/*
 *  upkg: tool for manipulating Unreal Tournament packages.
 *  Copyright (C) 2009 Nick Bowler
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include <glib-object.h>
#include <ltdl.h>

#include <uobject/package.h>
#include "upkg.h"

#define U_PKG_GET_PRIV(o) \
	G_TYPE_INSTANCE_GET_PRIVATE(o, U_PKG_TYPE, struct upkg_priv)

struct upkg_priv {
	lt_dlhandle native;
};

G_DEFINE_TYPE(UPkg, u_pkg, G_TYPE_TYPE_MODULE);

/* Package search path. */
static char  *search_path;
static size_t search_path_sz;

/* List of package file extensions, in descending order of precedence. */
static const char u_pkg_exts[][5] = { ".u", ".utx", ".umx", ".uax", ".unr" };

static char *str_cpy_lower(char *dst, const char *src)
{
	size_t i;

	for (i = 0; src[i]; i++)
		dst[i] = tolower(src[i]);
	dst[i] = 0;

	return dst;
}

static int str_cmp_lower(const char *s1, const char *s2)
{
	size_t i;

	for (i = 0; s1[i] && s2[i]; i++) {
		int c1 = tolower(s1[i]), c2 = tolower(s2[i]);
		if (c1 < c2)
			return -1;
		if (c1 > c2)
			return 1;
	}

	if (s1[i])
		return 1;
	if (s2[i])
		return -1;
	return 0;
}

static void dl_print_errors(const char *prefix)
{
	const char *err;
	while ((err = lt_dlerror())) {
		if (prefix) fprintf(stderr, "%s: ", prefix);
		fprintf(stderr, "%s\n", err);
	}
}

/*
 * Function for use with lt_dlforeachfile.  The user data must point to
 * a UPkg with the GTypeModule name field initialized.  If a suitable file
 * is found and could be successfully opened for reading, the pkg class member
 * will be filled in.
 */
static int find_package_by_name(const char *filename, void *data)
{
	GTypeModule *m = G_TYPE_MODULE(data);
	UPkg *upkg = U_PKG(data);

	const char *base;
	size_t len;
	char *buf;

	base = strrchr(filename, '/');
	if (base) {
		base++;
	} else {
		base = filename;
	}

	if (str_cmp_lower(base, m->name) != 0)
		return 0;

	len = strlen(filename);
	buf = malloc(len + sizeof **u_pkg_exts);
	if (!buf)
		return 0;
	strcpy(buf, filename);

	for (unsigned i = 0; i < sizeof u_pkg_exts / sizeof *u_pkg_exts; i++) {
		strcpy(buf+len, u_pkg_exts[i]);
		upkg->pkg = upkg_fopen(buf);
		if (!upkg->pkg) {
			free(buf);
			return 1;
		}
	}

	free(buf);
	return 0;
}

static gboolean u_pkg_load(GTypeModule *m)
{
	struct upkg_priv *priv = U_PKG_GET_PRIV(m);
	int (*init_func)(GTypeModule *);

	if (m->name) {
		priv->native = lt_dlopenext(m->name);
		if (!priv->native) {
			dl_print_errors(m->name);
			return FALSE;
		}

		init_func = lt_dlsym(priv->native, "init");
		if (!init_func || init_func(m) != 0) {
			dl_print_errors(__func__);
			lt_dlclose(priv->native);
			return FALSE;
		}
	}

	if (!U_PKG(m)->pkg) {
		lt_dlforeachfile(u_pkg_get_search_path(), find_package_by_name, m);
	}

	return TRUE;
}

static void u_pkg_unload(GTypeModule *m)
{
	struct upkg_priv *priv = U_PKG_GET_PRIV(m);
	void (*exit_func)(GTypeModule *);
	UPkg *upkg = U_PKG(m);

	if (priv->native) {
		exit_func = lt_dlsym(priv->native, "exit");
		if (exit_func) {
			exit_func(m);
		}

		if (lt_dlclose(priv->native) != 0) {
			dl_print_errors(__func__);
		}
	}

	if (upkg->pkg) {
		upkg_close(upkg->pkg);
		upkg->pkg = NULL;
	}
}

static void u_pkg_init(UPkg *pkg)
{

}

static void u_pkg_finalize(GObject *o)
{
	UPkg *upkg = U_PKG(o);

	if (upkg->pkg) {
		upkg_close(upkg->pkg);
	}
}

static void u_pkg_class_init(UPkgClass *class)
{
	GTypeModuleClass *modclass = G_TYPE_MODULE_CLASS(class);
	GObjectClass *objclass = G_OBJECT_CLASS(class);

	const char *modpath = getenv("UOBJECT_MODULE_PATH");

	g_type_class_add_private(class, sizeof (struct upkg_priv));

	if (lt_dlinit() != 0) {
		dl_print_errors(__func__);
	}

	if (modpath && lt_dlsetsearchpath(modpath) != 0) {
		dl_print_errors(__func__);
	}
	if (lt_dladdsearchdir(PKGLIBDIR) != 0) {
		dl_print_errors(__func__);
	}

	modclass->load     = u_pkg_load;
	modclass->unload   = u_pkg_unload;
	objclass->finalize = u_pkg_finalize;
}

static int expand_search_path(size_t need)
{
	size_t want = search_path_sz;
	if (want == 0) want = 1;

	while (want < need)
		want *= 2;

	if (want > search_path_sz) {
		char *new = realloc(search_path, want);
		if (!new) {
			return -1;
		}

		search_path    = new;
		search_path_sz = want;
	}

	return 0;
}

const char *u_pkg_get_search_path(void)
{
	return search_path ? search_path : "";
}

int u_pkg_set_search_path(const char *path)
{
	if (expand_search_path(strlen(path)+1) != 0)
		return -1;
	strcpy(search_path, path);
	return 0;
}

int u_pkg_add_search_dir(const char *path)
{
	size_t end = search_path ? strlen(search_path) : 0;

	if (end == 0) {
		return u_pkg_set_search_path(path);
	}

	if (expand_search_path(end + strlen(path) + 2) != 0)
		return -1;
	search_path[end] = LT_PATHSEP_CHAR;
	strcpy(search_path+end+1, path);
	return 0;
}

GTypeModule *u_pkg_new_by_name(const char *name)
{
	g_return_val_if_fail(name != NULL, NULL);

	char *pkgname = malloc(strlen(name)+1);
	if (!pkgname) {
		return NULL;
	}

	GTypeModule *mod = g_object_new(U_PKG_TYPE, NULL);
	if (!mod) {
		free(pkgname);
		return NULL;
	}

	mod->name = str_cpy_lower(pkgname, name);
	return mod;
}

GTypeModule *u_pkg_new_by_file(const char *filename)
{
	struct upkg *pkg = upkg_fopen(filename);
	if (!pkg) {
		return NULL;
	}

	GTypeModule *mod = g_object_new(U_PKG_TYPE, NULL);
	if (!mod) {
		upkg_close(pkg);
		return NULL;
	}

	mod->name = NULL;
	U_PKG(mod)->pkg = pkg;
	return mod;
}