#region

using System;
using System.ComponentModel;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;

#endregion

namespace CSFrameworkV5.Library.UIForm
{
    public enum FormSize
    {
        NORMAL = 0, //正常大小
        MAX = 1 //最大化
    }

    public partial class frmBaseUI : Form
    {
        private const int WM_NCHITTEST = 0x0084;

        private const int HTLEFT = 10; //左边界
        private const int HTRIGHT = 11; //右边界
        private const int HTTOP = 12; //上边界
        private const int HTTOPLEFT = 13; //左上角
        private const int HTTOPRIGHT = 14; //右上角
        private const int HTBOTTOM = 15; //下边界
        private const int HTBOTTOMLEFT = 0x10; //左下角
        private const int HTBOTTOMRIGHT = 17; //右下角

        /// <summary>
        ///     窗口默认大小
        ///     FormSize.NORMAL OR FormSize.MAX
        /// </summary>
        private FormSize defaultFormSize = FormSize.NORMAL;

        /// <summary>
        ///     是否允许最大化
        /// </summary>
        private bool maxVisible = true;

        private Point mPoint;

        /// <summary>
        ///     窗体标题
        /// </summary>
        private string titleText;

        /// <summary>
        ///     窗体标题是否显示
        /// </summary>
        private bool titleVisible = true;

        public frmBaseUI()
        {
            InitializeComponent();
        }

        [Description("窗口默认大小")]
        public FormSize DefaultFormSize
        {
            get => defaultFormSize;
            set
            {
                defaultFormSize = value;
                if (defaultFormSize == FormSize.MAX)
                {
                    //防止遮挡任务栏
                    MaximumSize = new Size(
                        Screen.PrimaryScreen.WorkingArea.Width,
                        Screen.PrimaryScreen.WorkingArea.Height);
                    WindowState = FormWindowState.Maximized;
                    //最大化图标切换
                }
            }
        }

        [Description("是否允许最大化")]
        public bool MaxVisible
        {
            get => maxVisible;
            set
            {
                maxVisible = value;
                if (!maxVisible)
                {
                    btnEXMin.Location = new Point(btnEXMax.Location.X, 12);
                    btnEXMax.Visible = false;
                }
                else
                {
                    btnEXMin.Location = new Point(btnEXMax.Location.X - 20, 12);
                    btnEXMax.Visible = true;
                }
            }
        }

        [Description("窗体标题")]
        public string TitleText
        {
            get => titleText;
            set
            {
                titleText = value;
                title.Text = titleText;
            }
        }

        [Description("窗体标题是否显示")]
        public bool TitleVisible
        {
            get => titleVisible;
            set
            {
                titleVisible = value;
                title.Visible = titleVisible;
            }
        }

        /// <summary>
        ///     关闭按钮事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnEXClose_ButtonClick(object sender, EventArgs e)
        {
            Close();
        }

        /// <summary>
        ///     最大化按钮事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnEXMax_ButtonClick(object sender, EventArgs e)
        {
            MaxNormalSwitch();
        }

        /// <summary>
        ///     最小化按钮事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnEXMin_ButtonClick(object sender, EventArgs e)
        {
            WindowState = FormWindowState.Minimized;
        }

        private void FormEX_Resize(object sender, EventArgs e)
        {
            Invalidate(); //使重绘
        }

        /// <summary>
        ///     最大化和正常状态切换
        /// </summary>
        private void MaxNormalSwitch()
        {
            if (WindowState ==
                FormWindowState.Maximized) //如果当前状态是最大化状态 则窗体需要恢复默认大小
            {
                WindowState = FormWindowState.Normal;
                //
            }
            else
            {
                //防止遮挡任务栏
                MaximumSize = new Size(Screen.PrimaryScreen.WorkingArea.Width,
                    Screen.PrimaryScreen.WorkingArea.Height);
                WindowState = FormWindowState.Maximized;
                //最大化图标切换
            }

            Invalidate(); //使重绘
        }

        private void titleBar_DoubleClick(object sender, EventArgs e)
        {
            MaxNormalSwitch();
        }

        /// <summary>
        ///     鼠标按下标题栏
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void titleBar_MouseDown(object sender, MouseEventArgs e)
        {
            mPoint = new Point(e.X, e.Y);
        }

        /// <summary>
        ///     鼠标在移动
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void titleBar_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
                Location = new Point(Location.X + e.X - mPoint.X,
                    Location.Y + e.Y - mPoint.Y);
        }

        #region 无边框窗体移动、放大、缩小

        protected override void WndProc(ref Message m)
        {
            switch (m.Msg)
            {
                case WM_NCHITTEST:
                    base.WndProc(ref m);
                    var vPoint = new Point((int)m.LParam & 0xFFFF,
                        ((int)m.LParam >> 16) & 0xFFFF);
                    vPoint = PointToClient(vPoint);
                    if (vPoint.X <= 5)
                    {
                        if (vPoint.Y <= 5)
                            m.Result = (IntPtr)HTTOPLEFT;
                        else if (vPoint.Y >= ClientSize.Height - 5)
                            m.Result = (IntPtr)HTBOTTOMLEFT;
                        else
                            m.Result = (IntPtr)HTLEFT;
                    }
                    else if (vPoint.X >= ClientSize.Width - 5)
                    {
                        if (vPoint.Y <= 5)
                            m.Result = (IntPtr)HTTOPRIGHT;
                        else if (vPoint.Y >= ClientSize.Height - 5)
                            m.Result = (IntPtr)HTBOTTOMRIGHT;
                        else
                            m.Result = (IntPtr)HTRIGHT;
                    }
                    else if (vPoint.Y <= 5)
                    {
                        m.Result = (IntPtr)HTTOP;
                    }
                    else if (vPoint.Y >= ClientSize.Height - 5)
                    {
                        m.Result = (IntPtr)HTBOTTOM;
                    }

                    break;
                case WM_NCPAINT: //四周阴影 box shadow
                    if (m_aeroEnabled)
                    {
                        var v = 2;
                        DwmSetWindowAttribute(Handle, 2, ref v, 4);
                        var margins = new MARGINS
                        {
                            bottomHeight = 1,
                            leftWidth = 1,
                            rightWidth = 1,
                            topHeight = 1
                        };
                        DwmExtendFrameIntoClientArea(Handle, ref margins);
                    }

                    break;
            }

            base.WndProc(ref m);

            if (m.Msg == WM_NCHITTEST &&
                (int)m.Result == HTCLIENT) // drag the form
                m.Result = (IntPtr)HTCAPTION;
        }

        #endregion

        #region 窗体四周阴影

        [DllImport("dwmapi.dll")]
        public static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd,
            ref MARGINS pMarInset);

        [DllImport("dwmapi.dll")]
        public static extern int DwmSetWindowAttribute(IntPtr hwnd, int attr,
            ref int attrValue, int attrSize);

        [DllImport("dwmapi.dll")]
        public static extern int DwmIsCompositionEnabled(ref int pfEnabled);

        private bool m_aeroEnabled; // variables for box shadow
        private const int CS_DROPSHADOW = 0x00020000;
        private const int WM_NCPAINT = 0x0085;
        private const int WM_ACTIVATEAPP = 0x001C;

        public struct MARGINS // struct for box shadow
        {
            public int leftWidth;
            public int rightWidth;
            public int topHeight;
            public int bottomHeight;
        }

        //private const int WM_NCHITTEST = 0x84;          // variables for dragging the form
        private const int HTCLIENT = 0x1;
        private const int HTCAPTION = 0x2;

        protected override CreateParams CreateParams
        {
            get
            {
                m_aeroEnabled = CheckAeroEnabled();

                var cp = base.CreateParams;
                if (!m_aeroEnabled) cp.ClassStyle |= CS_DROPSHADOW;

                return cp;
            }
        }

        private bool CheckAeroEnabled()
        {
            if (Environment.OSVersion.Version.Major >= 6)
            {
                var enabled = 0;
                DwmIsCompositionEnabled(ref enabled);
                return enabled == 1 ? true : false;
            }

            return false;
        }

        #endregion
    }
}