/*
 * Copyright (c) 2012-2018 Red Hat, Inc.
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *   Red Hat, Inc. - initial API and implementation
 */
package org.eclipse.che.multiuser.permission.workspace.server.filters;

import static java.util.function.Function.identity;
import static java.util.stream.Collectors.toMap;
import static org.eclipse.che.multiuser.permission.workspace.server.WorkspaceDomain.CONFIGURE;
import static org.eclipse.che.multiuser.permission.workspace.server.WorkspaceDomain.DELETE;
import static org.eclipse.che.multiuser.permission.workspace.server.WorkspaceDomain.DOMAIN_ID;
import static org.eclipse.che.multiuser.permission.workspace.server.WorkspaceDomain.READ;
import static org.eclipse.che.multiuser.permission.workspace.server.WorkspaceDomain.RUN;

import java.util.Map;
import java.util.Set;
import javax.inject.Inject;
import javax.ws.rs.Path;
import org.eclipse.che.account.api.AccountManager;
import org.eclipse.che.account.shared.model.Account;
import org.eclipse.che.api.core.ForbiddenException;
import org.eclipse.che.api.core.NotFoundException;
import org.eclipse.che.api.core.ServerException;
import org.eclipse.che.api.workspace.server.WorkspaceManager;
import org.eclipse.che.api.workspace.server.WorkspaceService;
import org.eclipse.che.api.workspace.server.model.impl.WorkspaceImpl;
import org.eclipse.che.commons.env.EnvironmentContext;
import org.eclipse.che.commons.subject.Subject;
import org.eclipse.che.everrest.CheMethodInvokerFilter;
import org.eclipse.che.multiuser.api.permission.server.SuperPrivilegesChecker;
import org.eclipse.che.multiuser.api.permission.server.account.AccountOperation;
import org.eclipse.che.multiuser.api.permission.server.account.AccountPermissionsChecker;
import org.everrest.core.Filter;
import org.everrest.core.resource.GenericResourceMethod;

/**
 * Restricts access to methods of {@link WorkspaceService} by users' permissions.
 *
 * <p>Filter contains rules for protecting of all methods of {@link WorkspaceService}.<br>
 * In case when requested method is unknown filter throws {@link ForbiddenException}
 *
 * @author Sergii Leschenko
 */
@Filter
@Path("/workspace{path:(/.*)?}")
public class WorkspacePermissionsFilter extends CheMethodInvokerFilter {
  private final WorkspaceManager workspaceManager;
  private final AccountManager accountManager;
  private final Map<String, AccountPermissionsChecker> accountTypeToPermissionsChecker;
  private final SuperPrivilegesChecker superPrivilegesChecker;

  @Inject
  public WorkspacePermissionsFilter(
      WorkspaceManager workspaceManager,
      AccountManager accountManager,
      Set<AccountPermissionsChecker> accountPermissionsCheckers,
      SuperPrivilegesChecker superPrivilegesChecker) {
    this.workspaceManager = workspaceManager;
    this.accountManager = accountManager;
    this.accountTypeToPermissionsChecker =
        accountPermissionsCheckers
            .stream()
            .collect(toMap(AccountPermissionsChecker::getAccountType, identity()));
    this.superPrivilegesChecker = superPrivilegesChecker;
  }

  @Override
  public void filter(GenericResourceMethod genericResourceMethod, Object[] arguments)
      throws ForbiddenException, ServerException, NotFoundException {
    final String methodName = genericResourceMethod.getMethod().getName();

    final Subject currentSubject = EnvironmentContext.getCurrent().getSubject();
    String action;
    String key;

    switch (methodName) {
      case "getSettings":
      case "getWorkspaces":
        // methods accessible to every user
        return;

      case "getByNamespace":
        {
          if (superPrivilegesChecker.hasSuperPrivileges()) {
            return;
          }
          checkAccountPermissions((String) arguments[1], AccountOperation.MANAGE_WORKSPACES);
          return;
        }

      case "create":
        {
          checkAccountPermissions((String) arguments[4], AccountOperation.CREATE_WORKSPACE);
          return;
        }

      case "delete":
        key = ((String) arguments[0]);
        action = DELETE;
        break;

      case "stop":
        if (superPrivilegesChecker.hasSuperPrivileges()) {
          return;
        }
        // fall through
      case "startById":
        key = ((String) arguments[0]);
        action = RUN;
        break;

      case "getByKey":
        if (superPrivilegesChecker.hasSuperPrivileges()) {
          return;
        }
        key = ((String) arguments[0]);
        action = READ;
        break;

      case "update":
        key = ((String) arguments[0]);
        action = CONFIGURE;
        break;

      default:
        throw new ForbiddenException("The user does not have permission to perform this operation");
    }

    final WorkspaceImpl workspace = workspaceManager.getWorkspace(key);
    try {
      checkAccountPermissions(workspace.getNamespace(), AccountOperation.MANAGE_WORKSPACES);
      // user is authorized to perform any operation if workspace belongs to account where he has
      // the corresponding permissions
    } catch (ForbiddenException e) {
      // check permissions on workspace level
      if (!currentSubject.hasPermission(DOMAIN_ID, workspace.getId(), action)) {
        throw new ForbiddenException(
            "The user does not have permission to "
                + action
                + " workspace with id '"
                + workspace.getId()
                + "'");
      }
    }
  }

  void checkAccountPermissions(String accountName, AccountOperation operation)
      throws ForbiddenException, NotFoundException, ServerException {
    if (accountName == null) {
      // default namespace will be used
      return;
    }

    final Account account = accountManager.getByName(accountName);

    AccountPermissionsChecker accountPermissionsChecker =
        accountTypeToPermissionsChecker.get(account.getType());

    if (accountPermissionsChecker == null) {
      throw new ForbiddenException("User is not authorized to use specified namespace");
    }

    accountPermissionsChecker.checkPermissions(account.getId(), operation);
  }
}
