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

const { Clutter, GObject, Meta, Shell } = imports.gi;

const Main = imports.ui.main;
const SwipeTracker = imports.ui.swipeTracker;

const WINDOW_ANIMATION_TIME = 250;

const WorkspaceAnimation = GObject.registerClass({
    Properties: {
        'progress': GObject.ParamSpec.double(
            'progress', 'progress', 'progress',
            GObject.ParamFlags.READWRITE,
            -1, 1, 0),
    },
}, class WorkspaceAnimation extends Clutter.Actor {
    _init(controller, from, to, direction) {
        super._init();

        this.connect('destroy', this._onDestroy.bind(this));

        this._controller = controller;
        this._curGroup = new Clutter.Actor();
        this._movingWindowBin = new Clutter.Actor();
        this._windows = [];
        this._surroundings = {};
        this._progress = 0;

        let wgroup = global.window_group;
        let windows = global.get_window_actors();

        this._container = new Clutter.Actor();
        this._container.add_actor(this._curGroup);

        this.add_actor(this._container);
        wgroup.add_actor(this);
        wgroup.add_actor(this._movingWindowBin);

        let workspaceManager = global.workspace_manager;
        let curWs = workspaceManager.get_workspace_by_index(from);

        for (let dir of Object.values(Meta.MotionDirection)) {
            let ws = null;

            if (to < 0)
                ws = curWs.get_neighbor(dir);
            else if (dir === direction)
                ws = workspaceManager.get_workspace_by_index(to);

            if (ws === null || ws === curWs) {
                this._surroundings[dir] = null;
                continue;
            }

            let [x, y] = this._getPositionForDirection(dir, curWs, ws);
            let info = {
                index: ws.index(),
                actor: new Clutter.Actor(),
                xDest: x,
                yDest: y,
            };
            this._surroundings[dir] = info;
            this._container.add_actor(info.actor);
            this._container.set_child_above_sibling(info.actor, null);

            info.actor.set_position(x, y);
        }

        wgroup.set_child_above_sibling(this._movingWindowBin, null);

        for (let i = 0; i < windows.length; i++) {
            let actor = windows[i];
            let window = actor.get_meta_window();

            if (!window.showing_on_its_workspace())
                continue;

            if (window.is_on_all_workspaces())
                continue;

            let record = {
                window: actor,
                parent: actor.get_parent(),
            };

            if (this._controller.movingWindow &&
                window === this._controller.movingWindow) {
                record.parent.remove_child(actor);
                this._movingWindow = record;
                this._windows.push(this._movingWindow);
                this._movingWindowBin.add_child(actor);
            } else if (window.get_workspace().index() === from) {
                record.parent.remove_child(actor);
                this._windows.push(record);
                this._curGroup.add_child(actor);
            } else {
                let visible = false;
                for (let dir of Object.values(Meta.MotionDirection)) {
                    let info = this._surroundings[dir];

                    if (!info || info.index !== window.get_workspace().index())
                        continue;

                    record.parent.remove_child(actor);
                    this._windows.push(record);
                    info.actor.add_child(actor);
                    visible = true;
                    break;
                }

                actor.visible = visible;
            }
        }

        for (let i = 0; i < this._windows.length; i++) {
            let w = this._windows[i];

            w.windowDestroyId = w.window.connect('destroy', () => {
                this._windows.splice(this._windows.indexOf(w), 1);
            });
        }

        global.display.connect('restacked', this._syncStacking.bind(this));
    }

    _onDestroy() {
        for (let i = 0; i < this._windows.length; i++) {
            let w = this._windows[i];

            w.window.disconnect(w.windowDestroyId);
            w.window.get_parent().remove_child(w.window);
            w.parent.add_child(w.window);

            if (w.window.get_meta_window().get_workspace() !==
                global.workspace_manager.get_active_workspace())
                w.window.hide();
        }

        this._movingWindowBin.destroy();
    }

    _getPositionForDirection(direction, fromWs, toWs) {
        let xDest = 0, yDest = 0;

        let oldWsIsFullscreen = fromWs.list_windows().some(w => w.is_fullscreen());
        let newWsIsFullscreen = toWs.list_windows().some(w => w.is_fullscreen());

        // We have to shift windows up or down by the height of the panel to prevent having a
        // visible gap between the windows while switching workspaces. Since fullscreen windows
        // hide the panel, they don't need to be shifted up or down.
        let shiftHeight = Main.panel.height;

        if (direction === Meta.MotionDirection.UP ||
            direction === Meta.MotionDirection.UP_LEFT ||
            direction === Meta.MotionDirection.UP_RIGHT)
            yDest = -global.screen_height + (oldWsIsFullscreen ? 0 : shiftHeight);
        else if (direction === Meta.MotionDirection.DOWN ||
            direction === Meta.MotionDirection.DOWN_LEFT ||
            direction === Meta.MotionDirection.DOWN_RIGHT)
            yDest = global.screen_height - (newWsIsFullscreen ? 0 : shiftHeight);

        if (direction === Meta.MotionDirection.LEFT ||
            direction === Meta.MotionDirection.UP_LEFT ||
            direction === Meta.MotionDirection.DOWN_LEFT)
            xDest = -global.screen_width;
        else if (direction === Meta.MotionDirection.RIGHT ||
                 direction === Meta.MotionDirection.UP_RIGHT ||
                 direction === Meta.MotionDirection.DOWN_RIGHT)
            xDest = global.screen_width;

        return [xDest, yDest];
    }

    _syncStacking() {
        let windows = global.get_window_actors();
        let lastCurSibling = null;
        let lastDirSibling = [];
        for (let i = 0; i < windows.length; i++) {
            if (windows[i].get_parent() === this._curGroup) {
                this._curGroup.set_child_above_sibling(windows[i], lastCurSibling);
                lastCurSibling = windows[i];
            } else {
                for (let dir of Object.values(Meta.MotionDirection)) {
                    let info = this._surroundings[dir];
                    if (!info || windows[i].get_parent() !== info.actor)
                        continue;

                    let sibling = lastDirSibling[dir];
                    if (sibling === undefined)
                        sibling = null;

                    info.actor.set_child_above_sibling(windows[i], sibling);
                    lastDirSibling[dir] = windows[i];
                    break;
                }
            }
        }
    }

    directionForProgress(progress) {
        if (global.workspace_manager.layout_rows === -1) {
            return progress > 0
                ? Meta.MotionDirection.DOWN
                : Meta.MotionDirection.UP;
        } else if (Clutter.get_default_text_direction() === Clutter.TextDirection.RTL) {
            return progress > 0
                ? Meta.MotionDirection.LEFT
                : Meta.MotionDirection.RIGHT;
        } else {
            return progress > 0
                ? Meta.MotionDirection.RIGHT
                : Meta.MotionDirection.LEFT;
        }
    }

    progressForDirection(dir) {
        if (global.workspace_manager.layout_rows === -1)
            return dir === Meta.MotionDirection.DOWN ? 1 : -1;
        else if (Clutter.get_default_text_direction() === Clutter.TextDirection.RTL)
            return dir === Meta.MotionDirection.LEFT ? 1 : -1;
        else
            return dir === Meta.MotionDirection.RIGHT ? 1 : -1;
    }

    get progress() {
        return this._progress;
    }

    set progress(progress) {
        this._progress = progress;

        let direction = this.directionForProgress(progress);
        let xPos = 0;
        let yPos = 0;

        if (global.workspace_manager.layout_rows === -1)
            yPos = -Math.round(progress * this._getDistance(direction));
        else if (Clutter.get_default_text_direction() === Clutter.TextDirection.RTL)
            xPos = Math.round(progress * this._getDistance(direction));
        else
            xPos = -Math.round(progress * this._getDistance(direction));

        this._container.set_position(xPos, yPos);
    }

    _getDistance(direction) {
        let info = this._surroundings[direction];
        if (!info)
            return 0;

        switch (direction) {
        case Meta.MotionDirection.UP:
            return -info.yDest;
        case Meta.MotionDirection.DOWN:
            return info.yDest;
        case Meta.MotionDirection.LEFT:
            return -info.xDest;
        case Meta.MotionDirection.RIGHT:
            return info.xDest;
        }

        return 0;
    }

    getProgressRange() {
        let baseDistance;
        if (global.workspace_manager.layout_rows !== -1)
            baseDistance = global.screen_width;
        else
            baseDistance = global.screen_height;

        let direction = this.directionForProgress(-1);
        let distance = this._getDistance(direction);
        let lower = -distance / baseDistance;

        direction = this.directionForProgress(1);
        distance = this._getDistance(direction);
        let upper = distance / baseDistance;

        return [lower, upper];
    }
});

var WorkspaceAnimationController = class {
    constructor() {
        this._blockAnimations = false;
        this._movingWindow = null;
        this._inProgress = false;
        this._gestureActivated = false;
        this._animation = null;

        Main.overview.connect('showing', () => {
            if (this._gestureActivated)
                this._switchWorkspaceStop();

            this._swipeTracker.enabled = false;
        });
        Main.overview.connect('hiding', () => {
            this._swipeTracker.enabled = true;
        });

        let swipeTracker = new SwipeTracker.SwipeTracker(global.stage,
            Shell.ActionMode.NORMAL, { allowDrag: false, allowScroll: false });
        swipeTracker.connect('begin', this._switchWorkspaceBegin.bind(this));
        swipeTracker.connect('update', this._switchWorkspaceUpdate.bind(this));
        swipeTracker.connect('end', this._switchWorkspaceEnd.bind(this));
        this._swipeTracker = swipeTracker;
    }

    _prepareWorkspaceSwitch(from, to, direction) {
        if (this._animation)
            return;

        this._animation = new WorkspaceAnimation(this, from, to, direction);
    }

    _finishWorkspaceSwitch() {
        if (this._animation)
            this._animation.destroy();
        this._animation = null;
        this._inProgress = false;
        this._gestureActivated = false;
        this.movingWindow = null;
    }

    animateSwitchWorkspace(from, to, direction, onComplete) {
        this._prepareWorkspaceSwitch(from, to, direction);
        this._inProgress = true;

        let progress = this._animation.progressForDirection(direction);

        this._animation.ease_property('progress', progress, {
            duration: WINDOW_ANIMATION_TIME,
            mode: Clutter.AnimationMode.EASE_OUT_CUBIC,
            onComplete: () => {
                this._finishWorkspaceSwitch();
                onComplete();
            },
        });
    }

    _switchWorkspaceBegin(tracker, monitor) {
        if (Meta.prefs_get_workspaces_only_on_primary() &&
            monitor !== Main.layoutManager.primaryIndex)
            return;

        let workspaceManager = global.workspace_manager;
        let horiz = workspaceManager.layout_rows !== -1;
        tracker.orientation = horiz
            ? Clutter.Orientation.HORIZONTAL
            : Clutter.Orientation.VERTICAL;

        let activeWorkspace = workspaceManager.get_active_workspace();

        let baseDistance;
        if (horiz)
            baseDistance = global.screen_width;
        else
            baseDistance = global.screen_height;

        let progress;
        if (this._gestureActivated) {
            this._animation.remove_all_transitions();
            progress = this._animation.progress;
        } else {
            this._prepareWorkspaceSwitch(activeWorkspace.index(), -1);
            progress = 0;
        }

        let [lower, upper] = this._animation.getProgressRange();
        if (progress < 0)
            progress *= -lower;
        else if (progress > 0)
            progress *= upper;

        let points = [];
        if (lower !== 0)
            points.push(lower);

        points.push(0);

        if (upper !== 0)
            points.push(upper);

        tracker.confirmSwipe(baseDistance, points, progress, 0);
    }

    _switchWorkspaceUpdate(tracker, progress) {
        // Translate the progress into [-1;1] range
        let [lower, upper] = this._animation.getProgressRange();
        if (progress < 0)
            progress /= -lower;
        else if (progress > 0)
            progress /= upper;

        this._animation.progress = progress;
    }

    _switchWorkspaceEnd(tracker, duration, endProgress) {
        if (!this._animation)
            return;

        // Translate the progress into [-1;1] range
        endProgress = Math.sign(endProgress);

        let workspaceManager = global.workspace_manager;
        let activeWorkspace = workspaceManager.get_active_workspace();
        let newWs = activeWorkspace;
        if (endProgress !== 0) {
            let direction = this._animation.directionForProgress(endProgress);
            newWs = activeWorkspace.get_neighbor(direction);
        }

        this._gestureActivated = true;

        this._animation.ease_property('progress', endProgress, {
            duration,
            mode: Clutter.AnimationMode.EASE_OUT_CUBIC,
            onComplete: () => {
                if (newWs !== activeWorkspace)
                    newWs.activate(global.get_current_time());
                this._finishWorkspaceSwitch();
            },
        });
    }

    _switchWorkspaceStop() {
        this._animation.progress = 0;
        this._finishWorkspaceSwitch();
    }

    isAnimating() {
        return this._animation !== null;
    }

    canCancelGesture() {
        return this.isAnimating() && this._gestureActivated;
    }

    set movingWindow(movingWindow) {
        this._movingWindow = movingWindow;
    }

    get movingWindow() {
        return this._movingWindow;
    }
};