/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.test.utility.classfile;

import java.io.IOException;
import java.util.Date;
import java.util.Enumeration;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

import org.eclipse.persistence.tools.workbench.utility.Classpath;
import org.eclipse.persistence.tools.workbench.utility.classfile.ClassFile;


/**
 * rip through some JARs, parsing the byte codes of all
 * the contained .class files, and logging some
 * performance statistics
 */
public class ClassFileJarScanner {
    private String jarFileName;
    private int totalEntries = 0;
    private int nonClassFiles = 0;
    private float matches = 0;
    private int mismatches = 0;
    private float elapsedSeconds = 0;

    public static void main(String[] args) throws IOException {
        System.out.println("begin...");
        System.out.println();

        ClassFileJarScanner scanner = new ClassFileJarScanner(toplinkJarFileName());
        scanner.scan();
        scanner.printSummary();

        System.out.println();

        scanner = new ClassFileJarScanner(Classpath.rtJarName());
        scanner.scan();
        scanner.printSummary();

        System.out.println();
        System.out.println("...end");
    }

    public static String toplinkJarFileName() {
        return Classpath.javaClasspath().entryForFileNamed("toplink_g.jar").fileName();
    }

    public ClassFileJarScanner(String jarFileName) {
        super();
        this.jarFileName = jarFileName;
    }

    public void scan() throws IOException {
        long startTime = (new Date()).getTime();
        this.scanUntimed();
        long endTime = (new Date()).getTime();
        this.elapsedSeconds = (endTime - startTime) / 1000f;
    }

    public void scanUntimed() throws IOException {
        JarFile jarFile = new JarFile(this.jarFileName);
        try {
            this.scanJarFile(jarFile);
        } finally {
            jarFile.close();
        }
    }

    private void scanJarFile(JarFile jarFile) {
        for (Enumeration entries = jarFile.entries(); entries.hasMoreElements(); ) {
            this.scanJarEntry(jarFile, (JarEntry) entries.nextElement());
        }
    }

    private void scanJarEntry(JarFile jarFile, JarEntry jarEntry) {
        this.totalEntries++;
        String jarEntryName = jarEntry.getName();
        if (jarEntryName.endsWith(".class")) {
            this.scanStream(jarFile, jarEntry, jarEntryName);
        } else {
            this.nonClassFiles++;
        }
    }

    private void scanStream(JarFile jarFile, JarEntry jarEntry, String jarEntryName) {
        boolean validClassStream = true;
        ClassFile classFile = null;
        try {
            classFile = ClassFile.fromArchiveEntry(jarFile, jarEntry);
        } catch (IOException ex) {
            System.out.println("IOException: " + ex);
            validClassStream = false;
        }
        // look for a "synthetic" class...
//        if (classFile.isSynthetic()) {
//            System.out.println("\"synthetic\" class: " + classFile.className());
//        }
        if (validClassStream && classFile.className().equals(jarEntryName.substring(0, jarEntryName.length() - 6).replace('/', '.'))) {
            this.matches++;
        } else {
            this.mismatches++;
            System.out.println("mismatch: " + jarEntryName + " vs. " + classFile.className());
        }
    }

    public void printSummary() {
        System.out.println("JAR: " + this.jarFileName);
        System.out.println("totalEntries: " + this.totalEntries);
        System.out.println("matches: " + this.matches);
        System.out.println("mismatches: " + this.mismatches);
        System.out.println("non-class files: " + this.nonClassFiles);
        System.out.println("elapsed time: " + this.elapsedSeconds + " seconds");
        System.out.println("performance: " + (this.matches/this.elapsedSeconds) + " class files/second");
        System.out.println("(approx. 1000/sec?)");
    }

}