/*
 * Copyright (c) 2012, 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.
 *
 * 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 org.graalvm.compiler.debug;

import java.util.Arrays;
import java.util.regex.Pattern;

import jdk.vm.ci.meta.JavaMethod;
import jdk.vm.ci.meta.JavaType;
import jdk.vm.ci.meta.Signature;

/**
 * This class implements a method filter that can filter based on class name, method name and
 * parameters. The syntax for the source pattern that is passed to the constructor is as follows:
 *
 * <pre>
 * SourcePatterns = SourcePattern ["," SourcePatterns] .
 * SourcePattern = [ Class "." ] method [ "(" [ Parameter { ";" Parameter } ] ")" ] .
 * Parameter = Class | "int" | "long" | "float" | "double" | "short" | "char" | "boolean" .
 * Class = { package "." } class .
 * </pre>
 *
 *
 * Glob pattern matching (*, ?) is allowed in all parts of the source pattern. Examples for valid
 * filters are:
 *
 * <ul>
 * <li>
 *
 * <pre>
 * visit(Argument;BlockScope)
 * </pre>
 *
 * Matches all methods named "visit", with the first parameter of type "Argument", and the second
 * parameter of type "BlockScope". The packages of the parameter types are irrelevant.</li>
 * <li>
 *
 * <pre>
 * arraycopy(Object;;;;)
 * </pre>
 *
 * Matches all methods named "arraycopy", with the first parameter of type "Object", and four more
 * parameters of any type. The packages of the parameter types are irrelevant.</li>
 * <li>
 *
 * <pre>
 * org.graalvm.compiler.core.graph.PostOrderNodeIterator.*
 * </pre>
 *
 * Matches all methods in the class "org.graalvm.compiler.core.graph.PostOrderNodeIterator".</li>
 * <li>
 *
 * <pre>
 * *
 * </pre>
 *
 * Matches all methods in all classes</li>
 * <li>
 *
 * <pre>
 * org.graalvm.compiler.core.graph.*.visit
 * </pre>
 *
 * Matches all methods named "visit" in classes in the package "org.graalvm.compiler.core.graph".
 * <li>
 *
 * <pre>
 * arraycopy,toString
 * </pre>
 *
 * Matches all methods named "arraycopy" or "toString", meaning that ',' acts as an <i>or</i>
 * operator.</li>
 * </ul>
 */
public class MethodFilter {

    private final Pattern clazz;
    private final Pattern methodName;
    private final Pattern[] signature;

    /**
     * Parses a string containing list of comma separated filter patterns into an array of
     * {@link MethodFilter}s.
     */
    public static MethodFilter[] parse(String commaSeparatedPatterns) {
        String[] filters = commaSeparatedPatterns.split(",");
        MethodFilter[] methodFilters = new MethodFilter[filters.length];
        for (int i = 0; i < filters.length; i++) {
            methodFilters[i] = new MethodFilter(filters[i]);
        }
        return methodFilters;
    }

    /**
     * Determines if a given method is matched by a given array of filters.
     */
    public static boolean matches(MethodFilter[] filters, JavaMethod method) {
        for (MethodFilter filter : filters) {
            if (filter.matches(method)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Determines if a given class name is matched by a given array of filters.
     */
    public static boolean matchesClassName(MethodFilter[] filters, String className) {
        for (MethodFilter filter : filters) {
            if (filter.matchesClassName(className)) {
                return true;
            }
        }
        return false;
    }

    public MethodFilter(String sourcePattern) {
        String pattern = sourcePattern.trim();

        // extract parameter part
        int pos = pattern.indexOf('(');
        if (pos != -1) {
            if (pattern.charAt(pattern.length() - 1) != ')') {
                throw new IllegalArgumentException("missing ')' at end of method filter pattern: " + pattern);
            }
            String[] signatureClasses = pattern.substring(pos + 1, pattern.length() - 1).split(";", -1);
            signature = new Pattern[signatureClasses.length];
            for (int i = 0; i < signatureClasses.length; i++) {
                signature[i] = createClassGlobPattern(signatureClasses[i].trim());
            }
            pattern = pattern.substring(0, pos);
        } else {
            signature = null;
        }

        // If there is at least one "." then everything before the last "." is the class name.
        // Otherwise, the pattern contains only the method name.
        pos = pattern.lastIndexOf('.');
        if (pos != -1) {
            clazz = createClassGlobPattern(pattern.substring(0, pos));
            methodName = Pattern.compile(createGlobString(pattern.substring(pos + 1)));
        } else {
            clazz = null;
            methodName = Pattern.compile(createGlobString(pattern));
        }
    }

    public static String createGlobString(String pattern) {
        return Pattern.quote(pattern).replace("?", "\\E.\\Q").replace("*", "\\E.*\\Q");
    }

    private static Pattern createClassGlobPattern(String pattern) {
        if (pattern.length() == 0) {
            return null;
        } else if (pattern.contains(".")) {
            return Pattern.compile(createGlobString(pattern));
        } else {
            return Pattern.compile("([^\\.\\$]*[\\.\\$])*" + createGlobString(pattern));
        }
    }

    public boolean hasSignature() {
        return signature != null;
    }

    /**
     * Determines if the class part of this filter matches a given class name.
     */
    public boolean matchesClassName(String className) {
        return clazz == null || clazz.matcher(className).matches();
    }

    public boolean matches(JavaMethod o) {
        // check method name first, since MetaUtil.toJavaName is expensive
        if (methodName != null && !methodName.matcher(o.getName()).matches()) {
            return false;
        }
        if (clazz != null && !clazz.matcher(o.getDeclaringClass().toJavaName()).matches()) {
            return false;
        }
        return matchesSignature(o.getSignature());
    }

    private boolean matchesSignature(Signature sig) {
        if (signature == null) {
            return true;
        }
        if (sig.getParameterCount(false) != signature.length) {
            return false;
        }
        for (int i = 0; i < signature.length; i++) {
            JavaType type = sig.getParameterType(i, null);
            String javaName = type.toJavaName();
            if (signature[i] != null && !signature[i].matcher(javaName).matches()) {
                return false;
            }
        }
        return true;
    }

    public boolean matches(String javaClassName, String name, Signature sig) {
        assert sig != null || signature == null;
        // check method name first, since MetaUtil.toJavaName is expensive
        if (methodName != null && !methodName.matcher(name).matches()) {
            return false;
        }
        if (clazz != null && !clazz.matcher(javaClassName).matches()) {
            return false;
        }
        return matchesSignature(sig);
    }

    @Override
    public String toString() {
        StringBuilder buf = new StringBuilder("MethodFilter[");
        String sep = "";
        if (clazz != null) {
            buf.append(sep).append("clazz=").append(clazz);
            sep = ", ";
        }
        if (methodName != null) {
            buf.append(sep).append("methodName=").append(methodName);
            sep = ", ";
        }
        if (signature != null) {
            buf.append(sep).append("signature=").append(Arrays.toString(signature));
            sep = ", ";
        }
        return buf.append("]").toString();
    }
}