//
//  Copyright (C) 2012 Tom Beckmann, Rico Tzschichholz
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
//

namespace Gala {
    public class Utils {
        // Cache xid:pixbuf and icon:pixbuf pairs to provide a faster way aquiring icons
        static HashTable<string, Gdk.Pixbuf> xid_pixbuf_cache;
        static HashTable<string, Gdk.Pixbuf> icon_pixbuf_cache;
        static uint cache_clear_timeout = 0;

        static Gdk.Pixbuf? close_pixbuf = null;
        static Gdk.Pixbuf? resize_pixbuf = null;

        static construct {
            xid_pixbuf_cache = new HashTable<string, Gdk.Pixbuf> (str_hash, str_equal);
            icon_pixbuf_cache = new HashTable<string, Gdk.Pixbuf> (str_hash, str_equal);
        }

        Utils () {
        }

        /**
         * Clean icon caches
         */
        static void clean_icon_cache (uint32[] xids) {
            var list = xid_pixbuf_cache.get_keys ();
            var pixbuf_list = icon_pixbuf_cache.get_values ();
            var icon_list = icon_pixbuf_cache.get_keys ();

            foreach (var xid_key in list) {
                var xid = (uint32)uint64.parse (xid_key.split ("::")[0]);
                if (!(xid in xids)) {
                    var pixbuf = xid_pixbuf_cache.get (xid_key);
                    for (var j = 0; j < pixbuf_list.length (); j++) {
                        if (pixbuf_list.nth_data (j) == pixbuf) {
                            xid_pixbuf_cache.remove (icon_list.nth_data (j));
                        }
                    }

                    xid_pixbuf_cache.remove (xid_key);
                }
            }
        }

        /**
         * Marks the given xids as no longer needed, the corresponding icons
         * may be freed now. Mainly for internal purposes.
         *
         * @param xids The xids of the window that no longer need icons
         */
        public static void request_clean_icon_cache (uint32[] xids) {
            if (cache_clear_timeout > 0)
                GLib.Source.remove (cache_clear_timeout);

            cache_clear_timeout = Timeout.add_seconds (30, () => {
                cache_clear_timeout = 0;
                Idle.add (() => {
                    clean_icon_cache (xids);
                    return false;
                });
                return false;
            });
        }

        /**
         * Returns a pixbuf for a given xid or a default icon
         *
         * @see get_icon_for_window
         */
        public static Gdk.Pixbuf get_icon_for_xid (uint32 xid, int size, int scale = 1, bool ignore_cache = false) {
            Gdk.Pixbuf? result = null;
            var xid_key = "%u::%i".printf (xid, size);

            if (!ignore_cache && (result = xid_pixbuf_cache.get (xid_key)) != null)
                return result;

            var app = Bamf.Matcher.get_default ().get_application_for_xid (xid);
            result = get_icon_for_application (app, size, scale, ignore_cache);

            xid_pixbuf_cache.set (xid_key, result);

            return result;
        }

        /**
         * Returns a pixbuf for this application or a default icon
         *
         * @see get_icon_for_window
         */
        static Gdk.Pixbuf get_icon_for_application (
            Bamf.Application? app,
            int size,
            int scale = 1,
            bool ignore_cache = false
        ) {
            Gdk.Pixbuf? image = null;
            bool not_cached = false;

            string? icon = null;
            string? icon_key = null;

            if (app != null && app.get_desktop_file () != null) {
                var appinfo = new DesktopAppInfo.from_filename (app.get_desktop_file ());
                if (appinfo != null) {
                    icon = Plank.DrawingService.get_icon_from_gicon (appinfo.get_icon ());
                    icon_key = "%s::%i::%i".printf (icon, size, scale);
                    if (ignore_cache || (image = icon_pixbuf_cache.get (icon_key)) == null) {
                        var scaled_size = size * scale;
                        var surface = Plank.DrawingService.load_icon_for_scale (icon, scaled_size, scaled_size, scale);
                        image = Gdk.pixbuf_get_from_surface (surface, 0, 0, scaled_size, scaled_size);
                        not_cached = true;
                    }
                }
            }

            if (image == null) {
                try {
                    unowned Gtk.IconTheme icon_theme = Gtk.IconTheme.get_default ();
                    icon = "application-default-icon";
                    icon_key = "%s::%i::%i".printf (icon, size, scale);
                    if ((image = icon_pixbuf_cache.get (icon_key)) == null) {
                        image = icon_theme.load_icon_for_scale (icon, size, scale, 0);
                        not_cached = true;
                    }
                } catch (Error e) {
                    warning (e.message);
                }
            }

            if (image == null) {
                icon = "";
                icon_key = "::%i".printf (size);
                if ((image = icon_pixbuf_cache.get (icon_key)) == null) {
                    image = new Gdk.Pixbuf (Gdk.Colorspace.RGB, true, 8, size, size);
                    image.fill (0x00000000);
                    not_cached = true;
                }
            }

            if (size * scale != image.width || size * scale != image.height)
                image = Plank.DrawingService.ar_scale (image, size * scale, size * scale);

            if (not_cached)
                icon_pixbuf_cache.set (icon_key, image);

            return image;
        }

        /**
         * Get the number of toplevel windows on a workspace excluding those that are
         * on all workspaces
         *
         * @param workspace The workspace on which to count the windows
         */
        public static uint get_n_windows (Meta.Workspace workspace) {
            var n = 0;
            foreach (weak Meta.Window window in workspace.list_windows ()) {
                if (window.on_all_workspaces)
                    continue;
                if (
                    window.window_type == Meta.WindowType.NORMAL ||
                    window.window_type == Meta.WindowType.DIALOG ||
                    window.window_type == Meta.WindowType.MODAL_DIALOG)
                    n ++;
            }

            return n;
        }

        /**
         * Creates an actor showing the current contents of the given WindowActor.
         *
         * @param actor      The actor from which to create a shnapshot
         * @param inner_rect The inner (actually visible) rectangle of the window
         * @param outer_rect The outer (input region) rectangle of the window
         *
         * @return           A copy of the actor at that time or %NULL
         */
        public static Clutter.Actor? get_window_actor_snapshot (
            Meta.WindowActor actor,
            Meta.Rectangle inner_rect,
            Meta.Rectangle outer_rect
        ) {
            var texture = actor.get_texture () as Meta.ShapedTexture;

            if (texture == null)
                return null;

            var surface = texture.get_image ({
                inner_rect.x - outer_rect.x,
                inner_rect.y - outer_rect.y,
                inner_rect.width,
                inner_rect.height
            });

            if (surface == null)
                return null;

            var canvas = new Clutter.Canvas ();
            var handler = canvas.draw.connect ((cr) => {
                cr.set_source_surface (surface, 0, 0);
                cr.paint ();
                return false;
            });
            canvas.set_size (inner_rect.width, inner_rect.height);
            SignalHandler.disconnect (canvas, handler);

            var container = new Clutter.Actor ();
            container.set_size (inner_rect.width, inner_rect.height);
            container.content = canvas;

            return container;
        }

#if HAS_MUTTER330
        /**
        * Ring the system bell, will most likely emit a <beep> error sound or, if the
        * audible bell is disabled, flash the display
        *
        * @param display The display to flash, if necessary
        */
        public static void bell (Meta.Display display) {
            if (Meta.Prefs.bell_is_audible ())
                Gdk.beep ();
            else
                display.get_compositor ().flash_display (display);
        }
#else
        /**
         * Ring the system bell, will most likely emit a <beep> error sound or, if the
         * audible bell is disabled, flash the screen
         *
         * @param screen The screen to flash, if necessary
         */
        public static void bell (Meta.Screen screen) {
            if (Meta.Prefs.bell_is_audible ())
                Gdk.beep ();
            else
                screen.get_display ().get_compositor ().flash_screen (screen);
        }
#endif

        public static int get_ui_scaling_factor () {
            return Meta.Backend.get_backend ().get_settings ().get_ui_scaling_factor ();
        }

        /**
         * Returns the pixbuf that is used for close buttons throughout gala at a
         * size of 36px
         *
         * @return the close button pixbuf or null if it failed to load
         */
        public static Gdk.Pixbuf? get_close_button_pixbuf () {
            var height = 36 * Utils.get_ui_scaling_factor ();
            if (close_pixbuf == null || close_pixbuf.height != height) {
                try {
                    close_pixbuf = new Gdk.Pixbuf.from_resource_at_scale (
                        Config.RESOURCEPATH + "/buttons/close.svg",
                        -1,
                        height,
                        true
                    );
                } catch (Error e) {
                    warning (e.message);
                    return null;
                }
            }

            return close_pixbuf;
        }

        /**
         * Creates a new reactive ClutterActor at 36px with the close pixbuf
         *
         * @return The close button actor
         */
        public static Clutter.Actor create_close_button () {
#if HAS_MUTTER336
            var texture = new Clutter.Actor ();
#else
            var texture = new Clutter.Texture ();
#endif
            var pixbuf = get_close_button_pixbuf ();

            texture.reactive = true;

            if (pixbuf != null) {
                try {
#if HAS_MUTTER336
                    var image = new Clutter.Image ();
                    Cogl.PixelFormat pixel_format = (pixbuf.get_has_alpha () ? Cogl.PixelFormat.RGBA_8888 : Cogl.PixelFormat.RGB_888);
                    image.set_data (pixbuf.get_pixels (), pixel_format, pixbuf.width, pixbuf.height, pixbuf.rowstride);
                    texture.set_content (image);
                    texture.set_size (pixbuf.width, pixbuf.height);
#else
                    texture.set_from_rgb_data (pixbuf.get_pixels (), pixbuf.get_has_alpha (),
                    pixbuf.get_width (), pixbuf.get_height (),
                    pixbuf.get_rowstride (), (pixbuf.get_has_alpha () ? 4 : 3), 0);
#endif
                } catch (Error e) {}
            } else {
                // we'll just make this red so there's at least something as an
                // indicator that loading failed. Should never happen and this
                // works as good as some weird fallback-image-failed-to-load pixbuf
                var scale = Utils.get_ui_scaling_factor ();
                texture.set_size (36 * scale, 36 * scale);
                texture.background_color = { 255, 0, 0, 255 };
            }

            return texture;
        }
        /**
         * Returns the pixbuf that is used for resize buttons throughout gala at a
         * size of 36px
         *
         * @return the close button pixbuf or null if it failed to load
         */
        public static Gdk.Pixbuf? get_resize_button_pixbuf () {
            var height = 36 * Utils.get_ui_scaling_factor ();
            if (resize_pixbuf == null || resize_pixbuf.height != height) {
                try {
                    resize_pixbuf = new Gdk.Pixbuf.from_resource_at_scale (
                        Config.RESOURCEPATH + "/buttons/resize.svg",
                        -1,
                        height,
                        true
                    );
                } catch (Error e) {
                    warning (e.message);
                    return null;
                }
            }

            return resize_pixbuf;
        }

        /**
         * Creates a new reactive ClutterActor at 36px with the resize pixbuf
         *
         * @return The resize button actor
         */
        public static Clutter.Actor create_resize_button () {
#if HAS_MUTTER336
            var texture = new Clutter.Actor ();
#else
            var texture = new Clutter.Texture ();
#endif
            var pixbuf = get_resize_button_pixbuf ();

            texture.reactive = true;

            if (pixbuf != null) {
                try {
#if HAS_MUTTER336
                    var image = new Clutter.Image ();
                    Cogl.PixelFormat pixel_format = (pixbuf.get_has_alpha () ? Cogl.PixelFormat.RGBA_8888 : Cogl.PixelFormat.RGB_888);
                    image.set_data (pixbuf.get_pixels (), pixel_format, pixbuf.width, pixbuf.height, pixbuf.rowstride);
                    texture.set_content (image);
                    texture.set_size (pixbuf.width, pixbuf.height);
#else
                    texture.set_from_rgb_data (pixbuf.get_pixels (), pixbuf.get_has_alpha (),
                    pixbuf.get_width (), pixbuf.get_height (),
                    pixbuf.get_rowstride (), (pixbuf.get_has_alpha () ? 4 : 3), 0);
#endif
                } catch (Error e) {}
            } else {
                // we'll just make this red so there's at least something as an
                // indicator that loading failed. Should never happen and this
                // works as good as some weird fallback-image-failed-to-load pixbuf
                var scale = Utils.get_ui_scaling_factor ();
                texture.set_size (36 * scale, 36 * scale);
                texture.background_color = { 255, 0, 0, 255 };
            }

            return texture;
        }

        static Gtk.CssProvider gala_css = null;
        public static unowned Gtk.CssProvider? get_gala_css () {
            if (gala_css == null) {
                gala_css = new Gtk.CssProvider ();
                gala_css.load_from_resource ("/io/elementary/desktop/gala/gala.css");
            }

            return gala_css;
        }
    }
}