// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-

const { Clutter, Cogl, Gio, GLib,
        GObject, Meta, Pango, Shell, St } = imports.gi;
const Mainloop = imports.mainloop;
const Signals = imports.signals;
const System = imports.system;

const History = imports.misc.history;
const ExtensionUtils = imports.misc.extensionUtils;
const ShellEntry = imports.ui.shellEntry;
const Tweener = imports.ui.tweener;
const Main = imports.ui.main;
const JsParse = imports.misc.jsParse;

const { ExtensionState } = ExtensionUtils;

const CHEVRON = '>>> ';

/* Imports...feel free to add here as needed */
var commandHeader = 'const { Clutter, Gio, GLib, GObject, Meta, Shell, St } = imports.gi; ' +
                    'const Main = imports.ui.main; ' +
                    'const Mainloop = imports.mainloop; ' +
                    'const Tweener = imports.ui.tweener; ' +
                    /* Utility functions...we should probably be able to use these
                     * in the shell core code too. */
                    'const stage = global.stage; ' +
                    /* Special lookingGlass functions */
                    'const inspect = Main.lookingGlass.inspect.bind(Main.lookingGlass); ' +
                    'const it = Main.lookingGlass.getIt(); ' +
                    'const r = Main.lookingGlass.getResult.bind(Main.lookingGlass); ';

const HISTORY_KEY = 'looking-glass-history';
// Time between tabs for them to count as a double-tab event
var AUTO_COMPLETE_DOUBLE_TAB_DELAY = 500;
var AUTO_COMPLETE_SHOW_COMPLETION_ANIMATION_DURATION = 0.2;
var AUTO_COMPLETE_GLOBAL_KEYWORDS = _getAutoCompleteGlobalKeywords();

function _getAutoCompleteGlobalKeywords() {
    const keywords = ['true', 'false', 'null', 'new'];
    // Don't add the private properties of window (i.e., ones starting with '_')
    const windowProperties = Object.getOwnPropertyNames(window).filter(
        a => a.charAt(0) != '_'
    );
    const headerProperties = JsParse.getDeclaredConstants(commandHeader);

    return keywords.concat(windowProperties).concat(headerProperties);
}

var AutoComplete = class AutoComplete {
    constructor(entry) {
        this._entry = entry;
        this._entry.connect('key-press-event', this._entryKeyPressEvent.bind(this));
        this._lastTabTime = global.get_current_time();
    }

    _processCompletionRequest(event) {
        if (event.completions.length == 0) {
            return;
        }
        // Unique match = go ahead and complete; multiple matches + single tab = complete the common starting string;
        // multiple matches + double tab = emit a suggest event with all possible options
        if (event.completions.length == 1) {
            this.additionalCompletionText(event.completions[0], event.attrHead);
            this.emit('completion', { completion: event.completions[0], type: 'whole-word' });
        } else if (event.completions.length > 1 && event.tabType === 'single') {
            let commonPrefix = JsParse.getCommonPrefix(event.completions);

            if (commonPrefix.length > 0) {
                this.additionalCompletionText(commonPrefix, event.attrHead);
                this.emit('completion', { completion: commonPrefix, type: 'prefix' });
                this.emit('suggest', { completions: event.completions });
            }
        } else if (event.completions.length > 1 && event.tabType === 'double') {
            this.emit('suggest', { completions: event.completions });
        }
    }

    _entryKeyPressEvent(actor, event) {
        let cursorPos = this._entry.clutter_text.get_cursor_position();
        let text = this._entry.get_text();
        if (cursorPos != -1) {
            text = text.slice(0, cursorPos);
        }
        if (event.get_key_symbol() == Clutter.Tab) {
            let [completions, attrHead] = JsParse.getCompletions(text, commandHeader, AUTO_COMPLETE_GLOBAL_KEYWORDS);
            let currTime = global.get_current_time();
            if ((currTime - this._lastTabTime) < AUTO_COMPLETE_DOUBLE_TAB_DELAY) {
                this._processCompletionRequest({ tabType: 'double',
                                                 completions: completions,
                                                 attrHead: attrHead });
            } else {
                this._processCompletionRequest({ tabType: 'single',
                                                 completions: completions,
                                                 attrHead: attrHead });
            }
            this._lastTabTime = currTime;
        }
        return Clutter.EVENT_PROPAGATE;
    }

    // Insert characters of text not already included in head at cursor position.  i.e., if text="abc" and head="a",
    // the string "bc" will be appended to this._entry
    additionalCompletionText(text, head) {
        let additionalCompletionText = text.slice(head.length);
        let cursorPos = this._entry.clutter_text.get_cursor_position();

        this._entry.clutter_text.insert_text(additionalCompletionText, cursorPos);
    }
};
Signals.addSignalMethods(AutoComplete.prototype);


var Notebook = class Notebook {
    constructor() {
        this.actor = new St.BoxLayout({ vertical: true });

        this.tabControls = new St.BoxLayout({ style_class: 'labels' });

        this._selectedIndex = -1;
        this._tabs = [];
    }

    appendPage(name, child) {
        let labelBox = new St.BoxLayout({ style_class: 'notebook-tab',
                                          reactive: true,
                                          track_hover: true });
        let label = new St.Button({ label: name });
        label.connect('clicked', () => {
            this.selectChild(child);
            return true;
        });
        labelBox.add(label, { expand: true });
        this.tabControls.add(labelBox);

        let scrollview = new St.ScrollView({ x_fill: true, y_fill: true });
        scrollview.get_hscroll_bar().hide();
        scrollview.add_actor(child);

        let tabData = { child: child,
                        labelBox: labelBox,
                        label: label,
                        scrollView: scrollview,
                        _scrollToBottom: false };
        this._tabs.push(tabData);
        scrollview.hide();
        this.actor.add(scrollview, { expand: true });

        let vAdjust = scrollview.vscroll.adjustment;
        vAdjust.connect('changed', () => this._onAdjustScopeChanged(tabData));
        vAdjust.connect('notify::value', () => this._onAdjustValueChanged(tabData));

        if (this._selectedIndex == -1)
            this.selectIndex(0);
    }

    _unselect() {
        if (this._selectedIndex < 0)
            return;
        let tabData = this._tabs[this._selectedIndex];
        tabData.labelBox.remove_style_pseudo_class('selected');
        tabData.scrollView.hide();
        this._selectedIndex = -1;
    }

    selectIndex(index) {
        if (index == this._selectedIndex)
            return;
        if (index < 0) {
            this._unselect();
            this.emit('selection', null);
            return;
        }

        // Focus the new tab before unmapping the old one
        let tabData = this._tabs[index];
        if (!tabData.scrollView.navigate_focus(null, St.DirectionType.TAB_FORWARD, false))
            this.actor.grab_key_focus();

        this._unselect();

        tabData.labelBox.add_style_pseudo_class('selected');
        tabData.scrollView.show();
        this._selectedIndex = index;
        this.emit('selection', tabData.child);
    }

    selectChild(child) {
        if (child == null) {
            this.selectIndex(-1);
        } else {
            for (let i = 0; i < this._tabs.length; i++) {
                let tabData = this._tabs[i];
                if (tabData.child == child) {
                    this.selectIndex(i);
                    return;
                }
            }
        }
    }

    scrollToBottom(index) {
        let tabData = this._tabs[index];
        tabData._scrollToBottom = true;

    }

    _onAdjustValueChanged(tabData) {
        let vAdjust = tabData.scrollView.vscroll.adjustment;
        if (vAdjust.value < (vAdjust.upper - vAdjust.lower - 0.5))
            tabData._scrolltoBottom = false;
    }

    _onAdjustScopeChanged(tabData) {
        if (!tabData._scrollToBottom)
            return;
        let vAdjust = tabData.scrollView.vscroll.adjustment;
        vAdjust.value = vAdjust.upper - vAdjust.page_size;
    }

    nextTab() {
        let nextIndex = this._selectedIndex;
        if (nextIndex < this._tabs.length - 1) {
            ++nextIndex;
        }

        this.selectIndex(nextIndex);
    }

    prevTab() {
        let prevIndex = this._selectedIndex;
        if (prevIndex > 0) {
            --prevIndex;
        }

        this.selectIndex(prevIndex);
    }
};
Signals.addSignalMethods(Notebook.prototype);

function objectToString(o) {
    if (typeof(o) == typeof(objectToString)) {
        // special case this since the default is way, way too verbose
        return '<js function>';
    } else {
        return `${o}`;
    }
}

var ObjLink = class ObjLink {
    constructor(lookingGlass, o, title) {
        let text;
        if (title)
            text = title;
        else
            text = objectToString(o);
        text = GLib.markup_escape_text(text, -1);
        this._obj = o;

        this.actor = new St.Button({ reactive: true,
                                     track_hover: true,
                                     style_class: 'shell-link',
                                     label: text });
        this.actor.get_child().single_line_mode = true;
        this.actor.connect('clicked', this._onClicked.bind(this));

        this._lookingGlass = lookingGlass;
    }

    _onClicked(link) {
        this._lookingGlass.inspectObject(this._obj, this.actor);
    }
};

var Result = class Result {
    constructor(lookingGlass, command, o, index) {
        this.index = index;
        this.o = o;

        this.actor = new St.BoxLayout({ vertical: true });
        this._lookingGlass = lookingGlass;

        let cmdTxt = new St.Label({ text: command });
        cmdTxt.clutter_text.ellipsize = Pango.EllipsizeMode.END;
        this.actor.add(cmdTxt);
        let box = new St.BoxLayout({});
        this.actor.add(box);
        let resultTxt = new St.Label({ text: `r(${index}) = ` });
        resultTxt.clutter_text.ellipsize = Pango.EllipsizeMode.END;
        box.add(resultTxt);
        let objLink = new ObjLink(this._lookingGlass, o);
        box.add(objLink.actor);
    }
};

var WindowList = class WindowList {
    constructor(lookingGlass) {
        this.actor = new St.BoxLayout({ name: 'Windows', vertical: true, style: 'spacing: 8px' });
        let tracker = Shell.WindowTracker.get_default();
        this._updateId = Main.initializeDeferredWork(this.actor, this._updateWindowList.bind(this));
        global.display.connect('window-created', this._updateWindowList.bind(this));
        tracker.connect('tracked-windows-changed', this._updateWindowList.bind(this));

        this._lookingGlass = lookingGlass;
    }

    _updateWindowList() {
        this.actor.destroy_all_children();
        let windows = global.get_window_actors();
        let tracker = Shell.WindowTracker.get_default();
        for (let i = 0; i < windows.length; i++) {
            let metaWindow = windows[i].metaWindow;
            // Avoid multiple connections
            if (!metaWindow._lookingGlassManaged) {
                metaWindow.connect('unmanaged', this._updateWindowList.bind(this));
                metaWindow._lookingGlassManaged = true;
            }
            let box = new St.BoxLayout({ vertical: true });
            this.actor.add(box);
            let windowLink = new ObjLink(this._lookingGlass, metaWindow, metaWindow.title);
            box.add(windowLink.actor, { x_align: St.Align.START, x_fill: false });
            let propsBox = new St.BoxLayout({ vertical: true, style: 'padding-left: 6px;' });
            box.add(propsBox);
            propsBox.add(new St.Label({ text: `wmclass: ${metaWindow.get_wm_class()}` }));
            let app = tracker.get_window_app(metaWindow);
            if (app != null && !app.is_window_backed()) {
                let icon = app.create_icon_texture(22);
                let propBox = new St.BoxLayout({ style: 'spacing: 6px; ' });
                propsBox.add(propBox);
                propBox.add(new St.Label({ text: 'app: ' }), { y_fill: false });
                let appLink = new ObjLink(this._lookingGlass, app, app.get_id());
                propBox.add(appLink.actor, { y_fill: false });
                propBox.add(icon, { y_fill: false });
            } else {
                propsBox.add(new St.Label({ text: '<untracked>' }));
            }
        }
    }
};
Signals.addSignalMethods(WindowList.prototype);

var ObjInspector = class ObjInspector {
    constructor(lookingGlass) {
        this._obj = null;
        this._previousObj = null;

        this._parentList = [];

        this.actor = new St.ScrollView({ pivot_point: new Clutter.Point({ x: 0.5, y: 0.5 }),
                                         x_fill: true, y_fill: true });
        this.actor.get_hscroll_bar().hide();
        this._container = new St.BoxLayout({ name: 'LookingGlassPropertyInspector',
                                             style_class: 'lg-dialog',
                                             vertical: true });
        this.actor.add_actor(this._container);

        this._lookingGlass = lookingGlass;
    }

    selectObject(obj, skipPrevious) {
        if (!skipPrevious)
            this._previousObj = this._obj;
        else
            this._previousObj = null;
        this._obj = obj;

        this._container.destroy_all_children();

        let hbox = new St.BoxLayout({ style_class: 'lg-obj-inspector-title' });
        this._container.add_actor(hbox);
        let label = new St.Label({ text: 'Inspecting: %s: %s'.format(typeof(obj),
                                                                     objectToString(obj)) });
        label.single_line_mode = true;
        hbox.add(label, { expand: true, y_fill: false });
        let button = new St.Button({ label: 'Insert', style_class: 'lg-obj-inspector-button' });
        button.connect('clicked', this._onInsert.bind(this));
        hbox.add(button);

        if (this._previousObj != null) {
            button = new St.Button({ label: 'Back', style_class: 'lg-obj-inspector-button' });
            button.connect('clicked', this._onBack.bind(this));
            hbox.add(button);
        }

        button = new St.Button({ style_class: 'window-close' });
        button.add_actor(new St.Icon({ icon_name: 'window-close-symbolic' }));
        button.connect('clicked', this.close.bind(this));
        hbox.add(button);
        if (typeof(obj) == typeof({})) {
            let properties = [];
            for (let propName in obj) {
                properties.push(propName);
            }
            properties.sort();

            for (let i = 0; i < properties.length; i++) {
                let propName = properties[i];
                let link;
                try {
                    let prop = obj[propName];
                    link = new ObjLink(this._lookingGlass, prop).actor;
                } catch (e) {
                    link = new St.Label({ text: '<error>' });
                }
                let hbox = new St.BoxLayout();
                hbox.add(new St.Label({ text: `${propName}: ` }));
                hbox.add(link);
                this._container.add_actor(hbox);
            }
        }
    }

    open(sourceActor) {
        if (this._open)
            return;
        this._previousObj = null;
        this._open = true;
        this.actor.show();
        if (sourceActor) {
            this.actor.set_scale(0, 0);
            Tweener.addTween(this.actor, { scale_x: 1, scale_y: 1,
                                           transition: 'easeOutQuad',
                                           time: 0.2 });
        } else {
            this.actor.set_scale(1, 1);
        }
    }

    close() {
        if (!this._open)
            return;
        this._open = false;
        this.actor.hide();
        this._previousObj = null;
        this._obj = null;
    }

    _onInsert() {
        let obj = this._obj;
        this.close();
        this._lookingGlass.insertObject(obj);
    }

    _onBack() {
        this.selectObject(this._previousObj, true);
    }
};

var RedBorderEffect = GObject.registerClass(
class RedBorderEffect extends Clutter.Effect {
    vfunc_paint() {
        let actor = this.get_actor();
        actor.continue_paint();

        let color = new Cogl.Color();
        color.init_from_4ub(0xff, 0, 0, 0xc4);
        Cogl.set_source_color(color);

        let geom = actor.get_allocation_geometry();
        let width = 2;

        // clockwise order
        Cogl.rectangle(0, 0, geom.width, width);
        Cogl.rectangle(geom.width - width, width,
                       geom.width, geom.height);
        Cogl.rectangle(0, geom.height,
                       geom.width - width, geom.height - width);
        Cogl.rectangle(0, geom.height - width,
                       width, width);
    }
});

var Inspector = GObject.registerClass({
    Signals: { 'closed': {},
               'target': { param_types: [Clutter.Actor.$gtype, GObject.TYPE_DOUBLE, GObject.TYPE_DOUBLE] } },
}, class Inspector extends Clutter.Actor {
    _init(lookingGlass) {
        super._init({ width: 0,
                      height: 0 });

        Main.uiGroup.add_actor(this);

        let eventHandler = new St.BoxLayout({ name: 'LookingGlassDialog',
                                              vertical: false,
                                              reactive: true });
        this._eventHandler = eventHandler;
        this.add_actor(eventHandler);
        this._displayText = new St.Label();
        eventHandler.add(this._displayText, { expand: true });

        eventHandler.connect('key-press-event', this._onKeyPressEvent.bind(this));
        eventHandler.connect('button-press-event', this._onButtonPressEvent.bind(this));
        eventHandler.connect('scroll-event', this._onScrollEvent.bind(this));
        eventHandler.connect('motion-event', this._onMotionEvent.bind(this));

        let dm = Clutter.DeviceManager.get_default();
        this._pointerDevice = dm.get_core_device(Clutter.InputDeviceType.POINTER_DEVICE);
        this._keyboardDevice = dm.get_core_device(Clutter.InputDeviceType.KEYBOARD_DEVICE);

        this._pointerDevice.grab(eventHandler);
        this._keyboardDevice.grab(eventHandler);

        // this._target is the actor currently shown by the inspector.
        // this._pointerTarget is the actor directly under the pointer.
        // Normally these are the same, but if you use the scroll wheel
        // to drill down, they'll diverge until you either scroll back
        // out, or move the pointer outside of _pointerTarget.
        this._target = null;
        this._pointerTarget = null;

        this._lookingGlass = lookingGlass;
    }

    vfunc_allocate(box, flags) {
        this.set_allocation(box, flags);

        if (!this._eventHandler)
            return;

        let primary = Main.layoutManager.primaryMonitor;

        let [minWidth, minHeight, natWidth, natHeight] =
            this._eventHandler.get_preferred_size();

        let childBox = new Clutter.ActorBox();
        childBox.x1 = primary.x + Math.floor((primary.width - natWidth) / 2);
        childBox.x2 = childBox.x1 + natWidth;
        childBox.y1 = primary.y + Math.floor((primary.height - natHeight) / 2);
        childBox.y2 = childBox.y1 + natHeight;
        this._eventHandler.allocate(childBox, flags);
    }

    _close() {
        this._pointerDevice.ungrab();
        this._keyboardDevice.ungrab();
        this._eventHandler.destroy();
        this._eventHandler = null;
        this.emit('closed');
    }

    _onKeyPressEvent(actor, event) {
        if (event.get_key_symbol() == Clutter.Escape)
            this._close();
        return Clutter.EVENT_STOP;
    }

    _onButtonPressEvent(actor, event) {
        if (this._target) {
            let [stageX, stageY] = event.get_coords();
            this.emit('target', this._target, stageX, stageY);
        }
        this._close();
        return Clutter.EVENT_STOP;
    }

    _onScrollEvent(actor, event) {
        switch (event.get_scroll_direction()) {
        case Clutter.ScrollDirection.UP: {
            // select parent
            let parent = this._target.get_parent();
            if (parent != null) {
                this._target = parent;
                this._update(event);
            }
            break;
        }

        case Clutter.ScrollDirection.DOWN:
            // select child
            if (this._target != this._pointerTarget) {
                let child = this._pointerTarget;
                while (child) {
                    let parent = child.get_parent();
                    if (parent == this._target)
                        break;
                    child = parent;
                }
                if (child) {
                    this._target = child;
                    this._update(event);
                }
            }
            break;

        default:
            break;
        }
        return Clutter.EVENT_STOP;
    }

    _onMotionEvent(actor, event) {
        this._update(event);
        return Clutter.EVENT_STOP;
    }

    _update(event) {
        let [stageX, stageY] = event.get_coords();
        let target = global.stage.get_actor_at_pos(Clutter.PickMode.ALL,
                                                   stageX,
                                                   stageY);

        if (target != this._pointerTarget)
            this._target = target;
        this._pointerTarget = target;

        let position = `[inspect x: ${stageX} y: ${stageY}]`;
        this._displayText.text = '';
        this._displayText.text = `${position} ${this._target}`;

        this._lookingGlass.setBorderPaintTarget(this._target);
    }
});

var Extensions = class Extensions {
    constructor(lookingGlass) {
        this._lookingGlass = lookingGlass;
        this.actor = new St.BoxLayout({ vertical: true,
                                        name: 'lookingGlassExtensions' });
        this._noExtensions = new St.Label({ style_class: 'lg-extensions-none',
                                            text: _("No extensions installed") });
        this._numExtensions = 0;
        this._extensionsList = new St.BoxLayout({ vertical: true,
                                                  style_class: 'lg-extensions-list' });
        this._extensionsList.add(this._noExtensions);
        this.actor.add(this._extensionsList);

        for (let uuid in ExtensionUtils.extensions)
            this._loadExtension(null, uuid);

        Main.extensionManager.connect('extension-loaded',
                                      this._loadExtension.bind(this));
    }

    _loadExtension(o, uuid) {
        let extension = ExtensionUtils.extensions[uuid];
        // There can be cases where we create dummy extension metadata
        // that's not really a proper extension. Don't bother with these.
        if (!extension.metadata.name)
            return;

        let extensionDisplay = this._createExtensionDisplay(extension);
        if (this._numExtensions == 0)
            this._extensionsList.remove_actor(this._noExtensions);

        this._numExtensions ++;
        this._extensionsList.add(extensionDisplay);
    }

    _onViewSource(actor) {
        let extension = actor._extension;
        let uri = extension.dir.get_uri();
        Gio.app_info_launch_default_for_uri(uri, global.create_app_launch_context(0, -1));
        this._lookingGlass.close();
    }

    _onWebPage(actor) {
        let extension = actor._extension;
        Gio.app_info_launch_default_for_uri(extension.metadata.url, global.create_app_launch_context(0, -1));
        this._lookingGlass.close();
    }

    _onViewErrors(actor) {
        let extension = actor._extension;
        let shouldShow = !actor._isShowing;

        if (shouldShow) {
            let errors = extension.errors;
            let errorDisplay = new St.BoxLayout({ vertical: true });
            if (errors && errors.length) {
                for (let i = 0; i < errors.length; i ++)
                    errorDisplay.add(new St.Label({ text: errors[i] }));
            } else {
                /* Translators: argument is an extension UUID. */
                let message = _("%s has not emitted any errors.").format(extension.uuid);
                errorDisplay.add(new St.Label({ text: message }));
            }

            actor._errorDisplay = errorDisplay;
            actor._parentBox.add(errorDisplay);
            actor.label = _("Hide Errors");
        } else {
            actor._errorDisplay.destroy();
            actor._errorDisplay = null;
            actor.label = _("Show Errors");
        }

        actor._isShowing = shouldShow;
    }

    _stateToString(extensionState) {
        switch (extensionState) {
        case ExtensionState.ENABLED:
            return _("Enabled");
        case ExtensionState.DISABLED:
        case ExtensionState.INITIALIZED:
            return _("Disabled");
        case ExtensionState.ERROR:
            return _("Error");
        case ExtensionState.OUT_OF_DATE:
            return _("Out of date");
        case ExtensionState.DOWNLOADING:
            return _("Downloading");
        }
        return 'Unknown'; // Not translated, shouldn't appear
    }

    _createExtensionDisplay(extension) {
        let box = new St.BoxLayout({ style_class: 'lg-extension', vertical: true });
        let name = new St.Label({ style_class: 'lg-extension-name',
                                  text: extension.metadata.name });
        box.add(name, { expand: true });
        let description = new St.Label({ style_class: 'lg-extension-description',
                                         text: extension.metadata.description || 'No description' });
        box.add(description, { expand: true });

        let metaBox = new St.BoxLayout({ style_class: 'lg-extension-meta' });
        box.add(metaBox);
        let state = new St.Label({ style_class: 'lg-extension-state',
                                   text: this._stateToString(extension.state) });
        metaBox.add(state);

        let viewsource = new St.Button({ reactive: true,
                                         track_hover: true,
                                         style_class: 'shell-link',
                                         label: _("View Source") });
        viewsource._extension = extension;
        viewsource.connect('clicked', this._onViewSource.bind(this));
        metaBox.add(viewsource);

        if (extension.metadata.url) {
            let webpage = new St.Button({ reactive: true,
                                          track_hover: true,
                                          style_class: 'shell-link',
                                          label: _("Web Page") });
            webpage._extension = extension;
            webpage.connect('clicked', this._onWebPage.bind(this));
            metaBox.add(webpage);
        }

        let viewerrors = new St.Button({ reactive: true,
                                         track_hover: true,
                                         style_class: 'shell-link',
                                         label: _("Show Errors") });
        viewerrors._extension = extension;
        viewerrors._parentBox = box;
        viewerrors._isShowing = false;
        viewerrors.connect('clicked', this._onViewErrors.bind(this));
        metaBox.add(viewerrors);

        return box;
    }
};

var LookingGlass = class LookingGlass {
    constructor() {
        this._borderPaintTarget = null;
        this._redBorderEffect = new RedBorderEffect();

        this._open = false;

        this._it = null;
        this._offset = 0;
        this._results = [];

        // Sort of magic, but...eh.
        this._maxItems = 150;

        this.actor = new St.BoxLayout({ name: 'LookingGlassDialog',
                                        style_class: 'lg-dialog',
                                        vertical: true,
                                        visible: false,
                                        reactive: true });
        this.actor.connect('key-press-event', this._globalKeyPressEvent.bind(this));

        this._interfaceSettings = new Gio.Settings({ schema_id: 'org.gnome.desktop.interface' });
        this._interfaceSettings.connect('changed::monospace-font-name',
                                        this._updateFont.bind(this));
        this._updateFont();

        // We want it to appear to slide out from underneath the panel
        Main.uiGroup.add_actor(this.actor);
        Main.uiGroup.set_child_below_sibling(this.actor,
                                             Main.layoutManager.panelBox);
        Main.layoutManager.panelBox.connect('allocation-changed',
                                            this._queueResize.bind(this));
        Main.layoutManager.keyboardBox.connect('allocation-changed',
                                               this._queueResize.bind(this));

        this._objInspector = new ObjInspector(this);
        Main.uiGroup.add_actor(this._objInspector.actor);
        this._objInspector.actor.hide();

        let toolbar = new St.BoxLayout({ name: 'Toolbar' });
        this.actor.add_actor(toolbar);
        let inspectIcon = new St.Icon({ icon_name: 'gtk-color-picker',
                                        icon_size: 24 });
        toolbar.add_actor(inspectIcon);
        inspectIcon.reactive = true;
        inspectIcon.connect('button-press-event', () => {
            let inspector = new Inspector(this);
            inspector.connect('target', (i, target, stageX, stageY) => {
                this._pushResult(`inspect(${Math.round(stageX)}, ${Math.round(stageY)})`, target);
            });
            inspector.connect('closed', () => {
                this.actor.show();
                global.stage.set_key_focus(this._entry);
            });
            this.actor.hide();
            return Clutter.EVENT_STOP;
        });

        let gcIcon = new St.Icon({ icon_name: 'user-trash-full',
                                   icon_size: 24 });
        toolbar.add_actor(gcIcon);
        gcIcon.reactive = true;
        gcIcon.connect('button-press-event', () => {
            gcIcon.icon_name = 'user-trash';
            System.gc();
            this._timeoutId = Mainloop.timeout_add(500, () => {
                gcIcon.icon_name = 'user-trash-full';
                this._timeoutId = 0;
                return GLib.SOURCE_REMOVE;
            });
            GLib.Source.set_name_by_id(this._timeoutId, '[gnome-shell] gcIcon.icon_name = \'user-trash-full\'');
            return Clutter.EVENT_PROPAGATE;
        });

        let notebook = new Notebook();
        this._notebook = notebook;
        this.actor.add(notebook.actor, { expand: true });

        let emptyBox = new St.Bin();
        toolbar.add(emptyBox, { expand: true });
        toolbar.add_actor(notebook.tabControls);

        this._evalBox = new St.BoxLayout({ name: 'EvalBox', vertical: true });
        notebook.appendPage('Evaluator', this._evalBox);

        this._resultsArea = new St.BoxLayout({ name: 'ResultsArea', vertical: true });
        this._evalBox.add(this._resultsArea, { expand: true });

        this._entryArea = new St.BoxLayout({ name: 'EntryArea' });
        this._evalBox.add_actor(this._entryArea);

        let label = new St.Label({ text: CHEVRON });
        this._entryArea.add(label);

        this._entry = new St.Entry({ can_focus: true });
        ShellEntry.addContextMenu(this._entry);
        this._entryArea.add(this._entry, { expand: true });

        this._windowList = new WindowList(this);
        notebook.appendPage('Windows', this._windowList.actor);

        this._extensions = new Extensions(this);
        notebook.appendPage('Extensions', this._extensions.actor);

        this._entry.clutter_text.connect('activate', (o, e) => {
            // Hide any completions we are currently showing
            this._hideCompletions();

            let text = o.get_text();
            // Ensure we don't get newlines in the command; the history file is
            // newline-separated.
            text = text.replace('\n', ' ');
            // Strip leading and trailing whitespace
            text = text.replace(/^\s+/g, '').replace(/\s+$/g, '');
            if (text == '')
                return true;
            this._evaluate(text);
            return true;
        });

        this._history = new History.HistoryManager({ gsettingsKey: HISTORY_KEY, 
                                                     entry: this._entry.clutter_text });

        this._autoComplete = new AutoComplete(this._entry);
        this._autoComplete.connect('suggest', (a, e) => {
            this._showCompletions(e.completions);
        });
        // If a completion is completed unambiguously, the currently-displayed completion
        // suggestions become irrelevant.
        this._autoComplete.connect('completion', (a, e) => {
            if (e.type == 'whole-word')
                this._hideCompletions();
        });

        this._resize();
    }

    _updateFont() {
        let fontName = this._interfaceSettings.get_string('monospace-font-name');
        let fontDesc = Pango.FontDescription.from_string(fontName);
        // We ignore everything but size and style; you'd be crazy to set your system-wide
        // monospace font to be bold/oblique/etc. Could easily be added here.
        let size = fontDesc.get_size() / 1024.;
        let unit = fontDesc.get_size_is_absolute() ? 'px' : 'pt';
        this.actor.style = `
            font-size: ${size}${unit};
            font-family: "${fontDesc.get_family()}";`;
    }

    setBorderPaintTarget(obj) {
        if (this._borderPaintTarget != null)
            this._borderPaintTarget.remove_effect(this._redBorderEffect);
        this._borderPaintTarget = obj;
        if (this._borderPaintTarget != null)
            this._borderPaintTarget.add_effect(this._redBorderEffect);
    }

    _pushResult(command, obj) {
        let index = this._results.length + this._offset;
        let result = new Result(this, CHEVRON + command, obj, index);
        this._results.push(result);
        this._resultsArea.add(result.actor);
        if (obj instanceof Clutter.Actor)
            this.setBorderPaintTarget(obj);

        let children = this._resultsArea.get_children();
        if (children.length > this._maxItems) {
            this._results.shift();
            children[0].destroy();
            this._offset++;
        }
        this._it = obj;

        // Scroll to bottom
        this._notebook.scrollToBottom(0);
    }

    _showCompletions(completions) {
        if (!this._completionActor) {
            this._completionActor = new St.Label({ name: 'LookingGlassAutoCompletionText', style_class: 'lg-completions-text' });
            this._completionActor.clutter_text.ellipsize = Pango.EllipsizeMode.NONE;
            this._completionActor.clutter_text.line_wrap = true;
            this._evalBox.insert_child_below(this._completionActor, this._entryArea);
        }

        this._completionActor.set_text(completions.join(', '));

        // Setting the height to -1 allows us to get its actual preferred height rather than
        // whatever was last given in set_height by Tweener.
        this._completionActor.set_height(-1);
        let [minHeight, naturalHeight] = this._completionActor.get_preferred_height(this._resultsArea.get_width());

        // Don't reanimate if we are already visible
        if (this._completionActor.visible) {
            this._completionActor.height = naturalHeight;
        } else {
            this._completionActor.show();
            Tweener.removeTweens(this._completionActor);
            Tweener.addTween(this._completionActor, { time: AUTO_COMPLETE_SHOW_COMPLETION_ANIMATION_DURATION / St.get_slow_down_factor(),
                                                      transition: 'easeOutQuad',
                                                      height: naturalHeight,
                                                      opacity: 255
                                                    });
        }
    }

    _hideCompletions() {
        if (this._completionActor) {
            Tweener.removeTweens(this._completionActor);
            Tweener.addTween(this._completionActor, { time: AUTO_COMPLETE_SHOW_COMPLETION_ANIMATION_DURATION / St.get_slow_down_factor(),
                                                      transition: 'easeOutQuad',
                                                      height: 0,
                                                      opacity: 0,
                                                      onComplete: () => {
                                                          this._completionActor.hide();
                                                      }
                                                    });
        }
    }

    _evaluate(command) {
        this._history.addItem(command);

        let lines = command.split(';');
        lines.push(`return ${lines.pop()}`);

        let fullCmd = commandHeader + lines.join(';');

        let resultObj;
        try {
            resultObj = Function(fullCmd)();
        } catch (e) {
            resultObj = `<exception ${e}>`;
        }

        this._pushResult(command, resultObj);
        this._entry.text = '';
    }

    inspect(x, y) {
        return global.stage.get_actor_at_pos(Clutter.PickMode.REACTIVE, x, y);
    }

    getIt() {
        return this._it;
    }

    getResult(idx) {
        return this._results[idx - this._offset].o;
    }

    toggle() {
        if (this._open)
            this.close();
        else
            this.open();
    }

    _queueResize() {
        Meta.later_add(Meta.LaterType.BEFORE_REDRAW, () => this._resize());
    }

    _resize() {
        let primary = Main.layoutManager.primaryMonitor;
        let myWidth = primary.width * 0.7;
        let availableHeight = primary.height - Main.layoutManager.keyboardBox.height;
        let myHeight = Math.min(primary.height * 0.7, availableHeight * 0.9);
        this.actor.x = primary.x + (primary.width - myWidth) / 2;
        this._hiddenY = primary.y + Main.layoutManager.panelBox.height - myHeight;
        this._targetY = this._hiddenY + myHeight;
        this.actor.y = this._hiddenY;
        this.actor.width = myWidth;
        this.actor.height = myHeight;
        this._objInspector.actor.set_size(Math.floor(myWidth * 0.8), Math.floor(myHeight * 0.8));
        this._objInspector.actor.set_position(this.actor.x + Math.floor(myWidth * 0.1),
                                              this._targetY + Math.floor(myHeight * 0.1));
    }

    insertObject(obj) {
        this._pushResult('<insert>', obj);
    }

    inspectObject(obj, sourceActor) {
        this._objInspector.open(sourceActor);
        this._objInspector.selectObject(obj);
    }

    // Handle key events which are relevant for all tabs of the LookingGlass
    _globalKeyPressEvent(actor, event) {
        let symbol = event.get_key_symbol();
        let modifierState = event.get_state();
        if (symbol == Clutter.Escape) {
            if (this._objInspector.actor.visible) {
                this._objInspector.close();
            } else {
                this.close();
            }
            return Clutter.EVENT_STOP;
        }
        // Ctrl+PgUp and Ctrl+PgDown switches tabs in the notebook view
        if (modifierState & Clutter.ModifierType.CONTROL_MASK) {
            if (symbol == Clutter.KEY_Page_Up) {
                this._notebook.prevTab();
            } else if (symbol == Clutter.KEY_Page_Down) {
                this._notebook.nextTab();
            }
        }
        return Clutter.EVENT_PROPAGATE;
    }

    open() {
        if (this._open)
            return;

        if (!Main.pushModal(this._entry, { actionMode: Shell.ActionMode.LOOKING_GLASS }))
            return;

        this._notebook.selectIndex(0);
        this.actor.show();
        this._open = true;
        this._history.lastItem();

        Tweener.removeTweens(this.actor);

        // We inverse compensate for the slow-down so you can change the factor
        // through LookingGlass without long waits.
        Tweener.addTween(this.actor, { time: 0.5 / St.get_slow_down_factor(),
                                       transition: 'easeOutQuad',
                                       y: this._targetY
                                     });
    }

    close() {
        if (!this._open)
            return;

        this._objInspector.actor.hide();

        this._open = false;
        Tweener.removeTweens(this.actor);

        this.setBorderPaintTarget(null);

        Main.popModal(this._entry);

        Tweener.addTween(this.actor, { time: Math.min(0.5 / St.get_slow_down_factor(), 0.5),
                                       transition: 'easeOutQuad',
                                       y: this._hiddenY,
                                       onComplete: () => {
                                           this.actor.hide();
                                       }
                                     });
    }
};
Signals.addSignalMethods(LookingGlass.prototype);