/* Licensed to Stichting The Commons Conservancy (TCC) under one or more
 * contributor license agreements.  See the AUTHORS file distributed with
 * this work for additional information regarding copyright ownership.
 * TCC licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#include <gtk/gtk.h>
#include <gio/gunixinputstream.h>
#include <gio/gunixoutputstream.h>
#include <json-glib/json-glib.h>

#include "signtext.h"
#include "crypto.h"
#include "message.h"
#include "config.h"

void
message_cancel(SignTextData *signtext)
{
  const char *uuid = adw_view_stack_get_visible_child_name(signtext->stack);

  SignTextInstance *instance = g_object_get_data(G_OBJECT (signtext->stack), uuid);

  if (instance) {

    /*
     * Send an error to show we cancelled.
     */
    message_send_error(instance, "error:userCancel");

    signtext_instance_free(instance);

  }

}


/*
 * After receiving a parsed JSON message read from stdin, we end up here in the main UI
 * thread.
 *
 * Parse the message, and create or update the UI pages in the stacks for each message we
 * receive.
 */
static void
message_receive_done (GObject *source_object,
                      GAsyncResult *res,
                      gpointer user_data)
{
  SignTextData *signtext = user_data;
  SignTextInstance *instance;
  GError *gerror = NULL;
  JsonParser *parser = NULL;

#if 0
  g_printerr("message_receive_done\n");
#endif

  parser = g_task_propagate_pointer (G_TASK (res), &gerror);

  if (parser) {

    GUri *uri;
    JsonObject *message;
    JsonNode *request;
    const gchar *url, *uuid;
    gint64 id;

    /* parse the message */
    JsonNode *root = json_parser_get_root (parser);
    json_node_seal(root);

    message = json_node_get_object(root);
    if (!message) {
      gerror = g_error_new(RST_CORE_ERROR, RST_CORE_ERROR_MISSING_ROOT, "JSON payload was empty.");
      goto fatal;
    }

    url = json_object_get_string_member(message, "url");
    if (!url) {
      gerror = g_error_new(RST_CORE_ERROR, RST_CORE_ERROR_MISSING_URL, "JSON payload has missing 'url'.");
      goto fatal;
    }

    uri = g_uri_parse(url, G_URI_FLAGS_NONE, &gerror);
    if (!uri) {
      gerror = g_error_new(RST_CORE_ERROR, RST_CORE_ERROR_URL_INVALID, "JSON payload has invalid 'url'.");
      goto fatal;
    }

    uuid = json_object_get_string_member(message, "uuid");
    if (!uuid) {
      gerror = g_error_new(RST_CORE_ERROR, RST_CORE_ERROR_MISSING_UUID, "JSON payload has missing 'uuid'.");
      goto fatal;
    }

    id = json_object_get_int_member(message, "id");
    if (!id) {
      gerror = g_error_new(RST_CORE_ERROR, RST_CORE_ERROR_MISSING_ID, "JSON payload has missing/invalid/zero 'id'.");
      goto fatal;
    }

    request = json_object_get_member(message, "request");
    if (!request) {
      gerror = g_error_new(RST_CORE_ERROR, RST_CORE_ERROR_MISSING_REQUEST, "JSON payload has missing 'request'.");
      goto fatal;
    }

    instance = g_object_get_data(G_OBJECT (signtext->stack), uuid);

    if (instance) {

    }
    else {
      instance = signtext_instance_new(signtext, id, uuid, uri);

//      instance->box = GTK_LIST_BOX(gtk_list_box_new());
//      gtk_widget_set_vexpand (GTK_WIDGET(instance->box), 1);

//      g_object_set_data_full(G_OBJECT (signtext->stack), instance->uuid, instance, (GDestroyNotify)signtext_instance_free);

//      adw_view_stack_add_titled(signtext->stack, GTK_WIDGET (instance->page), instance->uuid, g_uri_get_host(instance->uri));

//      instance->stack = signtext->stack;

    }

    /*
     * Process request.
     *
     * A string request is a data payload, append it to existing text buffer and
     * send back an ACK.
     */
    if (json_node_get_value_type(request) == G_TYPE_STRING) {

      GtkTextIter end;

      gtk_text_buffer_get_end_iter(instance->buffer, &end);
      gtk_text_buffer_insert(instance->buffer, &end, json_node_get_string(request), -1);

      /*
       * A response with a value of TRUE means ACK, send us the next bit of data.
       */
      message_send_boolean_response(instance, TRUE);

    }

    /*
     * An object request means the data is done and we're ready to let the end user
     * see the UI.
     *
     * Make the UI visible.
     */
    else if (json_node_get_node_type(request) == JSON_NODE_OBJECT) {

        GListStore *certificates;

        JsonArray *cas = json_object_get_array_member(json_node_get_object(request), "CAs");

        if (cas) {
            guint len = json_array_get_length(cas);
            guint i;

            for (i = 0; i < len; i++) {
                const gchar *ca = json_array_get_string_element(cas, i);

                crypto_instance_append_ca(instance, ca, &gerror);
            }

        }

#if 0
        /* port to gtk4 */
        certificates = crypto_filter(instance, signtext->certificates);
#endif

        certificates = signtext->certificates;

        crypto_instance_start(instance, certificates);
 
        gtk_widget_set_visible (GTK_WIDGET(signtext->window), 1);
        gtk_window_present(GTK_WINDOW(signtext->window));
        gtk_widget_set_visible(GTK_WIDGET(instance->progress), FALSE);

    }

    /*
     * A boolean request is an ack/nak.
     */
    else if (json_node_get_value_type(request) == G_TYPE_BOOLEAN) {

      if (json_node_get_boolean(request)) {

        /* ack, send the next bit */
        crypto_sign_continue(instance);

      }
      else {

        /* nak, close everything down */
        signtext_instance_free(instance);

      }
    }

    /*
     * Anything else is an error.
     */
    else {
      gerror = g_error_new(RST_CORE_ERROR, RST_CORE_ERROR_REQUEST_NOT_RECOGNISED, "JSON payload 'request' is not recognised.");
      goto fatal;
    }

    g_object_unref(parser);

  }

  if (gerror) {

    AdwDialog* dialog;
 
fatal:
 
    dialog = adw_alert_dialog_new ("Redwax SignText - Error", NULL);
    adw_alert_dialog_format_body (ADW_ALERT_DIALOG (dialog),
                                           ("Error: %s"),
                                           gerror->message);

    adw_alert_dialog_add_response(ADW_ALERT_DIALOG (dialog), "Ok", "Ok");

    adw_dialog_present (dialog, instance->signtext->window);

    g_error_free (gerror);
  }

}

static void
message_receive_do (GTask *task,
               gpointer source_obj,
               gpointer task_data,
               GCancellable *cancellable)
{
  JsonParser *parser = NULL;
  GError *gerror = NULL;
  gchar *buf = NULL;
  GInputStream *stream = NULL;

  guint32 size;
  gsize count;

#if 0
  g_printerr("message_receive_do\n");
#endif

  stream = g_unix_input_stream_new (STDIN_FILENO, FALSE);

  if (!g_input_stream_read_all(stream, (gchar *)(&size), sizeof(size), &count, cancellable, &gerror)) {

    g_printerr("message_receive_do: read size failed\n");
    goto done;
  }

  buf = g_malloc(size);

  if (!buf) {

    g_printerr("message_receive_do: allocation failed\n");
    goto done;
  }

  if (!g_input_stream_read_all(stream, buf, size, &count, cancellable, &gerror)) {

    g_printerr("message_receive_do: read message failed\n");
    goto done;
  }

  parser = json_parser_new();

  if (!json_parser_load_from_data(parser, buf, size, &gerror)) {

    //g_main_loop_quit()

    g_printerr("message_receive_do: parse json failed\n");

    // handle error
    goto done;
  }

#if 0
  g_printerr("Payload received: %.*s\n", (int)size, buf);
#endif

  g_task_return_pointer(task, g_object_ref(parser), g_object_unref);

done:
  if (buf) {
    g_free(buf);
  }
  if (parser) {
    g_object_unref(parser);
  }
  if (stream) {
    g_object_unref(stream);
  }

  if (gerror) {
    g_task_return_error (task, gerror);
  }

  return;
}

/*
 * In the main UI thread, we want to receive a single JSON message on stdin.
 *
 * Spawn a GTask to make this happen in a seperate thread, and return immediately. We
 * will eventually do the work in message_receive_do() in a sub-thread, and then we will
 * eventually process the result in message_receive_done() in the UI thread, at which
 * point we will update our UI and if necessary, handle any errors.
 */
void
message_receive(SignTextData *signtext)
{
  GTask *task = g_task_new (signtext->window, signtext->cancellable, message_receive_done, signtext);
  g_task_run_in_thread (task, message_receive_do);
  g_object_unref (task);
}

static void
message_send_done (GObject *source_object,
                      GAsyncResult *res,
                      gpointer user_data)
{
  SignTextData *signtext = user_data;
  GError *gerror = NULL;

#if 0
  g_printerr("message_send_done\n");
#endif

  g_task_propagate_boolean (G_TASK (res), &gerror);

  if (gerror) {

    AdwDialog* dialog;    
 
    dialog = adw_alert_dialog_new ("Redwax SignText - Error", NULL);
    adw_alert_dialog_format_body (ADW_ALERT_DIALOG (dialog),
                                           ("Error: %s"),
                                           gerror->message);
  
    adw_dialog_present (dialog, signtext->window);

    g_error_free (gerror);

  }
  else {

    message_receive(signtext);
  }
}

static void
message_send_do (GTask *task,
               gpointer source_obj,
               gpointer task_data,
               GCancellable *cancellable)
{
  JsonNode *root = task_data;
  JsonGenerator *generator = NULL;
  GError *gerror = NULL;
  gchar *buf = NULL;
  GOutputStream *stream = NULL;

  guint32 size;
  gsize count;

#if 0
  g_printerr("message_send_do\n");
#endif

  generator = json_generator_new();

  json_generator_set_root(generator, root);

  stream = g_unix_output_stream_new (STDOUT_FILENO, FALSE);

  buf = json_generator_to_data(generator, &count);
  size = count;

  if (!g_output_stream_write_all(stream, (gchar *)(&size), sizeof(size), &count, cancellable, &gerror)) {

    g_printerr("message_send_do: write message size failed\n");
    goto done;
  }

  if (!g_output_stream_write_all(stream, buf, size, &count, cancellable, &gerror)) {

    g_printerr("message_send_do: write message content failed\n");
    goto done;
  }

#if 0
  g_printerr("Payload sent: %.*s\n", (int)size, buf);
#endif

done:
  if (buf) {
    g_free(buf);
  }
  if (generator) {
    g_object_unref(generator);
  }
  if (stream) {
    g_object_unref(stream);
  }

  if (gerror) {
    g_task_return_error (task, gerror);
  }
  else {
    g_task_return_boolean(task, TRUE);
  }

  return;
}

/*
 * In the main UI thread, we want to send a single JSON message on stdout.
 *
 * Spawn a GTask to make this happen in a separate thread, and return immediately. We
 * will eventually do the work of sending the message in message_send_do() in a
 * sub-thread, and then we will eventually receive either success or an error in the
 * main thread in message_send_done().
 *
 * At this point the loop is completed by repeating the request to receive the next
 * single JSON message on stdin.
 *
 * The JsonNode is freed at the end of the task.
 */
static void
message_send(SignTextData *signtext, JsonNode *root)
{
  GTask *task = g_task_new (signtext->window, signtext->cancellable, message_send_done, signtext);
  g_task_set_task_data (task, root, (GDestroyNotify)json_node_free);
  g_task_run_in_thread (task, message_send_do);
  g_object_unref (task);
}

void
message_send_error(SignTextInstance *instance, gchar *error)
{
  JsonBuilder *builder;
  JsonNode *root;

  builder = json_builder_new_immutable();
  json_builder_begin_object(builder);
  json_builder_set_member_name(builder, "uuid");
  json_builder_add_string_value(builder, instance->uuid);
  json_builder_set_member_name(builder, "id");
  json_builder_add_int_value(builder, instance->id);
  json_builder_set_member_name(builder, "error");
  json_builder_add_string_value(builder, "error:userCancel");
  json_builder_end_object(builder);

  root = json_builder_get_root(builder);

  message_send(instance->signtext, root);

  g_object_unref(builder);
}

void
message_send_boolean_response(SignTextInstance *instance, gboolean response)
{
  JsonBuilder *builder;
  JsonNode *root;

  builder = json_builder_new_immutable();
  json_builder_begin_object(builder);
  json_builder_set_member_name(builder, "uuid");
  json_builder_add_string_value(builder, instance->uuid);
  json_builder_set_member_name(builder, "id");
  json_builder_add_int_value(builder, instance->id);
  json_builder_set_member_name(builder, "response");
  json_builder_add_boolean_value(builder, response);
  json_builder_end_object(builder);

  root = json_builder_get_root(builder);

  message_send(instance->signtext, root);

  g_object_unref(builder);
}

void
message_send_string_response(SignTextInstance *instance, gchar *response)
{
  JsonBuilder *builder;
  JsonNode *root;

  builder = json_builder_new_immutable();
  json_builder_begin_object(builder);
  json_builder_set_member_name(builder, "uuid");
  json_builder_add_string_value(builder, instance->uuid);
  json_builder_set_member_name(builder, "id");
  json_builder_add_int_value(builder, instance->id);
  json_builder_set_member_name(builder, "response");
  json_builder_add_string_value(builder, response);
  json_builder_end_object(builder);

  root = json_builder_get_root(builder);

  message_send(instance->signtext, root);

  g_object_unref(builder);
}