/*
 * Copyright 2013 Guidewire Software, Inc.
 */

package gw.internal.gosu.properties;

import gw.fs.IFile;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.TreeSet;

/**
 * Makes available the standard system properties, which should be available on all JVMs
 */
public class SystemPropertiesPropertySet implements PropertySet {

  public static final PropertySetSource SOURCE = new PropertySetSource() {

    private final PropertySet _propertySet = new SystemPropertiesPropertySet();

    @Override
    public Set<String> getPropertySetNames() {
      return Collections.singleton(_propertySet.getName());
    }

    @Override
    public PropertySet getPropertySet(String name) {
      if (!_propertySet.getName().equalsIgnoreCase(name)) {
        throw new IllegalArgumentException(name + " is not the name of the SystemProperties property set");
      }
      return _propertySet;
    }

    @Override
    public PropertySet getPropertySetForFile(IFile file) {
      return null;
    }

    @Override
    public IFile getFile(String name) {
      return null;
    }

  };

  private final Set<String> _keys = Collections.unmodifiableSet(new TreeSet<String>(Arrays.asList(
          "java.version",
          "java.vendor",
          "java.vendor.url",
          "java.home",
          "java.vm.specification.version",
          "java.vm.specification.vendor",
          "java.vm.specification.name",
          "java.vm.version",
          "java.vm.vendor",
          "java.vm.name",
          "java.specification.version",
          "java.specification.vendor",
          "java.specification.name",
          "java.class.version",
          "java.class.path",
          "java.library.path",
          "java.io.tmpdir",
          "java.compiler",
          "java.ext.dirs",
          "os.name",
          "os.arch",
          "os.version",
          "file.separator",
          "path.separator",
          "line.separator",
          "user.name",
          "user.home",
          "user.dir"
  )));

  private SystemPropertiesPropertySet() {}

  @Override
  public Set<String> getKeys() {
    return _keys;
  }

  @Override
  public String getName() {
    return "gw.lang.SystemProperties";
  }

  @Override
  public String getValue(String key) {
    return System.getProperty(key);
  }

}