/*
 * Copyright (C) 2014 Red Hat
 *
 * This file is part of openconnect-gui.
 *
 * openconnect-gui 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.
 *
 * 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 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 "vpninfo.h"
#include "config.h"
#include "dialog/MyCertMsgBox.h"
#include "dialog/MyInputDialog.h"
#include "dialog/MyMsgBox.h"
#include "dialog/mainwindow.h"
#include "gtdb.h"
#include "logger.h"
#include "server_storage.h"

#include <QDir>

#include <cstdarg>
#include <cstdio>

static int last_form_empty;

static void stats_vfn(void* privdata, const struct oc_stats* stats)
{
    VpnInfo* vpn = static_cast<VpnInfo*>(privdata);
    const char* cipher;
    QString dtls;

    cipher = openconnect_get_dtls_cipher(vpn->vpninfo);
    if (cipher != nullptr) {
        dtls = QLatin1String(cipher);
    }

    vpn->m->updateStats(stats, dtls);
}

static void progress_vfn(void* privdata, int level, const char* fmt, ...)
{
    VpnInfo* vpn = static_cast<VpnInfo*>(privdata);
    char buf[512];
    size_t len;
    va_list args;

    /* don't spam */
    if (level == PRG_TRACE)
        return;

    buf[0] = 0;
    va_start(args, fmt);
    vsnprintf(buf, sizeof(buf), fmt, args);
    va_end(args);

    len = strlen(buf);
    if (buf[len - 1] == '\n')
        buf[len - 1] = 0;
    Logger::instance().addMessage(buf);
}

static int process_auth_form(void* privdata, struct oc_auth_form* form)
{
    VpnInfo* vpn = static_cast<VpnInfo*>(privdata);
    bool ok;
    QString text;
    struct oc_form_opt* opt;
    QStringList gitems;
    QStringList ditems;
    int i, idx;

    if (form->banner) {
        Logger::instance().addMessage(QLatin1String(form->banner));
    }

    if (form->message) {
        Logger::instance().addMessage(QLatin1String(form->message));
    }

    if (form->error) {
        Logger::instance().addMessage(QLatin1String(form->error));
    }

    int empty = 1;
    if (form->authgroup_opt) {
        struct oc_form_opt_select* select_opt = form->authgroup_opt;

        for (i = 0; i < select_opt->nr_choices; i++) {
            ditems << select_opt->choices[i]->label;
            gitems << select_opt->choices[i]->name;
        }

        if (select_opt->nr_choices == 1) {
            openconnect_set_option_value(&select_opt->form,
                select_opt->choices[0]->name);
        } else if (gitems.contains(vpn->ss->get_groupname())) {
            openconnect_set_option_value(&select_opt->form,
                vpn->ss->get_groupname().toLatin1().data());
        } else {
            {
                MyInputDialog dialog(vpn->m,
                    QLatin1String(select_opt->form.name),
                    QLatin1String(select_opt->form.label),
                    ditems);
                dialog.show();
                ok = dialog.result(text);
            }

            if (!ok)
                goto fail;

            idx = ditems.indexOf(text);
            if (idx == -1)
                goto fail;

            openconnect_set_option_value(&select_opt->form,
                select_opt->choices[idx]->name);
            text = QLatin1String(select_opt->choices[idx]->name);

            Logger::instance().addMessage(QLatin1String("Saving group: ") + text);
            vpn->ss->set_groupname(text);
        }

        if (vpn->authgroup_set == 0) {
            vpn->authgroup_set = 1;
            return OC_FORM_RESULT_NEWGROUP;
        }
    }

    for (opt = form->opts; opt; opt = opt->next) {
        text.clear();
        if (opt->flags & OC_FORM_OPT_IGNORE)
            continue;

        if (opt->type == OC_FORM_OPT_SELECT) {
            QStringList items;
            struct oc_form_opt_select* select_opt = reinterpret_cast<oc_form_opt_select*>(opt);

            Logger::instance().addMessage(QLatin1String("Select form: ") + QLatin1String(opt->name));

            if (select_opt == form->authgroup_opt) {
                continue;
            }

            for (i = 0; i < select_opt->nr_choices; i++) {
                items << select_opt->choices[i]->label;
            }

            {
                MyInputDialog dialog(vpn->m, QLatin1String(opt->name),
                    QLatin1String(opt->label), items);
                dialog.show();
                ok = dialog.result(text);
            }

            if (!ok)
                goto fail;

            idx = ditems.indexOf(text);
            if (idx == -1)
                goto fail;

            openconnect_set_option_value(opt, select_opt->choices[idx]->name);
            empty = 0;
        } else if (opt->type == OC_FORM_OPT_TEXT) {
            Logger::instance().addMessage(QLatin1String("Text form: ") + QLatin1String(opt->name));

            if (vpn->form_attempt == 0
                && vpn->ss->get_username().isEmpty() == false
                && strcasecmp(opt->name, "username") == 0) {
                openconnect_set_option_value(opt,
                    vpn->ss->get_username().toLatin1().data());
                empty = 0;
                continue;
            }

            do {
                MyInputDialog dialog(vpn->m, QLatin1String(opt->name),
                    QLatin1String(opt->label),
                    QLineEdit::Normal);
                dialog.show();
                ok = dialog.result(text);

                if (!ok)
                    goto fail;
            } while (text.isEmpty());

            if (strcasecmp(opt->name, "username") == 0) {
                vpn->ss->set_username(text);
            }

            openconnect_set_option_value(opt, text.toLatin1().data());
            vpn->form_attempt++;
            empty = 0;
        } else if (opt->type == OC_FORM_OPT_PASSWORD) {
            Logger::instance().addMessage(QLatin1String("Password form: ") + QLatin1String(opt->name));

            if (vpn->form_pass_attempt == 0
                && vpn->ss->get_password().isEmpty() == false
                && strcasecmp(opt->name, "password") == 0) {
                openconnect_set_option_value(opt,
                    vpn->ss->get_password().toLatin1().data());
                empty = 0;
                continue;
            }

            do {
                MyInputDialog dialog(vpn->m, QLatin1String(opt->name),
                    QLatin1String(opt->label),
                    QLineEdit::Password);
                dialog.show();
                ok = dialog.result(text);

                if (!ok)
                    goto fail;
            } while (text.isEmpty() == true);

            if (strcasecmp(opt->name, "password") == 0
                && (vpn->password_set == 0 || vpn->form_pass_attempt != 0)) {
                vpn->ss->set_password(text);
                vpn->password_set = 1;
            }
            openconnect_set_option_value(opt, text.toLatin1().data());
            vpn->form_pass_attempt++;
            empty = 0;
        } else {
            Logger::instance().addMessage(QLatin1String("unknown type ") + QString::number((int)opt->type));
        }
    }

    /* prevent infinite loops if the authgroup requires certificate auth only */
    if (last_form_empty && empty) {
        return OC_FORM_RESULT_CANCELLED;
    }
    last_form_empty = empty;

    return OC_FORM_RESULT_OK;
fail:
    return OC_FORM_RESULT_CANCELLED;
}

static int validate_peer_cert(void* privdata, const char* reason)
{
    VpnInfo* vpn = static_cast<VpnInfo*>(privdata);
    unsigned char* der = nullptr;
    int der_size = openconnect_get_peer_cert_DER(vpn->vpninfo, &der);
    if (der_size <= 0) {
        Logger::instance().addMessage(QObject::tr("Peer's certificate has invalid size!"));
        return -1;
    }

    const char* hash = openconnect_get_peer_cert_hash(vpn->vpninfo);
    if (hash == nullptr) {
        Logger::instance().addMessage(QObject::tr("Error getting peer's certificate hash"));
        return -1;
    }

    gnutls_datum_t raw;
    raw.data = der;
    raw.size = der_size;

    gtdb tdb(vpn->ss);
    int ret = gnutls_verify_stored_pubkey(reinterpret_cast<const char*>(&tdb),
        tdb.tdb, "", "", GNUTLS_CRT_X509, &raw, 0);

    char* details = openconnect_get_peer_cert_details(vpn->vpninfo);
    QString dstr;
    if (details != nullptr) {
        dstr = QString::fromUtf8(details);
        free(details);
    }

    bool save = false;
    if (ret == GNUTLS_E_NO_CERTIFICATE_FOUND) {
        Logger::instance().addMessage(QObject::tr("peer is unknown"));

        QString hostInfoStr = QObject::tr("Host: ") + vpn->ss->get_servername() + QObject::tr("\n") + hash;
        MyCertMsgBox msgBox(
            vpn->m,
            QObject::tr("You are connecting for the first time to this peer.\n"
                        "You have no guarantee that the server is the computer you think it is.\n\n"
                        "If the information provided bellow is valid and you trust this host, "
                        "hit 'Accurate information' to remember it and to carry on connecting.\n"
                        "If you do not trust this host, hit Cancel to abandon the connection."),
            hostInfoStr,
            QObject::tr("Accurate information"),
            dstr);
        msgBox.show();
        if (msgBox.result() == false) {
            return -1;
        }

        save = true;
    } else if (ret == GNUTLS_E_CERTIFICATE_KEY_MISMATCH) {
        Logger::instance().addMessage(QObject::tr("peer's key has changed!"));

        QString str = QObject::tr("Host: ") + vpn->ss->get_servername() + QObject::tr("\n") + hash;

        MyCertMsgBox msgBox(vpn->m,
            QObject::tr("This peer is known and associated with a different key."
                        "It may be that the server has multiple keys "
                        "or you are (or were in the past) under attack. "
                        "Do you want to proceed?"),
            str,
            QObject::tr("The key was changed by the administrator"),
            dstr);
        msgBox.show();
        if (msgBox.result() == false) {
            return -1;
        }

        save = true;
    } else if (ret < 0) {
        QString str = QObject::tr("Could not verify certificate: ");
        str += gnutls_strerror(ret);
        Logger::instance().addMessage(str);
        return -1;
    }

    if (save != false) {
        Logger::instance().addMessage(QObject::tr("saving peer's public key"));
        ret = gnutls_store_pubkey(reinterpret_cast<const char*>(&tdb), tdb.tdb,
            "", "", GNUTLS_CRT_X509, &raw, 0, 0);
        if (ret < 0) {
            QString str = QObject::tr("Could not store certificate: ");
            str += gnutls_strerror(ret);
            Logger::instance().addMessage(str);
        } else {
            vpn->ss->save();
        }
    }
    return 0;
}

static int lock_token_vfn(void* privdata)
{
    VpnInfo* vpn = static_cast<VpnInfo*>(privdata);

    openconnect_set_token_mode(vpn->vpninfo,
        (oc_token_mode_t)vpn->ss->get_token_type(),
        vpn->ss->get_token_str().toLatin1().data());

    return 0;
}

static int unlock_token_vfn(void* privdata, const char* newtok)
{
    VpnInfo* vpn = static_cast<VpnInfo*>(privdata);

    vpn->ss->set_token_str(newtok);
    vpn->ss->save();
    return 0;
}

static void setup_tun_vfn(void* privdata)
{
    VpnInfo* vpn = static_cast<VpnInfo*>(privdata);

    QByteArray vpncScriptFullPath;
    vpncScriptFullPath.append(QCoreApplication::applicationDirPath());
    vpncScriptFullPath.append(QDir::separator());
    vpncScriptFullPath.append(DEFAULT_VPNC_SCRIPT);
    int ret = openconnect_setup_tun_device(vpn->vpninfo, vpncScriptFullPath.constData(), NULL);
    if (ret != 0) {
        vpn->last_err = QObject::tr("Error setting up the TUN device");
        //FIXME: ???        return ret;
    }

    vpn->logVpncScriptOutput();
}

static inline int set_sock_block(int fd)
{
#ifdef _WIN32
    unsigned long mode = 0;
    return ioctlsocket(fd, FIONBIO, &mode);
#else
    return fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) & ~O_NONBLOCK);
#endif
}

VpnInfo::VpnInfo(QString name, StoredServer* ss, MainWindow* m)
{
    this->vpninfo = openconnect_vpninfo_new(name.toLatin1().data(), validate_peer_cert, nullptr,
        process_auth_form, progress_vfn, this);
    if (this->vpninfo == nullptr) {
        throw std::runtime_error("initial setup fails");
    }

    this->cmd_fd = openconnect_setup_cmd_pipe(vpninfo);
    if (this->cmd_fd == INVALID_SOCKET) {
        Logger::instance().addMessage(QObject::tr("invalid socket"));
        throw std::runtime_error("pipe setup fails");
    }
    set_sock_block(this->cmd_fd);

    this->last_err = "";
    this->ss = ss;
    this->m = m;
    authgroup_set = 0;
    password_set = 0;
    form_attempt = 0;
    form_pass_attempt = 0;
    openconnect_set_stats_handler(this->vpninfo, stats_vfn);
    if (ss->get_token_str().isEmpty() == false) {
        openconnect_set_token_callbacks(this->vpninfo, this, lock_token_vfn, unlock_token_vfn);
        openconnect_set_token_mode(this->vpninfo,
            (oc_token_mode_t)ss->get_token_type(),
            ss->get_token_str().toLatin1().data());
    }

    openconnect_set_protocol(vpninfo, ss->get_protocol_name());

    openconnect_set_setup_tun_handler(vpninfo, setup_tun_vfn);
}

VpnInfo::~VpnInfo()
{
    if (vpninfo != nullptr) {
        openconnect_vpninfo_free(vpninfo);
    }

    if (ss != nullptr) {
        delete ss;
    }
}

void VpnInfo::parse_url(const char* url)
{
    openconnect_parse_url(this->vpninfo, const_cast<char*>(url));
}

int VpnInfo::connect()
{
    int ret;
    QString cert_file, key_file;
    QString ca_file;

    cert_file = ss->get_cert_file();
    ca_file = ss->get_ca_cert_file();
    key_file = ss->get_key_file();

    if (key_file.isEmpty() == true)
        key_file = cert_file;

    if (cert_file.isEmpty() != true) {
        openconnect_set_client_cert(vpninfo, cert_file.toLatin1().data(),
            key_file.toLatin1().data());
    }

    if (ca_file.isEmpty() != true) {
        openconnect_set_system_trust(vpninfo, 0);
        openconnect_set_cafile(vpninfo, ca_file.toLatin1().data());
    }

#ifdef Q_OS_WIN32
    const QString osName{ "win" };
#elif defined Q_OS_OSX
    const QString osName{ "mac-intel" };
#elif defined Q_OS_LINUX
    const QString osName = QString("linux%1").arg(QSysInfo::buildCpuArchitecture() == "i386" ? "" : "-64").toStdString().c_str();
#elif defined Q_OS_FREEBSD
    const QString osName = QString("freebsd%1").arg(QSysInfo::buildCpuArchitecture() == "i386" ? "" : "-64").toStdString().c_str();
#else
#error Define OS string of other platforms...
#endif
    openconnect_set_reported_os(vpninfo, osName.toStdString().c_str());

    ret = openconnect_obtain_cookie(vpninfo);
    if (ret != 0) {
        this->last_err = QObject::tr("Authentication error; cannot obtain cookie");
        return ret;
    }

    ret = openconnect_make_cstp_connection(vpninfo);
    if (ret != 0) {
        this->last_err = QObject::tr("Error establishing the CSTP channel");
        return ret;
    }

    return 0;
}

int VpnInfo::dtls_connect()
{
    if (this->ss->get_disable_udp() != true) {
        int ret = openconnect_setup_dtls(vpninfo,
            ss->get_dtls_reconnect_timeout());
        if (ret != 0) {
            this->last_err = QObject::tr("Error setting up DTLS");
            return ret;
        }
    }

    return 0;
}

void VpnInfo::mainloop()
{
    while (true) {
        int ret = openconnect_mainloop(vpninfo,
            ss->get_reconnect_timeout(),
            RECONNECT_INTERVAL_MIN);
        if (ret != 0) {
            this->last_err = QObject::tr("Disconnected");
            logVpncScriptOutput();
            break;
        }
    }
}

void VpnInfo::get_info(QString& dns, QString& ip, QString& ip6)
{
    const struct oc_ip_info* info;
    int ret = openconnect_get_ip_info(this->vpninfo, &info, nullptr, nullptr);
    if (ret == 0) {
        if (info->addr) {
            ip = info->addr;
            if (info->netmask) {
                ip += "/";
                ip += info->netmask;
            }
        }
        if (info->addr6) {
            ip6 = info->addr6;
            if (info->netmask6) {
                ip6 += "/";
                ip6 += info->netmask6;
            }
        }

        dns = info->dns[0];
        if (info->dns[1]) {
            dns += ", ";
            dns += info->dns[1];
        }
        if (info->dns[2]) {
            dns += " ";
            dns += info->dns[2];
        }
    }
    return;
}

void VpnInfo::get_cipher_info(QString& cstp, QString& dtls)
{
    const char* cipher = openconnect_get_cstp_cipher(this->vpninfo);
    if (cipher != nullptr) {
        cstp = QLatin1String(cipher);
    }
    cipher = openconnect_get_dtls_cipher(this->vpninfo);
    if (cipher != nullptr) {
        dtls = QLatin1String(cipher);
    }
}

SOCKET VpnInfo::get_cmd_fd() const
{
    return cmd_fd;
}

void VpnInfo::reset_vpn()
{
    openconnect_reset_ssl(vpninfo);
    form_pass_attempt = 0;
    password_set = 0;
    authgroup_set = 0;
    form_attempt = 0;
}

bool VpnInfo::get_minimize() const
{
    return ss->get_minimize();
}

void VpnInfo::logVpncScriptOutput()
{
    /* now read %temp%\\vpnc.log and post it to our log */
    QString tfile = QDir::tempPath() + QDir::separator() + QLatin1String("vpnc.log");
    QFile file(tfile);
    if (file.open(QIODevice::ReadOnly) == true) {
        QTextStream in(&file);

        QString bannerMessage;
        bool processBannerMessage = false;

        while (!in.atEnd()) {
            const QString line{ in.readLine() };
            Logger::instance().addMessage(line);

            if (line == QLatin1String("--------------------- BANNER ---------------------")) {
                processBannerMessage = true;
                continue;
            }
            if (line == QLatin1String("------------------- BANNER end -------------------")) {
                processBannerMessage = false;
                continue;
            }
            if (processBannerMessage) {
                bannerMessage += line + "\n";
            }
        }
        file.close();
        if (file.remove() != true) {
            Logger::instance().addMessage(QLatin1String("Could not remove ") + tfile + ": " + QString::number((int)file.error()));
        }

        if (ss->get_batch_mode() != true && bannerMessage.isEmpty() == false) {
            // TODO: msgbox title; e.g. Accept/Continue + Disconnect on buttons
            MyMsgBox msgBox(this->m,
                bannerMessage,
                QString(""),
                QString("Accept"));
            msgBox.show();
            if (msgBox.result() == false) {
                this->m->on_disconnectClicked();
            }
        }
    } else {
        Logger::instance().addMessage(QLatin1String("Could not open ") + tfile + ": " + QString::number((int)file.error()));
    }
}
