// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
/* exported InputMethod */
const { Clutter, GLib, Gio, GObject, IBus } = imports.gi;

const Keyboard = imports.ui.status.keyboard;

Gio._promisify(IBus.Bus.prototype,
    'create_input_context_async', 'create_input_context_async_finish');

var HIDE_PANEL_TIME = 50;

var InputMethod = GObject.registerClass(
class InputMethod extends Clutter.InputMethod {
    _init() {
        super._init();
        this._hints = 0;
        this._purpose = 0;
        this._currentFocus = null;
        this._preeditStr = '';
        this._preeditPos = 0;
        this._preeditVisible = false;
        this._hidePanelId = 0;
        this._ibus = IBus.Bus.new_async();
        this._ibus.connect('connected', this._onConnected.bind(this));
        this._ibus.connect('disconnected', this._clear.bind(this));
        this.connect('notify::can-show-preedit', this._updateCapabilities.bind(this));

        this._inputSourceManager = Keyboard.getInputSourceManager();
        this._sourceChangedId = this._inputSourceManager.connect('current-source-changed',
                                                                 this._onSourceChanged.bind(this));
        this._currentSource = this._inputSourceManager.currentSource;

        if (this._ibus.is_connected())
            this._onConnected();
    }

    get currentFocus() {
        return this._currentFocus;
    }

    _updateCapabilities() {
        let caps = IBus.Capabilite.PREEDIT_TEXT | IBus.Capabilite.FOCUS | IBus.Capabilite.SURROUNDING_TEXT;

        if (this._context)
            this._context.set_capabilities(caps);
    }

    _onSourceChanged() {
        this._currentSource = this._inputSourceManager.currentSource;
    }

    async _onConnected() {
        this._cancellable = new Gio.Cancellable();
        try {
            this._context = await this._ibus.create_input_context_async(
                'scarecrow-shell', -1, this._cancellable);
        } catch (e) {
            if (!e.matches(Gio.IOErrorEnum, Gio.IOErrorEnum.CANCELLED)) {
                logError(e);
                this._clear();
            }
            return;
        }

        this._context.connect('commit-text', this._onCommitText.bind(this));
        this._context.connect('delete-surrounding-text', this._onDeleteSurroundingText.bind(this));
        this._context.connect('update-preedit-text', this._onUpdatePreeditText.bind(this));
        this._context.connect('show-preedit-text', this._onShowPreeditText.bind(this));
        this._context.connect('hide-preedit-text', this._onHidePreeditText.bind(this));
        this._context.connect('forward-key-event', this._onForwardKeyEvent.bind(this));
        this._context.connect('destroy', this._clear.bind(this));

        this._updateCapabilities();
    }

    _clear() {
        if (this._cancellable) {
            this._cancellable.cancel();
            this._cancellable = null;
        }

        this._context = null;
        this._hints = 0;
        this._purpose = 0;
        this._preeditStr = '';
        this._preeditPos = 0;
        this._preeditVisible = false;
    }

    _emitRequestSurrounding() {
        if (this._context.needs_surrounding_text())
            this.emit('request-surrounding');
    }

    _onCommitText(_context, text) {
        this.commit(text.get_text());
    }

    _onDeleteSurroundingText(_context, offset, nchars) {
        try {
            this.delete_surrounding(offset, nchars);
        } catch (e) {
            // We may get out of bounds for negative offset on older vater
            this.delete_surrounding(0, nchars + offset);
        }
    }

    _onUpdatePreeditText(_context, text, pos, visible) {
        if (text == null)
            return;

        let preedit = text.get_text();

        if (visible)
            this.set_preedit_text(preedit, pos);
        else if (this._preeditVisible)
            this.set_preedit_text(null, pos);

        this._preeditStr = preedit;
        this._preeditPos = pos;
        this._preeditVisible = visible;
    }

    _onShowPreeditText() {
        this._preeditVisible = true;
        this.set_preedit_text(this._preeditStr, this._preeditPos);
    }

    _onHidePreeditText() {
        this.set_preedit_text(null, this._preeditPos);
        this._preeditVisible = false;
    }

    _onForwardKeyEvent(_context, keyval, keycode, state) {
        let press = (state & IBus.ModifierType.RELEASE_MASK) == 0;
        state &= ~IBus.ModifierType.RELEASE_MASK;

        let curEvent = Clutter.get_current_event();
        let time;
        if (curEvent)
            time = curEvent.get_time();
        else
            time = global.display.get_current_time_roundtrip();

        this.forward_key(keyval, keycode + 8, state & Clutter.ModifierType.MODIFIER_MASK, time, press);
    }

    vfunc_focus_in(focus) {
        this._currentFocus = focus;
        if (this._context) {
            this._context.focus_in();
            this._emitRequestSurrounding();
        }

        if (this._hidePanelId) {
            GLib.source_remove(this._hidePanelId);
            this._hidePanelId = 0;
        }
    }

    vfunc_focus_out() {
        this._currentFocus = null;
        if (this._context)
            this._context.focus_out();

        if (this._preeditStr) {
            // Unset any preedit text
            this.set_preedit_text(null, 0);
            this._preeditStr = null;
        }

        this._hidePanelId = GLib.timeout_add(GLib.PRIORITY_DEFAULT, HIDE_PANEL_TIME, () => {
            this.set_input_panel_state(Clutter.InputPanelState.OFF);
            this._hidePanelId = 0;
            return GLib.SOURCE_REMOVE;
        });
    }

    vfunc_reset() {
        if (this._context) {
            this._context.reset();
            this._emitRequestSurrounding();
        }

        if (this._preeditStr) {
            // Unset any preedit text
            this.set_preedit_text(null, 0);
            this._preeditStr = null;
        }
    }

    vfunc_set_cursor_location(rect) {
        if (this._context) {
            this._context.set_cursor_location(rect.get_x(), rect.get_y(),
                                              rect.get_width(), rect.get_height());
            this._emitRequestSurrounding();
        }
    }

    vfunc_set_surrounding(text, cursor, anchor) {
        if (!this._context || !text)
            return;

        let ibusText = IBus.Text.new_from_string(text);
        this._context.set_surrounding_text(ibusText, cursor, anchor);
    }

    vfunc_update_content_hints(hints) {
        let ibusHints = 0;
        if (hints & Clutter.InputContentHintFlags.COMPLETION)
            ibusHints |= IBus.InputHints.WORD_COMPLETION;
        if (hints & Clutter.InputContentHintFlags.SPELLCHECK)
            ibusHints |= IBus.InputHints.SPELLCHECK;
        if (hints & Clutter.InputContentHintFlags.AUTO_CAPITALIZATION)
            ibusHints |= IBus.InputHints.UPPERCASE_SENTENCES;
        if (hints & Clutter.InputContentHintFlags.LOWERCASE)
            ibusHints |= IBus.InputHints.LOWERCASE;
        if (hints & Clutter.InputContentHintFlags.UPPERCASE)
            ibusHints |= IBus.InputHints.UPPERCASE_CHARS;
        if (hints & Clutter.InputContentHintFlags.TITLECASE)
            ibusHints |= IBus.InputHints.UPPERCASE_WORDS;

        this._hints = ibusHints;
        if (this._context)
            this._context.set_content_type(this._purpose, this._hints);
    }

    vfunc_update_content_purpose(purpose) {
        let ibusPurpose = 0;
        if (purpose == Clutter.InputContentPurpose.NORMAL)
            ibusPurpose = IBus.InputPurpose.FREE_FORM;
        else if (purpose == Clutter.InputContentPurpose.ALPHA)
            ibusPurpose = IBus.InputPurpose.ALPHA;
        else if (purpose == Clutter.InputContentPurpose.DIGITS)
            ibusPurpose = IBus.InputPurpose.DIGITS;
        else if (purpose == Clutter.InputContentPurpose.NUMBER)
            ibusPurpose = IBus.InputPurpose.NUMBER;
        else if (purpose == Clutter.InputContentPurpose.PHONE)
            ibusPurpose = IBus.InputPurpose.PHONE;
        else if (purpose == Clutter.InputContentPurpose.URL)
            ibusPurpose = IBus.InputPurpose.URL;
        else if (purpose == Clutter.InputContentPurpose.EMAIL)
            ibusPurpose = IBus.InputPurpose.EMAIL;
        else if (purpose == Clutter.InputContentPurpose.NAME)
            ibusPurpose = IBus.InputPurpose.NAME;
        else if (purpose == Clutter.InputContentPurpose.PASSWORD)
            ibusPurpose = IBus.InputPurpose.PASSWORD;

        this._purpose = ibusPurpose;
        if (this._context)
            this._context.set_content_type(this._purpose, this._hints);
    }

    vfunc_filter_key_event(event) {
        if (!this._context)
            return false;
        if (!this._currentSource)
            return false;

        let state = event.get_state();
        if (state & IBus.ModifierType.IGNORED_MASK)
            return false;

        if (event.type() == Clutter.EventType.KEY_RELEASE)
            state |= IBus.ModifierType.RELEASE_MASK;

        this._context.process_key_event_async(
            event.get_key_symbol(),
            event.get_key_code() - 8, // Convert XKB keycodes to evcodes
            state, -1, this._cancellable,
            (context, res) => {
                if (context != this._context)
                    return;

                try {
                    let retval = context.process_key_event_async_finish(res);
                    this.notify_key_event(event, retval);
                } catch (e) {
                    if (!e.matches(Gio.IOErrorEnum, Gio.IOErrorEnum.CANCELLED))
                        log(`Error processing key on IM: ${e.message}`);
                }
            });
        return true;
    }
});
