#include <glib.h>
#include <glib-object.h>
#include <gtk/gtk.h>

#include "preload.h"
#include "wallpapers.h"
#include "walls_conf.h"

static gboolean preload_thread_exit = FALSE;
static GHashTable *hashtable = NULL;
static GMutex *preload_hashtable_mutex = NULL, *preload_thread_mutex = NULL;
static GThread *preload_thread = NULL;

static gpointer preload_thread_func(gpointer);

struct preload_thread_data_t {
	GArray *array;
	gint win_width, win_height;
};

static void preload_hash_table_free(gpointer data) {
	struct preload_hash_table_value_t *pt;

	pt = data;

	if(pt->pb)
		g_object_unref(pt->pb);

	g_object_unref(pt->pb_orig);

	g_free(data);
}

void preload_init() {
	preload_hashtable_mutex = g_mutex_new();
	preload_thread_mutex = g_mutex_new();

	hashtable = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, preload_hash_table_free);
}

void preload_free() {
	if(preload_thread) {
		preload_thread_exit = TRUE;
		g_thread_join(preload_thread);
	}

	g_mutex_free(preload_hashtable_mutex);
	g_mutex_free(preload_thread_mutex);

	g_hash_table_destroy(hashtable);
	preload_hashtable_mutex = NULL;
}

#define preload_index(i) (((i) / 2) + 1) * (((i) % 2 * (-2) + 1))

static GArray *preload_prepare_data(GtkWidget *thumbview) {
	GList *list;
	GArray *array;
	GtkTreePath *sel_path, *path;
	GtkTreeModel *model;
	GtkTreeIter iter;
	GValue value = {0};
	gchar *filename;
	guint list_len;
	gint selected_index, *indices, index;
	gboolean b;

	array = g_array_new(FALSE, FALSE, sizeof(gchar*));

	list = gtk_icon_view_get_selected_items(GTK_ICON_VIEW(thumbview));

	list_len = g_list_length(list);

	if(list_len != 1) {
		g_list_foreach(list, (GFunc)gtk_tree_path_free, NULL);
		g_list_free(list);

		return array;
	}

	sel_path = g_list_nth_data(list, 0);

	indices = gtk_tree_path_get_indices(sel_path);
	if(!indices) {
		g_warning("preload_thread: Failed to get indices");

		g_list_foreach(list, (GFunc)gtk_tree_path_free, NULL);
		g_list_free(list);

		return array;
	}

	selected_index = indices[0];

	model = gtk_icon_view_get_model(GTK_ICON_VIEW(thumbview));

	/* Make sure the selected pixbuf is also preloaded. */
	if(gtk_tree_model_get_iter(model, &iter, sel_path)) {
		gtk_tree_model_get_value(model, &iter, 1, &value);
		filename = g_value_dup_string(&value);
		g_value_unset(&value);

		g_array_append_val(array, filename);
	}

	for(gint i = 0; i < config.max_preload; i++) {
		/* Make sure the selected pixbuf is also preloaded. */
		if(array->len == 0 && gtk_tree_model_get_iter(model, &iter, sel_path)) {
			gtk_tree_model_get_value(model, &iter, 1, &value);
			filename = g_value_dup_string(&value);
			g_value_unset(&value);

			g_array_append_val(array, filename);
		}

		index = selected_index + preload_index(i);
		if(index < 0) {
			continue;
		}

		path = gtk_tree_path_new_from_indices(index, -1);

		if(gtk_tree_path_get_depth(path) != 1) {
			/* Assume we're out of bounds. */
			gtk_tree_path_free(path);
			continue;
		}

		b = gtk_tree_model_get_iter(model, &iter, path);

		gtk_tree_path_free(path);

		if(b == FALSE)
			continue;

		gtk_tree_model_get_value(model, &iter, 1, &value);
		filename = g_value_dup_string(&value);
		g_value_unset(&value);

		g_array_append_val(array, filename);
	}

	g_list_foreach(list, (GFunc)gtk_tree_path_free, NULL);
	g_list_free(list);

	return array;
}

void preload_start_thread(GtkWidget *thumbview, gint win_width, gint win_height) {
	struct preload_thread_data_t *data;
	GError *error = NULL;

	if(preload_thread) {
		preload_thread_exit = TRUE;
		g_thread_join(preload_thread);
	}

	data = g_malloc(sizeof(struct preload_thread_data_t));

	data->array = preload_prepare_data(thumbview);
	data->win_width = win_width;
	data->win_height = win_height;

	preload_thread_exit = FALSE;
	preload_thread = g_thread_create(preload_thread_func, data, TRUE, &error);

	if(!preload_thread) {
		g_error("%s", error->message);
		g_error_free(error);
	}
}

void preload_clear() {
	g_mutex_lock(preload_hashtable_mutex);
	g_hash_table_remove_all(hashtable);
	g_mutex_unlock(preload_hashtable_mutex);
}

void preload_clear_sized() {
	GHashTableIter iter;
	struct preload_hash_table_value_t *data;

	g_mutex_lock(preload_hashtable_mutex);

	g_hash_table_iter_init(&iter, hashtable);

	while(g_hash_table_iter_next(&iter, NULL, (gpointer)&data)) {
		if(data->pb) {
			g_object_unref(data->pb);
			data->pb = NULL;
		}
	}

	g_mutex_unlock(preload_hashtable_mutex);
}

static void preload_add(const gchar *filename, gpointer data) {
	g_mutex_lock(preload_hashtable_mutex);

	g_hash_table_replace(hashtable, g_strdup(filename), data);

	g_mutex_unlock(preload_hashtable_mutex);
}

gpointer preload_get(const gchar *filename) {
	gpointer data;

	g_mutex_lock(preload_hashtable_mutex);

	data = g_hash_table_lookup(hashtable, filename);

	g_mutex_unlock(preload_hashtable_mutex);

	return data;
}

inline static void add_pixbuf(const gchar *filename, gpointer _data) {
	struct preload_thread_data_t *data;
	struct preload_hash_table_value_t *value;
	GdkPixbuf *orig, *pb;
	GError *error = NULL;
	gint width, height;
	gdouble ratio;

	/* Check if we already loaded this filename. */
	if(preload_get(filename))
		return;

	orig = gdk_pixbuf_new_from_file(filename, &error);

	if(!orig) {
		g_warning("%s", error->message);
		g_error_free(error);
		return;
	}

	data = _data;

	pb = resize_pixbuf(orig, data->win_width, data->win_height, &width, &height, &ratio);

	value = g_malloc(sizeof(struct preload_hash_table_value_t));

	value->pb_orig = orig;

	if(pb) {
		value->pb = pb;
		value->width = width;
		value->height = height;
		value->ratio = ratio;
	} else {
		value->pb = NULL;
		value->width = 0;
		value->height = 0;
		value->ratio = 0;
	}

	preload_add(filename, value);
}

static gpointer preload_thread_func(gpointer _data) {
	struct preload_thread_data_t *data;
	GArray *array;
	GList *keys;
	gchar *added_name;
	const gchar *key_name;
	gboolean found;

	data = _data;
	array = data->array;

	g_mutex_lock(preload_hashtable_mutex);
	keys = g_hash_table_get_keys(hashtable);
	g_mutex_unlock(preload_hashtable_mutex);

	for(int i = 0; i < g_list_length(keys) && preload_thread_exit == FALSE; i++) {
		found = FALSE;
		key_name = g_list_nth_data(keys, i);
		for(int j = 0; j < array->len && preload_thread_exit == FALSE; j++) {
			added_name = g_array_index(array, gchar*, j);
			if(g_strcmp0(key_name, added_name) == 0) {
				found = TRUE;
				break;
			}
		}
		if(found == FALSE) {
			g_mutex_lock(preload_hashtable_mutex);
			g_hash_table_remove(hashtable, key_name);
			g_mutex_unlock(preload_hashtable_mutex);
		}
	}

	for(int i = 0; i < array->len && preload_thread_exit == FALSE; i++) {
		added_name = g_array_index(array, gchar*, i);
		add_pixbuf(added_name, data);
	}

	g_list_free(keys);
	g_array_free(array, TRUE);

	g_free(data);
	preload_thread = NULL;
	return NULL;
}