#include <unistd.h>

#include <glib/gstdio.h>
#include <gtk/gtk.h>

#include "db.h"
#include "thumbnails.h"

GThread *thumb_thread = NULL;
gboolean thumb_thread_exit = FALSE;

inline static gchar *get_wall_thumb_name(const gchar *filepath) {
	GChecksum *ck;
	gchar *s;
	gchar *cksum;

	ck = g_checksum_new(G_CHECKSUM_MD5);
	s = g_strdup_printf("file://%s", filepath);
	g_checksum_update(ck, (const guchar*)s, -1);
	g_free(s);
	cksum = g_strdup_printf("%s/.thumbnails/normal/%s.png", g_get_home_dir(), g_checksum_get_string(ck));
	g_checksum_free(ck);
	return cksum;
}

inline static time_t get_mtime(const gchar *filepath) {
	struct stat sb;

	if(g_stat(filepath, &sb) == 0) {
		return sb.st_mtime;
	} else {
		return 0;
	}
}

inline static gboolean is_thumb_modified(GdkPixbuf *pb, const gchar *filename, const gchar *thumbname) {
	time_t mtime, pb_mtime, thumb_mtime;
	const gchar *mtime_s;

	mtime = get_mtime(filename);
	mtime_s = gdk_pixbuf_get_option(pb, "tEXt::Thumb::MTime");
	pb_mtime = g_ascii_strtoll(mtime_s, NULL, 10);

	/* Original file modified since thumbnail creation. */
	if(mtime != pb_mtime)
		return TRUE;

	thumb_mtime = get_mtime(thumbname);
	/* Original file newer than thumbnail. */
	if(mtime > thumb_mtime)
		return TRUE;

	return FALSE;
}

GdkPixbuf *get_thumbnail(const gchar *filepath) {
	GdkPixbuf *pb, *pb2;
	gint win_width, win_height, img_width, img_height, width, height;
	gdouble scalex, scaley, width_ratio, height_ratio;
	GError *error = NULL;
	gchar *thumbname, *mtime, *width_s, *height_s;

	thumbname = get_wall_thumb_name(filepath);

	if(g_access(thumbname, F_OK) == 0) {
		pb = gdk_pixbuf_new_from_file(thumbname, &error);
		if(pb && !is_thumb_modified(pb, filepath, thumbname)) {
			g_free(thumbname);
			return pb;
		} else if(pb) {
			g_object_unref(pb);
		}
	}

	pb = gdk_pixbuf_new_from_file(filepath, &error);

	if(!pb) {
		g_warning("%s", error->message);
		g_error_free(error);
		g_free(thumbname);
		return NULL;
	}

	img_width = gdk_pixbuf_get_width(pb);
	img_height = gdk_pixbuf_get_height(pb);
	win_width = win_height = 128;

	width_ratio = (gdouble)img_width / (gdouble)win_width;
	height_ratio = (gdouble)img_height / (gdouble)win_height;
	if(width_ratio > height_ratio) {
		width = win_width;
		height = (gint)(1.0 / width_ratio * img_height);
	} else {
		height = win_height;
		width = (gint)(1.0 / height_ratio * img_width);
	}
	scalex = (gdouble)width / (gdouble)img_width;
	scaley = (gdouble)height / (gdouble)img_height;

	pb2 = gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8, width, height);
	gdk_pixbuf_scale(pb, pb2, 0, 0, width, height, 0, 0, scalex, scaley, GDK_INTERP_BILINEAR);
	g_object_unref(pb);

	error = NULL;
	mtime = g_strdup_printf("%lu", (unsigned long)get_mtime(filepath));
	width_s = g_strdup_printf("%d", img_width);
	height_s = g_strdup_printf("%d", img_height);
	if(!gdk_pixbuf_save(pb2, thumbname, "png", &error,
				"tEXt::Thumb::URI", filepath,
				"tEXt::Thumb::MTime", mtime,
				"tEXt::Software", "walls",
				"tEXt::Thumb::Image::Width", width_s,
				"tEXt::Thumb::Image::Height", height_s,
				NULL)) {
		g_warning("%s", error->message);
		g_error_free(error);
	}

	g_free(mtime);
	g_free(width_s);
	g_free(height_s);
	g_free(thumbname);

	return pb2;
}

gpointer add_thumbs_thread(gpointer data) {
	GtkListStore *liststore;
	GtkTreeIter iter;
	GtkTreePath *path;
	int n;
	GValue value = {0};
	GdkPixbuf *pb = NULL;
	const gchar *filepath;

	thumb_thread_exit = FALSE;

	liststore = GTK_LIST_STORE(data);

	if(!gtk_tree_model_get_iter_first(GTK_TREE_MODEL(liststore), &iter)) {
		return NULL;
	}

	n = gtk_tree_model_iter_n_children(GTK_TREE_MODEL(liststore), NULL);

	for(int i = 0; i < n; i++) {
		if(thumb_thread_exit == TRUE)
			break;

		gtk_tree_model_get_value(GTK_TREE_MODEL(liststore), &iter, 1, &value);
		filepath = g_value_get_string(&value);
		pb = get_thumbnail(filepath);
		g_value_unset(&value);
		if(pb) {
			gtk_list_store_set(liststore, &iter, 0, pb, -1);

			path = gtk_tree_model_get_path(GTK_TREE_MODEL(liststore), &iter);

			if(path)
				gtk_tree_model_row_changed(GTK_TREE_MODEL(liststore), path, &iter);

			g_object_unref(pb);
		}
		gtk_tree_model_iter_next(GTK_TREE_MODEL(liststore), &iter);
	}

	thumb_thread = NULL;

	return NULL;
}