/*
 * Copyright (c) 2017, 2023 Oracle and/or its affiliates and others.
 * All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package jakarta.servlet;

import jakarta.servlet.annotation.HttpConstraint;
import jakarta.servlet.annotation.ServletSecurity.EmptyRoleSemantic;
import jakarta.servlet.annotation.ServletSecurity.TransportGuarantee;

/**
 * Java Class representation of an {@link HttpConstraint} annotation value.
 *
 * @since Servlet 3.0
 */
public class HttpConstraintElement {

    private final EmptyRoleSemantic emptyRoleSemantic;
    private final TransportGuarantee transportGuarantee;
    private final String[] rolesAllowed;

    /**
     * Constructs a default HTTP constraint element
     */
    public HttpConstraintElement() {
        this(EmptyRoleSemantic.PERMIT);
    }

    /**
     * Convenience constructor to establish <tt>EmptyRoleSemantic.DENY</tt>
     *
     * @param semantic should be EmptyRoleSemantic.DENY
     */
    public HttpConstraintElement(EmptyRoleSemantic semantic) {
        this(semantic, TransportGuarantee.NONE);
    }

    /**
     * Constructor to establish non-empty getRolesAllowed and/or <tt>TransportGuarantee.CONFIDENTIAL</tt>.
     *
     * @param guarantee <tt>TransportGuarantee.NONE</tt> or <tt>TransportGuarantee.CONFIDENTIAL</tt>
     * @param roleNames the names of the roles that are to be allowed access
     */
    public HttpConstraintElement(TransportGuarantee guarantee, String... roleNames) {
        this(EmptyRoleSemantic.PERMIT, guarantee, roleNames);
    }

    /**
     * Constructor to establish all of getEmptyRoleSemantic, getRolesAllowed, and getTransportGuarantee.
     *
     * @param semantic <tt>EmptyRoleSemantic.DENY</tt> or <tt>EmptyRoleSemantic.PERMIT</tt>
     * @param guarantee <tt>TransportGuarantee.NONE</tt> or <tt>TransportGuarantee.CONFIDENTIAL</tt>
     * @param roleNames the names of the roles that are to be allowed access, or missing if the semantic is
     * <tt>EmptyRoleSemantic.DENY</tt>
     */
    public HttpConstraintElement(EmptyRoleSemantic semantic, TransportGuarantee guarantee, String... roleNames) {
        if (semantic == EmptyRoleSemantic.DENY && roleNames.length > 0) {
            throw new IllegalArgumentException("Deny semantic with rolesAllowed");
        }
        this.emptyRoleSemantic = semantic;
        this.transportGuarantee = guarantee;
        this.rolesAllowed = copyStrings(roleNames);
    }

    /**
     * Gets the default authorization semantic.
     *
     * <p>
     * This value is insignificant when <code>getRolesAllowed</code> returns a non-empty array, and should not be specified
     * when a non-empty array is specified for <tt>getRolesAllowed</tt>.
     *
     * @return the {@link EmptyRoleSemantic} to be applied when <code>getRolesAllowed</code> returns an empty (that is,
     * zero-length) array
     */
    public EmptyRoleSemantic getEmptyRoleSemantic() {
        return this.emptyRoleSemantic;
    }

    /**
     * Gets the data protection requirement (i.e., whether or not SSL/TLS is required) that must be satisfied by the
     * transport connection.
     *
     * @return the {@link TransportGuarantee} indicating the data protection that must be provided by the connection
     */
    public TransportGuarantee getTransportGuarantee() {
        return this.transportGuarantee;
    }

    /**
     * Gets the names of the authorized roles.
     *
     * <p>
     * Duplicate role names appearing in getRolesAllowed are insignificant and may be discarded. The String <tt>"*"</tt> has
     * no special meaning as a role name (should it occur in getRolesAllowed).
     *
     * @return a (possibly empty) array of role names. When the array is empty, its meaning depends on the value of
     * {@link #getEmptyRoleSemantic}. If its value is <tt>DENY</tt>, and <code>getRolesAllowed</code> returns an empty
     * array, access is to be denied independent of authentication state and identity. Conversely, if its value is
     * <code>PERMIT</code>, it indicates that access is to be allowed independent of authentication state and identity. When
     * the array contains the names of one or more roles, it indicates that access is contingent on membership in at least
     * one of the named roles (independent of the value of {@link #getEmptyRoleSemantic}).
     */
    public String[] getRolesAllowed() {
        return copyStrings(this.rolesAllowed);
    }

    private String[] copyStrings(String[] strings) {
        String[] arr = null;
        if (strings != null) {
            int len = strings.length;
            arr = new String[len];
            if (len > 0) {
                System.arraycopy(strings, 0, arr, 0, len);
            }
        }

        return ((arr != null) ? arr : new String[0]);
    }
}
