/* 
* Copyright (C) 2011 pengjianbo iBoxPay Information Technology Co.,Ltd. 
* 
* All right reserved. 
* 
* This software is the confidential and proprietary 
* information of iBoxPay Company of China. 
* ("Confidential Information"). You shall not disclose 
* such Confidential Information and shall use it only 
* in accordance with the terms of the contract agreement 
* you entered into with iBoxpay inc. 
* 
* $Id: CountDownTimer.java 552 2013-10-09 07:21:31Z huangliqing $
* 
*/

package com.moral.andbrickslib.utils;

import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;

/**
 * 解决系统的CountDownTimer cancel失效问题 <br/>
 *
 * Schedule a countdown until a time in the future, with
 * regular notifications on intervals along the way.
 *
 * Example of showing a 30 second countdown in a text field:
 *
 * <pre class="prettyprint">
 * new CountdownTimer(30000, 1000) {
 *
 * public void onTick(long millisUntilFinished) {
 * mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
 * }
 *
 * public void onFinish() {
 * mTextField.setText("done!");
 * }
 * }.start();
 * </pre>
 *
 * The calls to {@link #onTick(long)} are synchronized to this object so that
 * one call to {@link #onTick(long)} won't ever occur before the previous
 * callback is complete.  This is only relevant when the implementation of
 * {@link #onTick(long)} takes an amount of time to execute that is significant
 * compared to the countdown interval.
 */
public abstract class CountDownTimer {

    private static final int MSG = 1;
    /**
     * Millis since epoch when alarm should stop.
     */
    private final long mMillisInFuture;

    /**
     * The interval in millis that the user receives callbacks
     */
    private final long mCountdownInterval;
    private boolean mCanceled = false;
    private long mStopTimeInFuture;
    // handles counting down
    private Handler mHandler = new Handler() {

        @Override public void handleMessage(Message msg) {

            synchronized (CountDownTimer.this) {
                final long millisLeft = mStopTimeInFuture - SystemClock.elapsedRealtime();

                if (millisLeft <= 0 || mCanceled) {
                    onFinish();
                } else if (millisLeft < mCountdownInterval) {
                    // no tick, just delay until done
                    sendMessageDelayed(obtainMessage(MSG), millisLeft);
                } else {
                    long lastTickStart = SystemClock.elapsedRealtime();
                    onTick(millisLeft);

                    // take into account user's onTick taking time to execute
                    long delay = lastTickStart + mCountdownInterval - SystemClock.elapsedRealtime();

                    // special case: user's onTick took more than interval to
                    // complete, skip to next interval
                    while (delay < 0) delay += mCountdownInterval;

                    sendMessageDelayed(obtainMessage(MSG), delay);
                }
            }
        }
    };

    /**
     * @param millisInFuture The number of millis in the future from the call
     * to {@link #start()} until the countdown is done and {@link #onFinish()}
     * is called.
     * @param countDownInterval The interval along the way to receive
     * {@link #onTick(long)} callbacks.
     */
    public CountDownTimer(long millisInFuture, long countDownInterval) {
        mMillisInFuture = millisInFuture;
        mCountdownInterval = countDownInterval;
    }

    /**
     * Cancel the countdown.
     */
    public final void cancel() {
        mHandler.removeMessages(MSG);
        mCanceled = true;
    }

    /**
     * Start the countdown.
     */
    public synchronized final CountDownTimer start() {
        if (mMillisInFuture <= 0) {
            onFinish();
            return this;
        }
        mStopTimeInFuture = SystemClock.elapsedRealtime() + mMillisInFuture;
        mHandler.sendMessage(mHandler.obtainMessage(MSG));
        mCanceled = false;
        return this;
    }

    /**
     * Callback fired on regular interval.
     *
     * @param millisUntilFinished The amount of time until finished.
     */
    public abstract void onTick(long millisUntilFinished);

    /**
     * Callback fired when the time is up.
     */
    public abstract void onFinish();
}