/*

 * Copyright (c) 2012, 2014, 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.

 */

/*

 * @test

 * @bug 7157626 8001112

 * @summary Test major version for all legal combinations for -source and -target

 * @author sgoel

 *

 */

import java.io.*;

import java.nio.*;

import java.util.*;

import java.util.regex.*;

public class ClassVersionChecker {

    int errors;

    String[] jdk = {"","1.6","1.7","1.8"};

    File javaFile = null;

    public static void main(String[] args) throws Throwable {

        new ClassVersionChecker().run();

    }

    void run() throws Exception {

        writeTestFile();

        /* Rules applicable for -source and -target combinations

         * 1. If both empty, version num is for the current release

         * 2. If source is not empty and target is empty, version is based on source

         * 3. If both non-empty, version is based on target

         */

        /* -source (0=>empty,1=>1.2,...) X -target (0=>empty,1=>1.2,...)

         * ver[0][0] => no -source or -target was given

         * -1 => invalid combinations

         */

        int[][] ver =

                {{52, -1, -1, -1},

                 {52, 50, 51, 52},

                 {52, -1, 51, 52},

                 {52, -1, -1, 52}};

        // Loop to run all possible combinations of source/target values

        for (int i = 0; i< ver.length; i++) {

            for (int j = 0 ; j< ver[i].length; j++) {

                if(ver[i][j] != -1) {

                    logMsg("Index values for i = " + i + " j = " + j);

                    logMsg("Running for src = " + jdk[i] + " target = "+jdk[j] +" expected = " + ver[i][j]);

                    test(i,j, ver[i][j]);

                }

            }

        }

        if (errors > 0)

            throw new Exception(errors + " errors found");

    }

    void test (int i, int j, int expected) {

        File classFile = compileTestFile(i, j, javaFile);

        short majorVer = getMajorVersion(classFile);

        checkVersion(majorVer, expected);

    }

    void writeTestFile() throws IOException {

        javaFile = new File("Test.java");

        try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(javaFile)));) {

            out.println("class Test { ");

            out.println("  public void foo() { }");

            out.println("}");

        } catch (IOException ioe) {

            error("IOException while creating Test.java" + ioe);

        }

    }

    File compileTestFile(int i , int j, File f) {

        int rc = -1;

        // Src and target are empty

        if (i == 0 && j == 0 ) {

            rc = compile("-g", f.getPath());

        } else if( j == 0 ) {  // target is empty

            rc = compile("-source", jdk[i], "-g", f.getPath());

        } else {

            rc = compile("-source", jdk[i], "-target", jdk[j], "-g", f.getPath());

        }

        if (rc != 0)

            throw new Error("compilation failed. rc=" + rc);

        String path = f.getPath();

        return new File(path.substring(0, path.length() - 5) + ".class");

    }

    int compile(String... args) {

        return com.sun.tools.javac.Main.compile(args);

    }

    void logMsg (String str) {

        System.out.println(str);

    }

    short getMajorVersion(File f) {

        List<String> args = new ArrayList<String>();

        short majorVer = 0;

        try(DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream(f)));) {

            in.readInt();

            in.readShort();

            majorVer = in.readShort();

            System.out.println("major version:" +  majorVer);

        } catch (IOException e) {

            error("IOException while reading Test.class" + e);

        }

        return majorVer;

    }

    void checkVersion(short majorVer, int expected) {

        if (majorVer != expected ) {

            error("versions did not match, Expected: " + expected + "Got: " + majorVer);

        }

    }

    void error(String msg) {

       System.out.println("error: " + msg);

       errors++;

    }

}