/*
 * SPDX-FileCopyrightText: 2016-2016 CSSlayer <wengxt@gmail.com>
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 */

#include "dbusfrontend.h"
#include <cassert>
#include <cstdint>
#include <memory>
#include <optional>
#include <string>
#include <tuple>
#include <unordered_map>
#include <utility>
#include <vector>
#include <fcitx-utils/handlertable.h>
#include "fcitx-utils/capabilityflags.h"
#include "fcitx-utils/dbus/bus.h"
#include "fcitx-utils/dbus/message.h"
#include "fcitx-utils/dbus/objectvtable.h"
#include "fcitx-utils/dbus/servicewatcher.h"
#include "fcitx-utils/dbus/variant.h"
#include "fcitx-utils/flags.h"
#include "fcitx-utils/key.h"
#include "fcitx-utils/log.h"
#include "fcitx-utils/misc_p.h"
#include "fcitx-utils/rect.h"
#include "fcitx-utils/stringutils.h"
#include "fcitx/addonfactory.h"
#include "fcitx/addoninstance.h"
#include "fcitx/event.h"
#include "fcitx/inputcontext.h"
#include "fcitx/inputmethodentry.h"
#include "fcitx/inputmethodmanager.h"
#include "fcitx/instance.h"
#include "fcitx/misc_p.h"
#include "fcitx/text.h"
#include "fcitx/userinterface.h"
#include "fcitx/userinterfacemanager.h"
#include "dbus_public.h"

#define FCITX_INPUTMETHOD_DBUS_INTERFACE "org.fcitx.Fcitx.InputMethod1"
#define FCITX_INPUTCONTEXT_DBUS_INTERFACE "org.fcitx.Fcitx.InputContext1"

namespace fcitx {

namespace {

enum {
    BATCHED_COMMIT_STRING = 0,
    BATCHED_PREEDIT,
    BATCHED_FORWARD_KEY,
    BATCHED_DELETE_SURROUNDING
};

using DBusBlockedEvent = dbus::DBusStruct<uint32_t, dbus::Variant>;

bool useClientSideUI(Instance *instance) {
    if (instance->userInterfaceManager().currentUI() != "kimpanel") {
        return true;
    }
    const static DesktopType desktop = getDesktopType();
    return desktop != DesktopType::GNOME;
}

bool x11UseClientSideUI() {
    static const bool value = checkBoolEnvVar("FCITX_X11_USE_CLIENT_SIDE_UI");
    return value;
}

std::vector<dbus::DBusStruct<std::string, int>>
buildFormattedTextVector(const Text &text) {
    std::vector<dbus::DBusStruct<std::string, int>> vector;
    for (int i = 0, e = text.size(); i < e; i++) {
        vector.emplace_back(std::make_tuple(
            text.stringAt(i), static_cast<int>(text.formatAt(i))));
    }
    return vector;
}

std::string
getArgument(const std::unordered_map<std::string, std::string> &args,
            const std::string &name, const std::string &defaultValue = "") {
    if (const auto *value = findValue(args, name)) {
        return *value;
    }
    return defaultValue;
}

} // namespace

class InputMethod1 : public dbus::ObjectVTable<InputMethod1> {
public:
    InputMethod1(DBusFrontendModule *module, dbus::Bus *bus, const char *path)
        : module_(module), instance_(module->instance()), bus_(bus),
          watcher_(std::make_unique<dbus::ServiceWatcher>(*bus_)) {
        bus_->addObjectVTable(path, FCITX_INPUTMETHOD_DBUS_INTERFACE, *this);
    }

    std::tuple<dbus::ObjectPath, std::vector<uint8_t>> createInputContext(
        const std::vector<dbus::DBusStruct<std::string, std::string>> &args);

    uint32_t version() { return 1; }

    dbus::ServiceWatcher &serviceWatcher() { return *watcher_; }
    dbus::Bus *bus() { return bus_; }
    Instance *instance() { return module_->instance(); }

private:
    FCITX_OBJECT_VTABLE_METHOD(createInputContext, "CreateInputContext",
                               "a(ss)", "oay");
    FCITX_OBJECT_VTABLE_METHOD(version, "Version", "", "u");

    DBusFrontendModule *module_;
    Instance *instance_;
    dbus::Bus *bus_;
    std::unique_ptr<dbus::ServiceWatcher> watcher_;
};

class DBusInputContext1 : public InputContext,
                          public dbus::ObjectVTable<DBusInputContext1> {
public:
    DBusInputContext1(int id, InputContextManager &icManager, InputMethod1 *im,
                      const std::string &sender,
                      const std::unordered_map<std::string, std::string> &args)
        : InputContext(icManager, getArgument(args, "program")),
          path_("/org/freedesktop/portal/inputcontext/" + std::to_string(id)),
          im_(im), handler_(im_->serviceWatcher().watchService(
                       sender,
                       [this](const std::string &, const std::string &,
                              const std::string &newName) {
                           if (newName.empty()) {
                               delete this;
                           }
                       })),
          name_(sender) {
        processKeyEventMethod.setClosureFunction(
            [this](dbus::Message message, const dbus::ObjectMethod &method) {
                if (capabilityFlags().test(CapabilityFlag::KeyEventOrderFix)) {
                    InputContextEventBlocker blocker(this);
                    return method(std::move(message));
                }
                return method(std::move(message));
            });

        setClientControlVirtualkeyboardShow(
            getArgument(args, "clientControlVirtualkeyboardShow", "false") ==
            "true");
        setClientControlVirtualkeyboardHide(
            getArgument(args, "clientControlVirtualkeyboardHide", "false") ==
            "true");
        created();

        setFocusGroup(
            im->instance()->defaultFocusGroup(getArgument(args, "display")));

        vkVisibilityChanged_ = im_->instance()->watchEvent(
            EventType::VirtualKeyboardVisibilityChanged,
            EventWatcherPhase::PreInputMethod, [this](Event &) {
                virtualKeyboardVisibilityChangedTo(
                    name_, im_->instance()
                               ->userInterfaceManager()
                               .isVirtualKeyboardVisible());
            });
    }

    ~DBusInputContext1() { InputContext::destroy(); }

    const char *frontend() const override { return "dbus"; }

    const dbus::ObjectPath &path() const { return path_; }

    void updateIM(const InputMethodEntry *entry) {
        currentIMTo(name_, entry->name(), entry->uniqueName(),
                    entry->languageCode());
    }

    void commitStringImpl(const std::string &text) override {
        if (blocked_) {
            blockedEvents_.emplace_back(BATCHED_COMMIT_STRING, text);
        } else {
            commitStringDBusTo(name_, text);
        }
    }

    void updatePreeditImpl() override {
        auto preedit =
            im_->instance()->outputFilter(this, inputPanel().clientPreedit());
        std::vector<dbus::DBusStruct<std::string, int>> strs =
            buildFormattedTextVector(preedit);
        if (blocked_) {
            blockedEvents_.emplace_back(
                BATCHED_PREEDIT,
                dbus::DBusStruct<
                    std::vector<dbus::DBusStruct<std::string, int32_t>>,
                    int32_t>(strs, preedit.cursor()));
        } else {
            updateFormattedPreeditTo(name_, strs, preedit.cursor());
        }
    }

    void deleteSurroundingTextImpl(int offset, unsigned int size) override {
        if (blocked_) {
            blockedEvents_.emplace_back(
                BATCHED_DELETE_SURROUNDING,
                dbus::DBusStruct<int32_t, uint32_t>(offset, size));
        } else {
            deleteSurroundingTextDBusTo(name_, offset, size);
        }
    }

    void updateClientSideUIImpl() override {
        auto *instance = im_->instance();

        std::vector<dbus::DBusStruct<std::string, int>> preeditStrings;
        std::vector<dbus::DBusStruct<std::string, int>> auxUpStrings;
        std::vector<dbus::DBusStruct<std::string, int>> auxDownStrings;
        std::vector<dbus::DBusStruct<std::string, std::string>> candidates;

        if (instance->inputMethodMode() == InputMethodMode::OnScreenKeyboard) {
            updateClientSideUITo(name_, preeditStrings, -1, auxUpStrings,
                                 auxDownStrings, candidates, -1, 0, false,
                                 false);
            return;
        }

        auto preedit = instance->outputFilter(this, inputPanel().preedit());
        auto auxUp = instance->outputFilter(this, inputPanel().auxUp());
        auto auxDown = instance->outputFilter(this, inputPanel().auxDown());
        auto candidateList = inputPanel().candidateList();
        int cursorIndex = 0;

        preeditStrings = buildFormattedTextVector(preedit);
        auxUpStrings = buildFormattedTextVector(auxUp);
        auxDownStrings = buildFormattedTextVector(auxDown);
        bool hasPrev = false;
        bool hasNext = false;
        int layoutHint = 0;
        if (candidateList) {
            for (int i = 0, e = candidateList->size(); i < e; i++) {
                const auto &candidate = candidateList->candidate(i);
                if (candidate.isPlaceHolder()) {
                    continue;
                }
                Text labelText = candidate.hasCustomLabel()
                                     ? candidate.customLabel()
                                     : candidateList->label(i);
                labelText = instance->outputFilter(this, labelText);
                Text candidateText =
                    instance->outputFilter(this, candidate.textWithComment());
                candidates.emplace_back(std::make_tuple(
                    labelText.toString(), candidateText.toString()));
            }
            cursorIndex = candidateList->cursorIndex();
            if (auto *pageable = candidateList->toPageable()) {
                hasPrev = pageable->hasPrev();
                hasNext = pageable->hasNext();
            }
            layoutHint = static_cast<int>(candidateList->layoutHint());
        }
        updateClientSideUITo(name_, preeditStrings, preedit.cursor(),
                             auxUpStrings, auxDownStrings, candidates,
                             cursorIndex, layoutHint, hasPrev, hasNext);
    }

    void forwardKeyImpl(const ForwardKeyEvent &key) override {
        if (blocked_) {
            blockedEvents_.emplace_back(
                BATCHED_FORWARD_KEY,
                dbus::DBusStruct<uint32_t, uint32_t, bool>(
                    static_cast<uint32_t>(key.rawKey().sym()),
                    static_cast<uint32_t>(key.rawKey().states()),
                    key.isRelease()));
        } else {
            forwardKeyDBusTo(name_, static_cast<uint32_t>(key.rawKey().sym()),
                             static_cast<uint32_t>(key.rawKey().states()),
                             key.isRelease());
            bus()->flush();
        }
    }

#define CHECK_SENDER_OR_RETURN                                                 \
    if (currentMessage()->sender() != name_)                                   \
    return

    void focusInDBus() {
        CHECK_SENDER_OR_RETURN;
        focusIn();
    }

    void focusOutDBus() {
        CHECK_SENDER_OR_RETURN;
        focusOut();
    }

    void resetDBus() {
        CHECK_SENDER_OR_RETURN;
        reset();
    }

    void setCursorRectDBus(int x, int y, int w, int h) {
        CHECK_SENDER_OR_RETURN;
        setCursorRect(Rect{x, y, x + w, y + h});
    }

    void setCursorRectV2DBus(int x, int y, int w, int h, double scale) {
        CHECK_SENDER_OR_RETURN;
        setCursorRect(Rect{x, y, x + w, y + h}, scale);
    }

    void setSupportedCapability(uint64_t cap) {
        CHECK_SENDER_OR_RETURN;
        supportedCapability_ = cap;
    }

    void setCapability(uint64_t cap) {
        CHECK_SENDER_OR_RETURN;
        // 1. Due to a bug in SDL, it might send garbage over the wire.
        // This a workaround to make sure it can work more likely.
        // The flag is most to ClientSideInputPanel (0~39bit).
        // 2. For new bits such as 40bit(Disable) or above, we should
        // use supportedCapability_'s value to get all the effective bits.
        if (supportedCapability_.has_value()) {
            cap &= supportedCapability_.value();
        } else if ((cap & (~static_cast<uint64_t>(0xffffffffffULL))) != 0ULL) {
            cap &= 0xffffffffULL;
        }
        rawCapabilityFlags_ = CapabilityFlags(cap);
        updateCapability();
    }

    void setSurroundingText(const std::string &str, uint32_t cursor,
                            uint32_t anchor) {
        CHECK_SENDER_OR_RETURN;
        surroundingText().setText(str, cursor, anchor);
        updateSurroundingText();
    }

    void setSurroundingTextPosition(uint32_t cursor, uint32_t anchor) {
        CHECK_SENDER_OR_RETURN;
        surroundingText().setCursor(cursor, anchor);
        updateSurroundingText();
    }

    void destroyDBus() {
        CHECK_SENDER_OR_RETURN;
        delete this;
    }

    bool processKeyEvent(uint32_t keyval, uint32_t keycode, uint32_t state,
                         bool isRelease, uint32_t time) {
        CHECK_SENDER_OR_RETURN false;
        KeyEvent event(
            this, Key(static_cast<KeySym>(keyval), KeyStates(state), keycode),
            isRelease, time);
        // Force focus if there's keyevent.
        if (!hasFocus()) {
            focusIn();
        }

        return keyEvent(event);
    }

    std::tuple<std::vector<DBusBlockedEvent>, bool>
    processKeyEventBatch(uint32_t keyval, uint32_t keycode, uint32_t state,
                         bool isRelease, uint32_t time);

    void prevPage() {
        CHECK_SENDER_OR_RETURN;
        if (auto candidateList = inputPanel().candidateList()) {
            if (auto *pageable = candidateList->toPageable()) {
                if (pageable->hasPrev()) {
                    pageable->prev();
                    updateUserInterface(UserInterfaceComponent::InputPanel);
                }
            }
        }
    }

    void nextPage() {
        CHECK_SENDER_OR_RETURN;
        if (auto candidateList = inputPanel().candidateList()) {
            if (auto *pageable = candidateList->toPageable()) {
                if (pageable->hasNext()) {
                    pageable->next();
                    updateUserInterface(UserInterfaceComponent::InputPanel);
                }
            }
        }
    }

    void selectCandidate(int idx) {
        CHECK_SENDER_OR_RETURN;
        if (auto candidateList = inputPanel().candidateList()) {
            const auto *candidate =
                nthCandidateIgnorePlaceholder(*candidateList, idx);
            if (candidate) {
                candidate->select(this);
            }
        }
    }

    void updateCapability() {
        CapabilityFlags flags = rawCapabilityFlags_;
        if (stringutils::startsWith(display(), "x11:")) {
            if (!x11UseClientSideUI()) {
                flags = flags.unset(CapabilityFlag::ClientSideInputPanel);
            }
        } else if (stringutils::startsWith(display(), "wayland:")) {
            if (!useClientSideUI(im_->instance())) {
                flags = flags.unset(CapabilityFlag::ClientSideInputPanel);
            }
        }
        setCapabilityFlags(flags);
    }

    void invokeActionDBus(uint32_t action, int32_t cursor) {
        InvokeActionEvent event(static_cast<InvokeActionEvent::Action>(action),
                                cursor, this);
        if (!hasFocus()) {
            focusIn();
        }
        invokeAction(event);
    }

    bool isVirtualKeyboardVisibleDBus() const {
        CHECK_SENDER_OR_RETURN false;

        return isVirtualKeyboardVisible();
    }

    void showVirtualKeyboardDBus() {
        CHECK_SENDER_OR_RETURN;

        if (!hasFocus()) {
            focusIn();
        }

        showVirtualKeyboard();
    }

    void hideVirtualKeyboardDBus() const {
        CHECK_SENDER_OR_RETURN;

        hideVirtualKeyboard();
    }

    void setBlocked() {
        assert(!blocked_);
        blocked_ = true;
    }

    void setUnblocked(std::vector<DBusBlockedEvent> &event) {
        blocked_ = false;
        event = std::move(blockedEvents_);
        blockedEvents_.clear();
    }

    void sendFocusOut() { notifyFocusOutTo(name_); }

private:
    FCITX_OBJECT_VTABLE_METHOD(focusInDBus, "FocusIn", "", "");
    FCITX_OBJECT_VTABLE_METHOD(focusOutDBus, "FocusOut", "", "");
    FCITX_OBJECT_VTABLE_METHOD(resetDBus, "Reset", "", "");
    FCITX_OBJECT_VTABLE_METHOD(setCursorRectDBus, "SetCursorRect", "iiii", "");
    FCITX_OBJECT_VTABLE_METHOD(setCursorRectV2DBus, "SetCursorRectV2", "iiiid",
                               "");
    FCITX_OBJECT_VTABLE_METHOD(setCapability, "SetCapability", "t", "");
    FCITX_OBJECT_VTABLE_METHOD(setSupportedCapability, "SetSupportedCapability",
                               "t", "");
    FCITX_OBJECT_VTABLE_METHOD(setSurroundingText, "SetSurroundingText", "suu",
                               "");
    FCITX_OBJECT_VTABLE_METHOD(setSurroundingTextPosition,
                               "SetSurroundingTextPosition", "uu", "");
    FCITX_OBJECT_VTABLE_METHOD(destroyDBus, "DestroyIC", "", "");
    FCITX_OBJECT_VTABLE_METHOD(processKeyEvent, "ProcessKeyEvent", "uuubu",
                               "b");
    FCITX_OBJECT_VTABLE_METHOD(processKeyEventBatch, "ProcessKeyEventBatch",
                               "uuubu", "a(uv)b");

    FCITX_OBJECT_VTABLE_METHOD(prevPage, "PrevPage", "", "");
    FCITX_OBJECT_VTABLE_METHOD(nextPage, "NextPage", "", "");
    FCITX_OBJECT_VTABLE_METHOD(selectCandidate, "SelectCandidate", "i", "");
    FCITX_OBJECT_VTABLE_METHOD(invokeActionDBus, "InvokeAction", "ui", "");

    FCITX_OBJECT_VTABLE_METHOD(isVirtualKeyboardVisibleDBus,
                               "IsVirtualKeyboardVisible", "", "b");
    FCITX_OBJECT_VTABLE_METHOD(showVirtualKeyboardDBus, "ShowVirtualKeyboard",
                               "", "");
    FCITX_OBJECT_VTABLE_METHOD(hideVirtualKeyboardDBus, "HideVirtualKeyboard",
                               "", "");

    FCITX_OBJECT_VTABLE_SIGNAL(commitStringDBus, "CommitString", "s");
    FCITX_OBJECT_VTABLE_SIGNAL(currentIM, "CurrentIM", "sss");
    FCITX_OBJECT_VTABLE_SIGNAL(updateFormattedPreedit, "UpdateFormattedPreedit",
                               "a(si)i");
    FCITX_OBJECT_VTABLE_SIGNAL(deleteSurroundingTextDBus,
                               "DeleteSurroundingText", "iu");
    // This contains:
    // - a(si)i preedit
    // - a(si) aux up
    // - a(si) aux down
    // - a(ss) candidate label + text
    // - i candidate index
    // - i candidate layout
    // - bb prev page / next page
    FCITX_OBJECT_VTABLE_SIGNAL(updateClientSideUI, "UpdateClientSideUI",
                               "a(si)ia(si)a(si)a(ss)iibb");
    FCITX_OBJECT_VTABLE_SIGNAL(forwardKeyDBus, "ForwardKey", "uub");
    FCITX_OBJECT_VTABLE_SIGNAL(notifyFocusOut, "NotifyFocusOut", "");

    FCITX_OBJECT_VTABLE_SIGNAL(virtualKeyboardVisibilityChanged,
                               "VirtualKeyboardVisibilityChanged", "b");

    dbus::ObjectPath path_;
    InputMethod1 *im_;
    std::unique_ptr<HandlerTableEntry<dbus::ServiceWatcherCallback>> handler_;
    std::string name_;
    CapabilityFlags rawCapabilityFlags_;
    std::optional<uint64_t> supportedCapability_;
    bool blocked_ = false;
    std::vector<DBusBlockedEvent> blockedEvents_;
    std::unique_ptr<HandlerTableEntry<EventHandler>> vkVisibilityChanged_;
};

std::tuple<dbus::ObjectPath, std::vector<uint8_t>>
InputMethod1::createInputContext(
    const std::vector<dbus::DBusStruct<std::string, std::string>> &args) {
    std::unordered_map<std::string, std::string> strMap;
    for (const auto &p : args) {
        const auto &[key, value] = p.data();
        strMap[key] = value;
    }

    auto sender = currentMessage()->sender();
    auto *ic = new DBusInputContext1(module_->nextIcIdx(),
                                     instance_->inputContextManager(), this,
                                     sender, strMap);

    bus_->addObjectVTable(ic->path().path(), FCITX_INPUTCONTEXT_DBUS_INTERFACE,
                          *ic);
    return std::make_tuple(
        ic->path(), std::vector<uint8_t>(ic->uuid().begin(), ic->uuid().end()));
}

std::tuple<std::vector<DBusBlockedEvent>, bool>
DBusInputContext1::processKeyEventBatch(uint32_t keyval, uint32_t keycode,
                                        uint32_t state, bool isRelease,
                                        uint32_t time) {
    CHECK_SENDER_OR_RETURN{};
    setBlocked();

    KeyEvent event(this,
                   Key(static_cast<KeySym>(keyval), KeyStates(state), keycode),
                   isRelease, time);
    // Force focus if there's keyevent.
    if (!hasFocus()) {
        focusIn();
    }

    bool keyresult = keyEvent(event);

    std::vector<DBusBlockedEvent> result;
    setUnblocked(result);
    return {result, keyresult};
}

#define FCITX_PORTAL_DBUS_SERVICE "org.freedesktop.portal.Fcitx"

DBusFrontendModule::DBusFrontendModule(Instance *instance)
    : instance_(instance),
      portalBus_(std::make_unique<dbus::Bus>(bus()->address())),
      inputMethod1_(std::make_unique<InputMethod1>(
          this, bus(), "/org/freedesktop/portal/inputmethod")),
      inputMethod1Compatible_(std::make_unique<InputMethod1>(
          this, portalBus_.get(), "/inputmethod")),
      portalInputMethod1_(std::make_unique<InputMethod1>(
          this, portalBus_.get(), "/org/freedesktop/portal/inputmethod")) {

    portalBus_->attachEventLoop(&instance->eventLoop());
    if (!portalBus_->requestName(
            FCITX_PORTAL_DBUS_SERVICE,
            Flags<dbus::RequestNameFlag>{dbus::RequestNameFlag::ReplaceExisting,
                                         dbus::RequestNameFlag::Queue})) {
        FCITX_WARN() << "Can not get portal dbus name right now.";
    }

    events_.emplace_back(instance_->watchEvent(
        EventType::InputContextInputMethodActivated, EventWatcherPhase::Default,
        [this](Event &event) {
            auto &activated = static_cast<InputMethodActivatedEvent &>(event);
            auto *ic = activated.inputContext();
            if (ic->frontendName() == "dbus") {
                if (const auto *entry = instance_->inputMethodManager().entry(
                        activated.name())) {
                    static_cast<DBusInputContext1 *>(ic)->updateIM(entry);
                }
            }
        }));
    events_.emplace_back(instance_->watchEvent(
        EventType::UIChanged, EventWatcherPhase::Default, [this](Event &) {
            instance_->inputContextManager().foreach([](InputContext *ic) {
                if (ic->frontendName() == "dbus") {
                    static_cast<DBusInputContext1 *>(ic)->updateCapability();
                    if (ic->capabilityFlags().test(
                            CapabilityFlag::ClientSideInputPanel)) {
                        static_cast<DBusInputContext1 *>(ic)
                            ->updateClientSideUIImpl();
                    }
                }
                return true;
            });
        }));
    events_.emplace_back(instance_->watchEvent(
        EventType::InputContextFocusOut, EventWatcherPhase::PreInputMethod,
        [](Event &event) {
            // Right now we do this regardless of it's coming from client or
            // server. We may want to save some dbus message if we can
            // distinguish between two different type of focus out event.
            auto &focusOut = static_cast<FocusOutEvent &>(event);
            InputContext *ic = focusOut.inputContext();
            if (ic->frontendName() == "dbus") {
                static_cast<DBusInputContext1 *>(ic)->sendFocusOut();
            }
        }));
}

DBusFrontendModule::~DBusFrontendModule() {
    portalBus_->releaseName(FCITX_PORTAL_DBUS_SERVICE);
}

dbus::Bus *DBusFrontendModule::bus() {
    return dbus()->call<IDBusModule::bus>();
}

class DBusFrontendModuleFactory : public AddonFactory {
public:
    AddonInstance *create(AddonManager *manager) override {
        return new DBusFrontendModule(manager->instance());
    }
};
} // namespace fcitx

FCITX_ADDON_FACTORY_V2(dbusfrontend, fcitx::DBusFrontendModuleFactory);
