/*
 * Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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.amazonaws.services.s3.model;

/**
 * Specifies constants defining an access permission, as granted to grantees in
 * an {@link AccessControlList}. Only a limited set of permission are available;
 * each one is represented as a value in this enumeration.
 */
public enum Permission {

    /**
     * Provides READ, WRITE, READ_ACP, and WRITE_ACP permissions.
     * <p>
     * It does not convey additional rights and is provided only for
     * convenience.
     * </p>
     */
    FullControl("FULL_CONTROL", "x-amz-grant-full-control"),

    /**
     * Grants permission to list the bucket when applied to a bucket. Grants
     * permission to read object data and/or metadata when applied to an object.
     */
    Read("READ", "x-amz-grant-read"),

    /**
     * Grants permission to create, overwrite, and delete any objects in the
     * bucket.
     * <p>
     * This permission is not supported for objects.
     * </p>
     */
    Write("WRITE", "x-amz-grant-write"),

    /**
     * Grants permission to read the ACL for the applicable bucket or object.
     * <p>
     * The owner of a bucket or object always implicitly has this permission.
     * </p>
     */
    ReadAcp("READ_ACP", "x-amz-grant-read-acp"),

    /**
     * Gives permission to overwrite the ACP for the applicable bucket or
     * object.
     * <p>
     * The owner of a bucket or object always has this permission implicitly.
     * </p>
     * <p>
     * Granting this permission is equivalent to granting
     * <code>FULL_CONTROL</code>because the grant recipient can make any changes
     * to the ACP.
     * </p>
     */
    WriteAcp("WRITE_ACP", "x-amz-grant-write-acp");

    private String permissionString;
    private String headerName;

    private Permission(String permissionString, String headerName) {
        this.permissionString = permissionString;
        this.headerName = headerName;
    }

    /**
     * Returns the name of the header used to grant this permission.
     */
    public String getHeaderName() {
        return headerName;
    }

    /**
     * Gets the string representation of this permission object as defined by
     * Amazon S3, eg. <code>FULL_CONTROL</code>.
     *
     * @return The string representation of this permission object as defined by
     *         Amazon S3, eg. <code>FULL_CONTROL</code>.
     */
    @Override
    public String toString() {
        return permissionString;
    }

    /**
     * Returns the {@link Permission} enumeration value representing the
     * specified Amazon S3 Region ID string. If specified string doesn't map to
     * a known Amazon S3 Region, returns <code>null</code>.
     *
     * @param str A string representation of an Amazon S3 permission, eg.
     *            <code>FULL_CONTROL</code>
     * @return The {@link Permission} object represented by the given permission
     *         string, Returns <code>null</code> if the string isn't a valid
     *         representation of an Amazon S3 permission.
     */
    public static Permission parsePermission(String str) {
        for (Permission permission : Permission.values()) {
            if (permission.permissionString.equals(str)) {
                return permission;
            }
        }

        return null;
    }

}