/* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */

const Signals = imports.signals;
const Mainloop = imports.mainloop;
const Tweener = imports.tweener.tweener;
const Clutter = imports.gi.Clutter;
const Gio = imports.gi.Gio;
const Gtk = imports.gi.Gtk;

const Main = imports.ui.main;
const Panel = imports.ui.panel;
const Meta = imports.gi.Meta;
const Shell = imports.gi.Shell;
const AppDisplay = imports.ui.appdisplay;

const OVERLAY_BACKGROUND_COLOR = new Clutter.Color();
OVERLAY_BACKGROUND_COLOR.from_pixel(0x000000ff);

const SIDESHOW_PAD = 6;
const SIDESHOW_MIN_WIDTH = 250;
const SIDESHOW_SEARCH_BG_COLOR = new Clutter.Color();
SIDESHOW_SEARCH_BG_COLOR.from_pixel(0xffffffff);
const SIDESHOW_TEXT_COLOR = new Clutter.Color();
SIDESHOW_TEXT_COLOR.from_pixel(0xffffffff);

// Time for initial animation going into overlay mode
const ANIMATION_TIME = 0.5;

// How much to scale the desktop down by in overlay mode
const DESKTOP_SCALE = 0.75;

// Windows are slightly translucent in the overlay mode
const WINDOW_OPACITY = 0.9 * 255;

// Define a layout scheme for small window counts. For larger
// counts we fall back to an algorithm. We need more schemes here
// unless we have a really good algorithm.
//
// Each triplet is [xCenter, yCenter, scale] where the scale
// is relative to the width of the desktop.
const POSITIONS = {
    1: [[0.5, 0.5, 0.8]],
    2: [[0.25, 0.5, 0.4], [0.75, 0.5, 0.4]],
    3: [[0.25, 0.25, 0.33],  [0.75, 0.25, 0.33],  [0.5, 0.75, 0.33]],
    4: [[0.25, 0.25, 0.33],   [0.75, 0.25, 0.33], [0.75, 0.75, 0.33], [0.25, 0.75, 0.33]],
    5: [[0.165, 0.25, 0.28], [0.495, 0.25, 0.28], [0.825, 0.25, 0.28], [0.25, 0.75, 0.4], [0.75, 0.75, 0.4]]
};

function Sideshow(width) {
    this._init(width);
}

Sideshow.prototype = {
    _init : function(width) {
        let me = this;

        let global = Shell.Global.get();
        this._group = new Clutter.Group();
        this._group.hide();
        global.stage.add_actor(this._group);
        let icontheme = Gtk.IconTheme.get_default();
        let rect = new Clutter.Rectangle({ color: SIDESHOW_SEARCH_BG_COLOR,
                                             x: SIDESHOW_PAD,
                                             y: Panel.PANEL_HEIGHT + SIDESHOW_PAD,
                                             width: width,
                                             height: 24});
        this._group.add_actor(rect);

        let searchIconTexture = new Clutter.Texture({ x: SIDESHOW_PAD + 2,
                                                      y: rect.y + 2 });
        let searchIconPath = icontheme.lookup_icon('gtk-find', 16, 0).get_filename();
        searchIconTexture.set_from_file(searchIconPath);
        this._group.add_actor(searchIconTexture);

        this._searchEntry = new Clutter.Entry({
                                             font_name: "Sans 14px",
                                             x: searchIconTexture.x
                                                 + searchIconTexture.width + 4,
                                             y: searchIconTexture.y,
                                             width: rect.width - (searchIconTexture.x),
                                             height: searchIconTexture.height});
        this._group.add_actor(this._searchEntry);
        global.stage.set_key_focus(this._searchEntry);
        this._searchQueued = false;
        this._searchActive = false;
        this._searchEntry.connect('notify::text', function (se, prop) {
            if (me._searchQueued)
                return;
            Mainloop.timeout_add(250, function() {
                let text = me._searchEntry.text;
                me._searchQueued = false;
                me._searchActive = text != '';
                me._appdisplay.setSearch(text);
                return false;
            });
        });
        this._searchEntry.connect('activate', function (se) {
            me._appdisplay.searchActivate();
            return true;
        });
        this._searchEntry.connect('key-press-event', function (se, e) {
            let code = e.get_code();
            if (code == 111) {
                me._appdisplay.selectUp();
                return true;
            } else if (code == 116) {
                me._appdisplay.selectDown();
                return true;
            }
            return false;
        });

        let appsText = new Clutter.Label({ color: SIDESHOW_TEXT_COLOR,
                                           font_name: "Sans Bold 14px",
                                           text: "Applications",
                                           x: SIDESHOW_PAD,
                                           y: this._searchEntry.y + this._searchEntry.height + 10,
                                           height: 16});
        this._group.add_actor(appsText);

        let menuY = appsText.y + appsText.height + 6;
        this._appdisplay = new AppDisplay.AppDisplay(SIDESHOW_PAD,
                menuY, width, global.screen_height - menuY);

        /* Proxy the activated signal */
        this._appdisplay.connect('activated', function(appdisplay) {
          me.emit('activated');
        });
    },

    show: function() {
          this._group.show();
          this._appdisplay.show();
    },

    hide: function() {
          this._group.hide();
          this._appdisplay.hide();
    }
};
Signals.addSignalMethods(Sideshow.prototype);

function Overlay() {
    this._init();
}

Overlay.prototype = {
    _init : function() {
        let me = this;

        let global = Shell.Global.get();

        this._group = new Clutter.Group();
        this.visible = false;

        let background = new Clutter.Rectangle({ color: OVERLAY_BACKGROUND_COLOR,
                                                 reactive: true,
                                                 x: 0,
                                                 y: Panel.PANEL_HEIGHT,
                                                 width: global.screen_width,
                                                 height: global.screen_width - Panel.PANEL_HEIGHT });
        this._group.add_actor(background);

        this._group.hide();
        global.overlay_group.add_actor(this._group);

    this._windowClones = [];

        // TODO - recalculate everything when desktop size changes
        this._recalculateSize();

        this._sideshow = new Sideshow(this._desktopX - 10);
        this._sideshow.connect('activated', function(sideshow) {
            // TODO - have some sort of animation/effect while
            // transitioning to the new app.  We definitely need
            // startup-notification integration at least.
            me._deactivate();
        });
    },

    _recalculateSize: function () {
        let global = Shell.Global.get();
        let screenWidth = global.screen_width;
        let screenHeight = global.screen_height;
        // The desktop windows are shown on top of a scaled down version of the
        // desktop. This is positioned at the right side of the screen
        this._desktopWidth = screenWidth * DESKTOP_SCALE;
        this._desktopHeight = screenHeight * DESKTOP_SCALE;
        this._desktopX = screenWidth - this._desktopWidth - 10;
        this._desktopY = Panel.PANEL_HEIGHT + (screenHeight - this._desktopHeight - Panel.PANEL_HEIGHT) / 2;
    },

    show : function() {
        if (this.visible)
            return;

        this.visible = true;

        let global = Shell.Global.get();

        let windows = global.get_windows();
        let desktopWindow = null;

        this._recalculateSize();

        for (let i = 0; i < windows.length; i++)
            if (windows[i].get_window_type() == Meta.WindowType.DESKTOP)
                desktopWindow = windows[i];

        // If a file manager is displaying desktop icons, there will be a desktop window.
        // This window will have the size of the whole desktop. When such window is not present
        // (e.g. when the preference for showing icons on the desktop is disabled by the user
        // or we are running inside a Xephyr window), we should create a desktop rectangle
        // to serve as the background.
        if (desktopWindow)
            this._createDesktopClone(desktopWindow);
        else
            this._createDesktopRectangle();

        // Count the total number of windows so we know what layout scheme to use
        let numberOfWindows = 0;
        for (let i = 0; i < windows.length; i++) {
            let w = windows[i];
            if (w == desktopWindow || w.is_override_redirect())
                continue;

            numberOfWindows++;
        }

        // Now create actors for all the desktop windows. Do it in
        // reverse order so that the active actor ends up on top
        let windowIndex = 0;
        for (let i = windows.length - 1; i >= 0; i--) {
            let w = windows[i];
            if (w == desktopWindow || w.is_override_redirect())
                continue;
            this._createWindowClone(w, numberOfWindows - windowIndex - 1, numberOfWindows);

            windowIndex++;
        }

        this._sideshow.show();

        // All the the actors in the window group are completely obscured,
        // hiding the group holding them while the overlay is displayed greatly
        // increases performance of the overlay especially when there are many
        // windows visible.
        //
        // If we switched to displaying the actors in the overlay rather than
        // clones of them, this would obviously no longer be necessary.
        global.window_group.hide()
        this._group.show();
    },

    hide : function() {
        if (!this.visible)
            return;

        let global = Shell.Global.get();

        this.visible = false;
        global.window_group.show()
        this._group.hide();

        for (let i = 0; i < this._windowClones.length; i++) {
            this._windowClones[i].destroy();
        }

        this._sideshow.hide();

        this._windowClones = [];
    },

    _createDesktopClone : function(w) {
        let clone = new Clutter.CloneTexture({ parent_texture: w.get_texture(),
                                               reactive: true,
                                               x: 0,
                                               y: 0 });
        this._addDesktop(clone);
    },

    _createDesktopRectangle : function() {
        let global = Shell.Global.get();
        // In the case when we have a desktop window from the file manager, its height is
        // full-screen, i.e. it includes the height of the panel, so we should not subtract
        // the height of the panel from global.screen_height here either to have them show
        // up identically.
        // We are also using (0,0) coordinates in both cases which makes the background
        // window animate out from behind the panel.
        let desktopRectangle = new Clutter.Rectangle({ color: global.stage.color,
                                                        reactive: true,
                                                        x: 0,
                                                        y: 0,
                                                        width: global.screen_width,
                                                        height: global.screen_height });
        this._addDesktop(desktopRectangle);
    },

    _addDesktop : function(desktop) {
        let me = this;

        this._windowClones.push(desktop);
        this._group.add_actor(desktop);

        // Since the right side only moves a little bit (the width of padding
        // we add) it looks less jittery to put the anchor there.
        desktop.move_anchor_point_from_gravity(Clutter.Gravity.NORTH_EAST);
        Tweener.addTween(desktop,
                         { x: this._desktopX + this._desktopWidth,
                           y: this._desktopY,
                           scale_x: DESKTOP_SCALE,
                           scale_y: DESKTOP_SCALE,
                           time: ANIMATION_TIME,
                           transition: "easeOutQuad"
                         });

        desktop.connect("button-press-event",
                      function() {
                          me._deactivate();
                      });
    },

    // windowIndex == 0 => top in stacking order
    _computeWindowPosition : function(windowIndex, numberOfWindows) {
        if (numberOfWindows in POSITIONS)
            return POSITIONS[numberOfWindows][windowIndex];

        // If we don't have a predefined scheme for this window count, overlap the windows
        // along the diagonal of the desktop (improve this!)
        let fraction = Math.sqrt(1/numberOfWindows);

        // The top window goes at the lower right - this is different from the
        // fixed position schemes where the windows are in "reading order"
        // and the top window goes at the upper left.
        let pos = (numberOfWindows - windowIndex - 1) / (numberOfWindows - 1);
        let xCenter = (fraction / 2) + (1 - fraction) * pos;
        let yCenter = xCenter;

        return [xCenter, yCenter, fraction];
    },

    _createWindowClone : function(w, windowIndex, numberOfWindows) {
        let me = this;

        // We show the window using "clones" of the texture .. separate
        // actors that mirror the original actors for the window. For
        // animation purposes, it may be better to actually move the
        // original actors about instead.

        let clone = new Clutter.CloneTexture({ parent_texture: w.get_texture(),
                                               reactive: true,
                                               x: w.x,
                                               y: w.y });

        let [xCenter, yCenter, fraction] = this._computeWindowPosition(windowIndex, numberOfWindows);

        let desiredSize = this._desktopWidth * fraction;

        xCenter = this._desktopX + xCenter * this._desktopWidth;
        yCenter = this._desktopY + yCenter * this._desktopHeight;

        let size = clone.width;
        if (clone.height > size)
            size = clone.height;

        // Never scale up
        let scale = desiredSize / size;
        if (scale > 1)
            scale = 1;

        this._group.add_actor(clone);
        this._windowClones.push(clone);

        Tweener.addTween(clone,
                         { x: xCenter - 0.5 * scale * w.width,
                           y: yCenter - 0.5 * scale * w.height,
                           scale_x: scale,
                           scale_y: scale,
                           time: ANIMATION_TIME,
                           opacity: WINDOW_OPACITY,
                           transition: "easeOutQuad"
                          });

        clone.connect("button-press-event",
                      function(clone, event) {
                          me._activateWindow(w, event.get_time());
                      });
    },

    _activateWindow : function(w, time) {
        this._deactivate();
        w.get_meta_window().activate(time);
    },

    _deactivate : function() {
        Main.hide_overlay();
    }
};