/*
 * Yorkie - A task-oriented GnuPG frontend
 * Copyright (C) 2020 Damien Goutte-Gattat
 *
 * 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>
#endif

#include "encrypt.h"

#include <glib.h>
#include <gtk/gtk.h>

#include <gpgme.h>

#include "error.h"
#include "gpgutil.h"
#include "util.h"



/* Context structure and associated functions. */

typedef struct {
    gpgme_ctx_t     gpgme;

    GtkListStore   *public_keys;
    unsigned        selected_keys;

    gboolean        symmetric;
    gboolean        sign;
    gboolean        detached;
    gboolean        armored;

    const char     *original_filename;
    char           *output_filename;
    char           *output_basename;
    gboolean        output_filename_userset;

    GtkWidget      *ok_button;
    GtkWidget      *detached_button;
    GtkWidget      *output_button;
} yki_encrypt_data_t;

static void
set_default_output_filename(yki_encrypt_data_t *yki, const char *original)
{
    if ( yki->output_filename_userset )
        return;

    if ( original )
        yki->original_filename = original;

    g_free(yki->output_filename);
    g_free(yki->output_basename);
    yki->output_filename = g_strdup_printf("%s.%s", yki->original_filename, yki->armored ? "asc" : "gpg");
    yki->output_basename = g_path_get_basename(yki->output_filename);

    gtk_button_set_label(GTK_BUTTON(yki->output_button), yki->output_basename);
}



/* GUI stuff. */

static void
update_buttons(yki_encrypt_data_t *yki)
{
    gtk_widget_set_sensitive(yki->ok_button,
            yki->symmetric ||
            yki->selected_keys ||
            yki->sign);

    gtk_widget_set_sensitive(yki->detached_button,
            yki->sign &&
            ! ( yki->symmetric || yki->selected_keys));
}

static void
symmetric_encrypt_toggled(GtkWidget *widget, gpointer data)
{
    ((yki_encrypt_data_t *)data)->symmetric = gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(widget));
    update_buttons((yki_encrypt_data_t *)data);
}

static void
sign_toggled(GtkWidget *widget, gpointer data)
{
    ((yki_encrypt_data_t *)data)->sign = gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(widget));
    update_buttons((yki_encrypt_data_t *)data);
}

static void
detach_sign_toggled(GtkWidget *widget, gpointer data)
{
    ((yki_encrypt_data_t *)data)->detached = gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(widget));
}

static void
armored_toggled(GtkWidget *widget, gpointer data)
{
    ((yki_encrypt_data_t *)data)->armored = gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(widget));
    set_default_output_filename((yki_encrypt_data_t *)data, NULL);
}

static void
public_key_toggled(GtkCellRendererToggle   *renderer,
                   gchar                   *path,
                   gpointer                 data)
{
    yki_encrypt_data_t *yki = (yki_encrypt_data_t *)data;
    GtkTreeIter iter;
    gboolean selected;

    gtk_tree_model_get_iter_from_string(GTK_TREE_MODEL(yki->public_keys), &iter, path);
    gtk_tree_model_get(GTK_TREE_MODEL(yki->public_keys), &iter, 0, &selected, -1);

    selected = !selected;
    yki->selected_keys += selected ? 1 : -1;

    gtk_list_store_set(GTK_LIST_STORE(yki->public_keys), &iter, 0, selected, -1);

    update_buttons(yki);
}

static void
output_clicked(GtkButton *button, gpointer data)
{
    yki_encrypt_data_t *yki = (yki_encrypt_data_t *)data;
    GtkWidget *dlg;

    dlg = gtk_file_chooser_dialog_new("Save as",
                                      NULL,
                                      GTK_FILE_CHOOSER_ACTION_SAVE,
                                      "_Cancel", GTK_RESPONSE_CANCEL,
                                      "_OK", GTK_RESPONSE_ACCEPT,
                                      NULL);
    gtk_file_chooser_set_filename(GTK_FILE_CHOOSER(dlg), yki->output_filename);
    gtk_file_chooser_set_current_name(GTK_FILE_CHOOSER(dlg), yki->output_basename);
    gtk_file_chooser_set_do_overwrite_confirmation(GTK_FILE_CHOOSER(dlg), TRUE);

    if ( gtk_dialog_run(GTK_DIALOG(dlg)) == GTK_RESPONSE_ACCEPT ) {
        g_free(yki->output_filename);
        g_free(yki->output_basename);
        yki->output_filename = gtk_file_chooser_get_filename(GTK_FILE_CHOOSER(dlg));
        yki->output_filename_userset = TRUE;
        yki->output_basename = g_path_get_basename(yki->output_filename);
        gtk_button_set_label(GTK_BUTTON(yki->output_button), yki->output_basename);
    }

    gtk_widget_destroy(dlg);
}

static gboolean
public_key_search(GtkTreeModel *model,
                  gint          column,
                  const gchar  *pattern,
                  GtkTreeIter  *iter,
                  gpointer      data)
{
    gchar *uid;

    gtk_tree_model_get(model, iter, 1, &uid, -1);
    return g_strstr_len(uid, -1, pattern) ? FALSE : TRUE;
}

static GtkDialog *
create_encrypt_dialog(yki_encrypt_data_t *yki)
{
    GtkBuilder *builder;
    GObject *widget;
    GtkCellRenderer *renderer;
    GtkTreeViewColumn *column;

    builder = gtk_builder_new_from_resource("/org/incenp/Yorkie/yki-encrypt.ui");

    g_signal_connect(gtk_builder_get_object(builder, "chkSymEncrypt"),
                     "clicked", G_CALLBACK(symmetric_encrypt_toggled), yki);
    g_signal_connect(gtk_builder_get_object(builder, "chkSign"),
                     "clicked", G_CALLBACK(sign_toggled), yki);
    g_signal_connect(gtk_builder_get_object(builder, "chkDetachSign"),
                     "clicked", G_CALLBACK(detach_sign_toggled), yki);
    g_signal_connect(gtk_builder_get_object(builder, "chkArmor"),
                     "clicked", G_CALLBACK(armored_toggled), yki);
    g_signal_connect(gtk_builder_get_object(builder, "btnOutput"),
                     "clicked", G_CALLBACK(output_clicked), yki);

    widget = gtk_builder_get_object(builder, "trvPublicKeys");
    yki->public_keys = GTK_LIST_STORE(gtk_tree_view_get_model(GTK_TREE_VIEW(widget)));
    gtk_tree_view_set_search_column(GTK_TREE_VIEW(widget), 1);
    gtk_tree_view_set_search_equal_func(GTK_TREE_VIEW(widget), public_key_search, NULL, NULL);

    renderer = gtk_cell_renderer_toggle_new();
    column = gtk_tree_view_column_new_with_attributes("Selected", renderer, "active", 0, NULL);
    gtk_tree_view_append_column(GTK_TREE_VIEW(widget), column);
    g_signal_connect(renderer, "toggled", G_CALLBACK(public_key_toggled), yki);

    renderer = gtk_cell_renderer_text_new();
    column = gtk_tree_view_column_new_with_attributes("User ID", renderer, "text", 1, NULL);
    gtk_tree_view_append_column(GTK_TREE_VIEW(widget), column);

    yki->ok_button = GTK_WIDGET(gtk_builder_get_object(builder, "btnOK"));
    yki->detached_button = GTK_WIDGET(gtk_builder_get_object(builder, "chkDetachSign"));
    yki->output_button = GTK_WIDGET(gtk_builder_get_object(builder, "btnOutput"));

    gtk_button_set_always_show_image(GTK_BUTTON(yki->output_button), TRUE);

    update_buttons(yki);

    return GTK_DIALOG(gtk_builder_get_object(builder, "dlgEncrypt"));
}



/* Dealing with public keys. */

static int
populate_public_key_list(gpgme_ctx_t ctx, GtkListStore *key_list, GError **error)
{
    GtkTreeIter iter;
    gpgme_key_t key;
    gpgme_error_t gerr;

    gerr = gpgme_op_keylist_start(ctx, NULL, 0);
    while ( ! gerr ) {
        gerr = gpgme_op_keylist_next(ctx, &key);
        if ( ! gerr ) {

            if ( key->revoked || key->expired || key->disabled || key->invalid || ! key->can_encrypt )
                continue;

            gtk_list_store_append(key_list, &iter);
            gtk_list_store_set(key_list, &iter,
                               0, FALSE,               /* Selected key? */
                               1, key->uids[0].uid,    /* User ID */
                               2, key,                 /* The key itself */
                               -1);
        }
    }
    if ( gpgme_err_code(gerr) == GPG_ERR_EOF )
        gerr = 0;   /* Normal end of list, not an error condition */

    if ( gerr )
        yki_error_gpgme(error, YKI_ERROR_GPGME_KEYLIST, gerr);

    return gpgme_err_code(gerr) == 0;
}

static gboolean
free_key_in_list(GtkTreeModel *store, GtkTreePath *path, GtkTreeIter *iter, gpointer data)
{
    gpgme_key_t key;

    gtk_tree_model_get(store, iter, 2, &key, -1);
    gpgme_key_release(key);

    return TRUE;
}

static gpgme_key_t *
get_selected_keys(yki_encrypt_data_t *yki)
{
    gpgme_key_t *keys;
    GtkTreeIter iter;
    gboolean loop;
    unsigned i;

    keys = g_malloc((yki->selected_keys + 1) * sizeof(gpgme_key_t));
    loop = gtk_tree_model_get_iter_first(GTK_TREE_MODEL(yki->public_keys), &iter);
    i = 0;

    while ( loop ) {
        gboolean selected;
        gpointer key;

        gtk_tree_model_get(GTK_TREE_MODEL(yki->public_keys), &iter, 0, &selected, 2, &key, -1);
        if ( selected )
            keys[i++] = (gpgme_key_t)key;

        loop = gtk_tree_model_iter_next(GTK_TREE_MODEL(yki->public_keys), &iter);
    }
    keys[i] = NULL;

    return keys;
}



/* Actual encryption or sign operation. */

#define yki_can_encrypt(yki)    ((yki).selected_keys || (yki).symmetric || (yki).sign)

static int
do_encrypt(yki_encrypt_data_t *yki, gpgme_data_t in, gpgme_data_t out, GError **error)
{
    gpgme_error_t gerr = 0;

    if ( yki->symmetric || yki->selected_keys ) {
        gpgme_key_t *keys = get_selected_keys(yki);
        gpgme_encrypt_flags_t flags = yki->symmetric ? GPGME_ENCRYPT_SYMMETRIC : 0;

        if ( yki->sign )
            gerr = gpgme_op_encrypt_sign(yki->gpgme, keys, flags, in, out);
        else
            gerr = gpgme_op_encrypt(yki->gpgme, keys, flags, in, out);

        g_free(keys);
    }
    else if ( yki->sign ) {
        gpgme_sig_mode_t mode = yki->detached ? GPGME_SIG_MODE_DETACH : GPGME_SIG_MODE_NORMAL;

        gerr = gpgme_op_sign(yki->gpgme, in, out, mode);
    }
    else
        g_assert_not_reached();

    if ( gerr )
        yki_error_gpgme(error, YKI_ERROR_GPGME_CRYPTO, gerr);

    return gpgme_err_code(gerr) == 0;
}



/* Public interface. */


int
yki_encrypt(gpgme_ctx_t gpgme, const char *file, GError **error)
{
    yki_encrypt_data_t yki = { 0 };
    gpgutil_file_t in = { 0 }, out = { 0 };
    GtkDialog *dlg;
    int ret;

    g_assert(gpgme && file);

    yki.gpgme = gpgme;

    dlg = create_encrypt_dialog(&yki);
    ret = populate_public_key_list(gpgme, yki.public_keys, error);
    set_default_output_filename(&yki, file);

    if ( ret && gtk_dialog_run(dlg) == GTK_RESPONSE_OK && yki_can_encrypt(yki) ) {
        gpgme_set_armor(gpgme, yki.armored);

        /* Check with user before overwriting a file with the default filename. */
        if ( g_file_test(yki.output_filename, G_FILE_TEST_EXISTS) && ! yki.output_filename_userset )
            ret = yki_confirm_overwrite(yki.output_filename);

        if ( ret )
            ret = gpgutil_open_file(file, "r", &in, error);

        if ( ret )
            ret = gpgutil_open_file(yki.output_filename, "w", &out, error);

        if ( ret )
            ret = do_encrypt(&yki, in.buffer, out.buffer, error);
    }

    gpgutil_close_file(&in, NULL);
    gpgutil_close_file(&out, NULL);

    gtk_tree_model_foreach(GTK_TREE_MODEL(yki.public_keys), free_key_in_list, NULL);
    gtk_widget_destroy(GTK_WIDGET(dlg));

    g_free(yki.output_filename);
    g_free(yki.output_basename);

    return ret;
}