/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4; coding: utf-8 -*-
 *
 *   mooeditplugin.c
 *
 *   Copyright (C) 2004-2005 by Yevgen Muntyan <muntyan@math.tamu.edu>
 *
 *   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 2 of the License, or
 *   (at your option) any later version.
 *
 *   See COPYING file that comes with this distribution.
 */

#define MOOEDIT_COMPILATION
#include "mooedit/mooplugin.h"
#include <string.h>
#include <gmodule.h>


#define PLUGIN_PREFS_ENABLED "enabled"


static GSList *registered_plugins = NULL;   /* Plugin* */
static GSList *edit_windows = NULL;         /* WindowInfo* */


typedef struct {
    MooPluginInfo info;
    gpointer data;
    gboolean initialized;
    GModule *module;
} Plugin;

typedef struct {
    Plugin *plugin;
    gpointer data;
    GDestroyNotify free_func;
} PluginWindowData;

typedef struct {
    GSList *plugins; /* PluginWindowData* */
    MooEditWindow *window;
} WindowInfo;


static WindowInfo  *window_info_new     (MooEditWindow  *window);
static void         window_info_free    (WindowInfo     *window_info);
static WindowInfo  *window_info_lookup  (MooEditWindow  *window);

static Plugin      *plugin_new          (MooPluginInfo  *info,
                                         gpointer        plugin_data);
static void         plugin_free         (Plugin         *plugin);

static Plugin      *plugin_lookup       (const char     *id);
static const char  *plugin_id           (Plugin         *plugin);

static gboolean     plugin_enabled      (Plugin         *plugin);
static gboolean     plugin_init         (Plugin         *plugin);
static void         plugin_deinit       (Plugin         *plugin);

static void         moo_plugin_attach   (WindowInfo     *window_info,
                                         Plugin         *plugin);
static void         moo_plugin_detach   (WindowInfo     *window_info,
                                         Plugin         *plugin);

static const char  *make_prefs_key      (Plugin         *plugin,
                                         const char     *key);


gboolean
moo_plugin_register (MooPluginInfo *info,
                     gpointer       plugin_data)
{
    Plugin *plugin;
    GSList *l;
    const char *prefs_key;

    g_return_val_if_fail (info != NULL, FALSE);

    if (info->plugin_system_version != MOO_PLUGIN_CURRENT_VERSION)
    {
        g_warning ("%s: plugin of version %d is incompatible with "
                   "current version %d", G_STRLOC, info->plugin_system_version,
                   MOO_PLUGIN_CURRENT_VERSION);
        return FALSE;
    }

    g_return_val_if_fail (info->id && info->id[0], FALSE);
    g_return_val_if_fail (g_utf8_validate (info->id, -1, NULL), FALSE);
    g_return_val_if_fail (!info->name || g_utf8_validate (info->name, -1, NULL), FALSE);
    g_return_val_if_fail (!info->description || g_utf8_validate (info->description, -1, NULL), FALSE);
    g_return_val_if_fail (info->init || info->attach, FALSE);
    g_return_val_if_fail (info->params != NULL, FALSE);
    g_return_val_if_fail (info->prefs_params != NULL, FALSE);

    plugin = plugin_new (info, plugin_data);
    g_return_val_if_fail (plugin != NULL, FALSE);

    if (moo_plugin_lookup (plugin_id (plugin)))
    {
        g_warning ("plugin with id '%s' already registered", plugin_id (plugin));
        moo_plugin_unregister (plugin_id (plugin));
    }

    prefs_key = make_prefs_key (plugin, PLUGIN_PREFS_ENABLED);
    moo_prefs_new_key_bool (prefs_key, plugin_enabled (plugin));
    plugin->info.params->enabled = moo_prefs_get_bool (prefs_key);

    if (!plugin_init (plugin))
    {
        plugin_free (plugin);
        return FALSE;
    }

    registered_plugins = g_slist_append (registered_plugins, plugin);

    for (l = edit_windows; l != NULL; l = l->next)
    {
        WindowInfo *window_info = l->data;
        moo_plugin_attach (window_info, plugin);
    }

    return TRUE;
}


void
moo_plugin_unregister (const char *id)
{
    Plugin *plugin;
    GSList *l;

    g_return_if_fail (id != NULL);

    plugin = plugin_lookup (id);
    g_return_if_fail (plugin != NULL);

    registered_plugins = g_slist_remove (registered_plugins, plugin);

    for (l = edit_windows; l != NULL; l = l->next)
    {
        WindowInfo *window_info = l->data;
        moo_plugin_detach (window_info, plugin);
    }

    plugin_deinit (plugin);

    if (plugin->module)
        g_module_close (plugin->module);

    plugin_free (plugin);
}


void
_moo_plugin_window_attach (MooEditWindow *window)
{
    GSList *l;
    WindowInfo *window_info;

    g_return_if_fail (MOO_IS_EDIT_WINDOW (window));

    window_info = window_info_new (window);
    edit_windows = g_slist_append (edit_windows, window_info);

    for (l = registered_plugins; l != NULL; l = l->next)
    {
        Plugin *plugin = l->data;
        moo_plugin_attach (window_info, plugin);
    }
}


void
_moo_plugin_window_detach (MooEditWindow *window)
{
    WindowInfo *window_info;
    GSList *plugins, *l;

    g_return_if_fail (MOO_IS_EDIT_WINDOW (window));

    window_info = window_info_lookup (window);
    g_return_if_fail (window_info != NULL);

    plugins = g_slist_copy (window_info->plugins);
    plugins = g_slist_reverse (plugins);

    for (l = plugins; l != NULL; l = l->next)
    {
        PluginWindowData *window_data = l->data;
        moo_plugin_detach (window_info, window_data->plugin);
    }

    edit_windows = g_slist_remove (edit_windows, window_info);
    window_info_free (window_info);

    g_slist_free (plugins);
}


static PluginWindowData*
plugin_window_data_new (WindowInfo *window_info,
                        Plugin     *plugin)
{
    PluginWindowData *window_data;

    g_return_val_if_fail (window_info != NULL && plugin != NULL, NULL);

    window_data = g_new0 (PluginWindowData, 1);
    window_data->plugin = plugin;

    return window_data;
}


static void
plugin_window_data_free (PluginWindowData *window_data)
{
    g_free (window_data);
}


static PluginWindowData*
window_info_lookup_plugin (WindowInfo *window_info,
                           Plugin     *plugin)
{
    GSList *l;

    g_return_val_if_fail (window_info != NULL && plugin != NULL, NULL);

    for (l = window_info->plugins; l != NULL; l = l->next)
    {
        PluginWindowData *window_data = l->data;
        if (window_data->plugin == plugin)
            return window_data;
    }

    return NULL;
}


static void
moo_plugin_attach (WindowInfo   *window_info,
                   Plugin       *plugin)
{
    PluginWindowData *window_data;

    g_return_if_fail (window_info != NULL);
    g_return_if_fail (plugin != NULL);

    if (!plugin_enabled (plugin))
        return;

    window_data = plugin_window_data_new (window_info, plugin);
    window_info->plugins = g_slist_append (window_info->plugins, window_data);

    if (plugin->info.attach)
        plugin->info.attach (window_info->window, plugin->data, &plugin->info);
}


static void
moo_plugin_detach (WindowInfo *window_info,
                   Plugin     *plugin)
{
    PluginWindowData *window_data;

    window_data = window_info_lookup_plugin (window_info, plugin);

    if (!window_data)
        return;

    if (plugin->info.detach)
        plugin->info.detach (window_info->window, plugin->data, &plugin->info);

    if (window_data->data && window_data->free_func)
        window_data->free_func (window_data->data);

    window_info->plugins = g_slist_remove (window_info->plugins, window_data);
    plugin_window_data_free (window_data);
}


void
moo_plugin_set_window_data (const char     *plugin_id,
                            MooEditWindow  *window,
                            gpointer        data,
                            GDestroyNotify  free_func)
{
    PluginWindowData *window_data;
    WindowInfo *window_info = window_info_lookup (window);
    Plugin *plugin = plugin_lookup (plugin_id);

    g_return_if_fail (window_info != NULL && plugin != NULL);

    window_data = window_info_lookup_plugin (window_info, plugin);
    g_return_if_fail (window_data != NULL);

    if (window_data->data && window_data->free_func)
        window_data->free_func (window_data->data);

    window_data->data = data;
    window_data->free_func = free_func;
}


static WindowInfo*
window_info_new (MooEditWindow *window)
{
    WindowInfo *window_info;

    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), NULL);

    window_info = g_new0 (WindowInfo, 1);

    window_info->window = window;
    window_info->plugins = NULL;

    return window_info;
}


static void
window_info_free (WindowInfo *window_info)
{
    if (window_info)
    {
        g_assert (window_info->plugins == NULL);
        g_free (window_info);
    }
}


static WindowInfo*
window_info_lookup (MooEditWindow *window)
{
    GSList *l;

    g_return_val_if_fail (MOO_IS_EDIT_WINDOW (window), NULL);

    for (l = edit_windows; l != NULL; l = l->next)
    {
        WindowInfo *window_info = l->data;
        if (window_info->window == window)
            return window_info;
    }

    return NULL;
}


static MooPluginParams*
plugin_params_copy (MooPluginParams *params)
{
    MooPluginParams *copy;

    g_return_val_if_fail (params != NULL, NULL);

    copy = g_new0 (MooPluginParams, 1);
    copy->enabled = params->enabled;

    return copy;
}


static void
plugin_params_free (MooPluginParams *params)
{
    g_free (params);
}


static MooPluginPrefsParams*
plugin_prefs_params_copy (MooPluginPrefsParams *params)
{
    MooPluginPrefsParams *copy;

    g_return_val_if_fail (params != NULL, NULL);

    copy = g_new0 (MooPluginPrefsParams, 1);

    return copy;
}


static void
plugin_prefs_params_free (MooPluginPrefsParams *params)
{
    g_free (params);
}


static void
plugin_info_copy (MooPluginInfo *dest,
                  MooPluginInfo *src)
{
    dest->id = g_strdup (src->id);
    dest->name = g_strdup (src->name ? src->name : dest->id);
    dest->description = g_strdup (src->description ? src->description : dest->name);
    dest->author = g_strdup (src->author ? src->author : "<unknown person>");
    dest->version = g_strdup (src->version ? src->version : "<unknown version>");

    dest->init = src->init;
    dest->deinit = src->deinit;
    dest->attach = src->attach;
    dest->detach = src->detach;

    dest->params = plugin_params_copy (src->params);
    dest->prefs_params = plugin_prefs_params_copy (src->prefs_params);
}


static Plugin*
plugin_new (MooPluginInfo  *info,
            gpointer        plugin_data)
{
    Plugin *plugin = g_new0 (Plugin, 1);

    plugin->data = plugin_data;
    plugin->initialized = FALSE;

    plugin_info_copy (&plugin->info, info);

    return plugin;
}


static void
plugin_free (Plugin *plugin)
{
    if (plugin)
    {
        g_free ((char*) plugin->info.id);
        g_free ((char*) plugin->info.name);
        g_free ((char*) plugin->info.description);
        plugin_params_free (plugin->info.params);
        plugin_prefs_params_free (plugin->info.prefs_params);
        g_free (plugin);
    }
}


static Plugin*
plugin_lookup (const char *id)
{
    GSList *l;

    g_return_val_if_fail (id != NULL, NULL);

    for (l = registered_plugins; l != NULL; l = l->next)
    {
        Plugin *plugin = l->data;
        if (!strcmp (plugin->info.id, id))
            return plugin;
    }

    return NULL;
}


static const char*
plugin_id (Plugin *plugin)
{
    g_return_val_if_fail (plugin != NULL, NULL);
    return plugin->info.id;
}


static gboolean
plugin_enabled (Plugin *plugin)
{
    g_return_val_if_fail (plugin != NULL, FALSE);
    return plugin->info.params->enabled;
}


/* XXX should it attach? */
static gboolean
plugin_init (Plugin *plugin)
{
    g_return_val_if_fail (plugin != NULL, FALSE);

    if (!plugin_enabled (plugin) || plugin->initialized)
        return TRUE;

    if (!plugin->info.init ||
         plugin->info.init (plugin->data, &plugin->info))
    {
        plugin->initialized = TRUE;
        return TRUE;
    }
    else
    {
        return FALSE;
    }
}


/* XXX should it detach? */
static void
plugin_deinit (Plugin *plugin)
{
    g_return_if_fail (plugin != NULL);

    if (!plugin->initialized)
        return;

    if (plugin->info.deinit)
        plugin->info.deinit (plugin->data, &plugin->info);

    plugin->initialized = FALSE;
}


MooPluginInfo*
moo_plugin_lookup (const char *id)
{
    Plugin *plugin = plugin_lookup (id);
    return plugin ? &plugin->info : NULL;
}


gpointer
moo_plugin_get_data (const char *id)
{
    Plugin *plugin = plugin_lookup (id);
    return plugin ? plugin->data : NULL;
}


GSList*
moo_list_plugins (void)
{
    GSList *list = NULL, *l;

    for (l = registered_plugins; l != NULL; l = l->next)
    {
        Plugin *plugin = l->data;
        list = g_slist_prepend (list, g_strdup (plugin_id (plugin)));
    }

    return g_slist_reverse (list);
}


gpointer
moo_plugin_get_window_data (const char     *plugin_id,
                            MooEditWindow  *window)
{
    WindowInfo *window_info;
    Plugin *plugin;
    PluginWindowData *window_data;

    plugin = plugin_lookup (plugin_id);
    window_info = window_info_lookup (window);

    if (!window_info || !plugin)
        return NULL;

    window_data = window_info_lookup_plugin (window_info, plugin);

    return window_data ? window_data->data : NULL;
}


static const char*
make_prefs_key (Plugin             *plugin,
                const char         *key)
{
    static char *prefs_key = NULL;

    g_return_val_if_fail (plugin != NULL, NULL);
    g_return_val_if_fail (key != NULL, NULL);

    g_free (prefs_key);
    prefs_key = g_strdup_printf (MOO_PLUGIN_PREFS_ROOT "/%s/%s",
                                 plugin_id (plugin), key);
    return prefs_key;
}


static gboolean
moo_plugin_read_module (GModule            *module,
                        const char         *name)
{
    MooPluginModuleInitFunc init_func;
    char *init_func_name;
    gboolean result = FALSE;

    g_return_val_if_fail (module != NULL, FALSE);
    g_return_val_if_fail (name != NULL, FALSE);

    init_func_name = g_strdup_printf ("%s_init", name);

    if (!g_module_symbol (module, init_func_name, (gpointer*) &init_func))
        goto out;

    if (!init_func ())
        goto out;

    result = TRUE;

out:
    g_free (init_func_name);
    return result;
}


void
moo_plugin_read_dir (const char *path)
{
    GDir *dir;
    const char *name;

    g_return_if_fail (path != NULL);

    dir = g_dir_open (path, 0, NULL);

    if (!dir)
        return;

    while ((name = g_dir_read_name (dir)))
    {
        char *module_path, *prefix, *suffix;
        GModule *module;

        if (!g_str_has_suffix (name, "." G_MODULE_SUFFIX))
            continue;

        suffix = g_strrstr (name, "." G_MODULE_SUFFIX);
        prefix = g_strndup (name, suffix - name);

        module_path = g_build_filename (path, name, NULL);
        module = g_module_open (module_path, 0);

        if (module)
        {
            if (!moo_plugin_read_module (module, prefix))
                g_module_close (module);
        }
        else
        {
            g_message ("%s: %s", G_STRLOC, g_module_error ());
        }

        g_free (prefix);
        g_free (module_path);
    }

    g_dir_close (dir);
}