using System;
using UIKit;
using Shared.IO;
using CoreGraphics;
using Foundation;

namespace Shared
{
    /// <summary>
    /// 位置布局
    /// </summary>
    public class HorizontalPages : ViewGroup
    {
        readonly MyHorizontalPages iosUIScrolView;

        //readonly UIPageControl iosUIPageControl;

        /// <summary>
        /// 页面变化事件
        /// </summary>
        public Action<HorizontalPages,int> PageChange;

        /// <summary>
        /// 垂直方向滚动视图
        /// </summary>
        class MyHorizontalPages : UIScrollView
        {
            [Weak]  HorizontalPages HorizontalPages;
            //nfloat mLastX, mLastY, deltaX;
            public MyHorizontalPages(HorizontalPages HorizontalPages)
            {

                this.HorizontalPages = HorizontalPages;
                //this.ScrollEnabled = false;

                DecelerationStarted += (s, e) =>
                {
                    var tempUIScrolView = s as MyHorizontalPages;
                    //获取当前界面的索引
                    //System.Console.WriteLine($"DecelerationStarted-------{tempUIScrolView.ContentOffset.X}");
                    var tempPageIndex = Convert.ToInt32(tempUIScrolView.ContentOffset.X / (tempUIScrolView.Frame.Width - 2 * this.HorizontalPages._RowPadding + this.HorizontalPages._PagePadding));
                    this.HorizontalPages.PageIndex = tempPageIndex;
                };

                DraggingEnded += (s, e) =>
                {

                    var tempUIScrolView = s as MyHorizontalPages;
                    if (!e.Decelerate)
                    {
                       
                        //System.Console.WriteLine($"DraggingEnded-------{tempUIScrolView.ContentOffset.X}");
                        var tempPageIndex = Convert.ToInt32(tempUIScrolView.ContentOffset.X / (tempUIScrolView.Frame.Width - 2 * this.HorizontalPages._RowPadding + this.HorizontalPages._PagePadding));
                        this.HorizontalPages.PageIndex = tempPageIndex;
                    }
                };
            }
            /// <summary>
            /// 点击开始
            /// </summary>
            /// <param name="touches">Touches.</param>
            /// <param name="evt">Evt.</param>
            public override void TouchesBegan(NSSet touches, UIEvent evt)
            {
          
                HorizontalPages?.TouchEvent(EventActions.Down, (touches.AnyObject as UITouch).LocationInView(this));

                //CGPoint point = (touches.AnyObject as UITouch).LocationInView(this);
                ////记录点击的最新X坐标
                //mLastX = point.X;
                //bMove = false;
                //System.Console.WriteLine($"TouchesBegan-------{mLastX}");
            }

            int mTouchSlop = 20;
            bool bMove;
            /// <summary>
            ///  移动
            /// </summary>
            /// <param name="touches">Touches.</param>
            /// <param name="evt">Evt.</param>
            public override void TouchesMoved(NSSet touches, UIEvent evt)
            {


                HorizontalPages?.TouchEvent(EventActions.Move, (touches.AnyObject as UITouch).LocationInView(this));

                //CGPoint point = (touches.AnyObject as UITouch).LocationInView(this);
                //deltaX = point.X - mLastX;
                //if (Math.Abs(deltaX) >= mTouchSlop) {
                //    bMove = true;
                //}
                //System.Console.WriteLine($"deltaX-------{deltaX}");
        
            }
            /// <summary>
            /// 点击弹起
            /// </summary>
            /// <param name="touches">Touches.</param>
            /// <param name="evt">Evt.</param>
            public override void TouchesEnded(NSSet touches, UIEvent evt)
            {
                HorizontalPages?.TouchEvent(EventActions.Up, (touches.AnyObject as UITouch).LocationInView(this));

                //if (bMove)
                //{
                //    if (deltaX < 0)//左滑
                //    {
                //        this.HorizontalPages.PageIndex--;
                //    }
                //    else
                //    {
                //        this.HorizontalPages.PageIndex++;

                //    }
                //}
            }

            public override void TouchesCancelled(NSSet touches, UIEvent evt)
            {
                HorizontalPages?.TouchEvent(EventActions.Cancel, (touches.AnyObject as UITouch).LocationInView(this));
            }
            /// <summary>
            /// 框架默认加了两个UIImageView ，这样可以去掉默认添加
            /// </summary>
            /// <param name="view">View.</param>
            public override void AddSubview(UIView view)
            {
                if (view.GetType() == typeof(UIImageView) && view.Tag != int.MinValue)
                {
                    return;
                }

                if (view.ToString().Contains("UIScrollViewScrollIndicator"))
                {
                    return;
                }
                base.AddSubview(view);
            }
        }

        /// <summary>
        /// 构造函数
        /// </summary>
        public HorizontalPages()
        {
            viewGroup = new UIView();
            iosUIScrolView = new MyHorizontalPages(this) {  };  
            realViewGroup = iosUIScrolView;
            //启动翻页功能
            //iosUIScrolView.PagingEnabled = true;
            iosUIScrolView.ShowsHorizontalScrollIndicator = false;
            viewGroup.AddSubview(iosUIScrolView);
            _PagePadding = Application.GetRealWidth(50);
            _RowPadding = Application.GetRealWidth(100);

        }

         //两个Page之间的距离
        int _PagePadding;
        public int PagePadding
        {
            get
            {
                return _PagePadding;
            }
            set
            {
                _PagePadding = value;
                ReLocation();
            }
        }
        //page的外边距
        int _RowPadding;
        public int RowPadding
        {
            get
            {
                return _RowPadding;
            }
            set
            {
                _RowPadding = value;
                ReLocation();
            }
        }

        




        /// <summary>
        /// 是否允许滑动
        /// </summary>
        /// <value><c>true</c> if scroll enabled; otherwise, <c>false</c>.</value>
        public bool ScrollEnabled
        {
            get
            {
                return (iosUIScrolView as MyHorizontalPages).ScrollEnabled;
            }
            set
            {
                (iosUIScrolView as MyHorizontalPages).ScrollEnabled = value;
            }
        }

		int pageIndex;
		/// <summary>
		/// 设置或者获取当前的界面索引
		/// </summary>
		/// <value>The index of the page.</value>
		public int PageIndex
		{
			get
			{
				return pageIndex;
			}
			set
			{
                if (value < 0 || ChildrenCount <= value)
                {
                    return;
                }
                int beforePageIndex = pageIndex;
				pageIndex = value;
				if (!IsCanRefresh)
				{
					return;
				}
              
				var viewSize = iosUIScrolView.Frame.Size;


                var rect = new CGRect(pageIndex * viewSize.Width, 0, viewSize.Width, viewSize.Height);
                if (pageIndex != 0) {
                    var frame = iosUIScrolView.Subviews[pageIndex].Frame;
                    var w = frame.X - _RowPadding;

                    rect = new CGRect(w, 0, viewSize.Width, viewSize.Height);
                    //System.Console.WriteLine($"CGRect xx-------{w}");
                }

                //System.Console.WriteLine($"pageIndex xx-------{pageIndex}");
                iosUIScrolView.ScrollRectToVisible(rect, false);

                if (beforePageIndex != pageIndex)
                {  
                    PageChange?.Invoke(this, pageIndex);
                }
			}
		}
		/// <summary>
		/// 增加子控件
		/// </summary>
		/// <param name="view">View.</param>
		public override void AddChidren(View view)
		{
            //var v = Application.AverageScale;
            //var vv = Application.CurrentHeight;
            //var dddd = Application.DesignWidth;
			base.AddChidren(view);
			ReLocation();
		}

		/// <summary>
		/// 重新排位置及设备内容大小
		/// </summary>
		public virtual void ReLocation()
		{
			if (iosUIScrolView.Subviews.Length == 0)
			{
				return;
			}

            var frame0 = iosUIScrolView.Subviews[0].Frame;
            frame0.X = _RowPadding;
            iosUIScrolView.Subviews[0].Frame = frame0;



            for (int i = 1; i < iosUIScrolView.Subviews.Length; i++)
			{
				var frame = iosUIScrolView.Subviews[i].Frame;
				frame.X = iosUIScrolView.Subviews[i - 1].Frame.Right+_PagePadding;
				iosUIScrolView.Subviews[i].Frame = frame;
			}

			iosUIScrolView.ContentSize = new CoreGraphics.CGSize(iosUIScrolView.Subviews[iosUIScrolView.Subviews.Length - 1].Frame.Right+_RowPadding, iosUIScrolView.Frame.Height);
		}



		/// <summary>
		/// 控件宽度
		/// </summary>
		/// <value>The width.</value>
		public override int Width
		{
			get
			{
				return base.Width;
			}
			set
			{
				base.Width = value;
     
                if (!IsCanRefresh)
					return;
			}
		}

		/// <summary>
		/// 控件的高度
		/// </summary>
		/// <value>The height.</value>
		public override int Height
		{
			get
			{
				return base.Height;
			}
			set
			{
				base.Height = value;
				if (!IsCanRefresh)
					return;

			}
		}

        /// <summary>
        /// 移除当前控件
        /// </summary>
        /// <param name="view">View.</param>
        internal override void Remove(View view)
        {
            base.Remove(view);
            ReLocation();

            if (PageIndex > ChildrenCount - 1)
            {
                PageIndex = ChildrenCount - 1;
            }
 
        }

		/// <summary>
		/// 移除所有的控件
		/// </summary>
		public override void RemoveAll()
		{
			base.RemoveAll();
			ReLocation();
            PageIndex = 0;
		}

		/// <summary>
		/// 根据索引移除控件
		/// </summary>
		/// <param name="index">Index.</param>
		public override void RemoveAt(int index)
		{
            if (viewList.Count - 1 < index || index < 0)
            {
                return;
            }
            Remove(viewList[index]);
		}
    }
}