#include <sys/types.h>
#include <dirent.h>
#include <string.h>

#include "e-plugin-mono.h"

#include <mono/metadata/debug-helpers.h>
#include <mono/metadata/object.h>
#include <mono/metadata/appdomain.h>
#include <mono/metadata/assembly.h>
#include <mono/jit/jit.h>

static MonoDomain *domain;

/* ********************************************************************** */
static void *epm_parent_class;

typedef struct _EPluginMonoPrivate {
	MonoAssembly *assembly;
	MonoClass *klass;
	MonoObject *plugin;
	GHashTable *methods;
} EPluginMonoPrivate;

#define epm ((EPluginMono *)ep)

static char *
get_xml_prop(xmlNodePtr node, const char *id)
{
	char *p = xmlGetProp(node, id);
	char *out = NULL;

	if (p) {
		out = g_strdup(p);
		xmlFree(p);
	}

	return out;
}

/*
  Two approaches:
   You can have a Evolution.Plugin implementation which has every callback as methods on it.
   Or you can just use static methods for everything.

   All methods take a single (structured) argument.
*/

static void *
epm_invoke(EPlugin *ep, const char *name, void *data)
{
	EPluginMonoPrivate *p = epm->priv;
	MonoMethodDesc *d;
	MonoMethod *m;
	MonoObject *x = NULL, *res;
	void **params;

	/* we need to do this every time since we may be called from any thread for some uses */
	mono_thread_attach(domain);

	if (p->assembly == NULL) {
		p->assembly = mono_domain_assembly_open(domain, epm->location);
		if (p->assembly == NULL) {
			g_warning("can't load assembly '%s'", epm->location);
			return NULL;
		}

		if (epm->handler == NULL
		    || (p->klass = mono_class_from_name(mono_assembly_get_image(p->assembly), "", epm->handler)) == NULL) {
			printf("Using static callbacks only");
		} else {
			p->plugin = mono_object_new(domain, p->klass);
			/* could conceivably init with some context too */
			mono_runtime_object_init(p->plugin);
		}
	}

	m = g_hash_table_lookup(p->methods, name);
	if (m == NULL) {
		if (p->klass) {
			printf("looking up method '%s' in class\n", name);
			/* class method */
			d = mono_method_desc_new(name, FALSE);
			if (d == NULL) {
				g_warning("Can't create method descriptor for '%s'", name);
				return NULL;
			}

			m = mono_method_desc_search_in_class(d, p->klass);
			if (m == NULL) {
				g_warning("Can't find method callback '%s'", name);
				return NULL;
			}
		} else {
			printf("looking up static method '%s'\n", name);
			/* static method */
			d = mono_method_desc_new(name, FALSE);
			if (d == NULL) {
				g_warning("Can't create method descriptor for '%s'", name);
				return NULL;
			}

			m = mono_method_desc_search_in_image(d, mono_assembly_get_image(p->assembly));
			if (m == NULL) {
				g_warning("Can't find method callback '%s'", name);
				return NULL;
			}
		}

		g_hash_table_insert(p->methods, g_strdup(name), m);
	}

	params = g_malloc0(sizeof(*params)*1);
	params[0] = &data;
	res = mono_runtime_invoke(m, p->plugin, params, &x);
	/* do i need to free params?? */

	if (x)
		mono_print_unhandled_exception(x);

	if (res) {
		void **p = mono_object_unbox(res);
		printf("mono method returned '%p' %ld\n", *p, (long int)*p);
		return *p;
	} else
		return NULL;
}

static int
epm_construct(EPlugin *ep, xmlNodePtr root)
{
	if (((EPluginClass *)epm_parent_class)->construct(ep, root) == -1)
		return -1;

	epm->location = get_xml_prop(root, "location");
	epm->handler = get_xml_prop(root, "handler");

	if (epm->location == NULL)
		return -1;

	return 0;
}

static void
epm_finalise(GObject *o)
{
	EPlugin *ep = (EPlugin *)o;
	EPluginMonoPrivate *p = epm->priv;

	g_free(epm->location);
	g_free(epm->handler);

	g_hash_table_foreach(p->methods, (GHFunc)g_free, NULL);
	g_hash_table_destroy(p->methods);

	g_free(epm->priv);

	((GObjectClass *)epm_parent_class)->finalize(o);
}

static void
epm_class_init(EPluginClass *klass)
{
	((GObjectClass *)klass)->finalize = epm_finalise;
	klass->construct = epm_construct;
	klass->invoke = epm_invoke;
	klass->type = "mono";
}

static void
epm_init(GObject *o)
{
	EPlugin *ep = (EPlugin *)o;

	epm->priv = g_malloc0(sizeof(*epm->priv));
	epm->priv->methods = g_hash_table_new(g_str_hash, g_str_equal);
}

GType
e_plugin_mono_get_type(void)
{
	static GType type = 0;
	
	if (!type) {
		static const GTypeInfo info = {
			sizeof(EPluginMonoClass), NULL, NULL, (GClassInitFunc) epm_class_init, NULL, NULL,
			sizeof(EPluginMono), 0, (GInstanceInitFunc) epm_init,
		};

		epm_parent_class = g_type_class_ref(e_plugin_get_type());
		type = g_type_register_static(e_plugin_get_type(), "EPluginMono", &info, 0);
		domain = mono_jit_init("Evolution");
		mono_thread_attach(domain);
	}
	
	return type;
}