/*
    Copyright 2019 Bruce Anderson <banderson19com@san.rr.com>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) version 3, or any
    later version accepted by the membership of KDE e.V. (or its
    successor approved by the membership of KDE e.V.), which shall
    act as a proxy defined in Section 6 of version 3 of the license.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library.  If not, see <http://www.gnu.org/licenses/>.
*/
#include "debug.h"
#include "wireguardpeerwidget.h"
#include "wireguardtabwidget.h"
#include "ui_wireguardpeerwidget.h"
#include "uiutils.h"
#include "simpleipv4addressvalidator.h"
#include "simpleiplistvalidator.h"
#include "wireguardkeyvalidator.h"

#include <QStandardItemModel>
#include <QUrl>

#include <NetworkManagerQt/Utils>
#include <NetworkManagerQt/WireguardSetting>
#include <NetworkManagerQt/Ipv4Setting>
#include <NetworkManagerQt/Ipv6Setting>
#include <KColorScheme>
#include <KConfig>
#include <KConfigGroup>

// Keys for the NetworkManager configuration
#define PNM_SETTING_WIREGUARD_SETTING_NAME "wireguard"

#define PNM_WG_KEY_PEERS             "peers"
#define PNM_WG_KEY_MTU               "mtu"
#define PNM_WG_KEY_PEER_ROUTES       "peer-routes"
#define PNM_WG_PEER_KEY_ALLOWED_IPS          "allowed-ips"
#define PNM_WG_PEER_KEY_ENDPOINT             "endpoint"
#define PNM_WG_PEER_KEY_PERSISTENT_KEEPALIVE "persistent-keepalive"
#define PNM_WG_PEER_KEY_PRESHARED_KEY        "preshared-key"
#define PNM_WG_PEER_KEY_PRESHARED_KEY_FLAGS  "preshared-key-flags"
#define PNM_WG_PEER_KEY_PUBLIC_KEY           "public-key"

static WireGuardKeyValidator keyValidator;
static SimpleIpListValidator allowedIPsValidator(SimpleIpListValidator::WithCidr, SimpleIpListValidator::Both);

class WireGuardPeerWidget::Private
{
public:
    Private();
    ~Private();

    Ui_WireGuardPeersProp ui;
    NetworkManager::WireGuardSetting::Ptr setting;
    KSharedConfigPtr config;
    QPalette warningPalette;
    QPalette normalPalette;
    QVariantMap peerData;
    bool publicKeyValid;
    bool allowedIPsValid;
    bool endpointValid;
    bool presharedKeyValid;
};

WireGuardPeerWidget::Private::Private(void)
    : publicKeyValid(false)
    , allowedIPsValid(false)
    , endpointValid(true)
    , presharedKeyValid(true)
{
}

WireGuardPeerWidget::Private::~Private()
{
}

WireGuardPeerWidget::WireGuardPeerWidget(const QVariantMap &peerData, QWidget *parent, Qt::WindowFlags f)
    : QDialog(parent, f)
    , d(new Private)
{
    d->ui.setupUi(this);
    d->peerData = peerData;

    d->config = KSharedConfig::openConfig();
    d->warningPalette = KColorScheme::createApplicationPalette(d->config);
    d->normalPalette = KColorScheme::createApplicationPalette(d->config);
    KColorScheme::adjustBackground(d->warningPalette, KColorScheme::NegativeBackground, QPalette::Base,
                                   KColorScheme::ColorSet::View, d->config);

    KColorScheme::adjustBackground(d->normalPalette, KColorScheme::NormalBackground, QPalette::Base,
                                   KColorScheme::ColorSet::View, d->config);

    setWindowTitle(i18nc("@title: window wireguard peers properties",
                         "WireGuard peers properties"));
    connect(d->ui.publicKeyLineEdit, &QLineEdit::textChanged, this, &WireGuardPeerWidget::checkPublicKeyValid);
    connect(d->ui.allowedIPsLineEdit, &QLineEdit::textChanged, this, &WireGuardPeerWidget::checkAllowedIpsValid);
    connect(d->ui.endpointAddressLineEdit, &QLineEdit::textChanged, this, &WireGuardPeerWidget::checkEndpointValid);
    connect(d->ui.endpointPortLineEdit, &QLineEdit::textChanged, this, &WireGuardPeerWidget::checkEndpointValid);
    connect(d->ui.presharedKeyLineEdit, &PasswordField::textChanged, this, &WireGuardPeerWidget::checkPresharedKeyValid);
    connect(d->ui.presharedKeyLineEdit, &PasswordField::passwordOptionChanged, this, &WireGuardPeerWidget::saveKeyFlags);
    connect(d->ui.keepaliveLineEdit, &QLineEdit::textChanged, this, &WireGuardPeerWidget::saveKeepAlive);

    d->ui.presharedKeyLineEdit->setPasswordModeEnabled(true);
    d->ui.presharedKeyLineEdit->setPasswordOptionsEnabled(true);
    d->ui.presharedKeyLineEdit->setPasswordNotRequiredEnabled(true);
    d->ui.presharedKeyLineEdit->setPasswordNotSavedEnabled(false);

    // Create validator for endpoint port
    QIntValidator *portValidator = new QIntValidator(this);
    portValidator->setBottom(0);
    portValidator->setTop(65535);
    d->ui.endpointPortLineEdit->setValidator(portValidator);

    // Reuse the port validator for the persistent keepalive.
    // It is not a "port" but has the same limits
    d->ui.keepaliveLineEdit->setValidator(portValidator);

    KAcceleratorManager::manage(this);
    updatePeerWidgets();

    // Set the initial backgrounds on all the widgets
    checkPublicKeyValid();
    checkAllowedIpsValid();
    checkEndpointValid();
}

WireGuardPeerWidget::~WireGuardPeerWidget()
{
    delete d;
}

QVariantMap WireGuardPeerWidget::setting() const
{
    return d->peerData;
}

void WireGuardPeerWidget::checkPublicKeyValid()
{
    int pos = 0;
    QLineEdit *widget = d->ui.publicKeyLineEdit;
    QString value = widget->displayText();
    bool valid = QValidator::Acceptable == keyValidator.validate(value, pos);
    setBackground(widget, valid);
    d->peerData[PNM_WG_PEER_KEY_PUBLIC_KEY] = value;
    if (valid != d->publicKeyValid) {
        d->publicKeyValid = valid;
        slotWidgetChanged();
    }
}

void WireGuardPeerWidget::checkPresharedKeyValid()
{
    int pos = 0;
    PasswordField *widget = d->ui.presharedKeyLineEdit;
    QString value = widget->text();

    // The value in the preshared key field is ignored if the type
    // of password is set to "Ask every time" or "Not Required" so
    // it is valid if it is set to "Store for user only"
    // or "Store for all users" even if the password is bad
    PasswordField::PasswordOption option = d->ui.presharedKeyLineEdit->passwordOption();
    bool valid = (QValidator::Acceptable == keyValidator.validate(value, pos)
                  || option == PasswordField::NotRequired);
    setBackground(widget,  valid);
    if (value.isEmpty())
        d->peerData.remove(PNM_WG_PEER_KEY_PRESHARED_KEY);
    else
        d->peerData[PNM_WG_PEER_KEY_PRESHARED_KEY] = value;
    if (valid != d->presharedKeyValid) {
        d->presharedKeyValid = valid;
        slotWidgetChanged();
    }
}

void WireGuardPeerWidget::checkAllowedIpsValid()
{
    int pos = 0;
    QLineEdit *widget = d->ui.allowedIPsLineEdit;
    QString ipString = widget->displayText();
    QStringList rawIPList = ipString.split(',');
    QStringList ipList;

    bool valid = QValidator::Acceptable == allowedIPsValidator.validate(ipString, pos);
    setBackground(widget, valid);

    ipList.reserve(rawIPList.size());
    for (const QString &ip : rawIPList) {
        ipList.append(ip.trimmed());
    }

    d->peerData[PNM_WG_PEER_KEY_ALLOWED_IPS] = ipList;
    if (valid != d->allowedIPsValid) {
        d->allowedIPsValid = valid;
        slotWidgetChanged();
    }
}

WireGuardPeerWidget::EndPointValid WireGuardPeerWidget::isEndpointValid(QString &address, QString &port)
{
    // Create a Reg Expression validator to do a simple check for a valid qualified domain name
    // which checks to see that there are between 2 and 63 strings of at least 1 character each
    // separated by '.'. The full string must also be less than 255 characters long.
    static QRegExpValidator fqdnValidator(QRegExp(QLatin1String("(?=.{3,254}$)([a-zA-Z0-9][a-zA-Z0-9-]{0,62}\\.){1,63}[a-zA-Z]{1,63}")), nullptr);
    static SimpleIpV4AddressValidator ipv4Validator;
    static SimpleIpV6AddressValidator ipv6Validator;
    int pos = 0;

    bool addressValid = QValidator::Acceptable == fqdnValidator.validate(address, pos)
                        || QValidator::Acceptable == ipv4Validator.validate(address, pos)
                        || QValidator::Acceptable == ipv6Validator.validate(address, pos);
    bool bothEmpty = address.isEmpty() && port.isEmpty();
    // Because of the validator, if the port is non-empty, it is valid
    bool portValid = !port.isEmpty();
    
    if ((portValid && addressValid) || bothEmpty)
        return WireGuardPeerWidget::BothValid;
    else if (portValid)
        return WireGuardPeerWidget::PortValid;
    else if (addressValid)
        return WireGuardPeerWidget::AddressValid;
    else
        return WireGuardPeerWidget::BothInvalid;
}

void WireGuardPeerWidget::checkEndpointValid()
{
    QLineEdit *addressWidget = d->ui.endpointAddressLineEdit;
    QLineEdit *portWidget = d->ui.endpointPortLineEdit;
    QString addressString = addressWidget->displayText();
    QString portString = portWidget->displayText();

    QUrl temp;
    WireGuardPeerWidget::EndPointValid valid = isEndpointValid(addressString, portString);

    setBackground(addressWidget, WireGuardPeerWidget::BothValid == valid || WireGuardPeerWidget::AddressValid == valid);
    setBackground(portWidget, WireGuardPeerWidget::BothValid == valid || WireGuardPeerWidget::PortValid == valid);

    // If there is a ':' in the address string then it is an IPv6 address and
    // the output needs to be formatted as '[1:2:3:4:5:6:7:8]:123' otherwise
    // it is formatted as '1.2.3.4:123' or 'ab.com:123'
    QString stringToStore;
    if  (addressString.contains(":"))
        stringToStore = "[" + addressString.trimmed() + "]:" + portString.trimmed();
    else
        stringToStore = addressString.trimmed() + ":" + portString.trimmed();

    if (addressString.isEmpty() && portString.isEmpty())
        d->peerData.remove(PNM_WG_PEER_KEY_ENDPOINT);
    else
        d->peerData[PNM_WG_PEER_KEY_ENDPOINT] = stringToStore;

    if ((valid == WireGuardPeerWidget::BothValid) != d->endpointValid) {
        d->endpointValid = (valid == WireGuardPeerWidget::BothValid);
        slotWidgetChanged();
    }
}

bool WireGuardPeerWidget::isValid()
{
    return d->publicKeyValid
        && d->allowedIPsValid
        && d->endpointValid
        && d->presharedKeyValid;
}

void WireGuardPeerWidget::saveKeepAlive()
{
    QLineEdit *widget = d->ui.keepaliveLineEdit;
    QString value = widget->displayText();

    if (value.isEmpty())
        d->peerData.remove(PNM_WG_PEER_KEY_PERSISTENT_KEEPALIVE);
    else
        d->peerData[PNM_WG_PEER_KEY_PERSISTENT_KEEPALIVE] = value;
}

void WireGuardPeerWidget::saveKeyFlags()
{
    PasswordField::PasswordOption option = d->ui.presharedKeyLineEdit->passwordOption();
    switch (option) {
      case PasswordField::StoreForUser:
        d->peerData[PNM_WG_PEER_KEY_PRESHARED_KEY_FLAGS] = NetworkManager::Setting::AgentOwned;
        break;
      case PasswordField::StoreForAllUsers:
        d->peerData[PNM_WG_PEER_KEY_PRESHARED_KEY_FLAGS] = NetworkManager::Setting::None;
        break;
      // Always Ask is not a valid option for the preshared key so set it to AgentOwned instead
      case PasswordField::AlwaysAsk:
        d->peerData[PNM_WG_PEER_KEY_PRESHARED_KEY_FLAGS] = NetworkManager::Setting::AgentOwned;
        break;
      case PasswordField::NotRequired:
        d->peerData[PNM_WG_PEER_KEY_PRESHARED_KEY_FLAGS] = NetworkManager::Setting::NotRequired;
        break;
    }
    checkPresharedKeyValid();
}

void WireGuardPeerWidget::setBackground(QWidget *w, bool result) const
{
    if (result)
        w->setPalette(d->normalPalette);
    else
        w->setPalette(d->warningPalette);
}

void WireGuardPeerWidget::updatePeerWidgets()
{
    d->ui.presharedKeyLineEdit->setPasswordModeEnabled(true);

    if (d->peerData.contains(PNM_WG_PEER_KEY_PUBLIC_KEY))
        d->ui.publicKeyLineEdit->setText(d->peerData[PNM_WG_PEER_KEY_PUBLIC_KEY].toString());
    else
        d->ui.publicKeyLineEdit->clear();

    if (d->peerData.contains(PNM_WG_PEER_KEY_ALLOWED_IPS)) {
        QStringList allowedIps = d->peerData[PNM_WG_PEER_KEY_ALLOWED_IPS].toStringList();
        d->ui.allowedIPsLineEdit->setText(allowedIps.join(","));
    } else {
        d->ui.allowedIPsLineEdit->clear();
    }

    if (d->peerData.contains(PNM_WG_PEER_KEY_PERSISTENT_KEEPALIVE))
        d->ui.keepaliveLineEdit->setText(d->peerData[PNM_WG_PEER_KEY_PERSISTENT_KEEPALIVE].toString());
    else
        d->ui.keepaliveLineEdit->clear();

    // An endpoint is stored as <ipv4 | [ipv6] | fqdn>:<port>
    if (d->peerData.contains(PNM_WG_PEER_KEY_ENDPOINT)) {
        QString storedEndpoint = d->peerData[PNM_WG_PEER_KEY_ENDPOINT].toString();
        QStringList endpointList = storedEndpoint.contains("]:") ?
            d->peerData[PNM_WG_PEER_KEY_ENDPOINT].toString().split("]:") :
            d->peerData[PNM_WG_PEER_KEY_ENDPOINT].toString().split(":");

        d->ui.endpointAddressLineEdit->setText(endpointList[0].remove("["));
        d->ui.endpointPortLineEdit->setText(endpointList[1]);
    } else {
        d->ui.endpointAddressLineEdit->clear();
        d->ui.endpointPortLineEdit->clear();
    }
    if (d->peerData.contains(PNM_WG_PEER_KEY_PRESHARED_KEY))
        d->ui.presharedKeyLineEdit->setText(d->peerData[PNM_WG_PEER_KEY_PRESHARED_KEY].toString());
    else
        d->ui.presharedKeyLineEdit->setText("");

    if (d->peerData.contains(PNM_WG_PEER_KEY_PRESHARED_KEY_FLAGS)) {
        NetworkManager::Setting::SecretFlags type = static_cast<NetworkManager::Setting::SecretFlags>(d->peerData[PNM_WG_PEER_KEY_PRESHARED_KEY_FLAGS].toUInt());
        switch (type) {
          case NetworkManager::Setting::AgentOwned:
            d->ui.presharedKeyLineEdit->setPasswordOption(PasswordField::StoreForUser);
            break;
          case NetworkManager::Setting::None:
            d->ui.presharedKeyLineEdit->setPasswordOption(PasswordField::StoreForAllUsers);
            break;
          // Not saved is not a valid option for the private key so set it to StoreForUser instead
          case NetworkManager::Setting::NotSaved:
            d->ui.presharedKeyLineEdit->setPasswordOption(PasswordField::StoreForUser);
            break;
          case NetworkManager::Setting::NotRequired:
            d->ui.presharedKeyLineEdit->setPasswordOption(PasswordField::NotRequired);
            break;
        }
    } else {
        d->ui.presharedKeyLineEdit->setPasswordOption(PasswordField::NotRequired);
    }

    slotWidgetChanged();
}

void WireGuardPeerWidget::slotWidgetChanged()
{
    Q_EMIT notifyValid();
}
