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/*
 * Copyright 2002-2013 the original author or authors.
 *
 * 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.rei.ezup.util;

import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.concurrent.ConcurrentHashMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class AntPathMatcher {

    private static final Pattern VARIABLE_PATTERN = Pattern.compile("\\{[^/]+?\\}");

    public static final String DEFAULT_PATH_SEPARATOR = "/";

    private String pathSeparator = DEFAULT_PATH_SEPARATOR;

    private final Map stringMatcherCache = new ConcurrentHashMap<>(256);

    public boolean match(String pattern, String path) {

        if (path.startsWith(pathSeparator) != pattern.startsWith(pathSeparator)) {
            return false;
        }

        boolean trimTokens = true;
        String[] pattDirs = tokenizeToStringArray(pattern, pathSeparator, trimTokens, true);
        String[] pathDirs = tokenizeToStringArray(path, pathSeparator, trimTokens, true);

        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(pathSeparator) == path.endsWith(pathSeparator));
            }

            if (pattIdxStart == pattIdxEnd && pattDirs[pattIdxStart].equals("*") && path.endsWith(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;
        }

        // 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 = pattDirs[pattIdxStart + j + 1];
                    String subStr = 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;
    }

    private boolean matchStrings(String pattern, String str) {
        AntPathStringMatcher matcher = stringMatcherCache.computeIfAbsent(pattern, k -> new AntPathStringMatcher(pattern));
        return matcher.matchStrings(str);
    }

    private static String[] tokenizeToStringArray(String str, String delimiters, boolean trimTokens, boolean ignoreEmptyTokens) {
        if (str == null) {
            return null;
        }
        StringTokenizer st = new StringTokenizer(str, delimiters);
        List tokens = new ArrayList<>();
        while (st.hasMoreTokens()) {
            String token = st.nextToken();
            if (trimTokens) {
                token = token.trim();
            }
            if (!ignoreEmptyTokens || token.length() > 0) {
                tokens.add(token);
            }
        }
        return toStringArray(tokens);
    }

    private static String[] toStringArray(Collection collection) {
        if (collection == null) {
            return null;
        }
        return collection.toArray(new String[collection.size()]);
    }

    private static class AntPathStringMatcher {

        private static final Pattern GLOB_PATTERN = Pattern.compile("\\?|\\*|\\{((?:\\{[^/]+?\\}|[^/{}]|\\\\[{}])+?)\\}");

        private static final String DEFAULT_VARIABLE_PATTERN = "(.*)";

        private final Pattern pattern;

        private final List variableNames = new LinkedList<>();

        AntPathStringMatcher(String pattern) {
            StringBuilder patternBuilder = new StringBuilder();
            Matcher m = GLOB_PATTERN.matcher(pattern);
            int end = 0;
            while (m.find()) {
                patternBuilder.append(quote(pattern, end, m.start()));
                String match = m.group();
                if ("?".equals(match)) {
                    patternBuilder.append('.');
                } else if ("*".equals(match)) {
                    patternBuilder.append(".*");
                } else if (match.startsWith("{") && match.endsWith("}")) {
                    int colonIdx = match.indexOf(':');
                    if (colonIdx == -1) {
                        patternBuilder.append(DEFAULT_VARIABLE_PATTERN);
                        variableNames.add(m.group(1));
                    } else {
                        String variablePattern = match.substring(colonIdx + 1, match.length() - 1);
                        patternBuilder.append('(');
                        patternBuilder.append(variablePattern);
                        patternBuilder.append(')');
                        String variableName = match.substring(1, colonIdx);
                        variableNames.add(variableName);
                    }
                }
                end = m.end();
            }
            patternBuilder.append(quote(pattern, end, pattern.length()));
            this.pattern = Pattern.compile(patternBuilder.toString());
        }

        private String quote(String s, int start, int end) {
            if (start == end) {
                return "";
            }
            return Pattern.quote(s.substring(start, end));
        }

        boolean matchStrings(String str) {
            return pattern.matcher(str).matches();
        }
    }

}