/* JavaConfig - tool for getting paths for current java environment.

 * © 2011, 2012, 2014, 2017  Petr Písař <ppisar@redhat.com>

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 * 

 * This program 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 for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

class JavaConfig {

  private static String output = "";

  /*

   * Append text to output with proper padding or terminates if text is null.

   * @param text String to append.

   */

  private static void concatenate(String text) {

    if (text == null) {

      System.exit(2);

    }

    output = (output.equals("") ? ""  : output + " " ) + text;

  }

  /*

   * Show usage message and terminates program with given @exit_code.

   * @param exit_code code to return

   * */

  private static void usage(int exitCode) {

    System.out.print(

        "JavaConfig [OPTIONS]\n" +

        "  --home         Output path to Java home\n" +

        "  --libs-only-L  Output -L linker flags\n" +

        "  --version      Output Java version on first separate line\n"

    );

    System.exit(exitCode);

  }

  /*

   * @Return path to Java home or null in case of error.

   */

  public static String home() {

    return System.getProperty("java.home");

  }

  /*

   * @Return formated libary search path as -L compiler flag,

   * null if error occured.

   * */

  public static String libsOnlyL() {

    String value;

    String architecture = System.getProperty("os.arch");

    String home = home();

    String filesep = System.getProperty("file.separator");

    String paths[];

    /* The java.library.path works up to JDK 1.6. */

    if (null == (value = System.getProperty("java.library.path"))) {

      return null;

    }

    /* The java.library.path does not work since JDK 1.7. See

     * <https://bugzilla.redhat.com/show_bug.cgi?id=740762>.

     * The "client" subdirectory is need on AArch64 since JDK 1.8. See

     * <https://bugzilla.redhat.com/show_bug.cgi?id=1112012>. */

    if (null == architecture || null == home || null == filesep) {

      return null;

    }

    /* Experimental 32-bit ARM openjdk variant uses lib/aarch32. See

     * <https://bugzilla.redhat.com/show_bug.cgi?id=1412953>. */

    if (architecture.contentEquals("arm") && home.contains("aarch32")) {

      architecture = "aarch32";

    }

    value = value + ":" +

      home + filesep + "lib" + filesep + architecture + ":" +

      home + filesep + "lib" + filesep + architecture + filesep + "server" +

        ":" +

      home + filesep + "lib" + filesep + architecture + filesep + "client";

    /* Convert the colon-delimited paths to LDFLAGS format */

    paths = value.split(":");

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

      if (paths[i].equals("")) {

        continue;

      }

      if (i == 0) {

        value = "-L" + paths[i];

      } else {

        value = value + " -L" + paths[i];

      }

    }

    value = value + " -Wl,-rpath," + home + filesep + "lib" + architecture +

	    filesep + "server";

    return value;

  }

  /*

   * @Return version of Java home or null in case of error.

   */

  public static String version() {

    return System.getProperty("java.version");

  }

  /*

   * Entry point to this class.

   */

  public static void main(String argv[]) {

    if (argv.length < 1) {

      usage(1);

    }

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

      if (argv[i].equals("--home")) {

          concatenate(home());

      } else if (argv[i].equals("--libs-only-L")) {

          concatenate(libsOnlyL());

      } else if (argv[i].equals("--version")) {

          /* pkg-config prints version on first line */

          String version = version();

          if (null == version) {

            System.exit(2);

          }

          System.out.println(version);

      } else {

          usage(1);

      }

    }

    if (!output.equals("")) {

      System.out.println(output);

    }

    System.exit(0);

  }

}