/*

 * Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.javadoc.internal.doclets.toolkit.util;

import javax.lang.model.element.ModuleElement;

import javax.lang.model.element.PackageElement;

import javax.lang.model.element.TypeElement;

/**

 * Abstraction for immutable relative paths.

 * Paths always use '/' as a separator, and never begin or end with '/'.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public class DocPath {

    private final String path;

    /** The empty path. */

    public static final DocPath empty = new DocPath("");

    /** The empty path. */

    public static final DocPath parent = new DocPath("..");

    /**

     * Create a path from a string.

     */

    public static DocPath create(String p) {

        return (p == null) || p.isEmpty() ? empty : new DocPath(p);

    }

    /**

     * Return the path for a class.

     * For example, if the class is java.lang.Object,

     * the path is java/lang/Object.html.

     */

    public static DocPath forClass(Utils utils, TypeElement typeElement) {

        return (typeElement == null)

                ? empty

                : forPackage(utils.containingPackage(typeElement)).resolve(forName(utils, typeElement));

    }

    /**

     * Return the path for the simple name of the class.

     * For example, if the class is java.lang.Object,

     * the path is Object.html.

     */

    public static DocPath forName(Utils utils, TypeElement typeElement) {

        return (typeElement == null) ? empty : new DocPath(utils.getSimpleName(typeElement) + ".html");

    }

    public static DocPath forModule(ModuleElement mdle) {

        return mdle == null || mdle.isUnnamed()

                ? empty

                : DocPath.create(mdle.getQualifiedName().toString());

    }

    /**

     * Return the path for the package of a class.

     * For example, if the class is java.lang.Object,

     * the path is java/lang.

     */

    public static DocPath forPackage(Utils utils, TypeElement typeElement) {

        return (typeElement == null) ? empty : forPackage(utils.containingPackage(typeElement));

    }

    /**

     * Return the path for a package.

     * For example, if the package is java.lang,

     * the path is java/lang.

     */

    public static DocPath forPackage(PackageElement pkgElement) {

        return pkgElement == null || pkgElement.isUnnamed()

                ? empty

                : DocPath.create(pkgElement.getQualifiedName().toString().replace('.', '/'));

    }

    /**

     * Return the inverse path for a package.

     * For example, if the package is java.lang,

     * the inverse path is ../...

     */

    public static DocPath forRoot(PackageElement pkgElement) {

        String name = (pkgElement == null || pkgElement.isUnnamed())

                ? ""

                : pkgElement.getQualifiedName().toString();

        return new DocPath(name.replace('.', '/').replaceAll("[^/]+", ".."));

    }

    /**

     * Return the relative path from one package to another.

     */

    public static DocPath relativePath(PackageElement from, PackageElement to) {

        return forRoot(from).resolve(forPackage(to));

    }

    protected DocPath(String p) {

        path = (p.endsWith("/") ? p.substring(0, p.length() - 1) : p);

    }

    /** {@inheritDoc} */

    @Override

    public boolean equals(Object other) {

        return (other instanceof DocPath) && path.equals(((DocPath)other).path);

    }

    /** {@inheritDoc} */

    @Override

    public int hashCode() {

        return path.hashCode();

    }

    public DocPath basename() {

        int sep = path.lastIndexOf("/");

        return (sep == -1) ? this : new DocPath(path.substring(sep + 1));

    }

    public DocPath parent() {

        int sep = path.lastIndexOf("/");

        return (sep == -1) ? empty : new DocPath(path.substring(0, sep));

    }

    /**

     * Return the path formed by appending the specified string to the current path.

     */

    public DocPath resolve(String p) {

        if (p == null || p.isEmpty())

            return this;

        if (path.isEmpty())

            return new DocPath(p);

        return new DocPath(path + "/" + p);

    }

    /**

     * Return the path by appending the specified path to the current path.

     */

    public DocPath resolve(DocPath p) {

        if (p == null || p.isEmpty())

            return this;

        if (path.isEmpty())

            return p;

        return new DocPath(path + "/" + p.getPath());

    }

    /**

     * Return the inverse path for this path.

     * For example, if the path is a/b/c, the inverse path is ../../..

     */

    public DocPath invert() {

        return new DocPath(path.replaceAll("[^/]+", ".."));

    }

    /**

     * Return true if this path is empty.

     */

    public boolean isEmpty() {

        return path.isEmpty();

    }

    public DocLink fragment(String fragment) {

        return new DocLink(path, null, fragment);

    }

    public DocLink query(String query) {

        return new DocLink(path, query, null);

    }

    /**

     * Return this path as a string.

     */

    // This is provided instead of using toString() to help catch

    // unintended use of toString() in string concatenation sequences.

    public String getPath() {

        return path;

    }

}