/**
 * @file ssu.cpp
 * @copyright 2012 Jolla Ltd.
 * @author Bernd Wachter <bernd.wachter@jollamobile.com>
 * @date 2012
 */

#include <QtNetwork>
#include <QtXml/QDomDocument>

#if QT_VERSION >= QT_VERSION_CHECK(5, 0, 0)
#include <QUrlQuery>
#endif

#include <getdef.h>
#include <pwd.h>

#include "ssu.h"
#include "ssulog.h"
#include "ssuvariables.h"
#include "ssucoreconfig.h"
#include "ssurepomanager.h"

#include "../constants.h"

Ssu::Ssu(): QObject(){
  errorFlag = false;
  pendingRequests = 0;

#ifdef SSUCONFHACK
  // dirty hack to make sure we can write to the configuration
  // this is currently required since there's no global gconf,
  // and we migth not yet have users on bootstrap
  QFileInfo settingsInfo(SSU_CONFIGURATION);
  if (settingsInfo.groupId() != SSU_GROUP_ID ||
      !settingsInfo.permission(QFile::WriteGroup)){
    QProcess proc;
    proc.start("/usr/bin/ssuconfperm");
    proc.waitForFinished();
  }
#endif

  SsuCoreConfig *settings = SsuCoreConfig::instance();

#ifdef TARGET_ARCH
  if (!settings->contains("arch"))
    settings->setValue("arch", TARGET_ARCH);
#else
// FIXME, try to guess a matching architecture
#warning "TARGET_ARCH not defined"
#endif
  settings->sync();



  manager = new QNetworkAccessManager(this);
  connect(manager, SIGNAL(finished(QNetworkReply *)),
          SLOT(requestFinished(QNetworkReply *)));
}

// FIXME, the whole credentials stuff needs reworking
// should probably be part of repo handling instead of core configuration
QPair<QString, QString> Ssu::credentials(QString scope){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->credentials(scope);
}

QString Ssu::credentialsScope(QString repoName, bool rndRepo){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->credentialsScope(repoName, rndRepo);
}

QString Ssu::credentialsUrl(QString scope){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->credentialsUrl(scope);
}

bool Ssu::error(){
  return errorFlag;
}

// Wrappers around SsuCoreConfig
QString Ssu::flavour(){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->flavour();
}

int Ssu::deviceMode(){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->deviceMode();
}

QString Ssu::domain(){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->domain(true);
}

bool Ssu::isRegistered(){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->isRegistered();
}

QDateTime Ssu::lastCredentialsUpdate(){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->lastCredentialsUpdate();
}

QString Ssu::release(bool rnd){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->release(rnd);
}

void Ssu::setDeviceMode(int mode, int editMode){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  settings->setDeviceMode(mode, editMode);
}

void Ssu::setFlavour(QString flavour){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  settings->setFlavour(flavour);
}

void Ssu::setRelease(QString release, bool rnd){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  settings->setRelease(release, rnd);
}

void Ssu::setDomain(QString domain){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  settings->setDomain(domain);
}

bool Ssu::useSslVerify(){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  return settings->useSslVerify();
}

//...



QString Ssu::lastError(){
  return errorString;
}

bool Ssu::registerDevice(QDomDocument *response){
  QString certificateString = response->elementsByTagName("certificate").at(0).toElement().text();
  QSslCertificate certificate(certificateString.toLatin1());
  SsuLog *ssuLog = SsuLog::instance();
  SsuCoreConfig *settings = SsuCoreConfig::instance();

  if (certificate.isNull()){
    // make sure device is in unregistered state on failed registration
    settings->setValue("registered", false);
    setError("Certificate is invalid");
    return false;
  } else
    settings->setValue("certificate", certificate.toPem());

  QString privateKeyString = response->elementsByTagName("privateKey").at(0).toElement().text();
  QSslKey privateKey(privateKeyString.toLatin1(), QSsl::Rsa);

  if (privateKey.isNull()){
    settings->setValue("registered", false);
    setError("Private key is invalid");
    return false;
  } else
    settings->setValue("privateKey", privateKey.toPem());

  // oldUser is just for reference purposes, in case we want to notify
  // about owner changes for the device
  QString oldUser = response->elementsByTagName("user").at(0).toElement().text();
  ssuLog->print(LOG_DEBUG, QString("Old user for your device was: %1").arg(oldUser));

  // if we came that far everything required for device registration is done
  settings->setValue("registered", true);
  settings->sync();
  emit registrationStatusChanged();
  return true;
}

// RND repos have flavour (devel, testing, release), and release (latest, next)
// Release repos only have release (latest, next, version number)
QString Ssu::repoUrl(QString repoName, bool rndRepo,
                     QHash<QString, QString> repoParameters,
                     QHash<QString, QString> parametersOverride){
  SsuRepoManager manager;
  return manager.url(repoName, rndRepo, repoParameters, parametersOverride);
}

void Ssu::requestFinished(QNetworkReply *reply){
  QSslConfiguration sslConfiguration = reply->sslConfiguration();
  SsuLog *ssuLog = SsuLog::instance();
  SsuCoreConfig *settings = SsuCoreConfig::instance();

#if QT_VERSION >= QT_VERSION_CHECK(5, 0, 0)
  ssuLog->print(LOG_DEBUG, QString("Certificate used was issued for '%1' by '%2'. Complete chain:")
                .arg(sslConfiguration.peerCertificate().subjectInfo(QSslCertificate::CommonName).join(""))
                .arg(sslConfiguration.peerCertificate().issuerInfo(QSslCertificate::CommonName).join("")));

  foreach (const QSslCertificate cert, sslConfiguration.peerCertificateChain()){
    ssuLog->print(LOG_DEBUG, QString("-> %1").arg(cert.subjectInfo(QSslCertificate::CommonName).join("")));
  }
#else
  ssuLog->print(LOG_DEBUG, QString("Certificate used was issued for '%1' by '%2'. Complete chain:")
               .arg(sslConfiguration.peerCertificate().subjectInfo(QSslCertificate::CommonName))
               .arg(sslConfiguration.peerCertificate().issuerInfo(QSslCertificate::CommonName)));

  foreach (const QSslCertificate cert, sslConfiguration.peerCertificateChain()){
    ssuLog->print(LOG_DEBUG, QString("-> %1").arg(cert.subjectInfo(QSslCertificate::CommonName)));
  }
#endif

  /// @TODO: indicate that the device is not registered if there's a 404 on credentials update url
  // what sucks more, this or goto?
  do {
    if (settings->contains("home-url")){
      QString homeUrl = settings->value("home-url").toString().arg("");
      homeUrl.remove(QRegExp("//+$"));
      QNetworkRequest request = reply->request();

      if (request.url().toString().startsWith(homeUrl, Qt::CaseInsensitive)){
        // we don't care about errors on download request
        if (reply->error() > 0) break;
        QByteArray data = reply->readAll();
        storeAuthorizedKeys(data);
        break;
      }
    }

    if (reply->error() > 0){
      pendingRequests--;
      setError(reply->errorString());
      return;
    } else {
      QByteArray data = reply->readAll();
      qDebug() << "RequestOutput" << data;

      QDomDocument doc;
      QString xmlError;
      if (!doc.setContent(data, &xmlError)){
        pendingRequests--;
        setError(tr("Unable to parse server response (%1)").arg(xmlError));
        return;
      }

      QString action = doc.elementsByTagName("action").at(0).toElement().text();

      if (!verifyResponse(&doc)) break;

      if (action == "register"){
        if (!registerDevice(&doc)) break;
      } else if (action == "credentials"){
        if (!setCredentials(&doc)) break;
      } else {
        pendingRequests--;
        setError(tr("Response to unknown action encountered: %1").arg(action));
        return;
      }
    }
  } while (false);

  pendingRequests--;

  ssuLog->print(LOG_DEBUG, QString("Request finished, pending requests: %1").arg(pendingRequests));
  if (pendingRequests == 0)
    emit done();
}

void Ssu::sendRegistration(QString usernameDomain, QString password){
  errorFlag = false;

  QString ssuCaCertificate, ssuRegisterUrl;
  QString username, domainName;

  SsuLog *ssuLog = SsuLog::instance();
  SsuCoreConfig *settings = SsuCoreConfig::instance();

  // Username can include also domain, (user@domain), separate those
  if (usernameDomain.contains('@')) {
      // separate domain/username and set domain
      username = usernameDomain.section('@', 0, 0);
      domainName = usernameDomain.section('@', 1, 1);
      setDomain(domainName);
  } else {
      // No domain defined
      username = usernameDomain;
  }

  ssuCaCertificate = SsuRepoManager::caCertificatePath();
  if (ssuCaCertificate.isEmpty()){
    setError("CA certificate for SSU not set ('_ca-certificate in domain')");
    return;
  }

  if (!settings->contains("register-url")){
    ssuRegisterUrl = repoUrl("register-url");
    if (ssuRegisterUrl.isEmpty()){
      setError("URL for SSU registration not set (config key 'register-url')");
      return;
    }
  } else
    ssuRegisterUrl = settings->value("register-url").toString();

  QString IMEI = deviceInfo.deviceUid();
  if (IMEI == ""){
    setError("No valid UID available for your device. For phones: is your modem online?");
    return;
  }

  QSslConfiguration sslConfiguration;
  if (!useSslVerify())
    sslConfiguration.setPeerVerifyMode(QSslSocket::VerifyNone);

  sslConfiguration.setCaCertificates(QSslCertificate::fromPath(ssuCaCertificate));

  QNetworkRequest request;
  request.setUrl(QUrl(QString(ssuRegisterUrl)
                      .arg(IMEI)
                   ));
  request.setSslConfiguration(sslConfiguration);
  request.setRawHeader("Authorization", "Basic " +
                       QByteArray(QString("%1:%2")
                                  .arg(username).arg(password)
                                  .toLatin1()).toBase64());
  request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");

  QUrl form;

#if QT_VERSION >= QT_VERSION_CHECK(5, 0, 0)
  QUrlQuery q;
  q.addQueryItem("protocolVersion", SSU_PROTOCOL_VERSION);
  q.addQueryItem("deviceModel", deviceInfo.deviceModel());
  if (!domain().isEmpty()){
    q.addQueryItem("domain", domain());
  }

  form.setQuery(q);
#else
  form.addQueryItem("protocolVersion", SSU_PROTOCOL_VERSION);
  form.addQueryItem("deviceModel", deviceInfo.deviceModel());
  if (!domain().isEmpty()){
    form.addQueryItem("domain", domain());
  }
#endif

  qDebug() << "Sending request to " << request.url();
  //qDebug() << form.encodedQueryItems();

  QNetworkReply *reply;

  pendingRequests++;
#if QT_VERSION >= QT_VERSION_CHECK(5, 0, 0)
  reply = manager->post(request, form.query(QUrl::FullyEncoded).toStdString().c_str());
#else
  reply = manager->post(request, form.encodedQuery());
#endif
  // we could expose downloadProgress() from reply in case we want progress info

  QString homeUrl = settings->value("home-url").toString().arg(username);
  if (!homeUrl.isEmpty()){
    // clear header, the other request bits are reusable
    request.setHeader(QNetworkRequest::ContentTypeHeader, 0);
    request.setUrl(homeUrl + "/authorized_keys");
    ssuLog->print(LOG_DEBUG, QString("Trying to get SSH keys from %1").arg(request.url().toString()));
    pendingRequests++;
    manager->get(request);
  }
}

bool Ssu::setCredentials(QDomDocument *response){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  // generate list with all scopes for generic section, add sections
  QDomNodeList credentialsList = response->elementsByTagName("credentials");
  QStringList credentialScopes;
  for (int i=0;i<credentialsList.size();i++){
    QDomNode node = credentialsList.at(i);
    QString scope;

    QDomNamedNodeMap attributes = node.attributes();
    if (attributes.contains("scope")){
      scope = attributes.namedItem("scope").toAttr().value();
    } else {
      setError(tr("Credentials element does not have scope"));
      return false;
    }

    if (node.hasChildNodes()){
      QDomElement username = node.firstChildElement("username");
      QDomElement password = node.firstChildElement("password");
      if (username.isNull() || password.isNull()){
        setError(tr("Username and/or password not set"));
        return false;
      } else {
        settings->beginGroup("credentials-" + scope);
        settings->setValue("username", username.text());
        settings->setValue("password", password.text());
        settings->endGroup();
        settings->sync();
        credentialScopes.append(scope);
      }
    } else {
      setError("");
      return false;
    }
  }
  settings->setValue("credentialScopes", credentialScopes);
  settings->setValue("lastCredentialsUpdate", QDateTime::currentDateTime());
  settings->sync();
  emit credentialsChanged();

  return true;
}

void Ssu::setError(QString errorMessage){
  errorFlag = true;
  errorString = errorMessage;

  SsuLog *ssuLog = SsuLog::instance();

  // dump error message to systemd journal for easier debugging
  ssuLog->print(LOG_WARNING, errorMessage);

  // assume that we don't even need to wait for other pending requests,
  // and just die. This is only relevant for CLI, which will exit after done()
  emit done();
}

void Ssu::storeAuthorizedKeys(QByteArray data){
  QDir dir;
  SsuLog *ssuLog = SsuLog::instance();

  int uid_min = getdef_num("UID_MIN", -1);
  QString homePath;

  if (getuid() >= uid_min){
    homePath = dir.homePath();
  } else if (getuid() == 0){
    // place authorized_keys in the default users home when run with uid0
    struct passwd *pw = getpwuid(uid_min);
    if (pw == NULL){
      ssuLog->print(LOG_DEBUG, QString("Unable to find password entry for uid %1")
                    .arg(uid_min));
      return;
    }

    //homePath = QString(pw->pw_dir);
    homePath = pw->pw_dir;

    // use users uid/gid for creating the directories and files
    setegid(pw->pw_gid);
    seteuid(uid_min);
    ssuLog->print(LOG_DEBUG, QString("Dropping to %1/%2 for writing authorized keys")
                  .arg(uid_min)
                  .arg(pw->pw_gid));
  } else
    return;

  if (dir.exists(homePath + "/.ssh/authorized_keys")){
    ssuLog->print(LOG_DEBUG, QString(".ssh/authorized_keys already exists in %1")
                  .arg(homePath));
    return;
  }

  if (!dir.exists(homePath + "/.ssh"))
    if (!dir.mkdir(homePath + "/.ssh")){
      ssuLog->print(LOG_DEBUG, QString("Unable to create .ssh in %1")
                    .arg(homePath));
      return;
    }

  QFile::setPermissions(homePath + "/.ssh",
                        QFile::ReadOwner | QFile::WriteOwner | QFile::ExeOwner);

  QFile authorizedKeys(homePath + "/.ssh/authorized_keys");
  authorizedKeys.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Truncate);
  authorizedKeys.setPermissions(QFile::ReadOwner | QFile::WriteOwner);
  QTextStream out(&authorizedKeys);
  out << data;
  out.flush();
  authorizedKeys.close();

  if (getuid() == 0){
    seteuid(0);
    setegid(0);
  }
}

void Ssu::updateCredentials(bool force){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  errorFlag = false;

  SsuLog *ssuLog = SsuLog::instance();

  if (deviceInfo.deviceUid() == ""){
    setError("No valid UID available for your device. For phones: is your modem online?");
    return;
  }

  QString ssuCaCertificate, ssuCredentialsUrl;
  ssuCaCertificate = SsuRepoManager::caCertificatePath();
  if (ssuCaCertificate.isEmpty()){
    setError("CA certificate for SSU not set ('_ca-certificate in domain')");
    return;
  }

  if (!settings->contains("credentials-url")){
    ssuCredentialsUrl = repoUrl("credentials-url");
    if (ssuCredentialsUrl.isEmpty()){
      setError("URL for credentials update not set (config key 'credentials-url')");
      return;
    }
  } else
    ssuCredentialsUrl = settings->value("credentials-url").toString();

  if (!isRegistered()){
    setError("Device is not registered.");
    return;
  }

  if (!force){
    // skip updating if the last update was less than 30 minutes ago
    QDateTime now = QDateTime::currentDateTime();

    if (settings->contains("lastCredentialsUpdate")){
      QDateTime last = settings->value("lastCredentialsUpdate").toDateTime();
      if (last >= now.addSecs(-1800)){
        ssuLog->print(LOG_DEBUG, QString("Skipping credentials update, last update was at %1")
                     .arg(last.toString()));
        emit done();
        return;
      }
    }
  }

  // check when the last update was, decide if an update is required
  QSslConfiguration sslConfiguration;
  if (!useSslVerify())
    sslConfiguration.setPeerVerifyMode(QSslSocket::VerifyNone);

  QSslKey privateKey(settings->value("privateKey").toByteArray(), QSsl::Rsa);
  QSslCertificate certificate(settings->value("certificate").toByteArray());

  QList<QSslCertificate> caCertificates;
  caCertificates << QSslCertificate::fromPath(ssuCaCertificate);
  sslConfiguration.setCaCertificates(caCertificates);

  sslConfiguration.setPrivateKey(privateKey);
  sslConfiguration.setLocalCertificate(certificate);

  QNetworkRequest request;
  request.setUrl(QUrl(ssuCredentialsUrl.arg(deviceInfo.deviceUid())));

  ssuLog->print(LOG_DEBUG, QString("Sending credential update request to %1")
               .arg(request.url().toString()));
  request.setSslConfiguration(sslConfiguration);

  pendingRequests++;
  manager->get(request);
}


void Ssu::unregister(){
  SsuCoreConfig *settings = SsuCoreConfig::instance();
  settings->setValue("privateKey", "");
  settings->setValue("certificate", "");
  settings->setValue("registered", false);
  settings->sync();
  emit registrationStatusChanged();
}

bool Ssu::verifyResponse(QDomDocument *response){
  QString action = response->elementsByTagName("action").at(0).toElement().text();
  QString deviceId = response->elementsByTagName("deviceId").at(0).toElement().text();
  QString protocolVersion = response->elementsByTagName("protocolVersion").at(0).toElement().text();
  // compare device ids

  if (protocolVersion != SSU_PROTOCOL_VERSION){
    setError(
      tr("Response has unsupported protocol version %1, client requires version %2")
      .arg(protocolVersion)
      .arg(SSU_PROTOCOL_VERSION)
      );
    return false;
  }

  return true;
}