/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.jsecurity.util;

/**
 * <p>PathMatcher implementation for Ant-style path patterns.
 * Examples are provided below.</p>
 *
 * <p>Part of this mapping code has been kindly borrowed from
 * <a href="http://ant.apache.org">Apache Ant</a>.
 *
 * <p>The mapping matches URLs using the following rules:<br>
 * <ul>
 * <li>? matches one character</li>
 * <li>* matches zero or more characters</li>
 * <li>** matches zero or more 'directories' in a path</li>
 * </ul>
 *
 * <p>Some examples:<br>
 * <ul>
 * <li><code>com/t?st.jsp</code> - matches <code>com/test.jsp</code> but also
 * <code>com/tast.jsp</code> or <code>com/txst.jsp</code></li>
 * <li><code>com/*.jsp</code> - matches all <code>.jsp</code> files in the
 * <code>com</code> directory</li>
 * <li><code>com/&#42;&#42;/test.jsp</code> - matches all <code>test.jsp</code>
 * files underneath the <code>com</code> path</li>
 * <li><code>org/jsecurity/&#42;&#42;/*.jsp</code> - matches all <code>.jsp</code>
 * files underneath the <code>org/jsecurity</code> path</li>
 * <li><code>org/&#42;&#42;/servlet/bla.jsp</code> - matches
 * <code>org/jsecurity/servlet/bla.jsp</code> but also
 * <code>org/jsecurity/testing/servlet/bla.jsp</code> and
 * <code>org/servlet/bla.jsp</code></li>
 * </ul>
 *
 * <p><b>N.B.</b>: This class was borrowed (with much appreciation) from the
 * <a href="http://www.springframework.org">Spring Framework</a> with modifications.  We didn't want to reinvent the
 * wheel of great work they've done, but also didn't want to force every JSecurity user to depend on Spring</p>
 *
 * <p>As per the Apache 2.0 license, the original copyright notice and all author and copyright information have
 * remained in tact.</p>
 *
 * @author Alef Arendsen
 * @author Juergen Hoeller
 * @author Rob Harrop
 * @since 16.07.2003
 */
public class AntPathMatcher implements PatternMatcher {

    //TODO - complete JavaDoc

    /**
     * Default path separator: "/"
     */
    public static final String DEFAULT_PATH_SEPARATOR = "/";

    private String pathSeparator = DEFAULT_PATH_SEPARATOR;


    /**
     * Set the path separator to use for pattern parsing.
     * Default is "/", as in Ant.
     */
    public void setPathSeparator(String pathSeparator) {
        this.pathSeparator = (pathSeparator != null ? pathSeparator : DEFAULT_PATH_SEPARATOR);
    }


    public boolean isPattern(String path) {
        return (path.indexOf('*') != -1 || path.indexOf('?') != -1);
    }

    public boolean matches(String pattern, String source) {
        return match(pattern, source);
    }

    public boolean match(String pattern, String path) {
        return doMatch(pattern, path, true);
    }

    public boolean matchStart(String pattern, String path) {
        return doMatch(pattern, path, false);
    }


    /**
     * Actually match the given <code>path</code> against the given <code>pattern</code>.
     *
     * @param pattern   the pattern to match against
     * @param path      the path String to test
     * @param fullMatch whether a full pattern match is required
     *                  (else a pattern match as far as the given base path goes is sufficient)
     * @return <code>true</code> if the supplied <code>path</code> matched,
     *         <code>false</code> if it didn't
     */
    protected boolean doMatch(String pattern, String path, boolean fullMatch) {
        if (path.startsWith(this.pathSeparator) != pattern.startsWith(this.pathSeparator)) {
            return false;
        }

        String[] pattDirs = StringUtils.tokenizeToStringArray(pattern, this.pathSeparator);
        String[] pathDirs = StringUtils.tokenizeToStringArray(path, this.pathSeparator);

        int pattIdxStart = 0;
        int pattIdxEnd = pattDirs.length - 1;
        int pathIdxStart = 0;
        int pathIdxEnd = pathDirs.length - 1;

        // Match all elements up to the first **
        while (pattIdxStart <= pattIdxEnd && pathIdxStart <= pathIdxEnd) {
            String patDir = pattDirs[pattIdxStart];
            if ("**".equals(patDir)) {
                break;
            }
            if (!matchStrings(patDir, pathDirs[pathIdxStart])) {
                return false;
            }
            pattIdxStart++;
            pathIdxStart++;
        }

        if (pathIdxStart > pathIdxEnd) {
            // Path is exhausted, only match if rest of pattern is * or **'s
            if (pattIdxStart > pattIdxEnd) {
                return (pattern.endsWith(this.pathSeparator) ?
                        path.endsWith(this.pathSeparator) : !path.endsWith(this.pathSeparator));
            }
            if (!fullMatch) {
                return true;
            }
            if (pattIdxStart == pattIdxEnd && pattDirs[pattIdxStart].equals("*") &&
                    path.endsWith(this.pathSeparator)) {
                return true;
            }
            for (int i = pattIdxStart; i <= pattIdxEnd; i++) {
                if (!pattDirs[i].equals("**")) {
                    return false;
                }
            }
            return true;
        } else if (pattIdxStart > pattIdxEnd) {
            // String not exhausted, but pattern is. Failure.
            return false;
        } else if (!fullMatch && "**".equals(pattDirs[pattIdxStart])) {
            // Path start definitely matches due to "**" part in pattern.
            return true;
        }

        // up to last '**'
        while (pattIdxStart <= pattIdxEnd && pathIdxStart <= pathIdxEnd) {
            String patDir = pattDirs[pattIdxEnd];
            if (patDir.equals("**")) {
                break;
            }
            if (!matchStrings(patDir, pathDirs[pathIdxEnd])) {
                return false;
            }
            pattIdxEnd--;
            pathIdxEnd--;
        }
        if (pathIdxStart > pathIdxEnd) {
            // String is exhausted
            for (int i = pattIdxStart; i <= pattIdxEnd; i++) {
                if (!pattDirs[i].equals("**")) {
                    return false;
                }
            }
            return true;
        }

        while (pattIdxStart != pattIdxEnd && pathIdxStart <= pathIdxEnd) {
            int patIdxTmp = -1;
            for (int i = pattIdxStart + 1; i <= pattIdxEnd; i++) {
                if (pattDirs[i].equals("**")) {
                    patIdxTmp = i;
                    break;
                }
            }
            if (patIdxTmp == pattIdxStart + 1) {
                // '**/**' situation, so skip one
                pattIdxStart++;
                continue;
            }
            // Find the pattern between padIdxStart & padIdxTmp in str between
            // strIdxStart & strIdxEnd
            int patLength = (patIdxTmp - pattIdxStart - 1);
            int strLength = (pathIdxEnd - pathIdxStart + 1);
            int foundIdx = -1;

            strLoop:
            for (int i = 0; i <= strLength - patLength; i++) {
                for (int j = 0; j < patLength; j++) {
                    String subPat = (String) pattDirs[pattIdxStart + j + 1];
                    String subStr = (String) pathDirs[pathIdxStart + i + j];
                    if (!matchStrings(subPat, subStr)) {
                        continue strLoop;
                    }
                }
                foundIdx = pathIdxStart + i;
                break;
            }

            if (foundIdx == -1) {
                return false;
            }

            pattIdxStart = patIdxTmp;
            pathIdxStart = foundIdx + patLength;
        }

        for (int i = pattIdxStart; i <= pattIdxEnd; i++) {
            if (!pattDirs[i].equals("**")) {
                return false;
            }
        }

        return true;
    }

    /**
     * Tests whether or not a string matches against a pattern.
     * The pattern may contain two special characters:<br>
     * '*' means zero or more characters<br>
     * '?' means one and only one character
     *
     * @param pattern pattern to match against.
     *                Must not be <code>null</code>.
     * @param str     string which must be matched against the pattern.
     *                Must not be <code>null</code>.
     * @return <code>true</code> if the string matches against the
     *         pattern, or <code>false</code> otherwise.
     */
    private boolean matchStrings(String pattern, String str) {
        char[] patArr = pattern.toCharArray();
        char[] strArr = str.toCharArray();
        int patIdxStart = 0;
        int patIdxEnd = patArr.length - 1;
        int strIdxStart = 0;
        int strIdxEnd = strArr.length - 1;
        char ch;

        boolean containsStar = false;
        for (char aPatArr : patArr) {
            if (aPatArr == '*') {
                containsStar = true;
                break;
            }
        }

        if (!containsStar) {
            // No '*'s, so we make a shortcut
            if (patIdxEnd != strIdxEnd) {
                return false; // Pattern and string do not have the same size
            }
            for (int i = 0; i <= patIdxEnd; i++) {
                ch = patArr[i];
                if (ch != '?') {
                    if (ch != strArr[i]) {
                        return false;// Character mismatch
                    }
                }
            }
            return true; // String matches against pattern
        }


        if (patIdxEnd == 0) {
            return true; // Pattern contains only '*', which matches anything
        }

        // Process characters before first star
        while ((ch = patArr[patIdxStart]) != '*' && strIdxStart <= strIdxEnd) {
            if (ch != '?') {
                if (ch != strArr[strIdxStart]) {
                    return false;// Character mismatch
                }
            }
            patIdxStart++;
            strIdxStart++;
        }
        if (strIdxStart > strIdxEnd) {
            // All characters in the string are used. Check if only '*'s are
            // left in the pattern. If so, we succeeded. Otherwise failure.
            for (int i = patIdxStart; i <= patIdxEnd; i++) {
                if (patArr[i] != '*') {
                    return false;
                }
            }
            return true;
        }

        // Process characters after last star
        while ((ch = patArr[patIdxEnd]) != '*' && strIdxStart <= strIdxEnd) {
            if (ch != '?') {
                if (ch != strArr[strIdxEnd]) {
                    return false;// Character mismatch
                }
            }
            patIdxEnd--;
            strIdxEnd--;
        }
        if (strIdxStart > strIdxEnd) {
            // All characters in the string are used. Check if only '*'s are
            // left in the pattern. If so, we succeeded. Otherwise failure.
            for (int i = patIdxStart; i <= patIdxEnd; i++) {
                if (patArr[i] != '*') {
                    return false;
                }
            }
            return true;
        }

        // process pattern between stars. padIdxStart and patIdxEnd point
        // always to a '*'.
        while (patIdxStart != patIdxEnd && strIdxStart <= strIdxEnd) {
            int patIdxTmp = -1;
            for (int i = patIdxStart + 1; i <= patIdxEnd; i++) {
                if (patArr[i] == '*') {
                    patIdxTmp = i;
                    break;
                }
            }
            if (patIdxTmp == patIdxStart + 1) {
                // Two stars next to each other, skip the first one.
                patIdxStart++;
                continue;
            }
            // Find the pattern between padIdxStart & padIdxTmp in str between
            // strIdxStart & strIdxEnd
            int patLength = (patIdxTmp - patIdxStart - 1);
            int strLength = (strIdxEnd - strIdxStart + 1);
            int foundIdx = -1;
            strLoop:
            for (int i = 0; i <= strLength - patLength; i++) {
                for (int j = 0; j < patLength; j++) {
                    ch = patArr[patIdxStart + j + 1];
                    if (ch != '?') {
                        if (ch != strArr[strIdxStart + i + j]) {
                            continue strLoop;
                        }
                    }
                }

                foundIdx = strIdxStart + i;
                break;
            }

            if (foundIdx == -1) {
                return false;
            }

            patIdxStart = patIdxTmp;
            strIdxStart = foundIdx + patLength;
        }

        // All characters in the string are used. Check if only '*'s are left
        // in the pattern. If so, we succeeded. Otherwise failure.
        for (int i = patIdxStart; i <= patIdxEnd; i++) {
            if (patArr[i] != '*') {
                return false;
            }
        }

        return true;
    }

    /**
     * Given a pattern and a full path, determine the pattern-mapped part.
     * <p>For example:
     * <ul>
     * <li>'<code>/docs/cvs/commit.html</code>' and '<code>/docs/cvs/commit.html</code> -> ''</li>
     * <li>'<code>/docs/*</code>' and '<code>/docs/cvs/commit</code> -> '<code>cvs/commit</code>'</li>
     * <li>'<code>/docs/cvs/*.html</code>' and '<code>/docs/cvs/commit.html</code> -> '<code>commit.html</code>'</li>
     * <li>'<code>/docs/**</code>' and '<code>/docs/cvs/commit</code> -> '<code>cvs/commit</code>'</li>
     * <li>'<code>/docs/**\/*.html</code>' and '<code>/docs/cvs/commit.html</code> -> '<code>cvs/commit.html</code>'</li>
     * <li>'<code>/*.html</code>' and '<code>/docs/cvs/commit.html</code> -> '<code>docs/cvs/commit.html</code>'</li>
     * <li>'<code>*.html</code>' and '<code>/docs/cvs/commit.html</code> -> '<code>/docs/cvs/commit.html</code>'</li>
     * <li>'<code>*</code>' and '<code>/docs/cvs/commit.html</code> -> '<code>/docs/cvs/commit.html</code>'</li>
     * </ul>
     * <p>Assumes that {@link #match} returns <code>true</code> for '<code>pattern</code>'
     * and '<code>path</code>', but does <strong>not</strong> enforce this.
     */
    public String extractPathWithinPattern(String pattern, String path) {
        String[] patternParts = StringUtils.tokenizeToStringArray(pattern, this.pathSeparator);
        String[] pathParts = StringUtils.tokenizeToStringArray(path, this.pathSeparator);

        StringBuffer buffer = new StringBuffer();

        // Add any path parts that have a wildcarded pattern part.
        int puts = 0;
        for (int i = 0; i < patternParts.length; i++) {
            String patternPart = patternParts[i];
            if ((patternPart.indexOf('*') > -1 || patternPart.indexOf('?') > -1) && pathParts.length >= i + 1) {
                if (puts > 0 || (i == 0 && !pattern.startsWith(this.pathSeparator))) {
                    buffer.append(this.pathSeparator);
                }
                buffer.append(pathParts[i]);
                puts++;
            }
        }

        // Append any trailing path parts.
        for (int i = patternParts.length; i < pathParts.length; i++) {
            if (puts > 0 || i > 0) {
                buffer.append(this.pathSeparator);
            }
            buffer.append(pathParts[i]);
        }

        return buffer.toString();
    }

}