/**
 * Copyright 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.waveprotocol.wave.client.common.util;


/**
 * Information about the current user agent. Some of the information is
 * dynamically determined at runtime, other information is determined at compile
 * time as it is baked into the particular permutation with the deferred binding
 * mechanism.
 *
 * Methods that are statically evaluable allow conditional compilation for
 * different user agents.
 *
 * e.g. currently, the following code:
 *
 *   if (UserAgent.isIE()) {
 *     // do IE-specific implementation
 *   } else {
 *     // do non-IE implementation
 *   }
 *
 * should for "user.agent" set to "ie6" compile down to just the IE-specific
 * implementation.
 *
 * It is not exposed as part of this API which methods are statically determined
 * and which are not, as this may be subject to change. In general it should not
 * matter as the cost of a runtime check is very cheap. If it does matter, it is
 * up to the caller to know and keep track of the current state of affairs.
 *
 */
public abstract class UserAgent {

  /**
   * @return true iff the user agent uses webkit
   */
  public static boolean isWebkit() {
    return UserAgentStaticProperties.get().isWebkit();
  }

  /**
   * @return true iff the user agent uses mobile webkit
   */
  public static boolean isMobileWebkit() {
    return UserAgentStaticProperties.get().isMobileWebkit();
  }

  /**
   * @return true iff the user.agent GWT property is "safari"
   */
  public static boolean isSafari() {
    return UserAgentStaticProperties.get().isSafari();
  }

  /**
   * @return true iff the user.agent GWT property is "gecko" or "gecko1_8"
   */
  public static boolean isFirefox() {
    return UserAgentStaticProperties.get().isFirefox();
  }

  /**
   * @return true iff the user.agent GWT property is "ie6"
   */
  public static boolean isIE() {
    return UserAgentStaticProperties.get().isIE();
  }

  /**
   * @return true iff the user.agent GWT property is "android"
   */
  public static boolean isAndroid() {
    return UserAgentStaticProperties.get().isAndroid();
  }

  /**
   * @return true iff the user.agent GWT property is "iphone"
   */
  public static boolean isIPhone() {
    return UserAgentStaticProperties.get().isIPhone();
  }

  /**
   * @return true if this is the chrome browser
   */
  public static boolean isChrome() {
    return UserAgentRuntimeProperties.get().isChrome();
  }

  public static boolean isIE7() {
    return UserAgentRuntimeProperties.get().isIe7();
  }

  public static boolean isIE8() {
    return UserAgentRuntimeProperties.get().isIe8();
  }

  /**
   * @return true if we are on OSX
   */
  public static boolean isMac() {
    return UserAgentRuntimeProperties.get().isMac();
  }

  /**
   * @return true if we are on Windows
   */
  public static boolean isWin() {
    return UserAgentRuntimeProperties.get().isWin();
  }

  /**
   * @return true if we are on Linux
   */
  public static boolean isLinux() {
    return UserAgentRuntimeProperties.get().isLinux();
  }

  /**
   * Debug method that returns the user-agent string.
   *
   * NOTE(user): FOR DEBUGGING PURPOSES ONLY. DO NOT USE FOR PROGRAM LOGIC.
   */
  public static String debugUserAgentString() {
    return UserAgentRuntimeProperties.get().getUserAgent();
  }

  /**
   * @return whether the current user agent version is at least the one given by
   *         the method parameters.
   */
  public static boolean isAtLeastVersion(int major, int minor) {
    return UserAgentRuntimeProperties.get().isAtLeastVersion(major, minor);
  }

  /**
   * Do not use this for program logic - for debugging only. For program logic,
   * instead use {@link #isAtLeastVersion(int, int)}
   */
  public static int debugGetMajorVer() {
    return UserAgentRuntimeProperties.get().getMajorVer();
  }

  /**
   * Do not use this for program logic - for debugging only. For program logic,
   * instead use {@link #isAtLeastVersion(int, int)}
   */
  public static int debugGetMinorVer() {
    return UserAgentRuntimeProperties.get().getMinorVer();
  }

}