// SPDX-FileCopyrightText: Nheko Contributors
//
// SPDX-License-Identifier: GPL-3.0-or-later

#include <QDesktopServices>

#include <set>

#include <mtx/identifiers.hpp>
#include <mtx/requests.hpp>
#include <mtx/responses/login.hpp>
#include <mtx/responses/version.hpp>

#include "Config.h"
#include "Logging.h"
#include "LoginPage.h"
#include "MainWindow.h"
#include "MatrixClient.h"
#include "SSOHandler.h"
#include "UserSettingsPage.h"

using namespace mtx::identifiers;

LoginPage::LoginPage(QObject *parent)
  : QObject(parent)
  , inferredServerAddress_()
{
    [[maybe_unused]] static auto ignored = qRegisterMetaType<mtx::responses::Login>();

    connect(this, &LoginPage::versionOkCb, this, &LoginPage::versionOk, Qt::QueuedConnection);
    connect(this, &LoginPage::versionErrorCb, this, &LoginPage::versionError, Qt::QueuedConnection);
    connect(
      this,
      &LoginPage::loginOk,
      this,
      [this](const mtx::responses::Login &res) {
          loggingIn_ = false;
          emit loggingInChanged();

          http::client()->set_user(res.user_id);
          MainWindow::instance()->showChatPage();
      },
      Qt::QueuedConnection);
}
void
LoginPage::showError(const QString &msg)
{
    loggingIn_ = false;
    emit loggingInChanged();

    error_ = msg;
    emit errorOccurred();
}

void
LoginPage::setHomeserver(const QString &hs)
{
    if (hs != homeserver_) {
        homeserver_      = hs;
        homeserverValid_ = false;
        emit homeserverChanged();
        http::client()->set_server(hs.toStdString());
        checkHomeserverVersion();
    }
}

void
LoginPage::onMatrixIdEntered()
{
    clearErrors();

    homeserverValid_ = false;
    emit homeserverChanged();

    User user;
    try {
        user = parse<User>(mxid_.toStdString());
    } catch (const std::exception &) {
        mxidError_ = tr("You have entered an invalid Matrix ID e.g. @user:yourserver.example.com");
        emit mxidErrorChanged();
        return;
    }

    if (user.hostname().empty() || user.localpart().empty()) {
        mxidError_ = tr("You have entered an invalid Matrix ID e.g. @user:yourserver.example.com");
        emit mxidErrorChanged();
        return;
    } else {
        nhlog::net()->debug("hostname: {}", user.hostname());
    }

    if (user.hostname() != inferredServerAddress_.toStdString()) {
        homeserverNeeded_ = false;
        lookingUpHs_      = true;
        emit lookingUpHsChanged();

        http::client()->set_server(user.hostname());
        http::client()->verify_certificates(
          !UserSettings::instance()->disableCertificateValidation());
        homeserver_ = QString::fromStdString(user.hostname());
        emit homeserverChanged();

        http::client()->well_known(
          [this, orginal_hostname = user.hostname()](const mtx::responses::WellKnown &res,
                                                     mtx::http::RequestErr err) {
              // Ignore if server changed
              auto currentUser = parse<User>(mxid_.toStdString());
              if (currentUser.hostname() != orginal_hostname)
                  return;

              if (err) {
                  if (err->status_code == 404) {
                      nhlog::net()->info("Autodiscovery: No .well-known.");
                      checkHomeserverVersion();
                      return;
                  }

                  if (!err->parse_error.empty()) {
                      emit versionErrorCb(tr("Autodiscovery failed. Received malformed response."));
                      nhlog::net()->error("Autodiscovery failed. Received malformed response. {}",
                                          err->parse_error);
                      return;
                  }

                  emit versionErrorCb(tr("Autodiscovery failed. Unknown error when "
                                         "requesting .well-known."));
                  nhlog::net()->error("Autodiscovery failed. Unknown error when "
                                      "requesting .well-known. {}",
                                      *err);
                  return;
              }

              nhlog::net()->info("Autodiscovery: Discovered '" + res.homeserver.base_url + "'");
              http::client()->set_server(res.homeserver.base_url);
              emit homeserverChanged();
              checkHomeserverVersion();
          });
    }
}

void
LoginPage::checkHomeserverVersion()
{
    clearErrors();

    try {
        User user = parse<User>(mxid_.toStdString());
    } catch (const std::exception &) {
        mxidError_ = tr("You have entered an invalid Matrix ID e.g. @user:yourserver.example.com");
        emit mxidErrorChanged();
        return;
    }

    http::client()->versions([this](const mtx::responses::Versions &versions,
                                    mtx::http::RequestErr err) {
        if (err) {
            if (err->status_code == 404) {
                emit versionErrorCb(tr("The required endpoints were not found. "
                                       "Possibly not a Matrix server."));
                return;
            }

            if (!err->parse_error.empty()) {
                emit versionErrorCb(tr("Received malformed response. Make sure "
                                       "the homeserver domain is valid."));
                return;
            }

            nhlog::net()->error("Error requesting versions: {}", *err);

            emit versionErrorCb(
              tr("An unknown error occured. Make sure the homeserver domain is valid."));
            return;
        }

        if (std::find_if(
              versions.versions.cbegin(), versions.versions.cend(), [](const std::string &v) {
                  static const std::set<std::string_view, std::less<>> supported{
                    "v1.1",
                    "v1.2",
                    "v1.3",
                    "v1.4",
                    "v1.5",
                  };
                  return supported.count(v) != 0;
              }) == versions.versions.cend()) {
            emit versionErrorCb(
              tr("The selected server does not support a version of the Matrix protocol, that this "
                 "client understands (v1.1 to v1.5). You can't sign in."));
            return;
        }

        http::client()->get_login([this](mtx::responses::LoginFlows flows,
                                         mtx::http::RequestErr err) {
            if (err || flows.flows.empty())
                emit versionOkCb(true, false, {});

            QVariantList idps;
            bool ssoSupported      = false;
            bool passwordSupported = false;
            for (const auto &flow : flows.flows) {
                if (flow.type == mtx::user_interactive::auth_types::sso) {
                    ssoSupported = true;

                    for (const auto &idp : flow.identity_providers) {
                        SSOProvider prov;
                        if (idp.brand == "apple")
                            prov.name_ = tr("Sign in with Apple");
                        else if (idp.brand == "facebook")
                            prov.name_ = tr("Continue with Facebook");
                        else if (idp.brand == "google")
                            prov.name_ = tr("Sign in with Google");
                        else if (idp.brand == "twitter")
                            prov.name_ = tr("Sign in with Twitter");
                        else
                            prov.name_ = tr("Login using %1").arg(QString::fromStdString(idp.name));

                        prov.avatarUrl_ = QString::fromStdString(idp.icon);
                        prov.id_        = QString::fromStdString(idp.id);
                        idps.push_back(QVariant::fromValue(prov));
                    }

                    if (flow.identity_providers.empty()) {
                        SSOProvider prov;
                        prov.name_ = tr("SSO LOGIN");
                        idps.push_back(QVariant::fromValue(prov));
                    }
                } else if (flow.type == mtx::user_interactive::auth_types::password) {
                    passwordSupported = true;
                }
            }
            emit versionOkCb(passwordSupported, ssoSupported, idps);
        });
    });
}

void
LoginPage::versionError(const QString &error)
{
    showError(error);

    homeserverNeeded_ = true;
    lookingUpHs_      = false;
    homeserverValid_  = false;
    emit lookingUpHsChanged();
    emit versionLookedUp();
}

void
LoginPage::versionOk(bool passwordSupported, bool ssoSupported, QVariantList idps)
{
    passwordSupported_ = passwordSupported;
    ssoSupported_      = ssoSupported;
    identityProviders_ = idps;

    lookingUpHs_     = false;
    homeserverValid_ = true;
    emit homeserverChanged();
    emit lookingUpHsChanged();
    emit versionLookedUp();
}

void
LoginPage::onLoginButtonClicked(LoginMethod loginMethod,
                                const QString &userid,
                                const QString &password,
                                const QString &deviceName)
{
    clearErrors();

    User user;

    try {
        user = parse<User>(userid.toStdString());
    } catch (const std::exception &) {
        mxidError_ = tr("You have entered an invalid Matrix ID e.g. @user:yourserver.example.com");
        emit mxidErrorChanged();
        return;
    }

    if (loginMethod == LoginMethod::Password) {
        if (password.isEmpty())
            return showError(tr("Empty password"));

        http::client()->login(
          user.localpart(),
          password.toStdString(),
          deviceName.trimmed().isEmpty() ? initialDeviceName_() : deviceName.toStdString(),
          [this](const mtx::responses::Login &res, mtx::http::RequestErr err) {
              if (err) {
                  auto error = err->matrix_error.error;
                  if (error.empty())
                      error = err->parse_error;

                  showError(QString::fromStdString(error));
                  return;
              }

              if (res.well_known) {
                  http::client()->set_server(res.well_known->homeserver.base_url);
                  nhlog::net()->info("Login requested to use server: " +
                                     res.well_known->homeserver.base_url);
              }

              emit loginOk(res);
          });
    } else {
        auto sso = new SSOHandler();
        connect(sso,
                &SSOHandler::ssoSuccess,
                this,
                [this, sso, userid, deviceName](const std::string &token) {
                    mtx::requests::Login req{};
                    req.token                       = token;
                    req.type                        = mtx::user_interactive::auth_types::token;
                    req.initial_device_display_name = deviceName.trimmed().isEmpty()
                                                        ? initialDeviceName_()
                                                        : deviceName.toStdString();
                    http::client()->login(
                      req, [this](const mtx::responses::Login &res, mtx::http::RequestErr err) {
                          if (err) {
                              showError(QString::fromStdString(err->matrix_error.error));
                              emit errorOccurred();
                              return;
                          }

                          if (res.well_known) {
                              http::client()->set_server(res.well_known->homeserver.base_url);
                              nhlog::net()->info("Login requested to use server: " +
                                                 res.well_known->homeserver.base_url);
                          }

                          emit loginOk(res);
                      });
                    sso->deleteLater();
                });
        connect(sso, &SSOHandler::ssoFailed, this, [this, sso]() {
            showError(tr("SSO login failed"));
            emit errorOccurred();
            sso->deleteLater();
        });

        // password doubles as the idp id for SSO login
        QDesktopServices::openUrl(QString::fromStdString(
          http::client()->login_sso_redirect(sso->url(), password.toStdString())));
    }

    loggingIn_ = true;
    emit loggingInChanged();
}