/*
 * Copyright 2015 Javier S. Pedro <dev.git@javispedro.com>
 *
 * This file is part of MDock.
 *
 * MDock 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.
 *
 * MDock 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MDock.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <gtk/gtk.h>

#define WNCK_I_KNOW_THIS_IS_UNSTABLE 1
#include <libwnck/libwnck.h>

#include "mdock-widget.h"
#include "mdock-item.h"
#include "matcher.h"

struct _MDockWidgetPrivate
{
	gchar *settings_path;
	GSettings *settings;
	WnckScreen *wnck_screen;
	GSequence *items;
	GHashTable *appid_to_item;
	GHashTable *desktopid_to_item;
	GHashTable *window_to_item;
	gboolean loading_settings;
};

G_DEFINE_TYPE(MDockWidget, mdock_widget, GTK_TYPE_BOX)

#define MDOCK_WIDGET_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE((obj), MDOCK_TYPE_WIDGET, MDockWidgetPrivate))

enum {
	PROP_0,
	PROP_SETTINGS_PATH,
	N_PROPERTIES
};

static GParamSpec *obj_properties[N_PROPERTIES] = { NULL };

G_DEFINE_QUARK(mdock-widget-item-iter, mdock_widget_item_iter)

enum {
	DRAG_TYPE_ITEM,
	DRAG_TYPE_URILIST
};

static const GtkTargetEntry drag_types[] = {
    "application/x-mdock-item", GTK_TARGET_SAME_APP, DRAG_TYPE_ITEM,
    "text/uri-list", 0, DRAG_TYPE_URILIST
};

static void save_items_to_settings(MDockWidget *self)
{
	GSettings *settings = self->priv->settings;
	GSequenceIter *seq_iter = g_sequence_get_begin_iter(self->priv->items);
	GVariantBuilder builder;

	g_variant_builder_init(&builder, G_VARIANT_TYPE("as"));

	while (!g_sequence_iter_is_end(seq_iter)) {
		MDockItem *item = MDOCK_ITEM(g_sequence_get(seq_iter));

		if (mdock_item_get_pinned(item)) {
			GDesktopAppInfo *info = mdock_item_get_desktop_app_info(item);
			if (info) {
				g_variant_builder_add(&builder, "s", g_desktop_app_info_get_filename(info));
			}
		}

		seq_iter = g_sequence_iter_next(seq_iter);
	}

	self->priv->loading_settings = TRUE;
	g_settings_set(settings, "items", "as", &builder);
	self->priv->loading_settings = FALSE;
}

static void move_item_to_position(MDockWidget *self, GSequenceIter *iter, GSequenceIter *position)
{
	g_debug("moving item to position %d", g_sequence_iter_get_position(position));
	gtk_box_reorder_child(GTK_BOX(self), GTK_WIDGET(g_sequence_get(iter)),
		                  g_sequence_iter_get_position(position));
	g_sequence_move(iter, position);
}

static void handle_item_pinned_changed(MDockWidget *self, GParamSpec *spec, MDockItem *item)
{
	if (!self->priv->loading_settings) {
		save_items_to_settings(self);
	}
}

static void handle_item_drag_begin(MDockWidget *self, GdkDragContext *dc, MDockItem *item)
{
	g_debug("drag begin");
	gtk_drag_set_icon_pixbuf(dc, mdock_item_get_icon_pixbuf(item), 0, 0);
	gtk_widget_hide(GTK_WIDGET(item));
}

static void handle_item_drag_end(MDockWidget *self, GdkDragContext *dc, MDockItem *item)
{
	g_debug("drag end");
	gtk_widget_show(GTK_WIDGET(item));
}

static void handle_item_drag_data_get(MDockWidget *self, GdkDragContext *dc,
                                      GtkSelectionData *selection_data, guint target_type, guint timestamp, MDockItem *item)
{
	g_debug("data get");
	GSequenceIter *iter = g_object_get_qdata(G_OBJECT(item), mdock_widget_item_iter_quark());
	GDesktopAppInfo *appinfo = mdock_item_get_desktop_app_info(item);
	gint32 position = g_sequence_iter_get_position(iter);

	switch (target_type) {
	case DRAG_TYPE_ITEM:
		g_debug("data get item");
		gtk_selection_data_set(selection_data, gtk_selection_data_get_target(selection_data),
		                       sizeof(gint32)*8, (guchar*)&position, sizeof(gint32));
		break;
	case DRAG_TYPE_URILIST:
		g_debug("data get urilist");
		if (appinfo) {
			const gchar *strv[2] = { g_desktop_app_info_get_filename(appinfo), NULL };
			gtk_selection_data_set_uris(selection_data, (gchar**) strv);
		}
		break;
	}
}

static void handle_item_drag_data_delete(MDockWidget *self, GdkDragContext *dc, MDockItem *item)
{
	g_debug("data delete");
}

static GSequenceIter * find_drop_position_at_coordinates(MDockWidget *self, gint x, gint y)
{
	const guint icon_size = g_settings_get_uint(self->priv->settings, "icon-size");
	const guint spacing = gtk_box_get_spacing(GTK_BOX(self));
	const guint offset = icon_size / 4;
	if (gtk_orientable_get_orientation(GTK_ORIENTABLE(self)) == GTK_ORIENTATION_HORIZONTAL) {
		g_debug("dropped in position %d", x / icon_size);
		return g_sequence_get_iter_at_pos(self->priv->items, (x + offset) / (icon_size + spacing)) ;
	} else {
		return g_sequence_get_iter_at_pos(self->priv->items, (y + offset) / (icon_size + spacing));
	}
}

static void mdock_widget_drag_data_received(GtkWidget *widget, GdkDragContext *context,
                                            gint x, gint y, GtkSelectionData *selection_data,
                                            guint info, guint timestamp)
{
	g_debug("data received");
	MDockWidget *self = MDOCK_WIDGET(widget);
	const guchar *data = gtk_selection_data_get_data(selection_data);
	gchar **uris;

	switch (info) {
	case DRAG_TYPE_ITEM:
		g_debug("Got item");
		if (data) {
			gint32 position = *(gint32*)data;
			g_debug("Got position %u", position);
			GSequenceIter *iter = g_sequence_get_iter_at_pos(self->priv->items, position);
			g_warn_if_fail(iter);
			GSequenceIter *pos_iter = find_drop_position_at_coordinates(self, x, y);
			move_item_to_position(self, iter, pos_iter);
			if (mdock_item_get_pinned(MDOCK_ITEM(g_sequence_get(iter)))) {
				save_items_to_settings(self);
			}
		}
		gtk_drag_finish(context, TRUE, TRUE, timestamp);
		break;
	case DRAG_TYPE_URILIST:
		uris = gtk_selection_data_get_uris(selection_data);
		if (uris) {
			for (int i = 0; uris[i]; i++) {
				gchar *uri = uris[i];
				g_debug("Got uri %s", uri);
			}
			g_strfreev(uris);
		}

		gtk_drag_finish(context, TRUE, FALSE, timestamp);
		break;
	default:
		g_message("Drag target type not found");
		gtk_drag_finish(context, FALSE, FALSE, timestamp);
		break;
	}
}

static gboolean mdock_widget_drag_drop(GtkWidget *widget, GdkDragContext *context, gint x, gint y, guint timestamp)
{
	GtkTargetList *target_list = gtk_drag_dest_get_target_list(widget);
	GdkAtom target = gtk_drag_dest_find_target(widget, context, target_list);
	guint info;
	gboolean drag_ok = FALSE;

	if (target != GDK_NONE && gtk_target_list_find(target_list, target, &info)) {
		switch (info) {
		case DRAG_TYPE_ITEM:
		case DRAG_TYPE_URILIST:
			drag_ok = TRUE;
			break;
		default:
			break;
		}
	} else {
		g_message("Drag target type not found");
	}

	if (drag_ok) {
		gtk_drag_get_data(widget, context, target, timestamp);
	} else {
		gtk_drag_finish(context, FALSE, FALSE, timestamp);
	}

	return TRUE;
}

static gboolean mdock_widget_drag_motion(GtkWidget *widget, GdkDragContext *context, gint x, gint y, guint timestamp)
{
	GtkTargetList *target_list = gtk_drag_dest_get_target_list(widget);
	GdkAtom target = gtk_drag_dest_find_target(widget, context, target_list);
	guint info;
	gboolean drag_ok = FALSE;

	if (target != GDK_NONE && gtk_target_list_find(target_list, target, &info)) {
		switch (info) {
		case DRAG_TYPE_ITEM:
			gdk_drag_status(context, GDK_ACTION_MOVE, timestamp);
			drag_ok = TRUE;
			break;
		case DRAG_TYPE_URILIST:
			gdk_drag_status(context, GDK_ACTION_COPY, timestamp);
			drag_ok = TRUE;
			break;
		default:
			break;
		}
	} else {
		g_message("Drag target type not found");
	}

	if (drag_ok) {
		// TODO Draw placeholder
	} else {
		gdk_drag_status(context, 0, timestamp);
	}

	return TRUE;
}

static void connect_item(MDockWidget *self, MDockItem *item, GSequenceIter *position)
{
	g_object_set_qdata(G_OBJECT(item), mdock_widget_item_iter_quark(), position);

	g_signal_connect_object(item, "notify::pinned",
	                        G_CALLBACK(handle_item_pinned_changed), self,
	                        G_CONNECT_SWAPPED);

	g_settings_bind(self->priv->settings, "icon-size",
	                item, "icon-size",
	                G_SETTINGS_BIND_GET | G_SETTINGS_BIND_NO_SENSITIVITY);

	gtk_drag_source_set(GTK_WIDGET(item), GDK_BUTTON1_MASK,
	                    drag_types, G_N_ELEMENTS(drag_types),
	                    GDK_ACTION_MOVE);
	g_signal_connect_object(item, "drag-begin",
	                        G_CALLBACK(handle_item_drag_begin), self,
	                        G_CONNECT_SWAPPED);
	g_signal_connect_object(item, "drag-end",
	                        G_CALLBACK(handle_item_drag_end), self,
	                        G_CONNECT_SWAPPED);
	g_signal_connect_object(item, "drag-data-get",
	                        G_CALLBACK(handle_item_drag_data_get), self,
	                        G_CONNECT_SWAPPED);
	g_signal_connect_object(item, "drag-data-delete",
	                        G_CALLBACK(handle_item_drag_data_delete), self,
	                        G_CONNECT_SWAPPED);
}


static void reload_items_from_settings(MDockWidget *self)
{
	GSettings *settings = self->priv->settings;

	self->priv->loading_settings = TRUE;

	GVariantIter *set_iter;
	g_settings_get(settings, "items", "as", &set_iter);

	GSequenceIter *seq_iter = g_sequence_get_begin_iter(self->priv->items);

	gchar *value;
	while (g_variant_iter_next(set_iter, "s", &value)) {
		GDesktopAppInfo *set_appinfo = g_desktop_app_info_new_from_filename(value);
		const gchar *set_desktopid = g_app_info_get_id(G_APP_INFO(set_appinfo));

		GSequenceIter *iter = g_hash_table_lookup(self->priv->desktopid_to_item, set_desktopid);
		if (iter) {
			// This item is already on the dock, let's move it to the front and pin it.
			MDockItem *item = MDOCK_ITEM(g_sequence_get(iter));
			mdock_item_set_pinned(item, TRUE);
			g_sequence_move(iter, seq_iter);
		} else {
			// Item not already in the dock.
			MDockItem *item = mdock_item_new();
			mdock_item_set_desktop_app_info(item, set_appinfo);
			mdock_item_set_pinned(item, TRUE);

			iter = g_sequence_insert_before(seq_iter, item);
			g_hash_table_insert(self->priv->desktopid_to_item, g_strdup(set_desktopid), iter);

			connect_item(self, item, iter);

			gtk_widget_show(GTK_WIDGET(item));
			gtk_box_pack_start(GTK_BOX(self), GTK_WIDGET(item), FALSE, FALSE, 0);
			if (!g_sequence_iter_is_end(seq_iter)) {
				// Fix the order!
				gtk_box_reorder_child(GTK_BOX(self), GTK_WIDGET(item),
				                      g_sequence_iter_get_position(iter));
			}
		}

		g_object_unref(set_appinfo);
		g_free(value);
	}

	g_variant_iter_free(set_iter);

	self->priv->loading_settings = FALSE;
}

static void handle_active_window_changed(MDockWidget *self, WnckWindow *previous_window, WnckScreen *screen)
{
	WnckWindow *window = wnck_screen_get_active_window(screen);
	GSequenceIter *iter = g_hash_table_lookup(self->priv->window_to_item, window);
	if (iter) {
		MDockItem *item = MDOCK_ITEM(g_sequence_get(iter));
		mdock_item_set_last_active_window(item, window);
	}
}

static gboolean filter_deleted_group(gpointer key, gpointer value, gpointer user_data)
{
	return value == user_data;
}

static void handle_window_closed(MDockWidget *self, WnckWindow *window, WnckScreen *screen)
{
	GSequenceIter *iter = g_hash_table_lookup(self->priv->window_to_item, window);
	if (!iter) {
		// We never managed this window
		return;
	}

	MDockItem *item = MDOCK_ITEM(g_sequence_get(iter));
	mdock_item_remove_window(item, window);
	g_hash_table_remove(self->priv->window_to_item, window);

	if (mdock_item_get_num_windows(item) == 0 && !mdock_item_get_pinned(item)) {
		// Removing item from dock
		g_hash_table_foreach_remove(self->priv->appid_to_item, filter_deleted_group, iter);
		g_hash_table_foreach_remove(self->priv->desktopid_to_item, filter_deleted_group, iter);
		g_sequence_remove(iter);
		gtk_widget_destroy(GTK_WIDGET(item));
	}
}

static void handle_window_opened(MDockWidget *self, WnckWindow *window, WnckScreen *screen)
{
	if (wnck_window_is_skip_tasklist(window)) {
		return;
	}

	AppId *appid = app_id_from_window(window);
	GSequenceIter *iter = g_hash_table_lookup(self->priv->appid_to_item, appid);
	if (iter) {
		MDockItem *item = MDOCK_ITEM(g_sequence_get(iter));
		mdock_item_add_window(item, window);
		app_id_destroy(appid);
		g_hash_table_insert(self->priv->window_to_item, window, iter);
		return;
	}

	const gchar *desktopid = match_appid_to_desktopid(appid);
	if (desktopid) {
		iter = g_hash_table_lookup(self->priv->desktopid_to_item, desktopid);
		if (iter) {
			MDockItem *item = MDOCK_ITEM(g_sequence_get(iter));
			mdock_item_add_window(item, window);
			g_hash_table_insert(self->priv->appid_to_item, appid, iter); // takes ownership of appid
			g_hash_table_insert(self->priv->window_to_item, window, iter);
			return;
		}
	}

	MDockItem *item = mdock_item_new();
	iter = g_sequence_append(self->priv->items, item);
	if (desktopid) {
		GDesktopAppInfo *app_info = g_desktop_app_info_new(desktopid);
		mdock_item_set_desktop_app_info(item, app_info);
		g_object_unref(app_info);
	}

	connect_item(self, item, iter);

	mdock_item_add_window(item, window);

	g_hash_table_insert(self->priv->appid_to_item, appid, iter); // takes ownership of appid
	if (desktopid) {
		g_hash_table_insert(self->priv->desktopid_to_item, g_strdup(desktopid), iter);
	}
	g_hash_table_insert(self->priv->window_to_item, window, iter);

	gtk_widget_show(GTK_WIDGET(item));
	gtk_box_pack_start(GTK_BOX(self), GTK_WIDGET(item), FALSE, FALSE, 0);
}

static void handle_settings_items_changed(MDockWidget *self, gchar *key, GSettings *settings)
{
	if (!self->priv->loading_settings) {
		reload_items_from_settings(self);
	}
}

static void mdock_widget_constructed(GObject *obj)
{
	MDockWidget *self = MDOCK_WIDGET(obj);

	g_debug("Constructing with path: %s", self->priv->settings_path);
	self->priv->settings = g_settings_new_with_path("com.javispedro.mdock.widget",
	                                                self->priv->settings_path);
	g_signal_connect_object(self->priv->settings, "changed::items",
	                        G_CALLBACK(handle_settings_items_changed), self, G_CONNECT_SWAPPED);

	self->priv->wnck_screen = wnck_screen_get_default();
	g_signal_connect_object(self->priv->wnck_screen, "active-window-changed",
	                        G_CALLBACK(handle_active_window_changed), self, G_CONNECT_SWAPPED);
	g_signal_connect_object(self->priv->wnck_screen, "window-closed",
	                        G_CALLBACK(handle_window_closed), self, G_CONNECT_SWAPPED);
	g_signal_connect_object(self->priv->wnck_screen, "window-opened",
	                        G_CALLBACK(handle_window_opened), self, G_CONNECT_SWAPPED);

	self->priv->items = g_sequence_new(NULL);
	self->priv->appid_to_item = g_hash_table_new_full(app_id_hash, app_id_equal,
	                                                   (GDestroyNotify)app_id_destroy, NULL);
	self->priv->desktopid_to_item = g_hash_table_new_full(g_str_hash, g_str_equal,
	                                                       g_free, NULL);
	self->priv->window_to_item = g_hash_table_new_full(g_direct_hash, g_direct_equal,
	                                                    NULL, NULL);

	reload_items_from_settings(self);

	GList *windows = wnck_screen_get_windows_stacked(self->priv->wnck_screen);
	for (GList *l = windows; l; l = g_list_next(l)) {
		WnckWindow *window = l->data;
		handle_window_opened(self, window, self->priv->wnck_screen);
	}
}

static void mdock_widget_dispose(GObject *obj)
{
	MDockWidget *self = MDOCK_WIDGET(obj);
	if (self->priv->settings) {
		g_clear_object(&self->priv->settings);
	}
	if (self->priv->wnck_screen) {
		g_signal_handlers_disconnect_by_data(self->priv->wnck_screen, self);
		self->priv->wnck_screen = NULL;
	}
	G_OBJECT_CLASS(mdock_widget_parent_class)->dispose(obj);
}

static void mdock_widget_finalize(GObject *obj)
{
	MDockWidget *self = MDOCK_WIDGET(obj);
	g_free(self->priv->settings_path);
	g_sequence_free(self->priv->items);
	g_hash_table_destroy(self->priv->appid_to_item);
	g_hash_table_destroy(self->priv->desktopid_to_item);
	g_hash_table_destroy(self->priv->window_to_item);
	G_OBJECT_CLASS(mdock_widget_parent_class)->finalize(obj);
}

static void mdock_widget_set_property(GObject        *object,
                                      guint           property_id,
                                      const GValue   *value,
                                      GParamSpec     *pspec)
{
	MDockWidget *self = MDOCK_WIDGET(object);
	switch (property_id) {
	case PROP_SETTINGS_PATH:
		self->priv->settings_path = g_value_dup_string(value);
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, property_id, pspec);
		break;
	}
}

static void mdock_widget_get_property(GObject        *object,
                                      guint           property_id,
                                      GValue         *value,
                                      GParamSpec     *pspec)
{
	MDockWidget *self = MDOCK_WIDGET(object);
	switch (property_id) {
	case PROP_SETTINGS_PATH:
		g_value_set_string(value, self->priv->settings_path);
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, property_id, pspec);
		break;
	}
}

static void mdock_widget_init(MDockWidget *self)
{
	self->priv = MDOCK_WIDGET_GET_PRIVATE(self);

	gtk_drag_dest_set(GTK_WIDGET(self), 0,
	                  drag_types, G_N_ELEMENTS(drag_types),
	                  GDK_ACTION_MOVE);
}

static void mdock_widget_class_init(MDockWidgetClass *klass)
{
	GtkWidgetClass *widget_class = GTK_WIDGET_CLASS(klass);
	widget_class->drag_data_received = mdock_widget_drag_data_received;
	widget_class->drag_drop = mdock_widget_drag_drop;
	widget_class->drag_motion = mdock_widget_drag_motion;

	GObjectClass *obj_class = G_OBJECT_CLASS(klass);
	obj_class->constructed = mdock_widget_constructed;
	obj_class->dispose = mdock_widget_dispose;
	obj_class->finalize = mdock_widget_finalize;
	obj_class->set_property = mdock_widget_set_property;
	obj_class->get_property = mdock_widget_get_property;

	obj_properties[PROP_SETTINGS_PATH] = g_param_spec_string("settings-path",
	                                                         "Path to GSettings for this widget",
	                                                         "Set the path to GSettings for this widget",
	                                                         "/com/javispedro/mdock/standalone/",
	                                                         G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);

	g_object_class_install_properties(obj_class, N_PROPERTIES, obj_properties);

	g_type_class_add_private(klass, sizeof(MDockWidgetPrivate));
}

GtkWidget *mdock_widget_new(void)
{
	return GTK_WIDGET(g_object_new(MDOCK_TYPE_WIDGET, NULL));
}