/**
 * 下拉刷新控件
 * Author: wangjie
 * Email: tiantian.china.2@gmail.com
 * Date: 12/13/14.
 */
public class RefreshableView extends LinearLayout {
  private static final String TAG = RefreshableView.class.getSimpleName();

  public RefreshableView(Context context) {
    super(context);
    init(context);
  }

  public RefreshableView(Context context, AttributeSet attrs) {
    super(context, attrs);

    TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.refreshableView);
    for (int i = 0, len = a.length(); i < len; i++) {
      int attrIndex = a.getIndex(i);
      switch (attrIndex) {
        case R.styleable.refreshableView_interceptAllMoveEvents:
          interceptAllMoveEvents = a.getBoolean(i, false);
          break;
      }
    }
    a.recycle();

    init(context);
  }

  public RefreshableView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init(context);
  }

  /**
   * 刷新状态
   */
  public static final int STATE_REFRESH_NORMAL = 0x21;
  public static final int STATE_REFRESH_NOT_ARRIVED = 0x22;
  public static final int STATE_REFRESH_ARRIVED = 0x23;
  public static final int STATE_REFRESHING = 0x24;
  private int refreshState;
  // 刷新状态监听
  private RefreshableHelper refreshableHelper;

  public void setRefreshableHelper(RefreshableHelper refreshableHelper) {
    this.refreshableHelper = refreshableHelper;
  }

  private Context context;
  /**
   * 刷新的view
   */
  private View refreshHeaderView;
  /**
   * 刷新的view的真实高度
   */
  private int originRefreshHeight;
  /**
   * 有效下拉刷新需要达到的高度
   */
  private int refreshArrivedStateHeight;
  /**
   * 刷新时显示的高度
   */
  private int refreshingHeight;
  /**
   * 正常未刷新高度
   */
  private int refreshNormalHeight;


  /**
   * 默认不允许拦截（即，往子view传递事件），该属性只有在interceptAllMoveEvents为false的时候才有效
   */
  private boolean disallowIntercept = true;
  /**
   * xml中可设置它的值为false，表示不把移动的事件传递给子控件
   */
  private boolean interceptAllMoveEvents;

  private void init(Context context) {
    this.context = context;
    this.setOrientation(VERTICAL);

//    Log.d(TAG, "[init]originRefreshHeight: " + refreshHeaderView.getMeasuredHeight());
  }

  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);

    if (null != refreshableHelper) {
      refreshHeaderView = refreshableHelper.onInitRefreshHeaderView();
    }
//    refreshHeaderView = LayoutInflater.from(context).inflate(R.layout.refresh_head, null);
    if (null == refreshHeaderView) {
      Log.e(TAG, "refreshHeaderView is null!");
      return;
    }
    this.removeView(refreshHeaderView);
    this.addView(refreshHeaderView, 0);

    // 计算refreshHeadView尺寸
    int width = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
    int expandSpec = View.MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2, View.MeasureSpec.AT_MOST);
    refreshHeaderView.measure(width, expandSpec);

    Log.d(TAG, "[onSizeChanged]w: " + w + ", h: " + h);
    Log.d(TAG, "[onSizeChanged]oldw: " + oldw + ", oldh: " + oldh);
    Log.d(TAG, "[onSizeChanged]child counts: " + this.getChildCount());
    originRefreshHeight = refreshHeaderView.getMeasuredHeight();

    boolean isUseDefault = true;
    if (null != refreshableHelper) {
      isUseDefault = refreshableHelper.onInitRefreshHeight(originRefreshHeight);
    }

    // 初始化各个高度
    if (isUseDefault) {
      refreshArrivedStateHeight = originRefreshHeight;
      refreshingHeight = originRefreshHeight;
      refreshNormalHeight = 0;
    }
    Log.d(TAG, "[onSizeChanged]refreshHeaderView origin height: " + originRefreshHeight);
    changeViewHeight(refreshHeaderView, refreshNormalHeight);

    // 初始化为正常状态
    setRefreshState(STATE_REFRESH_NORMAL);

  }

  @Override
  public boolean dispatchTouchEvent(MotionEvent ev) {
    Log.d(TAG, "[dispatchTouchEvent]ev action: " + ev.getAction());
    return super.dispatchTouchEvent(ev);
  }

  @Override
  public boolean onInterceptTouchEvent(MotionEvent ev) {
    Log.d(TAG, "[onInterceptTouchEvent]ev action: " + ev.getAction());
    if (!interceptAllMoveEvents) {
      return !disallowIntercept;
    }
    // 如果设置了拦截所有move事件，即interceptAllMoveEvents为true
    if (MotionEvent.ACTION_MOVE == ev.getAction()) {
      return true;
    }
    return false;
  }

  @Override
  public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) {
    if (this.disallowIntercept == disallowIntercept) {
      return;
    }
    this.disallowIntercept = disallowIntercept;
    super.requestDisallowInterceptTouchEvent(disallowIntercept);
  }

  private float downY = Float.MAX_VALUE;

  @Override
  public boolean onTouchEvent(MotionEvent event) {
//    super.onTouchEvent(event);
    Log.d(TAG, "[onTouchEvent]ev action: " + event.getAction());
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        downY = event.getY();
        Log.d(TAG, "Down --> downY: " + downY);
        requestDisallowInterceptTouchEvent(true); // 保证事件可往下传递
        break;
      case MotionEvent.ACTION_MOVE:

        float curY = event.getY();
        float deltaY = curY - downY;
        // 是否是有效的往下拖动事件（则需要显示加载header）
        boolean isDropDownValidate = Float.MAX_VALUE != downY;
        /**
         * 修改拦截设置
         * 如果是有效往下拖动事件，则事件需要在本ViewGroup中处理，所以需要拦截不往子控件传递，即不允许拦截设为false
         * 如果是有效往下拖动事件，则事件传递给子控件处理，所以不需要拦截，并往子控件传递，即不允许拦截设为true
         */
        requestDisallowInterceptTouchEvent(!isDropDownValidate);

        downY = curY;
        Log.d(TAG, "Move --> deltaY(curY - downY): " + deltaY);
        int curHeight = refreshHeaderView.getMeasuredHeight();
        int exceptHeight = curHeight + (int) (deltaY / 2);

        // 如果当前没有处在正在刷新状态，则更新刷新状态
        if (STATE_REFRESHING != refreshState) {
          if (curHeight >= refreshArrivedStateHeight) { // 达到可刷新状态
            setRefreshState(STATE_REFRESH_ARRIVED);
          } else { // 未达到可刷新状态
            setRefreshState(STATE_REFRESH_NOT_ARRIVED);
          }
        }
        if (isDropDownValidate) {
          changeViewHeight(refreshHeaderView, Math.max(refreshNormalHeight, exceptHeight));
        } else { // 防止从子控件修改拦截后引发的downY为Float.MAX_VALUE的问题
          changeViewHeight(refreshHeaderView, Math.max(curHeight, exceptHeight));
        }

        break;
      case MotionEvent.ACTION_UP:
        downY = Float.MAX_VALUE;
        Log.d(TAG, "Up --> downY: " + downY);
        requestDisallowInterceptTouchEvent(true); // 保证事件可往下传递
        // 如果是达到刷新状态，则设置正在刷新状态的高度
        if (STATE_REFRESH_ARRIVED == refreshState) { // 达到了刷新的状态
          startHeightAnimation(refreshHeaderView, refreshHeaderView.getMeasuredHeight(), refreshingHeight);
          setRefreshState(STATE_REFRESHING);
        } else if (STATE_REFRESHING == refreshState) { // 正在刷新的状态
          startHeightAnimation(refreshHeaderView, refreshHeaderView.getMeasuredHeight(), refreshingHeight);
        } else {
          // 执行动画后回归正常状态
          startHeightAnimation(refreshHeaderView, refreshHeaderView.getMeasuredHeight(), refreshNormalHeight, normalAnimatorListener);
        }

        break;
      case MotionEvent.ACTION_CANCEL:
        Log.d(TAG, "cancel");
        break;
    }
    return true;
  }

  /**
   * 刷新完毕后调用此方法
   */
  public void onCompleteRefresh() {
    if (STATE_REFRESHING == refreshState) {
      setRefreshState(STATE_REFRESH_NORMAL);
      startHeightAnimation(refreshHeaderView, refreshHeaderView.getMeasuredHeight(), refreshNormalHeight);
    }
  }

  /**
   * 修改当前的刷新状态
   *
   * @param expectRefreshState
   */
  private void setRefreshState(int expectRefreshState) {
    if (expectRefreshState != refreshState) {
      refreshState = expectRefreshState;
      if (null != refreshableHelper) {
        refreshableHelper.onRefreshStateChanged(refreshHeaderView, refreshState);
      }
    }
  }


  /**
   * 改变某控件的高度
   *
   * @param view
   * @param height
   */
  private void changeViewHeight(View view, int height) {
    Log.d(TAG, "[changeViewHeight]change Height: " + height);
    ViewGroup.LayoutParams lp = view.getLayoutParams();
    lp.height = height;
    view.setLayoutParams(lp);
  }

  /**
   * 改变某控件的高度动画
   *
   * @param view
   * @param fromHeight
   * @param toHeight
   */
  private void startHeightAnimation(final View view, int fromHeight, int toHeight) {
    startHeightAnimation(view, fromHeight, toHeight, null);
  }

  private void startHeightAnimation(final View view, int fromHeight, int toHeight, Animator.AnimatorListener animatorListener) {
    if (toHeight == view.getMeasuredHeight()) {
      return;
    }
    ValueAnimator heightAnimator = ValueAnimator.ofInt(fromHeight, toHeight);
    heightAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
      @Override
      public void onAnimationUpdate(ValueAnimator valueAnimator) {
        Integer value = (Integer) valueAnimator.getAnimatedValue();
        if (null == value) return;
        changeViewHeight(view, value);
      }
    });
    if (null != animatorListener) {
      heightAnimator.addListener(animatorListener);
    }
    heightAnimator.setInterpolator(new LinearInterpolator());
    heightAnimator.setDuration(300/*ms*/);
    heightAnimator.start();
  }

  AnimatorListenerAdapter normalAnimatorListener = new AnimatorListenerAdapter() {
    @Override
    public void onAnimationEnd(Animator animation) {
      super.onAnimationEnd(animation);
      setRefreshState(STATE_REFRESH_NORMAL); // 回归正常状态
    }
  };

  public void setRefreshArrivedStateHeight(int refreshArrivedStateHeight) {
    this.refreshArrivedStateHeight = refreshArrivedStateHeight;
  }

  public void setRefreshingHeight(int refreshingHeight) {
    this.refreshingHeight = refreshingHeight;
  }

  public void setRefreshNormalHeight(int refreshNormalHeight) {
    this.refreshNormalHeight = refreshNormalHeight;
  }

  public int getOriginRefreshHeight() {
    return originRefreshHeight;
  }

<com.wangjie.refreshableview.RefreshableView
      xmlns:rv="http://schemas.android.com/apk/res/com.wangjie.refreshableview"
      android:id="@+id/main_refresh_view"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      rv:interceptAllMoveEvents="false"
      >
    <com.wangjie.refreshableview.NestScrollView android:layout_width="match_parent" android:layout_height="wrap_content"
        android:fillViewport="true"
        >

      <TextView
          android:id="@+id/main_tv"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:gravity="center"
          android:padding="20dp"
          android:textSize="18sp"
          android:text="Drop Down For Refresh\n\n\n\n\n\n\n\n\n\n\nDrop Down For Refresh\nDrop Down For Refresh\n\n\n\n\n\n\n\n\n\n\nDrop Down For Refresh\nDrop Down For Refresh\n\n\n\n\n\n\n\n\n\n\nDrop Down For Refresh\nDrop Down For Refresh\n\n\n\n\n\n\n\n\n\n\nDrop Down For Refresh"
          />

    </com.wangjie.refreshableview.NestScrollView>
  </com.wangjie.refreshableview.RefreshableView>

/**
 * Author: wangjie
 * Email: tiantian.china.2@gmail.com
 * Date: 12/13/14.
 */
public class NestScrollView extends ScrollView {
  private static final String TAG = NestScrollView.class.getSimpleName();

  public NestScrollView(Context context) {
    super(context);
  }

  public NestScrollView(Context context, AttributeSet attrs) {
    super(context, attrs);
  }

  public NestScrollView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
  }

  @Override
  public boolean dispatchTouchEvent(MotionEvent ev) {
    Log.d(TAG, "___[dispatchTouchEvent]ev action: " + ev.getAction());
    return super.dispatchTouchEvent(ev);
  }

  @Override
  public boolean onInterceptTouchEvent(MotionEvent ev) {
    super.onInterceptTouchEvent(ev);
    Log.d(TAG, "___[onInterceptTouchEvent]ev action: " + ev.getAction());
    if (MotionEvent.ACTION_MOVE == ev.getAction()) {
      return true;
    }
    return false;
  }

  float lastDownY;

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    super.onTouchEvent(event);
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        lastDownY = event.getY();
        parentRequestDisallowInterceptTouchEvent(true); // 保证事件可往下传递
        Log.d(TAG, "___Down");
        return true;
//        break;
      case MotionEvent.ACTION_MOVE:
        Log.d(TAG, "___move, this.getScrollY(): " + this.getScrollY());
        boolean isTop = event.getY() - lastDownY > 0 && this.getScrollY() == 0;
        if (isTop) { // 允许父控件拦截，即不允许父控件拦截设为false
          parentRequestDisallowInterceptTouchEvent(false);
          return false;
        } else { // 不允许父控件拦截，即不允许父控件拦截设为true
          parentRequestDisallowInterceptTouchEvent(true);
          return true;
        }
//        break;
      case MotionEvent.ACTION_UP:
        Log.d(TAG, "___up, this.getScrollY(): " + this.getScrollY());
        parentRequestDisallowInterceptTouchEvent(true); // 保证事件可往下传递
        break;
      case MotionEvent.ACTION_CANCEL:
        Log.d(TAG, "___cancel");
        break;
    }
    return false;
  }

  /**
   * 是否允许父控件拦截事件
   * @param disallowIntercept
   */
  private void parentRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
    ViewParent vp = getParent();
    if (null == vp) {
      return;
    }
    vp.requestDisallowInterceptTouchEvent(disallowIntercept);
  }

}