using System;
using Android.Content;
using Android.Views;
using Android.Views.Animations;

namespace Shared
{
    /// <summary>
    /// 音乐滑动视图
    /// </summary>
    public class MusicVerticalScrolViewLayout : ViewGroup
    {
        /// <summary>
        /// 构造函数
        /// </summary>
        public MusicVerticalScrolViewLayout()
        {
            viewGroup = new AndroidScrolView11(Application.Activity, this);
            var tempViewGroup = new Android.Widget.FrameLayout(Application.Activity);
            //ScrollView这样的控件需要先有个容器，而且容器高宽不能设定，而是由容器里的子控件高度决定
            viewGroup.AddView(tempViewGroup);
            realViewGroup = new Android.Widget.FrameLayout(Application.Activity);
            tempViewGroup.AddView(realViewGroup);
        }
      
        //这个方法检查过没有问题
        /// <summary>
        /// 添加子控件
        /// </summary>
        /// <param name="view">View.</param>
        public override void AddChidren(View view)
        {
            base.AddChidren(view);
            int height = 0;
            foreach(View tempView in viewList){
                if(height<tempView.Bottom)
                {
                    height = tempView.Bottom;
                }
            }
            realViewGroup.LayoutParameters.Height = height < viewGroup.LayoutParameters.Height ? viewGroup.LayoutParameters.Height+10 : height;
		}

        /// <summary>
        ///  根据绝对坐标来确定当前选择了哪个控件
        /// </summary>
        /// <returns><c>true</c>, if range of view was ined, <c>false</c> otherwise.</returns>
        /// <param name="view">View.</param>
        /// <param name="point">Point.</param>
        bool inRangeOfView(Android.Views.View view, Android.Graphics.Point point)
        {
            var location = new int[2];
            view.GetLocationOnScreen(location);
            int y = location[1];
            if (point.Y < y || point.Y > (y + view.Height))
            {
                return false;
            }
            return true;
        }

        bool isSameZone (Android.Views.View view)
        {
            var location = new int [2];
            view.GetLocationOnScreen (location);
            int y = location [1];
            if (y + view.Height / 2 < selectViewBeforeY || y > selectViewBeforeY + view.Height / 2) {
                return false;
            }
            return true;
        }

        /// <summary>
        /// 根据点击位置找出点击到的视图
        /// </summary>
        /// <returns>The view of point.</returns>
        /// <param name="point">Point.</param>
        /// <param name="view">Uiview.</param>
        Android.Views.View replaceViewOfPoint(Android.Views.View view, Android.Graphics.Point point)
        {
            //第一个是背景图
            for (int i = realViewGroup.ChildCount - 1; 0 <= i; i--)
            {
                var tempView = realViewGroup.GetChildAt(i);
                if (tempView != view)
                {
                    if (inRangeOfView(tempView, point))
                    {
                        return tempView;
                    }
                }
            }
            return null;
        }

        /// <summary>
        /// 
        /// </summary>
        public Action<View, View> ReplaceChanged;
        /// <summary>
        /// 长按事件
        /// </summary>
        public Action<View> LongPressAction;

        /// <summary>
        /// 根据点击位置找出点击到的视图
        /// </summary>
        /// <returns>返回点击到的视图</returns>
        /// <param name="point">当前点击位置</param>
        Android.Views.View selectedViewByPoint(Android.Graphics.Point point)
        {
            //第一个是背景图
            for (int i = realViewGroup.ChildCount - 1; 0 <= i; i--)
            {
                var tempView = realViewGroup.GetChildAt(i);
                {
                    if (inRangeOfView(tempView, point))
                    {
                        return tempView;
                    }
                }
            }
            return null;
        }
        /// <summary>
        /// 当前选中按键的初始点
        /// </summary>
        Android.Graphics.Point originPressPoint;

        /// <summary>
        /// 当前选中的视图起点
        /// </summary>
        Android.Graphics.Point selectedViewPoint;

        /// <summary>
        /// 当前选中的视图
        /// </summary>
        Android.Views.View selectedAndroidView;
        /// <summary>
        /// 准备交换位置的视图
        /// </summary>
        Android.Views.View replaceAndroidView;

        /// <summary>
        /// 获取当前View的中心点
        /// </summary>
        /// <returns>The point.</returns>
        /// <param name="view">View.</param>
        Android.Graphics.Point centerPoint(Android.Views.View view)
        {
            int[] location = new int[2];
            view.GetLocationOnScreen(location);
            int x = location[0];
            int y = location[1];
            x += view.Width / 2;
            y += view.Height / 2;
            return new Android.Graphics.Point(x, y);
        }


        float selectViewBeforeY;
        /// <summary>
        /// 点击开始的事件
        /// </summary>
        /// <param name="e">E.</param>
        internal void TouchEventDown(MotionEvent e){
			//找出当前点击位置的视图
			selectedAndroidView = selectedViewByPoint(new Android.Graphics.Point((int)e.RawX, (int)e.RawY));
			if (selectedAndroidView == null)
			{
				return ;
			}
			selectedAndroidView.BringToFront();
            var location = new int [2];
            selectedAndroidView.GetLocationOnScreen (location);
            selectViewBeforeY = location [1];
            originPressPoint = new Android.Graphics.Point((int)e.RawX, (int)e.RawY);
            selectedViewPoint = new Android.Graphics.Point((int)selectedAndroidView.GetX(), (int)selectedAndroidView.GetY());
            isFirst = true;
		}
        /// <summary>
        /// 点击事件移动
        /// </summary>
        /// <param name="e">E.</param>
        internal void TouchEventMove(MotionEvent e)
        {
            if (selectedAndroidView == null)
            {
                return;
            }
            //selectedAndroidView.SetX(selectedViewPoint.X + e.RawX - originPressPoint.X);
            selectedAndroidView.SetY(selectedViewPoint.Y + e.RawY - originPressPoint.Y);
            //获取当前视图进入了哪个视图的区域
            replaceAndroidView = replaceViewOfPoint(selectedAndroidView, centerPoint(selectedAndroidView));
            if (replaceAndroidView != null)
            {
                if (!isFirst)
                {
                    return;
                }
                isFirst = false;
                if (replaceAndroidView == null)
                {
                    return;
                }
                replaceAndroidView.ClearAnimation();
                /** 设置缩放动画 */
                replaceAndroidView.Animation = new AlphaAnimation(1.0f, .8f);
                replaceAndroidView.Animation.Duration = 1000;
                replaceAndroidView.Animation.StartNow(); 
            }
        }
        /// <summary>
        /// 点击事件弹起
        /// </summary>
        /// <param name="e">E.</param>
        internal void TouchEventUp(MotionEvent e)
        {
            if (selectedAndroidView == null)
            {
                return;
            }
            View selectedView = null;
            foreach (View view in viewList)
            {
                if (view.AndroidView == selectedAndroidView)
                {
                    selectedView = view;
                    break;
                }
            }

            //selectedAndroidView.SetX(selectedViewPoint.X);


            if(isSameZone(selectedAndroidView))
            {
                selectedAndroidView.SetY (selectedViewPoint.Y);
                return;
            }
            selectedAndroidView.SetY (selectedViewPoint.Y);


            if (replaceAndroidView == null)
            {
                if (LongPressAction != null)
                {
                    LongPressAction(selectedView);
                }
                return;
            }

            View replaceView = null;
            foreach (View view in viewList)
            {
                if (view.AndroidView == replaceAndroidView)
                {
                    replaceView = view;
                    break;
                }
            }
            if (ReplaceChanged != null)
            {
                ReplaceChanged(replaceView, selectedView);
            }
        }

        /// <summary>
        /// 给当前选择中的控件个动画缩小的效果
        /// </summary>
        internal void scaleSelectedAndroidView()
        {
            if (selectedAndroidView == null)
            {
                return;
            }
            selectedAndroidView.ClearAnimation();
            /** 设置缩放动画 */
            selectedAndroidView.Animation = new AlphaAnimation(1.0f, 0.8f);
            selectedAndroidView.Animation.Duration = 1000;
            selectedAndroidView.Animation.StartNow();
        }

        /// <summary>
        ///  是否第一次加载
        /// </summary>
        bool isFirst;

		/// <summary>
		/// 竖直方向滑动控件
		/// </summary>
        internal class AndroidScrolView11 : Android.Widget.ScrollView, GestureDetector.IOnGestureListener
		{
			MusicVerticalScrolViewLayout _view;
			/// <summary>
			/// 是否长按
			/// </summary>
			bool isLongPress;
			GestureDetector mGesture;

			
			/// <summary>
			/// 构造函数
			/// </summary>
			/// <param name="context">Context.</param>
			/// <param name="view">View.</param>
			public AndroidScrolView11(Context context, MusicVerticalScrolViewLayout view)
				: base(context)
			{
                _view = view;
                VerticalScrollBarEnabled = false;
				mGesture = new GestureDetector(context, this) { IsLongpressEnabled = true };
			}

            /// <summary>
            /// 重写点击事件
            /// </summary>
            /// <returns><c>true</c>, if touch event was oned, <c>false</c> otherwise.</returns>
            /// <param name="e">E.</param>
            public override bool OnTouchEvent(MotionEvent e)
            {
                //处理长按的事件
                if (isLongPress)
                {
                    switch (e.Action)
                    {
                        case MotionEventActions.Move:
                            _view.TouchEventMove(e);
                            break;
                        case MotionEventActions.Up:
                            _view.TouchEventUp(e);
                            break;
                    }
                    return true;
                }

                return base.OnTouchEvent(e);
            }

            //是否是活动状态
            bool isLive()
            {
                return Enabled && Visibility == ViewStates.Visible && 0 < Alpha;
            }

            public override bool OnInterceptTouchEvent(MotionEvent ev)
            {
                if (!isLive())
                {
                    return false;
                }
                mGesture.OnTouchEvent(ev);
                //如果是长按，就拦截事件，后面的事件是由自己的TouchEvent处理，子控件会收到取消事件，如果是快速滑动，事件也是自己处理
                if (isLongPress)
                {
                    return true;
                }
                //如果是滑动这里也会返回True
                return base.OnInterceptTouchEvent(ev);
            }

			/// <summary>
			/// 设置所有父视图禁止拦截事件
			/// </summary>
			/// <param name="b">如果设置True表示不要拦截，如果设置为False表示可以拦截</param>
			void requestParentDisallowInterceptTouchEvent(bool b)
			{
				var tempParent = Parent;
				while (tempParent != null)
				{   //告诉父类不要拦截这个视图的事件
					tempParent.RequestDisallowInterceptTouchEvent(b);
					tempParent = tempParent.Parent;
				}
			}

			public bool OnDown(MotionEvent e)
			{
				isLongPress = false;
                _view.TouchEventDown(e);
				requestParentDisallowInterceptTouchEvent(true);
				return false;
			}

			public bool OnFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
			{
				//迅速滑动，并松开  
				Shared.HDLUtils.WriteLine($"OnFling随便一划，坐标变化为X:{velocityX},Y:{velocityY}");
				return false;
			}

			public void OnLongPress(MotionEvent e)
			{
                isLongPress = true;
                _view.scaleSelectedAndroidView();
				Shared.HDLUtils.WriteLine("长按不放");
			}

			public bool OnScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
			{
				Shared.HDLUtils.WriteLine("OnScroll:在屏幕上滑动");
				return false;
			}

			public void OnShowPress(MotionEvent e)
			{
				Shared.HDLUtils.WriteLine("OnShowPress:手指按下一段时间，还没到长按");
			}

            public bool OnSingleTapUp(MotionEvent e)
            {
				requestParentDisallowInterceptTouchEvent(false);
				Shared.HDLUtils.WriteLine("OnSingleTapUp:手指弹起");
                return false;
            }
		}
    }

}