/* bz-backend.c
 *
 * Copyright 2025 Adam Masciola
 *
 * 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 <https://www.gnu.org/licenses/>.
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 */

#include "config.h"

#include "bz-backend.h"
#include "bz-transaction.h"

G_DEFINE_INTERFACE (BzBackend, bz_backend, G_TYPE_OBJECT)

static DexChannel *
bz_backend_real_create_notification_channel (BzBackend *self)
{
  return NULL;
}

static DexFuture *
bz_backend_real_load_local_package (BzBackend    *self,
                                    GFile        *file,
                                    GCancellable *cancellable)
{
  return dex_future_new_reject (G_IO_ERROR, G_IO_ERROR_UNKNOWN, "Unimplemented");
}

static DexFuture *
bz_backend_real_retrieve_remote_entries (BzBackend    *self,
                                         GCancellable *cancellable)
{
  return dex_future_new_reject (G_IO_ERROR, G_IO_ERROR_UNKNOWN, "Unimplemented");
}

static DexFuture *
bz_backend_real_retrieve_install_ids (BzBackend    *self,
                                      GCancellable *cancellable)
{
  return dex_future_new_reject (G_IO_ERROR, G_IO_ERROR_UNKNOWN, "Unimplemented");
}

static DexFuture *
bz_backend_real_retrieve_update_ids (BzBackend    *self,
                                     GCancellable *cancellable)
{
  return dex_future_new_reject (G_IO_ERROR, G_IO_ERROR_UNKNOWN, "Unimplemented");
}

static DexFuture *
bz_backend_real_list_repositories (BzBackend    *self,
                                   GCancellable *cancellable)
{
  return dex_future_new_reject (G_IO_ERROR, G_IO_ERROR_UNKNOWN, "Unimplemented");
}

static DexFuture *
bz_backend_real_schedule_transaction (BzBackend    *self,
                                      BzEntry     **installs,
                                      guint         n_installs,
                                      BzEntry     **updates,
                                      guint         n_updates,
                                      BzEntry     **removals,
                                      guint         n_removals,
                                      DexChannel   *channel,
                                      GCancellable *cancellable)
{
  return dex_future_new_reject (G_IO_ERROR, G_IO_ERROR_UNKNOWN, "Unimplemented");
}

static gboolean
bz_backend_real_cancel_task_for_entry (BzBackend *self,
                                       BzEntry   *entry)
{
  return FALSE;
}

static void
bz_backend_default_init (BzBackendInterface *iface)
{
  iface->create_notification_channel = bz_backend_real_create_notification_channel;
  iface->load_local_package          = bz_backend_real_load_local_package;
  iface->retrieve_remote_entries     = bz_backend_real_retrieve_remote_entries;
  iface->retrieve_install_ids        = bz_backend_real_retrieve_install_ids;
  iface->retrieve_update_ids         = bz_backend_real_retrieve_update_ids;
  iface->list_repositories           = bz_backend_real_list_repositories;
  iface->schedule_transaction        = bz_backend_real_schedule_transaction;
  iface->cancel_task_for_entry       = bz_backend_real_cancel_task_for_entry;
}

DexChannel *
bz_backend_create_notification_channel (BzBackend *self)
{
  g_return_val_if_fail (BZ_IS_BACKEND (self), NULL);

  return BZ_BACKEND_GET_IFACE (self)->create_notification_channel (self);
}

DexFuture *
bz_backend_load_local_package (BzBackend    *self,
                               GFile        *file,
                               GCancellable *cancellable)
{
  dex_return_error_if_fail (BZ_IS_BACKEND (self));
  dex_return_error_if_fail (G_IS_FILE (file));
  dex_return_error_if_fail (cancellable == NULL || G_IS_CANCELLABLE (self));

  return BZ_BACKEND_GET_IFACE (self)->load_local_package (self, file, cancellable);
}

DexFuture *
bz_backend_retrieve_remote_entries (BzBackend    *self,
                                    GCancellable *cancellable)
{
  dex_return_error_if_fail (BZ_IS_BACKEND (self));
  dex_return_error_if_fail (cancellable == NULL || G_IS_CANCELLABLE (self));

  return BZ_BACKEND_GET_IFACE (self)->retrieve_remote_entries (self, cancellable);
}

DexFuture *
bz_backend_retrieve_install_ids (BzBackend    *self,
                                 GCancellable *cancellable)
{
  dex_return_error_if_fail (BZ_IS_BACKEND (self));
  return BZ_BACKEND_GET_IFACE (self)->retrieve_install_ids (self, cancellable);
}

DexFuture *
bz_backend_retrieve_update_ids (BzBackend    *self,
                                GCancellable *cancellable)
{
  dex_return_error_if_fail (BZ_IS_BACKEND (self));
  return BZ_BACKEND_GET_IFACE (self)->retrieve_update_ids (self, cancellable);
}

DexFuture *
bz_backend_list_repositories (BzBackend    *self,
                              GCancellable *cancellable)
{
  dex_return_error_if_fail (BZ_IS_BACKEND (self));
  dex_return_error_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable));

  return BZ_BACKEND_GET_IFACE (self)->list_repositories (self, cancellable);
}

DexFuture *
bz_backend_schedule_transaction (BzBackend    *self,
                                 BzEntry     **installs,
                                 guint         n_installs,
                                 BzEntry     **updates,
                                 guint         n_updates,
                                 BzEntry     **removals,
                                 guint         n_removals,
                                 DexChannel   *channel,
                                 GCancellable *cancellable)
{
  dex_return_error_if_fail (BZ_IS_BACKEND (self));
  dex_return_error_if_fail ((installs != NULL && n_installs > 0) ||
                            (updates != NULL && n_updates > 0) ||
                            (removals != NULL && n_removals));
  if (installs != NULL)
    {
      for (guint i = 0; i < n_installs; i++)
        dex_return_error_if_fail (BZ_IS_ENTRY (installs[i]));
    }
  if (updates != NULL)
    {
      for (guint i = 0; i < n_updates; i++)
        dex_return_error_if_fail (BZ_IS_ENTRY (updates[i]));
    }
  if (removals != NULL)
    {
      for (guint i = 0; i < n_removals; i++)
        dex_return_error_if_fail (BZ_IS_ENTRY (removals[i]));
    }

  return BZ_BACKEND_GET_IFACE (self)->schedule_transaction (
      self,
      installs,
      n_installs,
      updates,
      n_updates,
      removals,
      n_removals,
      channel,
      cancellable);
}

DexFuture *
bz_backend_merge_and_schedule_transactions (BzBackend    *self,
                                            GListModel   *transactions,
                                            DexChannel   *channel,
                                            GCancellable *cancellable)
{
  guint n_items                     = 0;
  g_autoptr (GPtrArray) installs_pa = NULL;
  g_autoptr (GPtrArray) updates_pa  = NULL;
  g_autoptr (GPtrArray) removals_pa = NULL;

  dex_return_error_if_fail (G_IS_LIST_MODEL (transactions));

  n_items = g_list_model_get_n_items (transactions);
  dex_return_error_if_fail (n_items > 0);

  installs_pa = g_ptr_array_new_with_free_func (g_object_unref);
  updates_pa  = g_ptr_array_new_with_free_func (g_object_unref);
  removals_pa = g_ptr_array_new_with_free_func (g_object_unref);

  for (guint i = 0; i < n_items; i++)
    {
      g_autoptr (BzTransaction) transaction = NULL;
      GListModel *installs                  = NULL;
      GListModel *updates                   = NULL;
      GListModel *removals                  = NULL;
      guint       n_installs                = 0;
      guint       n_updates                 = 0;
      guint       n_removals                = 0;

      transaction = g_list_model_get_item (transactions, i);
      installs    = bz_transaction_get_installs (transaction);
      updates     = bz_transaction_get_updates (transaction);
      removals    = bz_transaction_get_removals (transaction);

      if (installs != NULL)
        n_installs = g_list_model_get_n_items (installs);
      if (updates != NULL)
        n_updates = g_list_model_get_n_items (updates);
      if (removals != NULL)
        n_removals = g_list_model_get_n_items (removals);

      for (guint j = 0; j < n_installs; j++)
        g_ptr_array_add (installs_pa, g_list_model_get_item (installs, j));
      for (guint j = 0; j < n_updates; j++)
        g_ptr_array_add (updates_pa, g_list_model_get_item (updates, j));
      for (guint j = 0; j < n_removals; j++)
        g_ptr_array_add (removals_pa, g_list_model_get_item (removals, j));
    }

  return bz_backend_schedule_transaction (
      self,
      (BzEntry **) installs_pa->pdata,
      installs_pa->len,
      (BzEntry **) updates_pa->pdata,
      updates_pa->len,
      (BzEntry **) removals_pa->pdata,
      removals_pa->len,
      channel,
      cancellable);
}

gboolean
bz_backend_cancel_task_for_entry (BzBackend *self,
                                  BzEntry   *entry)
{
  g_return_val_if_fail (BZ_IS_BACKEND (self), FALSE);
  g_return_val_if_fail (BZ_IS_ENTRY (entry), FALSE);

  return BZ_BACKEND_GET_IFACE (self)->cancel_task_for_entry (self, entry);
}