#include <gtk/gtk.h>
#include <gdk/gdkkeysyms.h>

static GtkWidget *main_window = NULL;

enum shape_type {
	SHAPE_TRIANGLE = 0,
	SHAPE_RECTANGLE,
	SHAPE_STAR,
	SHAPE_FLOWER,
	MAX_SHAPE_TYPE
};

struct shape_data {
	gint x;
	gint y;
	gint color;
	gint scale;
	enum shape_type shape;
} shape_data;

static GList *shape_list = NULL;

static GdkColor palette[] = {
	{ 0, 0x0000, 0x0000, 0xFFFF },
	{ 0, 0x0000, 0xFFFF, 0x0000 },
	{ 0, 0x0000, 0xC000, 0xFFFF },
	{ 0, 0x8000, 0x0000, 0xFFFF },
	{ 0, 0xFFFF, 0xFFFF, 0x0000 },
	{ 0, 0xFFFF, 0x0000, 0xC000 },
	{ 0, 0xFFFF, 0x0000, 0x0000 },
	{ 0, 0xFFFF, 0xA000, 0x0000 }
};
static const gint MAX_PALETTE = (sizeof(palette) / sizeof(palette[0]));

static gint shape_scales[10] = {
	20, 25, 30, 35, 40, 45, 50, 55, 60, 65
};

static gint scale = 0;

void drawing_area_destroy(GtkObject *object, gpointer user_data)
{
	GdkGC *gc = (GdkGC *)user_data;

	g_object_unref(gc);
}

void change_color(GdkGC *gc, GdkColor *color)
{
	gdk_colormap_alloc_color(gdk_colormap_get_system(), color, FALSE, TRUE);
	gdk_gc_set_foreground(gc, color);
}

void change_line_width(GdkGC *gc, gint line_width)
{
	gdk_gc_set_line_attributes(gc, line_width, GDK_LINE_SOLID, GDK_CAP_BUTT, GDK_JOIN_MITER);
}

void draw_triangle(GdkDrawable *drawable, GdkGC *gc, gint x, gint y, gint color, gint scale)
{
	GdkPoint points[3];

	points[0].x = x;
	points[0].y = y - shape_scales[scale];
	points[1].x = x - shape_scales[scale] * 0.866025;
	points[1].y = y + shape_scales[scale] * 0.5;
	points[2].x = x + shape_scales[scale] * 0.866025;
	points[2].y = y + shape_scales[scale] * 0.5;

	change_line_width(gc, scale / 2 + 1);
	change_color(gc, &palette[color]);
	gdk_draw_polygon(drawable, gc, FALSE, points, 3);
}

void draw_rectangle(GdkDrawable *drawable, GdkGC *gc, gint x, gint y, gint color, gint scale)
{
	gint size = shape_scales[scale] * 1.5;
	change_line_width(gc, scale / 2 + 1);
	change_color(gc, &palette[color]);
	gdk_draw_rectangle(drawable, gc, FALSE, x - size / 2, y - size / 2, size, size);
}

void draw_star(GdkDrawable *drawable, GdkGC *gc, gint x, gint y, gint color, gint scale)
{
	GdkPoint points[5];

	points[0].x = x;
	points[0].y = y - shape_scales[scale];
	points[1].x = x + shape_scales[scale] * 0.587785;
	points[1].y = y + shape_scales[scale] * 0.809017;
	points[2].x = x - shape_scales[scale] * 0.951057;
	points[2].y = y - shape_scales[scale] * 0.309017;
	points[3].x = x + shape_scales[scale] * 0.951057;
	points[3].y = y - shape_scales[scale] * 0.309017;
	points[4].x = x - shape_scales[scale] * 0.587785;
	points[4].y = y + shape_scales[scale] * 0.809017;

	change_line_width(gc, scale / 2 + 1);
	change_color(gc, &palette[color]);
	gdk_draw_polygon(drawable, gc, FALSE, points, 5);
}

void draw_flower(GdkDrawable *drawable, GdkGC *gc, gint x, gint y, gint color, gint scale)
{
	int i;
	GdkPoint points[8];
	gint r1;
	gint r2;

	points[0].x = x;
	points[0].y = y - shape_scales[scale];
	points[1].x = x - shape_scales[scale] * 0.707107;
	points[1].y = y - shape_scales[scale] * 0.707107;
	points[2].x = x - shape_scales[scale];
	points[2].y = y;
	points[3].x = x - shape_scales[scale] * 0.707107;
	points[3].y = y + shape_scales[scale] * 0.707107;
	points[4].x = x;
	points[4].y = y + shape_scales[scale];
	points[5].x = x + shape_scales[scale] * 0.707107;
	points[5].y = y + shape_scales[scale] * 0.707107;
	points[6].x = x + shape_scales[scale];
	points[6].y = y;
	points[7].x = x + shape_scales[scale] * 0.707107;
	points[7].y = y - shape_scales[scale] * 0.707107;

	r1 = shape_scales[scale];
	r2 = shape_scales[scale] * 0.4;

	change_line_width(gc, scale / 2 + 1);
	change_color(gc, &palette[color]);
	gdk_draw_arc(drawable, gc, FALSE, x - r1 / 2, y - r1 / 2, r1, r1, 0, 360 * 64);

	change_color(gc, &palette[(color + MAX_PALETTE / 2) % MAX_PALETTE]);
	for (i = 0; i < 8; i++) {
		gdk_draw_arc(drawable, gc, FALSE, points[i].x - r2 / 2, points[i].y - r2 / 2, r2, r2, 0, 360 * 64);
	}
}

void draw_shape(GdkDrawable *drawable, GdkGC *gc, const struct shape_data *shape)
{
	switch (shape->shape) {
	case SHAPE_TRIANGLE:
		draw_triangle(drawable, gc, shape->x, shape->y, shape->color, shape->scale);
		break;
	case SHAPE_RECTANGLE:
		draw_rectangle(drawable, gc, shape->x, shape->y, shape->color, shape->scale);
		break;
	case SHAPE_STAR:
		draw_star(drawable, gc, shape->x, shape->y, shape->color, shape->scale);
		break;
	case SHAPE_FLOWER:
		draw_flower(drawable, gc, shape->x, shape->y, shape->color, shape->scale);
		break;
	}
}

gboolean expose_event(GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
{
	GdkGC *gc = (GdkGC *)user_data;
	GList *cur;

	if (event->count != 0) {
		return TRUE;
	}

	for (cur = g_list_first(shape_list); cur != NULL; cur = g_list_next(cur)) {
		draw_shape(widget->window, gc, (struct shape_data *)cur->data);
	}

	return TRUE;
}

gboolean button_press_event(GtkWidget *widget, GdkEventButton *event, gpointer user_data)
{
	GdkGC *gc = (GdkGC *)user_data;
	struct shape_data *shape;

	shape = g_new(struct shape_data, 1);
	shape->x = (gint)event->x;
	shape->y = (gint)event->y;
	shape->color = g_random_int_range(0, MAX_PALETTE);
	shape->scale = scale;
	shape->shape = g_random_int_range(0, MAX_SHAPE_TYPE);

	shape_list = g_list_append(shape_list, shape);

	draw_shape(widget->window, gc, shape);
}

gboolean key_press_event(GtkWidget *widget, GdkEventKey *event, gpointer user_data)
{
	switch (event->keyval) {
	case GDK_0:
	case GDK_KP_0:
		scale = 0;
		break;
	case GDK_1:
	case GDK_KP_1:
		scale = 1;
		break;
	case GDK_2:
	case GDK_KP_2:
		scale = 2;
		break;
	case GDK_3:
	case GDK_KP_3:
		scale = 3;
		break;
	case GDK_4:
	case GDK_KP_4:
		scale = 4;
		break;
	case GDK_5:
	case GDK_KP_5:
		scale = 5;
		break;
	case GDK_6:
	case GDK_KP_6:
		scale = 6;
		break;
	case GDK_7:
	case GDK_KP_7:
		scale = 7;
		break;
	case GDK_8:
	case GDK_KP_8:
		scale = 8;
		break;
	case GDK_9:
	case GDK_KP_9:
		scale = 9;
		break;
	default:
		return FALSE;
	}

	return TRUE;
}

int main(int argc, char **argv)
{
	GtkWidget *drawing_area;
	GdkGC *gc;

	gtk_init(&argc, &argv);

	main_window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
	gtk_window_set_title(GTK_WINDOW(main_window), "GtkDrawingArea - test");
	g_signal_connect(G_OBJECT(main_window), "destroy",
					 G_CALLBACK(gtk_main_quit), NULL);

	drawing_area = gtk_drawing_area_new();
	gtk_widget_set_size_request(drawing_area, 400, 400);
	gtk_container_add(GTK_CONTAINER(main_window), drawing_area);

	gtk_widget_set_events(drawing_area,
						  GDK_EXPOSURE_MASK |
						  GDK_BUTTON_PRESS_MASK |
						  GDK_KEY_PRESS_MASK);
	GTK_WIDGET_SET_FLAGS(drawing_area, GTK_CAN_FOCUS);

	gtk_widget_show_all(main_window);

	gc = gdk_gc_new(drawing_area->window);
	change_line_width(gc, 1);

	g_signal_connect(G_OBJECT(drawing_area), "destroy",
					 G_CALLBACK(drawing_area_destroy), gc);
	g_signal_connect(G_OBJECT(drawing_area), "expose-event",
					 G_CALLBACK(expose_event), gc);
	g_signal_connect(G_OBJECT(drawing_area), "button-press-event",
					 G_CALLBACK(button_press_event), gc);
	g_signal_connect(G_OBJECT(drawing_area), "key-press-event",
					 G_CALLBACK(key_press_event), gc);

	gtk_main();
	return 0;
}