// Copyright (C) 2009 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;

import com.google.gerrit.common.Nullable;
import com.google.gerrit.reviewdb.client.Account;
import com.google.gerrit.server.account.CapabilityControl;
import com.google.gerrit.server.account.GroupMembership;
import com.google.inject.servlet.RequestScoped;

/**
 * Information about the currently logged in user.
 * <p>
 * This is a {@link RequestScoped} property managed by Guice.
 *
 * @see AnonymousUser
 * @see IdentifiedUser
 */
public abstract class CurrentUser {
  /** Unique key for plugin/extension specific data on a CurrentUser. */
  public static final class PropertyKey<T> {
    public static <T> PropertyKey<T> create() {
      return new PropertyKey<>();
    }

    private PropertyKey() {
    }
  }

  private final CapabilityControl.Factory capabilityControlFactory;
  private AccessPath accessPath = AccessPath.UNKNOWN;

  private CapabilityControl capabilities;

  protected CurrentUser(CapabilityControl.Factory capabilityControlFactory) {
    this.capabilityControlFactory = capabilityControlFactory;
  }

  /** How this user is accessing the Gerrit Code Review application. */
  public final AccessPath getAccessPath() {
    return accessPath;
  }

  public void setAccessPath(AccessPath path) {
    accessPath = path;
  }

  /**
   * Identity of the authenticated user.
   * <p>
   * In the normal case where a user authenticates as themselves
   * {@code getRealUser() == this}.
   * <p>
   * If {@code X-Gerrit-RunAs} or {@code suexec} was used this method returns
   * the identity of the account that has permission to act on behalf of this
   * user.
   */
  public CurrentUser getRealUser() {
    return this;
  }

  /**
   * Get the set of groups the user is currently a member of.
   * <p>
   * The returned set may be a subset of the user's actual groups; if the user's
   * account is currently deemed to be untrusted then the effective group set is
   * only the anonymous and registered user groups. To enable additional groups
   * (and gain their granted permissions) the user must update their account to
   * use only trusted authentication providers.
   *
   * @return active groups for this user.
   */
  public abstract GroupMembership getEffectiveGroups();

  /** Unique name of the user on this server, if one has been assigned. */
  public String getUserName() {
    return null;
  }

  /** Capabilities available to this user account. */
  public CapabilityControl getCapabilities() {
    if (capabilities == null) {
      capabilities = capabilityControlFactory.create(this);
    }
    return capabilities;
  }

  /** Check if user is the IdentifiedUser */
  public boolean isIdentifiedUser() {
    return false;
  }

  /** Cast to IdentifiedUser if possible. */
  public IdentifiedUser asIdentifiedUser() {
    throw new UnsupportedOperationException(
        getClass().getSimpleName() + " is not an IdentifiedUser");
  }

  /** Return account ID if {@link #isIdentifiedUser} is true. */
  public Account.Id getAccountId() {
    throw new UnsupportedOperationException(
        getClass().getSimpleName() + " is not an IdentifiedUser");
  }

  /** Check if the CurrentUser is an InternalUser. */
  public boolean isInternalUser() {
    return false;
  }

  /**
   * Lookup a previously stored property.
   *
   * @param key unique property key.
   * @return previously stored value, or {@code null}.
   */
  @Nullable
  public <T> T get(PropertyKey<T> key) {
    return null;
  }

  /**
   * Store a property for later retrieval.
   *
   * @param key unique property key.
   * @param value value to store; or {@code null} to clear the value.
   */
  public <T> void put(PropertyKey<T> key, @Nullable T value) {
  }
}