/*
 * Claws Mail -- a GTK based, lightweight, and fast e-mail client
 * Copyright (C) 2002-2022 the Claws Mail Team
 *
 * 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/>.
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#include "claws-features.h"
#endif

#include <stdio.h>
#ifdef HAVE_VALGRIND
#include <valgrind.h>
#endif

#include "defs.h"
#include <glib.h>
#ifdef ENABLE_NLS
#include <glib/gi18n.h>
#else
#define _(a) (a)
#define N_(a) (a)
#endif
#include <gmodule.h>

#include "utils.h"
#include "plugin.h"
#include "prefs.h"
#include "claws.h"
#include "timing.h"
#include "file-utils.h"

#ifdef G_OS_WIN32
#define PLUGINS_BLOCK_PREFIX "PluginsWin32_"
#else
#define PLUGINS_BLOCK_PREFIX "Plugins_"
#endif

struct _Plugin
{
	gchar	*filename;
	GModule	*module;
	const gchar *(*name) (void);
	const gchar *(*desc) (void);
	const gchar *(*version) (void);
	const gchar *(*type) (void);
	const gchar *(*licence) (void);
	struct PluginFeature *(*provides) (void);
	
	GSList *rdeps;
	gchar *error;
	gboolean unloaded_hidden;
	gboolean in_prefix_dir;
};

const gchar *plugin_feature_names[] =
	{ N_("Nothing"),
	  N_("a viewer"),
	  N_("a MIME parser"),
	  N_("folders"),
	  N_("filtering"),
	  N_("a privacy interface"),
	  N_("a notifier"),
	  N_("a utility"),
	  N_("things"),
	  NULL };

/* The plugin must be at least under one of these licences and have
   the corresponding token returned by the plugin_licence function.
 */
const gchar *plugin_licence_tokens[] = {
  "LGPL2.1+", "LGPLv2.1+", "LGPL2.1", "LGPLv2.1",
  "LGPL3+", "LGPLv3+", "LGPL3", "LGPLv3",
  "GPL3+", "GPLv3+", "GPL3", "GPLv3",
  "GPL2+", "GPLv2+",
  "Apache2.0", "Apache 2.0", "Apache v2.0",
  "2-clause BSD", "Simplified BSD", "FreeBSD",
  "3-clause BSD", "New BSD", "Modified BSD",
  NULL
};

/* Dual (or more) licences are allowed, must be separated by one of these.
 */
#define IS_LICENCE_SEP(a) ((a) == ',' || (a) == ';' || (a) == '|' || (a) == '/' || (a) == '\0')

/**
 * List of all loaded plugins
 */
GSList *plugins = NULL;
GSList *plugin_types = NULL;

/* 
 * List of plugins unloaded for some fixable reason
 */
static GSList *unloaded_plugins = NULL;

static gint list_find_by_string(gconstpointer data, gconstpointer str)
{
	return strcmp((gchar *)data, (gchar *)str) ? TRUE : FALSE;
}

static gint list_find_by_plugin_filename(const Plugin *plugin, const gchar *filename)
{
	/* FIXME: There is a problem in case of symlinks or when a
	   user tries to load a plugin with the same name from a
	   different directory.  I think it would be better to compare
	   only the basename of the filename here (case-insensitive on
	   W32). */
	cm_return_val_if_fail(plugin, 1);
	cm_return_val_if_fail(plugin->filename, 1);
	cm_return_val_if_fail(filename, 1);
	return strcmp(filename, plugin->filename);
}

static gboolean plugin_filename_is_standard_dir(const gchar *filename) {
	return strncmp(filename, get_plugin_dir(), strlen(get_plugin_dir())) == 0;
}

static gchar * plugin_canonical_name(const Plugin *plugin)
{
	if (plugin->in_prefix_dir == TRUE) {
		if (plugin_filename_is_standard_dir(plugin->filename) == TRUE) {
			gchar *plugin_name = g_path_get_basename(plugin->filename);
			return plugin_name;
		}
	}
	return g_strdup(plugin->filename);
}

void plugin_save_list(void)
{
	gchar *rcpath, *block;
	PrefFile *pfile;
	GSList *type_cur, *plugin_cur;
	Plugin *plugin;
	
	for (type_cur = plugin_types; type_cur != NULL; type_cur = g_slist_next(type_cur)) {
		rcpath = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S, COMMON_RC, NULL);
		block = g_strconcat(PLUGINS_BLOCK_PREFIX, type_cur->data, NULL);
		if ((pfile = prefs_write_open(rcpath)) == NULL ||
		    (prefs_set_block_label(pfile, block) < 0)) {
			g_warning("failed to write plugin list");
			g_free(rcpath);
			g_free(block);
			return;
		}
		g_free(block);

		for (plugin_cur = plugins; plugin_cur != NULL; plugin_cur = g_slist_next(plugin_cur)) {
			plugin = (Plugin *) plugin_cur->data;
			
			if (plugin->unloaded_hidden)
				continue;

			if (!strcmp(plugin->type(), type_cur->data)) {
				gchar * name = plugin_canonical_name(plugin);
				int err = fprintf(pfile->fp, "%s\n", name);
				g_free(name);
				if (err < 0)
					goto revert;
			}
		}
		for (plugin_cur = unloaded_plugins; plugin_cur != NULL; plugin_cur = g_slist_next(plugin_cur)) {
			plugin = (Plugin *) plugin_cur->data;

			if (plugin->unloaded_hidden)
				continue;
			
			if (!strcmp(plugin->type(), type_cur->data)) {
				gchar * name = plugin_canonical_name(plugin);
				int err = fprintf(pfile->fp, "%s\n", name);
				g_free(name);
				if (err < 0)
					goto revert;
			}
		}
		if (fprintf(pfile->fp, "\n") < 0)
			goto revert;

		if (prefs_file_close(pfile) < 0)
			g_warning("failed to write plugin list");

		g_free(rcpath);	
		
		continue;

revert:
		g_warning("failed to write plugin list");
		if (prefs_file_close_revert(pfile) < 0)
			g_warning("failed to revert plugin list");

		g_free(rcpath);	
	}
}

static gboolean plugin_is_loaded(const gchar *filename)
{
	return (g_slist_find_custom(plugins, filename, 
		  (GCompareFunc)list_find_by_plugin_filename) != NULL);
}

static Plugin *plugin_get_by_filename(const gchar *filename)
{
	GSList *cur = plugins;
	for(; cur; cur = cur->next) {
		Plugin *p = (Plugin *)cur->data;
		if (!strcmp(p->filename, filename)) {
			return p;
		} 
	}
	return NULL;
}

/** 
 * Loads a plugin dependancies
 * 
 * Plugin dependancies are, optionnaly, listed in a file in
 * get_plugin_dir()/$pluginname.deps.
 * \param filename The filename of the plugin for which we have to load deps
 * \param error The location where an error string can be stored
 * \return 0 on success, -1 otherwise
 */
static gint plugin_load_deps(const gchar *filename, gchar **error)
{
	gchar *tmp;
	gchar *deps_file = NULL;
	FILE *fp = NULL;
	gchar buf[BUFFSIZE];
	gchar *p;

	tmp = g_strdup(filename);
	if( (p = strrchr(tmp, '.')) )
	  *p = '\0';
	deps_file = g_strconcat(tmp, ".deps", NULL);
	g_free(tmp);
	
	fp = claws_fopen(deps_file, "rb");
	g_free(deps_file);
	
	if (!fp)
		return 0;
	
	while (claws_fgets(buf, sizeof(buf), fp) != NULL) {
		Plugin *dep_plugin = NULL;
		gchar *path = NULL;
		buf[strlen(buf)-1]='\0'; /* chop off \n */
		path = g_strconcat(get_plugin_dir(), buf,
				".", G_MODULE_SUFFIX, NULL);
		if ((dep_plugin = plugin_get_by_filename(path)) == NULL) {
			debug_print("trying to load %s\n", path);
			dep_plugin = plugin_load(path, error);
			if (dep_plugin == NULL) {
				g_free(path);
				claws_fclose(fp);
				return -1;
			}
			dep_plugin->in_prefix_dir = TRUE;
		}
		g_free(path);
		if (!g_slist_find_custom(dep_plugin->rdeps, 
				(gpointer) filename, list_find_by_string)) {
			debug_print("adding %s to %s rdeps\n",
				filename,
				dep_plugin->filename);
			dep_plugin->rdeps = 
				g_slist_append(dep_plugin->rdeps, 
					g_strdup(filename));
		}
	}
	claws_fclose(fp);
	return 0;
}

static void plugin_unload_rdeps(Plugin *plugin)
{
	GSList *cur = plugin->rdeps;
	debug_print("removing %s rdeps\n", plugin->filename);
	while (cur) {
		gchar *file = (gchar *)cur->data;
		Plugin *rdep_plugin = file?plugin_get_by_filename(file):NULL;
		debug_print(" rdep %s: %p\n", file, rdep_plugin);
		if (rdep_plugin) {
			plugin_unload(rdep_plugin);
		}
		g_free(file);
		cur = cur->next;
	}
	g_slist_free(plugin->rdeps);
	plugin->rdeps = NULL;
}

static void plugin_remove_from_unloaded_list (const gchar *filename)
{
	GSList *item = g_slist_find_custom(unloaded_plugins, 
				(gpointer) filename, (GCompareFunc)list_find_by_plugin_filename);
	Plugin *unloaded_plugin = item ? ((Plugin *)item->data):NULL;
	if (unloaded_plugin != NULL) {
		debug_print("removing %s from unloaded list\n", unloaded_plugin->filename);
		unloaded_plugins = g_slist_remove(unloaded_plugins, unloaded_plugin);
		g_module_close(unloaded_plugin->module);
		g_free(unloaded_plugin->filename);
		g_free(unloaded_plugin->error);
		g_free(unloaded_plugin);
	}
}

static gchar *plugin_check_features(struct PluginFeature *features) {
	int i = 0, j = 0;
	GSList *cur = plugins;

	if (features == NULL)
		return NULL;
	for(; cur; cur = cur->next) {
		Plugin *p = (Plugin *)cur->data;
		struct PluginFeature *cur_features = p->provides();
		if (p->unloaded_hidden)
			continue;
		for (j = 0; cur_features[j].type != PLUGIN_NOTHING; j++) {
			for (i = 0; features[i].type != PLUGIN_NOTHING; i++) {
				if (cur_features[j].type == features[i].type &&
				    !strcmp(cur_features[j].subtype, features[i].subtype)) {
					return g_strdup_printf(_(
						"This plugin provides %s (%s), which is "
						"already provided by the %s plugin."),
						_(plugin_feature_names[features[i].type]), 
						_(features[i].subtype),
						p->name());
				}
			}
		}
	}

	return NULL;
}

static gboolean plugin_licence_check(const gchar *licence) {
	gint i = 0;
	gint len = 0;
	
	if (licence != NULL) {
		len = strlen(licence);
	}
	if (len == 0) {
		g_warning("plugin licence check failed: empty licence");
		return FALSE;
	}
	while (plugin_licence_tokens[i] != NULL) {
		gchar *found = g_strstr_len(licence, len, plugin_licence_tokens[i]);
		if (found != NULL) {
			gint tlen = strlen(plugin_licence_tokens[i]);
			if (len != tlen) { /* not a single license */
				if (((found == licence) &&  (!IS_LICENCE_SEP(licence[tlen])))
						|| (!IS_LICENCE_SEP(*(found - 1))) 
						|| (!IS_LICENCE_SEP(*(found + tlen)))) {
					debug_print("plugin licence check failed: invalid separator\n");
					return FALSE;
				}
			}
			debug_print("plugin licence check passed: %s found\n", plugin_licence_tokens[i]);
			return TRUE;
		}
		++i;
	}
	debug_print("plugin licence check failed: %s is not a valid licence\n", licence);
	return FALSE;
}

static Plugin *plugin_load_in_default_dir(const gchar *filename, gchar **error)
{
	Plugin *plugin = NULL;
	gchar *filename_default_dir = NULL;
	gchar *default_error = NULL;
	gchar *plugin_name = g_path_get_basename(filename);

	filename_default_dir = g_strconcat(get_plugin_dir(), plugin_name, NULL);

	debug_print("trying to load %s in default plugin directory %s\n",
		    plugin_name, get_plugin_dir());

	g_free(plugin_name);

	plugin = plugin_load(filename_default_dir, &default_error);
	
	g_free(filename_default_dir);
	
	if (plugin) {
		g_free(*error);
		*error = NULL;
		plugin->in_prefix_dir = TRUE;

	} else {
		g_free(default_error);
	}

	return plugin;
}

/**
 * Loads a plugin
 *
 * \param filename The filename of the plugin to load
 * \param error The location where an error string can be stored
 * \return the plugin on success, NULL otherwise
 */
Plugin *plugin_load(const gchar *filename, gchar **error)
{
	Plugin *plugin;
	gint (*plugin_init) (gchar **error);
	gpointer plugin_name, plugin_desc, plugin_version;
	const gchar *(*plugin_type)(void);
	const gchar *(*plugin_licence)(void);
	struct PluginFeature *(*plugin_provides)(void);

	gint ok;
	START_TIMING((filename?filename:"NULL plugin"));
	cm_return_val_if_fail(filename != NULL, NULL);
	cm_return_val_if_fail(error != NULL, NULL);

	/* check duplicate plugin path name */
	if (plugin_is_loaded(filename)) {
		plugin = plugin_get_by_filename(filename);
		if (plugin->unloaded_hidden) {
			/* reshow it */
			goto init_plugin;
		} else {
			*error = g_strdup(_("Plugin already loaded"));
			return NULL;		
		}
	}			       
	
	plugin_remove_from_unloaded_list(filename);
	
	if (plugin_load_deps(filename, error) < 0)
		return NULL;
	plugin = g_new0(Plugin, 1);
	if (plugin == NULL) {
		*error = g_strdup(_("Failed to allocate memory for Plugin"));
		return NULL;
	}

	debug_print("trying to load `%s'\n", filename);
	plugin->module = g_module_open(filename, 0);
	if (plugin->module == NULL) {
		*error = g_strdup(g_module_error());
		g_free(plugin);
		if (!plugin_filename_is_standard_dir(filename))
			return plugin_load_in_default_dir(filename, error);
		else
			return NULL;
	} else {
		plugin->in_prefix_dir = FALSE;
        }

init_plugin:
	if (!g_module_symbol(plugin->module, "plugin_name", &plugin_name) ||
	    !g_module_symbol(plugin->module, "plugin_desc", &plugin_desc) ||
	    !g_module_symbol(plugin->module, "plugin_version", &plugin_version) ||
	    !g_module_symbol(plugin->module, "plugin_type", (gpointer)&plugin_type) ||
	    !g_module_symbol(plugin->module, "plugin_licence", (gpointer)&plugin_licence) ||
	    !g_module_symbol(plugin->module, "plugin_provides", (gpointer)&plugin_provides) ||
	    !g_module_symbol(plugin->module, "plugin_init", (gpointer)&plugin_init)) {
		*error = g_strdup(g_module_error());
		if (plugin->unloaded_hidden)
			return NULL;
		g_module_close(plugin->module);
		g_free(plugin);
		return NULL;
	}

	if (plugin_licence_check(plugin_licence()) != TRUE) {
		*error = g_strdup(_("This module is not licensed under a GPL v3 or later compatible license."));
		if (plugin->unloaded_hidden)
			return NULL;
		g_module_close(plugin->module);
		g_free(plugin);
		return NULL;
	}

	if (!strcmp(plugin_type(), "GTK")) {
		*error = g_strdup(_("This module is for Claws Mail GTK1."));
		if (plugin->unloaded_hidden)
			return NULL;
		g_module_close(plugin->module);
		g_free(plugin);
		return NULL;
	}

	if ((*error = plugin_check_features(plugin_provides())) != NULL) {
		if (plugin->unloaded_hidden)
			return NULL;
		g_module_close(plugin->module);
		g_free(plugin);
		return NULL;
	}
	plugin->name = plugin_name;
	plugin->desc = plugin_desc;
	plugin->version = plugin_version;
	plugin->type = plugin_type;
	plugin->licence = plugin_licence;
	plugin->provides = plugin_provides;
	plugin->filename = g_strdup(filename);
	plugin->error = NULL;

	if ((ok = plugin_init(error)) < 0) {
		if (*error)
			plugin->error = g_strdup(*error);
		unloaded_plugins = g_slist_append(unloaded_plugins, plugin);
		return NULL;
	}

	if (!plugin->unloaded_hidden)
		plugins = g_slist_append(plugins, plugin);
	plugin->unloaded_hidden = FALSE;

	debug_print("Plugin %s (from file %s) loaded\n", plugin->name(), filename);
	END_TIMING();
	return plugin;
}

void plugin_unload(Plugin *plugin)
{
	gboolean (*plugin_done) (void);
	gboolean can_unload = TRUE;

	plugin_unload_rdeps(plugin);

	if (plugin->unloaded_hidden)
		return;

	if (plugin->error) {
		plugin_remove_from_unloaded_list(plugin->filename);
		return;
	}
	if (g_module_symbol(plugin->module, "plugin_done", (gpointer) &plugin_done)) {
		can_unload = plugin_done();
	}

	if (can_unload) {
#ifdef HAVE_VALGRIND
		if (!RUNNING_ON_VALGRIND) {
			g_module_close(plugin->module);
		}
#else
		g_module_close(plugin->module);
#endif
		plugins = g_slist_remove(plugins, plugin);
		g_free(plugin->filename);
		g_free(plugin);
	} else {
		plugin->unloaded_hidden = TRUE;
	}

}

static void replace_old_plugin_name(gchar *plugin_name)
{
	gchar *old_name_end = g_strconcat("_plugin.", G_MODULE_SUFFIX, NULL);
	gchar *matches = strstr(plugin_name, old_name_end);

	if (!matches) {
		g_free(old_name_end);
		return;
	} else if (plugin_name + strlen(plugin_name) != matches + strlen(matches)) {
		g_free(old_name_end);
		return;
	} else {
		gchar *new_name_end = g_strconcat(".", G_MODULE_SUFFIX, NULL);
		int offset = strlen(plugin_name) - strlen(old_name_end);

		debug_print("Replacing old plugin name %s\n", plugin_name);
		
		strncpy(plugin_name + offset, new_name_end, strlen(old_name_end) - 1);
		debug_print(" to %s\n", plugin_name);
		g_free(new_name_end);
	}
	g_free(old_name_end);
}

void plugin_load_all(const gchar *type)
{
	gchar *rcpath;
	gchar buf[BUFFSIZE];
	PrefFile *pfile;
	gchar *error = NULL, *block;
	gint failed = 0;

	plugin_types = g_slist_append(plugin_types, g_strdup(type));

	rcpath = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S, COMMON_RC, NULL);	
	block = g_strconcat(PLUGINS_BLOCK_PREFIX, type, NULL);
	if ((pfile = prefs_read_open(rcpath)) == NULL ||
	    ((failed = prefs_set_block_label(pfile, block)) < 0)) {
		g_free(rcpath);
		g_free(block);
		if (!failed)
			prefs_file_close(pfile);
		return;
	}
	g_free(block);

	while (claws_fgets(buf, sizeof(buf), pfile->fp) != NULL) {
		if (buf[0] == '[')
			break;

		g_strstrip(buf);
		replace_old_plugin_name(buf);

		if ((buf[0] != '\0') && (plugin_load(buf, &error) == NULL)) {
			g_warning("plugin loading error: %s", error);
			g_free(error);
		}							
	}
	prefs_file_close(pfile);

	g_free(rcpath);
}

void plugin_unload_all(const gchar *type)
{
	GSList *list, *cur;

	list = g_slist_copy(plugins);
	list = g_slist_reverse(list);

	for(cur = list; cur != NULL; cur = g_slist_next(cur)) {
		Plugin *plugin = (Plugin *) cur->data;
		
		if (!strcmp(type, plugin->type()))
			plugin_unload(plugin);
	}
	g_slist_free(list);

	cur = g_slist_find_custom(plugin_types, (gpointer) type, list_find_by_string);
	if (cur) {
		g_free(cur->data);
		plugin_types = g_slist_remove(plugin_types, cur);
	}
}


/* Load those plugins we always want to use.  No error output; just
 * try. */
void plugin_load_standard_plugins (void)
{
	static const char *names[] = {
#ifdef G_OS_WIN32 
		"pgpmime",
		"pgpinline",
#else
		/* post-2.5 maybe 
		"bogofilter", */
#endif
		NULL
	};
	int i;
	gchar *error, *filename;
	
	for (i=0; names[i]; i++) {
		/* Simple hack to check whether the plugin has already
		 * been loaded but checking only for the basename. */
		GSList *cur = plugins;
		for(; cur; cur = cur->next) {
			Plugin *p = (Plugin *)cur->data;
			if (strstr(p->filename, names[i]))
				break;
		}
		if (!cur) { /* Not yet loaded. */
			/* FIXME: get_plugin_dir () returns with a trailing
			 * (back)slash; this should be fixed so that we can use
			 * g_module_build_path here. */
#ifdef G_OS_WIN32 
			filename = g_strconcat (get_plugin_dir(),
						names[i], NULL);
#else
			filename = g_strconcat (get_plugin_dir(),
						names[i], ".", G_MODULE_SUFFIX, NULL);
#endif
			error = NULL;
			plugin_load(filename, &error);
			g_free (error);
			g_free(filename);
		}
	}
}

GSList *plugin_get_list(void)
{
	GSList *new = NULL;
	GSList *cur = plugins;
	for (; cur; cur = cur->next) {
		Plugin *p = (Plugin *)cur->data;
		if (!p->unloaded_hidden)
			new = g_slist_prepend(new, p);
	}
	new = g_slist_reverse(new);
	return new;
}

Plugin *plugin_get_loaded_by_name(const gchar *name) 
{
	Plugin *plugin = NULL;
	GSList *new, *cur; 
	new = plugin_get_list();
	for (cur = new; cur; cur = g_slist_next(cur)) {
		plugin = (Plugin *)cur->data;
		if (!g_ascii_strcasecmp(plugin->name(), name)) 
			break;
		else 
			plugin = NULL;
	}
	g_slist_free(new);
	return plugin;
}

GSList *plugin_get_unloaded_list(void)
{
	return g_slist_copy(unloaded_plugins);
}

const gchar *plugin_get_name(Plugin *plugin)
{
	return plugin->name();
}

const gchar *plugin_get_desc(Plugin *plugin)
{
	return plugin->desc();
}

const gchar *plugin_get_version(Plugin *plugin)
{
	return plugin->version();
}

const gchar *plugin_get_error(Plugin *plugin)
{
	return plugin->error;
}

/* Generally called in plugin_init() function of each plugin. It check the
 * minimal and compiled version of claws binary required by the plugin.
 * If (@minimum_claws_version == 0 || @compiled_claws_version == 0), don't
 * check the corresponding version.
 *
 * If an error occurs {
 * 	If @error == NULL { don't allocate error string. }
 *	If @error != NULL { error string is allocated and must be freed after 
 *				call function. }
 * }
 * Returns: FALSE if an error occurs, TRUE if all is OK.
 */
gint check_plugin_version(guint32 minimum_claws_version,
			 guint32 compiled_claws_version,
			 const gchar *plugin_name,
			 gchar **error)
{
	guint32 claws_version = claws_get_version();

	if (compiled_claws_version != 0 && claws_version > compiled_claws_version) {
		if (error != NULL) {
			*error = (plugin_name && *plugin_name)
				? g_strdup_printf(_("Your version of Claws Mail is newer than the "
							"version the '%s' plugin was built with."),
						plugin_name)
				: g_strdup(_("Your version of Claws Mail is newer than the "
							"version the plugin was built with."));
		}
		return FALSE;
	}

	if (minimum_claws_version != 0 && claws_version < minimum_claws_version) {
		if (error != NULL) {
			*error = (plugin_name && *plugin_name)
				? g_strdup_printf(_("Your version of Claws Mail is too old for "
							"the '%s' plugin."), plugin_name)
				: g_strdup(_("Your version of Claws Mail is too old for the plugin."));
		}
		return FALSE;
	}
	return TRUE;
}