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

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

        readonly UIPageControl iosUIPageControl;

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

        /// <summary>
        /// 垂直方向滚动视图
        /// </summary>
        class MyPageLayout : UIScrollView
        {
            [Weak]  PageLayout pageLayout;
            public MyPageLayout(PageLayout pageLayout)
            {
                this.pageLayout = pageLayout;
                DecelerationEnded += (s, e) =>
                {
                    var tempUIScrolView = s as MyPageLayout;
                    //获取当前界面的索引
                    var tempPageIndex = Convert.ToInt32(tempUIScrolView.ContentOffset.X / tempUIScrolView.Frame.Width);

                    //通知界面索引变化
                    if (this.pageLayout.pageIndex != tempPageIndex)
                    {
                        this.pageLayout.pageIndex = tempPageIndex;
                        this.pageLayout.iosUIPageControl.CurrentPage = tempPageIndex;
                        this.pageLayout.PageChange?.Invoke(this.pageLayout, this.pageLayout.pageIndex);
                    }
                };
            }
            /// <summary>
            /// 点击开始
            /// </summary>
            /// <param name="touches">Touches.</param>
            /// <param name="evt">Evt.</param>
            public override void TouchesBegan(NSSet touches, UIEvent evt)
            {
                pageLayout?.TouchEvent(EventActions.Down, (touches.AnyObject as UITouch).LocationInView(this));
            }
            /// <summary>
            ///  移动
            /// </summary>
            /// <param name="touches">Touches.</param>
            /// <param name="evt">Evt.</param>
            public override void TouchesMoved(NSSet touches, UIEvent evt)
            {
                pageLayout?.TouchEvent(EventActions.Move, (touches.AnyObject as UITouch).LocationInView(this));
            }

            /// <summary>
            /// 点击弹起
            /// </summary>
            /// <param name="touches">Touches.</param>
            /// <param name="evt">Evt.</param>
            public override void TouchesEnded(NSSet touches, UIEvent evt)
            {
                pageLayout?.TouchEvent(EventActions.Up, (touches.AnyObject as UITouch).LocationInView(this));
            }

            public override void TouchesCancelled(NSSet touches, UIEvent evt)
            {
                pageLayout?.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 PageLayout()
        {
            viewGroup = new UIView();
            iosUIPageControl = new UIPageControl { Enabled = false };
            iosUIScrolView = new MyPageLayout(this) {  };
           
            realViewGroup = iosUIScrolView;

            var frame = iosUIPageControl.Frame;
            frame.Height = 16;
            iosUIPageControl.Frame = frame;
            //启动翻页功能
            iosUIScrolView.PagingEnabled = true;
            iosUIScrolView.Bounces = false;
            iosUIScrolView.ShowsHorizontalScrollIndicator = false;
            viewGroup.AddSubview(iosUIScrolView);
            viewGroup.AddSubview(iosUIPageControl);
            
        }

        
        /// <summary>
        ///  是否显示下面一排的点
        /// </summary>
        /// <value><c>true</c> if is show point; otherwise, <c>false</c>.</value>
        public bool IsShowPoint
        {
            get
            {
                return !iosUIPageControl.Hidden;
            }
            set
            {
                iosUIPageControl.Hidden = !value;
            }
        }

        /// <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 MyPageLayout).ScrollEnabled;
            }
            set
            {
                (iosUIScrolView as MyPageLayout).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);
                iosUIScrolView.ScrollRectToVisible(rect, false);

                if (beforePageIndex != pageIndex)
                {
                    iosUIPageControl.CurrentPage = 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);
			iosUIPageControl.Pages = ChildrenCount;
			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;
			}

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

			iosUIScrolView.ContentSize = new CoreGraphics.CGSize(iosUIScrolView.Subviews[iosUIScrolView.Subviews.Length - 1].Frame.Right, 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;
				var frame = iosUIPageControl.Frame;
				frame.Width = Width;
				iosUIPageControl.Frame = frame;
			}
		}

		/// <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;
				var frame = iosUIPageControl.Frame;
				frame.Y = Height - frame.Height;
				iosUIPageControl.Frame = frame;
			}
		}

        /// <summary>
        /// 移除当前控件
        /// </summary>
        /// <param name="view">View.</param>
        internal override void Remove(View view)
        {
            base.Remove(view);
            ReLocation();
            PageIndex = ChildrenCount - 1;
            iosUIPageControl.Pages = ChildrenCount;
            iosUIPageControl.CurrentPage = PageIndex;
        }

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

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