/*

 * Copyright (C) 2014, 2016, 2018  J. Ali Harlow <ali@juiblex.co.uk>

 *

 * 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.

 *

 * 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, write to the Free Software Foundation, Inc.,

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#include "config.h"

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <gtk/gtk.h>

#include <plover/plover.h>

#include <plover/transaction.h>

#include <plover-gtk/transactionhelper.h>

#include "plover/uri-handler.h"

/*

 * A PloverTransactionHelper uses a GtkAssistant to help a user run a

 * transaction.

 */

G_DEFINE_TYPE(PloverTransactionHelper,plover_transaction_helper,G_TYPE_OBJECT)

enum plover_transaction_type {

    TRANSACTION_TYPE_NULL=0,

    TRANSACTION_TYPE_INSTALL=1UL<<0,

    TRANSACTION_TYPE_REMOVE=1UL<<1,

    TRANSACTION_TYPE_UPDATE=TRANSACTION_TYPE_INSTALL|TRANSACTION_TYPE_REMOVE

};

typedef struct _PloverTransactionHelperPrivate {

    enum plover_transaction_type transaction_type;

    gchar *default_prefix;

} PloverTransactionHelperPrivate;

#define PLOVER_TRANSACTION_HELPER_GET_PRIVATE(obj)\

                                G_TYPE_INSTANCE_GET_PRIVATE(obj,\

				  PLOVER_TYPE_TRANSACTION_HELPER,\

				  PloverTransactionHelperPrivate)

enum {

    CLOSE=0,

    N_SIGNALS

};

static guint signals[N_SIGNALS];

static PloverTransaction *

  plover_transaction_helper_new_transaction(PloverTransactionHelper *helper,

  GError **error);

static void plover_transaction_helper_finalize(PloverTransactionHelper *helper)

{

    PloverTransactionHelperPrivate *priv;

    priv=PLOVER_TRANSACTION_HELPER_GET_PRIVATE(helper);

    g_free(priv->default_prefix);

    g_free(helper->error_primary_text);

    g_free(helper->base);

    g_free(helper->unsatisfied);

    if (helper->comps)

	plover_comps_free(helper->comps);

    plover_vector_free(helper->report_adding);

    plover_vector_free(helper->report_removing);

}

static void plover_transaction_helper_dispose(PloverTransactionHelper *helper)

{

    g_clear_error(&helper->error);

    if (helper->error_dialog)

    {

	g_signal_handlers_disconnect_by_data(helper->error_dialog,helper);

	gtk_widget_destroy(helper->error_dialog);

	helper->error_dialog=NULL;

    }

    if (helper->assistant)

    {

	g_signal_handlers_disconnect_by_data(helper->assistant,helper);

	g_clear_object(&helper->assistant);

    }

    g_clear_object(&helper->ui);

    g_slist_foreach(helper->transactions,(GFunc)g_object_unref,NULL);

    g_slist_free(helper->transactions);

    helper->transactions=NULL;

    g_clear_object(&helper->alternate_installed);

    g_clear_object(&helper->installed);

    g_clear_object(&helper->upstream);

    g_clear_object(&helper->relocated_upstream);

}

static void

  plover_transaction_helper_class_init(PloverTransactionHelperClass *klass)

{

    GObjectClass *gobject_class=G_OBJECT_CLASS(klass);

    gobject_class->finalize=

      (void (*)(GObject *))plover_transaction_helper_finalize;

    gobject_class->dispose=

      (void (*)(GObject *))plover_transaction_helper_dispose;

    g_type_class_add_private(klass,sizeof(PloverTransactionHelperPrivate));

    signals[CLOSE]=g_signal_newv("close",

      G_TYPE_FROM_CLASS(klass),G_SIGNAL_RUN_LAST,NULL,NULL,NULL,

      g_cclosure_marshal_VOID__VOID,G_TYPE_NONE,0,NULL);

}

static void plover_transaction_helper_init(PloverTransactionHelper *helper)

{

    helper->report_adding=plover_vector_new();

    helper->report_removing=plover_vector_new();

}

static void plover_transaction_helper_assistant_cancel(GtkAssistant *assistant,

  PloverTransactionHelper *helper)

{

    gtk_widget_hide(GTK_WIDGET(helper->assistant));

    gtk_assistant_set_current_page(helper->assistant,0);

    g_signal_emit(helper,signals[CLOSE],0);

}

static void plover_transaction_helper_assistant_close(GtkAssistant *assistant,

  PloverTransactionHelper *helper)

{

    gtk_widget_hide(GTK_WIDGET(helper->assistant));

    gtk_assistant_set_current_page(helper->assistant,0);

    g_signal_emit(helper,signals[CLOSE],0);

}

static void

  plover_transaction_helper_prepare_confirm(PloverTransactionHelper *helper)

{

    gchar *package_list,*add,*remove,*s;

    GtkLabel *label;

    struct plover_vector *report;

    if (helper->report_adding->len)

    {

	plover_vector_sort(helper->report_adding);

	if (helper->report_adding_dependencies)

	{

	    report=plover_vector_dup(helper->report_adding);

	    if (helper->report_adding->len==1)

		plover_vector_append(report,"its dependencies");

	    else

		plover_vector_append(report,"their dependencies");

	    package_list=plover_vector_format_for_display(report);

	    plover_vector_free(report);

	}

	else

	    package_list=

	      plover_vector_format_for_display(helper->report_adding);

	add=g_strconcat("Packages to be installed or updated: ",package_list,

	  ".",NULL);

	g_free(package_list);

    }

    else

	add=NULL;

    if (helper->report_removing->len)

    {

	plover_vector_sort(helper->report_removing);

	if (helper->report_removing_dependants)

	{

	    report=plover_vector_dup(helper->report_removing);

	    if (helper->report_adding->len==1)

		plover_vector_append(report,"its dependants");

	    else

		plover_vector_append(report,"their dependants");

	    package_list=plover_vector_format_for_display(report);

	    plover_vector_free(report);

	}

	else

	    package_list=

	      plover_vector_format_for_display(helper->report_removing);

	remove=g_strconcat("Packages to be removed: ",package_list,".",NULL);

	g_free(package_list);

    }

    else

	remove=NULL;

    label=GTK_LABEL(gtk_builder_get_object(helper->ui,"SISummaryOfWork"));

    if (add && remove)

	s=g_strconcat("<b>Installation Summary</b>\n\n",remove,"\n\n",add,NULL);

    else if (add || remove)

	s=g_strconcat("<b>Installation Summary</b>\n\n",add?add:remove,NULL);

    else

	s=g_strdup("<b>Installation Summary</b>\n\nNo changes scheduled");

    gtk_label_set_markup(label,s);

    g_free(s);

    g_free(add);

    g_free(remove);

}

static void plover_transaction_helper_run(PloverTransactionHelper *helper);

static void plover_transaction_helper_callback(GObject *source,

  GAsyncResult *result,gpointer user_data)

{

    GError *error=NULL;

    PloverTransactionHelper *helper=user_data;

    PloverTransaction *transaction=PLOVER_TRANSACTION(source);

    if (!plover_transaction_commit_finish(transaction,result,&error))

    {

	plover_transaction_helper_set_error(helper,error,

	  "Software installation failed");

	g_error_free(error);

    }

    else

	plover_transaction_helper_run(helper);

    /*

     * There may be status updates queued by transaction as idle events.

     * Process them now before we disconnect so that we don't lose them.

     */

    while(g_main_context_pending(NULL))

	g_main_context_iteration(NULL,FALSE);

    g_signal_handlers_disconnect_by_data(transaction,helper);

    g_object_unref(transaction);

}

static void plover_transaction_helper_transaction_status_changed(

  PloverTransaction *transaction,const char *status,

  PloverTransactionHelper *helper)

{

    GtkProgressBar *bar;

    bar=GTK_PROGRESS_BAR(gtk_builder_get_object(helper->ui,"SIProgressBar"));

    gtk_progress_bar_set_text(bar,status);

}

static void plover_transaction_helper_run(PloverTransactionHelper *helper)

{

    PloverTransaction *transaction;

    GtkWidget *page;

    page=GTK_WIDGET(gtk_builder_get_object(helper->ui,"SIProgress"));

    if (helper->transactions)

    {

	if (helper->assistant)

	    gtk_assistant_set_page_complete(helper->assistant,page,FALSE);

	transaction=helper->transactions->data;

	helper->transactions=g_slist_delete_link(helper->transactions,

	  helper->transactions);

	g_signal_connect(transaction,"status-changed",

	  G_CALLBACK(plover_transaction_helper_transaction_status_changed),

	  helper);

	plover_transaction_commit_async(transaction,NULL,

	  plover_transaction_helper_callback,helper);

    }

    else if (helper->assistant)

	gtk_assistant_set_page_complete(helper->assistant,page,TRUE);

}

static gboolean plover_transaction_helper_pulse(gpointer user_data)

{

    PloverTransactionHelper *helper=user_data;

    GtkWidget *w;

    GtkProgressBar *bar;

    if (!helper->assistant)

	return FALSE;

    w=GTK_WIDGET(gtk_builder_get_object(helper->ui,"SIProgress"));

    bar=GTK_PROGRESS_BAR(gtk_builder_get_object(helper->ui,"SIProgressBar"));

    if (gtk_assistant_get_page_complete(helper->assistant,w))

    {

	gtk_progress_bar_set_fraction(bar,1.0);

	helper->pulse_handler=0;

	return FALSE;

    }

    else

    {

	gtk_progress_bar_pulse(bar);

	return TRUE;

    }

}

static void

  plover_transaction_helper_prepare_progress(PloverTransactionHelper *helper)

{

    GError *error=NULL;

    GtkToggleButton *button;

    PloverTransaction *transaction;

    GSList *save_transactions;

    PloverTransactionHelperPrivate *priv;

    enum plover_transaction_type save_transaction_type;

    priv=PLOVER_TRANSACTION_HELPER_GET_PRIVATE(helper);

    button=GTK_TOGGLE_BUTTON(gtk_builder_get_object(helper->ui,

      "SIRemoveExisting"));

    if (gtk_toggle_button_get_active(button))

    {

	transaction=plover_transaction_helper_new_transaction(helper,&error);

	/*

	 * I think we want switch to the alternate installed set in the case of

	 * alternate_database_clashes, but not in the case of

	 * active_database_is_incompatible (see

	 * plover_transaction_helper_update_summary_page).

	 * Whether testing for helper->alternate_installed is sufficient I'm

	 * far from clear.

	 */

	if (helper->alternate_installed)

	    plover_transaction_set_installed(transaction,

	      helper->alternate_installed);

	if (transaction && !plover_transaction_remove(transaction,NULL,&error))

	{

	    g_object_unref(transaction);

	    transaction=NULL;

	}

	if (transaction)

	{

	    save_transactions=helper->transactions;

	    helper->transactions=NULL;

	    save_transaction_type=priv->transaction_type;

	    priv->transaction_type=0;

	    if (!plover_transaction_helper_add_transaction(helper,transaction,

	      NULL,PLOVER_TRANSACTION_HELPER_REPORT_REMOVE,&error))

	    {

		g_object_unref(transaction);

		transaction=NULL;

		helper->transactions=save_transactions;

		priv->transaction_type=save_transaction_type;

	    }

	    else

	    {

		g_slist_foreach(save_transactions,(GFunc)g_object_unref,NULL);

		g_slist_free(save_transactions);

	    }

	}

	if (!transaction)

	{

	    if (g_error_matches(error,PLOVER_POSIX_ERROR,ENOENT))

		g_clear_error(&error);

	    if (error)

	    {

		plover_transaction_helper_set_error(helper,error,

		  "Failed to remove existing packages");

		g_error_free(error);

		return;

	    }

	}

    }

    /*

     * Note that PloverTransaction does support cancelling a transaction, but

     * there are a number of challenges with using it:

     *	- cancellation is only supported during the file phase if razor

     *	  has atomic rollback,

     *  - cancellation is not supported during post-transaction scripts at all

     *    (since by the time the first script is started the atomic has already

     *    been committed) and these can take quite some time,

     *  - where a transaction has an embedded COMMIT, any rollback won't

     *    go back beyond this point.

     * To support user-cancel, then, we would need some mechanism to:

     *  - Comunicate that the operation is being cancelled and this may take

     *    some time,

     *  - Not allow cancellation at all after the last post-transaction script

     *    phase is started,

     *  - Report the partially completed transaction where cancellation

     *    occurred after a COMMIT point.

     * At present, this doesn't appear worth the effort.

     */

    if (helper->assistant)

	gtk_assistant_commit(helper->assistant);

    plover_transaction_helper_run(helper);

    helper->pulse_handler=g_timeout_add(100,plover_transaction_helper_pulse,

      helper);

}

static void plover_transaction_helper_assistant_prepare(GtkAssistant *assistant,

  GtkWidget *page,PloverTransactionHelper *helper)

{

    if (page==GTK_WIDGET(gtk_builder_get_object(helper->ui,"SIConfirm")))

	plover_transaction_helper_prepare_confirm(helper);

    else if (page==GTK_WIDGET(gtk_builder_get_object(helper->ui,"SIProgress")))

	plover_transaction_helper_prepare_progress(helper);

}

static void

  plover_transaction_helper_remove_existing_toggled(GtkToggleButton *button,

  PloverTransactionHelper *helper)

{

    GtkWidget *w;

    if (helper->assistant)

    {

	w=GTK_WIDGET(gtk_builder_get_object(helper->ui,"SIConfirm"));

	gtk_assistant_set_page_complete(helper->assistant,w,

	  gtk_toggle_button_get_active(button));

    }

}

PloverTransactionHelper *plover_transaction_helper_new(GtkBuilder *ui)

{

    gsize len;

    gchar *s,*directory,*contents;

    GError *error=NULL;

    GtkWidget *w;

    PloverTransactionHelper *helper;

    g_return_val_if_fail(ui == NULL || GTK_IS_BUILDER(ui),NULL);

    helper=PLOVER_TRANSACTION_HELPER(

      g_object_new(PLOVER_TYPE_TRANSACTION_HELPER,NULL));

    if (ui)

	helper->ui=g_object_ref(ui);

    else

	helper->ui=gtk_builder_new();

    helper->assistant=

      GTK_ASSISTANT(gtk_builder_get_object(helper->ui,"SoftwareInstallation"));

    if (!helper->assistant)

    {

	directory=g_strdup(g_getenv("PLOVER_DATADIR"));

	if (!directory)

	{

#ifdef WIN32

	    s=g_win32_get_package_installation_directory_of_module(NULL);

	    directory=g_build_filename(s,"share","plover",NULL);

	    g_free(s);

#else

	    directory=g_strdup(PLOVER_DATADIR);

#endif

	}

	s=g_build_filename(directory,"software-installation.ui",NULL);

	g_free(directory);

	(void)g_file_get_contents(s,&contents,&len,&error);

	g_free(s);

	if (!error)

	{

	    (void)gtk_builder_add_from_string(helper->ui,contents,len,&error);

	    g_free(contents);

	}

	if (error)

	{

	    g_critical("software-installation.ui: %s",error->message);

	    g_clear_error(&error);

	    g_set_error(&error,PLOVER_GENERAL_ERROR,PLOVER_GENERAL_ERROR_FAILED,

	      "Internal error (no user interface)");

	    plover_transaction_helper_set_error(helper,error,

	      "Can't start installer");

	    return helper;

	}

	helper->assistant=GTK_ASSISTANT(gtk_builder_get_object(helper->ui,

	  "SoftwareInstallation"));

    }

    if (!helper->assistant)

    {

	g_critical("\"SoftwareInstallation\" object not found");

	g_set_error(&error,PLOVER_GENERAL_ERROR,PLOVER_GENERAL_ERROR_FAILED,

	  "Internal error (missing wizard)");

	plover_transaction_helper_set_error(helper,error,

	  "Can't start installer");

	g_error_free(error);

	return helper;

    }

    else

	g_object_ref(helper->assistant);

    if (!GTK_IS_ASSISTANT(helper->assistant))

    {

	g_critical("\"SoftwareInstallation\" is not a GtkAssistant");

	g_set_error(&error,PLOVER_GENERAL_ERROR,PLOVER_GENERAL_ERROR_FAILED,

	  "Internal error (unexpected wizard type)");

	plover_transaction_helper_set_error(helper,error,

	  "Can't start installer");

	g_error_free(error);

	return helper;

    }

    g_signal_connect(helper->assistant,"cancel",

      G_CALLBACK(plover_transaction_helper_assistant_cancel),helper);

    g_signal_connect(helper->assistant,"close",

      G_CALLBACK(plover_transaction_helper_assistant_close),helper);

    g_signal_connect(helper->assistant,"prepare",

      G_CALLBACK(plover_transaction_helper_assistant_prepare),helper);

    w=GTK_WIDGET(gtk_builder_get_object(helper->ui,"SIRemoveExisting"));

    if (w)

	g_signal_connect(w,"toggled",

	  G_CALLBACK(plover_transaction_helper_remove_existing_toggled),helper);

    w=GTK_WIDGET(gtk_builder_get_object(helper->ui,"SIIntroduction"));

    if (w)

	gtk_assistant_set_page_complete(helper->assistant,w,TRUE);

    return helper;

}

PloverPackageSet *

  plover_transaction_helper_get_installed(PloverTransactionHelper *helper)

{

    gchar *s,*saved_database_uri;

    char *install_root,*local_database,*active_database,*alternate_database;

    const char *prefix;

    struct comps *comps;

    PloverPackageSet *alternate_installed,*installed;

    GError *error=NULL;

    struct razor_error *razor_error=NULL;

    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);

    if (!helper->installed)

    {

	comps=plover_transaction_helper_get_comps(helper,NULL);

	if (!comps)

	{

	    g_warning("plover_transaction_helper_get_installed: No comps");

	    return NULL;

	}

	install_root=getenv("RAZOR_ROOT");

	if (!install_root)

	    install_root="file:/";

	prefix=plover_transaction_helper_get_prefix(helper,NULL);

	if (prefix)

	{

	    s=g_strconcat(prefix,"/var/lib/razor",NULL);

	    local_database=razor_path_relative_to_uri(install_root,*s=='/'?s+1:s,

	      &razor_error);

	    g_free(s);

	    if (!local_database)

	    {

		g_warning("plover_transaction_helper_get_installed: %s",

		  razor_error_get_msg(razor_error));

		razor_error_free(razor_error);

		return NULL;

	    }

	}

	else

	    local_database=NULL;

	switch(comps->database)

	{

	    case COMPS_DATABASE_DISTRIBUTION_LOCAL:

		active_database=local_database;

		alternate_database=NULL;

		break;

	    case COMPS_DATABASE_GLOBAL:

		active_database=NULL;

		alternate_database=local_database;

		break;

	}

	saved_database_uri=g_strdup(razor_get_database_uri());

	if (prefix)

	{

	    razor_set_database_uri(alternate_database);

	    alternate_installed=plover_package_set_new();

	    if (!plover_package_set_open(alternate_installed,install_root,TRUE,

	      &error))

	    {

		g_object_unref(alternate_installed);

		g_warning("plover_transaction_helper_get_installed: %s",

		  error->message);

		g_error_free(error);

		free(local_database);

		razor_set_database_uri(saved_database_uri);

		g_free(saved_database_uri);

		return NULL;

	    }

	}

	else

	    alternate_installed=NULL;

	razor_set_database_uri(active_database);

	free(local_database);

	installed=plover_package_set_new();

	if (plover_package_set_open(installed,install_root,TRUE,&error))

	{

	    helper->alternate_installed=alternate_installed;

	    helper->installed=installed;

	}

	else

	{

	    g_object_unref(installed);

	    if (alternate_installed)

		g_object_unref(alternate_installed);

	    g_warning("plover_transaction_helper_get_installed: %s",error->message);

	    g_error_free(error);

	}

	razor_set_database_uri(saved_database_uri);

	g_free(saved_database_uri);

    }

    return helper->installed;

}

void plover_transaction_helper_set_installed(PloverTransactionHelper *helper,

  PloverPackageSet *installed)

{

    g_return_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper));

    g_return_if_fail(PLOVER_IS_PACKAGE_SET(installed));

    g_return_if_fail(helper->installed == NULL);

    g_clear_object(&helper->alternate_installed);

    helper->installed=g_object_ref(installed);

}

PloverRepository *

  plover_transaction_helper_get_upstream(PloverTransactionHelper *helper,

  GError **error)

{

    const char *base;

    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);

    if (!helper->upstream)

    {

	base=plover_transaction_helper_get_base(helper);

	helper->upstream=plover_repository_new_from_yum(base,error);

    }

    return helper->upstream;

}

void plover_transaction_helper_set_upstream(PloverTransactionHelper *helper,

  PloverRepository *upstream)

{

    g_return_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper));

    g_return_if_fail(PLOVER_IS_REPOSITORY(upstream));

    g_return_if_fail(helper->upstream == NULL);

    helper->upstream=g_object_ref(upstream);

}

const char *plover_transaction_helper_get_base(PloverTransactionHelper *helper)

{

    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);

    return helper->base;

}

void plover_transaction_helper_set_base(PloverTransactionHelper *helper,

  const char *base)

{

    g_return_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper));

    g_return_if_fail(helper->transactions == NULL);

    g_free(helper->base);

    helper->base=g_strdup(base);

}

struct comps *

  plover_transaction_helper_get_comps(PloverTransactionHelper *helper,

  GError **error)

{

    gchar *s;

    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);

    if (!helper->comps && helper->base)

    {

	s=g_strconcat(helper->base,"/repodata/comps.xml",NULL);

	helper->comps=plover_comps_new_from_file(s);

	if (!helper->comps)

	    g_set_error(error,PLOVER_GENERAL_ERROR,

	      PLOVER_GENERAL_ERROR_FAILED,"%s: %s",s,g_strerror(errno));

	g_free(s);

    }

    return helper->comps;

}

const char *

  plover_transaction_helper_get_prefix(PloverTransactionHelper *helper,

  GError **error)

{

    const char *prefix;

    struct comps *comps;

    PloverTransactionHelperPrivate *priv;

    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);

    g_return_val_if_fail(helper->base != NULL || plover_transaction_helper_get_installed(helper) != NULL,NULL);

    priv=PLOVER_TRANSACTION_HELPER_GET_PRIVATE(helper);

    if (helper->base)

    {

	comps=plover_transaction_helper_get_comps(helper,error);

	if (!comps)

	    return NULL;

	g_free(priv->default_prefix);

	priv->default_prefix=plover_comps_get_default_prefix(comps);

	return priv->default_prefix;

    }

    prefix=plover_package_set_guess_prefix(helper->installed,error);

    return prefix;

}

#if 0

static int plover_transaction_helper_package_count(void)

{

    int count=0;

    char *install_root;

    struct razor_set *set;

    struct razor_package *package;

    struct razor_package_iterator *pi;

    install_root=getenv("RAZOR_ROOT");

    if (!install_root)

	install_root="";

    set=razor_root_open_read_only(install_root,NULL);

    if (set)

    {

	pi=razor_package_iterator_create(set);

	while (razor_package_iterator_next(pi,&package,RAZOR_DETAIL_LAST))

	    count++;

	razor_package_iterator_destroy(pi);

	razor_set_unref(set);

    }

    return count;

}

#endif

static gboolean prefix_clashes(const char *prefix,const char *alt)

{

    return g_str_has_prefix(prefix,alt) &&

      (prefix[strlen(alt)]=='\0' || prefix[strlen(alt)]=='/');

}

static void

  plover_transaction_helper_update_summary_page(PloverTransactionHelper *helper,

  GError **error)

{

    int i,remove_count=0;

    gboolean alternate_database_clashes=FALSE;

    gboolean active_database_is_incompatible=FALSE;

    char *local_database,*active_database,*alternate_database;

    const char *alternate_prefix;

    gchar *prefix=NULL,*s;

    struct comps *comps=NULL;

    GtkWidget *container,*summary,*page;

    GtkButton *button;

    GtkLabel *label;

    g_return_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper));

    comps=plover_transaction_helper_get_comps(helper,error);

    if (comps)

	prefix=plover_comps_get_default_prefix(comps);

    else

	prefix=NULL;

    button=GTK_BUTTON(gtk_builder_get_object(helper->ui,"SIRemoveExisting"));

    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(button),FALSE);

    container=GTK_WIDGET(gtk_builder_get_object(helper->ui,

      "SIIncompatibleInstallation"));

    summary=GTK_WIDGET(gtk_builder_get_object(helper->ui,"SISummaryOfWork"));

    page=GTK_WIDGET(gtk_builder_get_object(helper->ui,"SIConfirm"));

    if (helper->check_vendor && prefix && helper->alternate_installed)

    {

	alternate_prefix=

	  plover_package_set_guess_prefix(helper->alternate_installed,NULL);

	if (alternate_prefix && prefix_clashes(prefix,alternate_prefix))

	{

	    alternate_database_clashes=TRUE;

	    remove_count=g_slist_length(

	      plover_package_set_get_packages(helper->alternate_installed));

	}

    }

    /*

     * Rather than try to be too clever, we only deal with one thing

     * at a time. That means that if the alternate database clashes

     * there's no point checking if the active database is compatible.

     */

    if (!alternate_database_clashes)

    {

	if (helper->check_vendor && prefix &&

	  !plover_package_set_files_match_prefix(helper->installed,prefix))

	{

	    active_database_is_incompatible=TRUE;

	    remove_count=

	      g_slist_length(plover_package_set_get_packages(helper->installed));

	}

    }

    if (alternate_database_clashes || active_database_is_incompatible)

    {

	g_assert(comps!=NULL);

	label=GTK_LABEL(gtk_builder_get_object(helper->ui,

	  "SIIncompatibleInstallationLabel"));

	if (alternate_database_clashes)

	    s=g_strdup_printf("<b>Incompatible Installation</b>\n\n"

	      "There is an existing installation under %s\n"

	      "which is not compatible with this distribution. In order\n"

	      "to continue, the existing installation must be uninstalled.",

	      comps->vendor);

	else /* active_database_is_incompatible */

	    s=g_strdup_printf("<b>Incompatible Installation</b>\n\n"

	      "The existing installation is not from %s.\n In order "

	      "to continue, all the existing packages must be removed.",

	      comps->vendor);

	gtk_label_set_markup(label,s);

	g_free(s);

	s=g_strdup_printf("Remove %d existing package%s",remove_count,

	  remove_count==1?"":"s");

	gtk_button_set_label(button,s);

	g_free(s);

	gtk_widget_show(container);

	gtk_widget_hide(summary);

	if (helper->assistant)

	    gtk_assistant_set_page_complete(helper->assistant,page,FALSE);

    }

    else

    {

	gtk_widget_hide(container);

	gtk_widget_show(summary);

	if (helper->assistant)

	    gtk_assistant_set_page_complete(helper->assistant,page,TRUE);

    }

    g_free(prefix);

}

void plover_transaction_helper_set_check_vendor(PloverTransactionHelper *helper,

  gboolean check_vendor)

{

    g_return_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper));

    if (helper->check_vendor!=check_vendor)

    {

	helper->check_vendor=check_vendor;

	if (helper->transactions)

	    plover_transaction_helper_update_summary_page(helper,NULL);

    }

}

/*

 * If plover_transaction_helper_add_transaction() fails with an error

 * of PLOVER_GENERAL_ERROR,PLOVER_GENERAL_ERROR_REQUIREMENTS_NOT_MET

 * then plover_transaction_helper_get_unsatisfied() can be used to

 * retrieve a textual description of the problem.

 */

const char *

  plover_transaction_helper_get_unsatisfied(PloverTransactionHelper *helper)

{

    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);

    return helper->unsatisfied;

}

#define PLOVER_TRANSACTION_HELPER_IS_VALID_REPORT_ACTION(action) \

  ((action)==PLOVER_TRANSACTION_HELPER_REPORT_INSTALL || \

  (action)==PLOVER_TRANSACTION_HELPER_REPORT_REMOVE || \

  (action)==PLOVER_TRANSACTION_HELPER_REPORT_UPDATE)

gboolean

  plover_transaction_helper_add_transaction(PloverTransactionHelper *helper,

  PloverTransaction *transaction,struct plover_vector *report_packages,

  PloverTransactionHelperReportAction report_action,GError **error)

{

    int i,count;

    gboolean other_packages;

    const char *s,*name;

    enum razor_install_action action;

    struct razor_install_iterator *ii;

    struct razor_set *report_set;

    struct razor_package *package;

    struct plover_vector *tasked_packages;

    PloverTransactionHelperPrivate *priv;

    GtkWidget *w;

    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),FALSE);

    g_return_val_if_fail(PLOVER_IS_TRANSACTION(transaction),FALSE);

    g_return_val_if_fail(PLOVER_TRANSACTION_HELPER_IS_VALID_REPORT_ACTION(report_action),FALSE);

    g_return_val_if_fail(plover_transaction_get_system_set(transaction)!=NULL,FALSE);

    priv=PLOVER_TRANSACTION_HELPER_GET_PRIVATE(helper);

    g_free(helper->unsatisfied);

    helper->unsatisfied=NULL;

    if (!plover_transaction_resolve(transaction,error))

    {

	s=plover_transaction_get_unsatisfied(transaction);

	helper->unsatisfied=g_strdup(s);

	return FALSE;

    }

    ii=plover_transaction_get_install_iterator(transaction,error);

    if (!ii)

	return FALSE;

    if (report_action==PLOVER_TRANSACTION_HELPER_REPORT_REMOVE)

	report_set=plover_transaction_get_system_set(transaction);

    else

	report_set=plover_transaction_get_next_set(transaction,error);

    if (!report_set)

	return FALSE;

    tasked_packages=plover_vector_new();

    other_packages=FALSE;

    while (razor_install_iterator_next(ii,&package,&action,&count))

    {

	if (action==report_action || action==RAZOR_INSTALL_ACTION_ADD &&

	  report_action==PLOVER_TRANSACTION_HELPER_REPORT_UPDATE)

	{

	    razor_package_get_details(report_set,package,RAZOR_DETAIL_NAME,

	      &name,RAZOR_DETAIL_LAST);

	    if (!report_packages ||

	      plover_vector_contains(report_packages,name))

		plover_vector_append(tasked_packages,name);

	    else

		other_packages=TRUE;

	}

    }

    if (!tasked_packages->len)

    {

	/*

	 * If there are no reportable packages tasked for action there

	 * shouldn't by any packages at all, but let's be paranoid.

	 */

	other_packages=FALSE;

	razor_install_iterator_rewind(ii);

	while (razor_install_iterator_next(ii,&package,&action,&count))

	{

	    if (action==report_action)

	    {

		razor_package_get_details(report_set,package,RAZOR_DETAIL_NAME,

		  &name,RAZOR_DETAIL_LAST);

		plover_vector_append(tasked_packages,name);

	    }

	}

    }

    if (!tasked_packages->len)

    {

	g_set_error(error,PLOVER_GENERAL_ERROR,

	  PLOVER_GENERAL_ERROR_NO_WORK,"Transaction includes no %s actions",

	  report_action==PLOVER_TRANSACTION_HELPER_REPORT_REMOVE?

	  "remove":"add");

	plover_vector_free(tasked_packages);

	return FALSE;

    }

    if (!helper->transactions)

	plover_transaction_helper_update_summary_page(helper,error);

    g_object_ref(transaction);

    helper->transactions=g_slist_append(helper->transactions,transaction);

    if (report_action==PLOVER_TRANSACTION_HELPER_REPORT_REMOVE)

    {

	priv->transaction_type|=TRANSACTION_TYPE_REMOVE;

	for(i=0;i<tasked_packages->len;i++)

	{

	    s=tasked_packages->strings[i];

	    if (!plover_vector_contains(helper->report_removing,s))

		plover_vector_append(helper->report_removing,s);

	}

	helper->report_removing_dependants|=other_packages;

    }

    else

    {

	if (report_action==PLOVER_TRANSACTION_HELPER_REPORT_UPDATE)

	    priv->transaction_type|=TRANSACTION_TYPE_REMOVE;

	priv->transaction_type|=TRANSACTION_TYPE_INSTALL;

	for(i=0;i<tasked_packages->len;i++)

	{

	    s=tasked_packages->strings[i];

	    if (!plover_vector_contains(helper->report_adding,s))

		plover_vector_append(helper->report_adding,s);

	}

	helper->report_adding_dependencies|=other_packages;

    }

    w=GTK_WIDGET(gtk_builder_get_object(helper->ui,"SIProgressLabel"));

    switch(priv->transaction_type)

    {

	case TRANSACTION_TYPE_INSTALL:

	    gtk_label_set_markup(GTK_LABEL(w),

	      "<b>Installing the Software</b>\n\n"

	      "Please wait while the Installation Assistant "

	      "installs the software.\n"

	      "This may take several minutes.");

	    break;

	case TRANSACTION_TYPE_REMOVE:

	    gtk_label_set_markup(GTK_LABEL(w),

	      "<b>Removing Packages</b>\n\n"

	      "Please wait while the Installation Assistant "

	      "removes packages.\n"

	      "This may take several minutes.");

	    break;

	default:

	case TRANSACTION_TYPE_UPDATE:

	    gtk_label_set_markup(GTK_LABEL(w),

	      "<b>Updating the Software</b>\n\n"

	      "Please wait while the Installation Assistant "

	      "updates the software.\n"

	      "This may take several minutes.");

	    break;

    }

    plover_vector_free(tasked_packages);

    return TRUE;

}

static PloverTransaction *

  plover_transaction_helper_new_transaction(PloverTransactionHelper *helper,

  GError **error)

{

    gboolean ok;

    const char *base,*prefix;

    GError *tmp_error=NULL;

    PloverTransaction *transaction;

    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);

    g_return_val_if_fail(plover_transaction_helper_get_installed(helper) != NULL,NULL);

    prefix=plover_transaction_helper_get_prefix(helper,&tmp_error);

    if (tmp_error)

    {

	g_propagate_error(error,tmp_error);

	return NULL;

    }

    transaction=plover_transaction_new();

    plover_transaction_set_prefix(transaction,prefix);

    plover_transaction_set_installed(transaction,helper->installed);

    if (helper->upstream)

	ok=plover_transaction_set_upstream(transaction,helper->upstream,error);

    else

    {

	base=plover_transaction_helper_get_base(helper);

	ok=plover_transaction_set_upstream_from_yum(transaction,base,error);

    }

    if (!ok)

    {

	g_object_unref(transaction);

	transaction=NULL;

    }

    return transaction;

}

struct plover_vector *plover_transaction_helper_group_get_default_packages(

  PloverTransactionHelper *helper,const char *group,GError **error)

{

    gboolean changed;

    struct comps *comps;

    struct comps_group *grp;

    struct comps_requirement *pkg;

    struct plover_vector *default_packages;

    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),FALSE);

    comps=plover_transaction_helper_get_comps(helper,error);

    if (!comps)

	return NULL;