// Copyright (C) 2013 The Android Open Source Project
//
// Licensed 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.

package com.google.gerrit.server.restapi.account;

import com.google.gerrit.entities.Account;
import com.google.gerrit.extensions.client.GeneralPreferencesInfo;
import com.google.gerrit.extensions.config.DownloadScheme;
import com.google.gerrit.extensions.registration.DynamicMap;
import com.google.gerrit.extensions.registration.Extension;
import com.google.gerrit.extensions.restapi.IdString;
import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
import com.google.gerrit.extensions.restapi.Response;
import com.google.gerrit.extensions.restapi.RestApiException;
import com.google.gerrit.extensions.restapi.RestReadView;
import com.google.gerrit.server.CurrentUser;
import com.google.gerrit.server.account.AccountCache;
import com.google.gerrit.server.account.AccountResource;
import com.google.gerrit.server.account.AccountState;
import com.google.gerrit.server.permissions.GlobalPermission;
import com.google.gerrit.server.permissions.PermissionBackend;
import com.google.gerrit.server.permissions.PermissionBackendException;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.Singleton;

/**
 * REST endpoint to get the general preferences of an account.
 *
 * <p>This REST endpoint handles {@code GET /accounts/<account-identifier>/preferences} requests.
 *
 * <p>Diff preferences can be retrieved by {@link GetDiffPreferences} and edit preferences can be
 * retrieved by {@link GetEditPreferences}.
 *
 * <p>Default general preferences that apply for all accounts can be retrieved by {@link
 * com.google.gerrit.server.restapi.config.GetPreferences}.
 */
@Singleton
public class GetPreferences implements RestReadView<AccountResource> {
  private final Provider<CurrentUser> self;
  private final PermissionBackend permissionBackend;
  private final AccountCache accountCache;
  private final DynamicMap<DownloadScheme> downloadSchemes;

  @Inject
  GetPreferences(
      Provider<CurrentUser> self,
      PermissionBackend permissionBackend,
      AccountCache accountCache,
      DynamicMap<DownloadScheme> downloadSchemes) {
    this.self = self;
    this.permissionBackend = permissionBackend;
    this.accountCache = accountCache;
    this.downloadSchemes = downloadSchemes;
  }

  @Override
  public Response<GeneralPreferencesInfo> apply(AccountResource rsrc)
      throws RestApiException, PermissionBackendException {
    if (!self.get().hasSameAccountId(rsrc.getUser())) {
      permissionBackend.currentUser().check(GlobalPermission.MODIFY_ACCOUNT);
    }

    Account.Id id = rsrc.getUser().getAccountId();
    GeneralPreferencesInfo preferencesInfo =
        accountCache
            .get(id)
            .map(AccountState::generalPreferences)
            .orElseThrow(() -> new ResourceNotFoundException(IdString.fromDecoded(id.toString())));
    return Response.ok(unsetDownloadSchemeIfUnsupported(preferencesInfo));
  }

  private GeneralPreferencesInfo unsetDownloadSchemeIfUnsupported(
      GeneralPreferencesInfo preferencesInfo) {
    if (preferencesInfo.downloadScheme == null) {
      return preferencesInfo;
    }

    for (Extension<DownloadScheme> e : downloadSchemes) {
      if (e.getExportName().equals(preferencesInfo.downloadScheme)
          && e.getProvider().get().isEnabled()) {
        return preferencesInfo;
      }
    }

    preferencesInfo.downloadScheme = null;
    return preferencesInfo;
  }
}