
    */
//       1         2         3         4         5         6         7         8
// 45678901234567890123456789012345678901234567890123456789012345678901234567890

#ifndef PROXYFACE_HXX
#define PROXYFACE_HXX

#ifdef QT_NETWORK_LIB
#include <QtNetwork/QNetworkProxy>
#include <QtNetwork/QNetworkAccessManager>
#include <QtNetwork/QNetworkReply>
#include <QtCore/QTimer>
#include <QtCore/QDebug>
#include <map>
#endif

#include <list>
#include <string>
#include <sstream>

//! auto proxy configuration
namespace proxy {

  //! exceptions
  namespace exc {
    
    //! unspecific error
    class error: std::exception {
      public:
        virtual const char* what() const throw() {
          return "Auto Proxy Detection Error";
        }
    };

  }

  //! Proxy types
  enum Type {
    DIRECT,  //< direct connection, no proxy
    DEFAULT, //< default proxy
    HTTP,    //< HTTP proxy host
    SOCKS    //<SOCKS5 proxy
  };

  //! One proxy
  struct Proxy {
      Proxy(): type(DIRECT), port(0) {}
      Proxy(Type t, std::string h, unsigned int p): type(t), host(h), port(p) {}
      Proxy(Type t, std::string h, std::string p): type(t), host(h), port(0) {
        std::stringstream(p)>>port;
      }
      Type type;
      std::string host;
      unsigned int port;
  };

  //! List of proxies, type -> url and port
  typedef std::list<Proxy> List;
  
  //! Unified Interface for accessing proxy::Face
  /*! Abstract interface, impementation for Unix and Windoze differs.
      
      Instanciate proxy::Face, which is a typedef to your
      platform's implementation.
      
      @code
      proxy::Auto pf;        // keep for program life time (because of caching)
      proxy::List pf.proxies("http://swisssign.com");
      [...]                  // set proxy, read from http://swisssign.com
      @endcode

      @example test.cxx */
  class Interface
#ifdef QT_NETWORK_LIB
    : public QObject
#endif
  {
#ifdef QT_NETWORK_LIB
      Q_OBJECT;
#endif
    public:
      //! Keep your instance as long as possible, because of caching.
      Interface() {
#ifdef QT_NETWORK_LIB
        if (!connect(&_timeout, SIGNAL(timeout()), SLOT(timeout())))
          qFatal("connect failed");
#endif
      }
      virtual ~Interface() {}
      //! Get list of proxies for a given URL.
      virtual List proxies(const std::string& url) = 0;
#ifdef QT_NETWORK_LIB
      //! If Qt Network is available you may check the proxies found
      /*! First checks for direct access to the target. If this is not
          possible, starts scan for proxies.

          Returns immediately and signals proxyFound() if a valid
          configuration has been found, or proxyError() in case of
          timeout. You should wait for either of the signals, before you
          can call this method again.

          @param url the url to find a proxy for
          @param timeout [ms] time to give up search */
      void proxy(const std::string& url, int timeout=2000) {
        qDebug()<<"Search proxy for URL, direct and default"
                <<"url="<<url.data()<<"timeout="<<timeout;
        for (Requests::iterator it(_requests.begin()); it!=_requests.end(); ++it)
          delete it->second.first;
        _requests.clear();
        _direct = true; // first try direct access
        QNetworkProxy directProxy(QNetworkProxy::NoProxy);
        setupProxyCheck(directProxy, url);
        QNetworkProxy defaultProxy;
        setupProxyCheck(defaultProxy, url);
        _timeout.setSingleShot(true);
        _timeout.setInterval(timeout);
        _timeout.start();
      }
      //! If Qt Network is available you may check the proxies found
      /*! @copydoc proxy(const std::string&, int) */
      void proxy(const QUrl& url, int timeout=2000) {
        proxy(url.toString().toStdString(), timeout);
      }
      //! If Qt Network is available you may check the proxies found
      /*! @copydoc proxy(const std::string&, int) */
      void proxy(const QString& url, int timeout=2000) {
        proxy(url.toStdString(), timeout);
      }
      static QString toString(const QNetworkProxy& p) {
        switch (p.type()) {
          case QNetworkProxy::NoProxy:
            return QString("direct://");
          case QNetworkProxy::DefaultProxy:
            if (QNetworkProxy::applicationProxy().type()
                !=QNetworkProxy::DefaultProxy)
              return QString("Default Proxy: %1")
                .arg(toString(QNetworkProxy::applicationProxy()));
            else
              return QString("Default Proxy: **ERROR**"
                             " application proxy is configured as"
                             " QNetworkProxy::DefaultProxy");
          case QNetworkProxy::Socks5Proxy:
            return QString("socks://%1:%2").arg(p.hostName()).arg(p.port());
          case QNetworkProxy::HttpProxy:
            return QString("http://%1:%2").arg(p.hostName()).arg(p.port());
          case QNetworkProxy::HttpCachingProxy:
            return QString("http-cache://%1:%2").arg(p.hostName()).arg(p.port());
          case QNetworkProxy::FtpCachingProxy:
            return QString("ftp-cache://%1:%2").arg(p.hostName()).arg(p.port());
        }
        return QString("**ERROR** illegal proxy type");
      }
    Q_SIGNALS:
      //! Signals a valid proxy for the URL requested earlier.
      void proxyFound(const QUrl&, const QNetworkProxy&);
      //! Signals a timeout, and no valid proxy for the URL requested earlier.
      void proxyError(QNetworkReply::NetworkError);
    private:
      void setupProxyCheck(const QNetworkProxy& prxy, const std::string& url) {
        qDebug()<<"Testing proxy for url:"<<toString(prxy)<<"url="<<url.data();
        QNetworkAccessManager* manager(new QNetworkAccessManager);
        manager->setProxy(prxy);
        if (!connect(manager, SIGNAL(finished(QNetworkReply*)),
                    this, SLOT(replyFinished(QNetworkReply*))))
          qFatal("connect failed");
        _requests.insert
          (std::make_pair(manager->head
                          (QNetworkRequest
                           (QUrl(QString::fromStdString(url)))),
                          std::make_pair(manager, prxy)));
      }
    private Q_SLOTS:
      void timeout() {
        _timeout.stop();
        std::string url;
        for (Requests::iterator it(_requests.begin());
             it!=_requests.end(); ++it) {
          url = it->first->url().toString().toStdString();
          delete it->second.first;
        }
        _requests.clear();
        qDebug()<<"Proxy detection timed out"<<"url="<<url.data();
        if (_direct && url.size()) {
          qDebug()<<"Direct or preconfigured proxy not available,"
            " try autoproxy negotiation";
          _direct = false;
          List l(proxies(url));
          for (List::const_iterator it(l.begin()); it!=l.end(); ++it) {
            QNetworkProxy prxy((it->type==DEFAULT?QNetworkProxy::DefaultProxy
                                :(it->type==HTTP?QNetworkProxy::HttpProxy
                                  :(it->type==SOCKS?QNetworkProxy::Socks5Proxy
                                    :QNetworkProxy::NoProxy))),
                               QString::fromStdString(it->host), it->port);
            setupProxyCheck(prxy, url);
          }
          _timeout.start();
        } else {
          qDebug()<<"No proxy at all, giving up - offline?";
          proxyError(QNetworkReply::TimeoutError);
        }
      }
      void replyFinished(QNetworkReply* reply) {
        _timeout.stop();
        QNetworkProxy prxy(_requests[reply].second);
        QUrl url(reply->url());
        for (Requests::iterator it(_requests.begin()); it!=_requests.end(); ++it)
          delete it->second.first;
        _requests.clear();
        qDebug()<<"SUCCESS - Valid proxy found for url:"
                <<"url="<<url<<"proxy="<<toString(prxy);
        proxyFound(url, prxy);
      }
    private:
      typedef std::map
          <QNetworkReply*, std::pair<QNetworkAccessManager*, QNetworkProxy> >
          Requests;
      Requests _requests;
      bool _direct;
      QTimer _timeout;
#endif
  };
}

#ifdef WIN32
// use windoze proprietary winhttp
#include <proxyface/windoze.hxx>
namespace proxy {
  typedef Windoze Face;
}
#else
// normal operating systems: use http://code.google.com/p/libproxy
#include <proxyface/unix.hxx>
namespace proxy {
  typedef Unix Face;
}
#endif

#endif