/*
 * e-mail-extension-registry.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) version 3.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 */

#include "e-mail-extension-registry.h"

#include <string.h>

#include <libebackend/libebackend.h>

#include "e-mail-formatter-extension.h"
#include "e-mail-parser-extension.h"

#define E_MAIL_EXTENSION_REGISTRY_GET_PRIVATE(obj) \
	(G_TYPE_INSTANCE_GET_PRIVATE \
	((obj), E_TYPE_MAIL_EXTENSION_REGISTRY, EMailExtensionRegistryPrivate))

struct _EMailExtensionRegistryPrivate {
	GHashTable *table;
};

G_DEFINE_ABSTRACT_TYPE (
	EMailExtensionRegistry,
	e_mail_extension_registry,
	G_TYPE_OBJECT)

/**
 * EMailExtensionRegistry:
 *
 * The #EMailExtensionRegistry is an abstract class representing a registry
 * for #EMailExtension<!-//>s.
 *
 * #EMailParser and #EMailFormatter both have internally a registry object
 * based on the #EMailExtensionRegistry.
 *
 * One extension can registry itself for more mime-types.
 */

static void
destroy_queue (GQueue *queue)
{
	g_queue_free_full (queue, g_object_unref);
}

static void
mail_extension_registry_add_extension (EMailExtensionRegistry *registry,
                                       const gchar **mime_types,
                                       GType extension_type)
{
	GObject *extension;
	gint ii;

	if (mime_types == NULL) {
		g_critical (
			"%s does not define any MIME types",
			g_type_name (extension_type));
		return;
	}

	extension = g_object_new (extension_type, NULL);

	for (ii = 0; mime_types[ii] != NULL; ii++) {
		GQueue *queue;

		queue = g_hash_table_lookup (
			registry->priv->table, mime_types[ii]);
		if (queue == NULL) {
			queue = g_queue_new ();
			g_hash_table_insert (
				registry->priv->table,
				(gpointer) mime_types[ii],
				queue);
		}

		g_queue_push_head (queue, g_object_ref (extension));

		if (camel_debug ("emformat:registry")) {
			printf (
				"Added extension '%s' for type '%s'\n",
				g_type_name (extension_type),
				mime_types[ii]);
		}
	}

	g_object_unref (extension);
}

static void
mail_extension_registry_finalize (GObject *object)
{
	EMailExtensionRegistryPrivate *priv;

	priv = E_MAIL_EXTENSION_REGISTRY_GET_PRIVATE (object);

	g_hash_table_destroy (priv->table);

	/* Chain up to parent's finalize() method. */
	G_OBJECT_CLASS (e_mail_extension_registry_parent_class)->
		finalize (object);
}

void
e_mail_extension_registry_class_init (EMailExtensionRegistryClass *class)
{
	GObjectClass *object_class;

	g_type_class_add_private (
		class, sizeof (EMailExtensionRegistryPrivate));

	object_class = G_OBJECT_CLASS (class);
	object_class->finalize = mail_extension_registry_finalize;
}

void
e_mail_extension_registry_init (EMailExtensionRegistry *registry)
{
	registry->priv = E_MAIL_EXTENSION_REGISTRY_GET_PRIVATE (registry);

	registry->priv->table = g_hash_table_new_full (
		(GHashFunc) g_str_hash,
		(GEqualFunc) g_str_equal,
		(GDestroyNotify) NULL,
		(GDestroyNotify) destroy_queue);
}

/**
 * e_mail_extension_registry_get_for_mime_type:
 * @regstry: An #EMailExtensionRegistry
 * @mime_type: A string with mime-type to look up
 *
 * Tries to lookup list of #EMailExtension<!-//>s that has registryed themselves
 * as handlers for the @mime_type.
 *
 * Return value: Returns #GQueue of #EMailExtension<!-//>s or %NULL when there
 * are no extension registryed for given @mime_type.
 */
GQueue *
e_mail_extension_registry_get_for_mime_type (EMailExtensionRegistry *registry,
                                             const gchar *mime_type)
{
	g_return_val_if_fail (E_IS_MAIL_EXTENSION_REGISTRY (registry), NULL);
	g_return_val_if_fail (mime_type && *mime_type, NULL);

	return g_hash_table_lookup (registry->priv->table, mime_type);
}

/**
 * e_mail_extension_registry_get_fallback:
 * @registry: An #EMailExtensionRegistry
 * @mime_type: A string with mime-type whose fallback to look up
 *
 * Tries to lookup fallback parsers for given mime type. For instance, for
 * multipart/alternative, it will try to lookup multipart/ * parser.
 *
 * Return Value: Returns #QGueue of #EMailExtension<!-//>>s or %NULL when there
 * are no extensions registryed for the fallback type.
 */
GQueue *
e_mail_extension_registry_get_fallback (EMailExtensionRegistry *registry,
                                        const gchar *mime_type)
{
	gchar *s, *type;
	gsize len;
	GQueue *parsers;

	g_return_val_if_fail (E_IS_MAIL_EXTENSION_REGISTRY (registry), NULL);
	g_return_val_if_fail (mime_type && *mime_type, NULL);

	s = strchr (mime_type, '/');
	if (!s)
		return NULL;

	len = s - mime_type;

	s = g_alloca (len);
	strncpy (s, mime_type, len);
	type = g_ascii_strdown (s, len);
	s = g_strdup_printf ("%s/*", type);

	parsers = g_hash_table_lookup (registry->priv->table, s);

	g_free (type);
	g_free (s);

	return parsers;
}

/******************************************************************************/

G_DEFINE_TYPE_WITH_CODE (
	EMailParserExtensionRegistry,
	e_mail_parser_extension_registry,
	E_TYPE_MAIL_EXTENSION_REGISTRY,
	G_IMPLEMENT_INTERFACE (E_TYPE_EXTENSIBLE, NULL))

static void
e_mail_parser_extension_registry_class_init (EMailParserExtensionRegistryClass *class)
{
}

static void
e_mail_parser_extension_registry_init (EMailParserExtensionRegistry *registry)
{
}

void
e_mail_parser_extension_registry_load (EMailParserExtensionRegistry *registry)
{
	GType *children;
	GType base_extension_type;
	guint ii, n_children;

	g_return_if_fail (E_IS_MAIL_PARSER_EXTENSION_REGISTRY (registry));

	base_extension_type = E_TYPE_MAIL_PARSER_EXTENSION;
	children = g_type_children (base_extension_type, &n_children);

	for (ii = 0; ii < n_children; ii++) {
		EMailParserExtensionClass *class;

		if (G_TYPE_IS_ABSTRACT (children[ii]))
			continue;

		class = g_type_class_ref (children[ii]);

		mail_extension_registry_add_extension (
			E_MAIL_EXTENSION_REGISTRY (registry),
			class->mime_types, children[ii]);

		g_type_class_unref (class);
	}

	g_free (children);
}

/******************************************************************************/

G_DEFINE_TYPE_WITH_CODE (
	EMailFormatterExtensionRegistry,
	e_mail_formatter_extension_registry,
	E_TYPE_MAIL_EXTENSION_REGISTRY,
	G_IMPLEMENT_INTERFACE (E_TYPE_EXTENSIBLE, NULL))

static void
e_mail_formatter_extension_registry_class_init (EMailFormatterExtensionRegistryClass *class)
{
}

static void
e_mail_formatter_extension_registry_init (EMailFormatterExtensionRegistry *registry)
{
}

void
e_mail_formatter_extension_registry_load (EMailFormatterExtensionRegistry *registry,
                                          GType base_extension_type)
{
	GType *children;
	guint ii, n_children;

	g_return_if_fail (E_IS_MAIL_FORMATTER_EXTENSION_REGISTRY (registry));

	children = g_type_children (base_extension_type, &n_children);

	for (ii = 0; ii < n_children; ii++) {
		EMailFormatterExtensionClass *class;

		if (G_TYPE_IS_ABSTRACT (children[ii]))
			continue;

		class = g_type_class_ref (children[ii]);

		mail_extension_registry_add_extension (
			E_MAIL_EXTENSION_REGISTRY (registry),
			class->mime_types, children[ii]);

		g_type_class_unref (class);
	}

	g_free (children);
}