using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Text;

namespace VDash.WindowSelectors
{
    public interface IWindowSelector
    {
        IntPtr GetWindowHandle();
        WindowInfo GetWindowInfo();
        bool WindowExists();
    }

    public class WindowNotFoundException : Exception
    {
        public WindowNotFoundException(string message) : base(message)
        {

        }
    }

    public class WindowInfo
    {
        #region P/Invokes
        private delegate bool EnumWindowsProc(IntPtr hWnd, int lPar);
        [DllImport("user32.dll")]
        private static extern int EnumWindows(EnumWindowsProc callPtr, int lPar);

        [DllImport("user32.dll")]
        static extern bool EnumDesktopWindows(IntPtr hDesktop, EnumWindowsProc lpfn, int lPar);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);

        [DllImport("user32.dll")]
        private static extern bool IsWindowVisible(IntPtr hWnd);
        #endregion


        public string Title { get; private set; }
        public IntPtr hWnd { get; private set; }
        public bool IsVisible { get; private set; }

        public WindowInfo(string title, IntPtr hWnd, bool isVisible)
        {
            Title = title;
            this.hWnd = hWnd;
            this.IsVisible = isVisible;
        }

        public override string ToString()
        {
            return Title;
        }

        /// <summary>
        /// Gets a list of all windows in the current desktop session.
        /// </summary>
        /// <returns></returns>
        public static WindowInfo[] GetWindowList()
        {
            List<WindowInfo> windows = new List<WindowInfo>();

            EnumWindowsProc del = ((IntPtr hWnd, int lPar) =>
            {
                StringBuilder sb = new StringBuilder(255);

                GetWindowText(hWnd, sb, 255);
                bool isVisible = IsWindowVisible(hWnd);

                var windowInfo = new WindowInfo(sb.ToString(), hWnd, isVisible);

                windows.Add(windowInfo);

                return true;
            });

            EnumDesktopWindows(IntPtr.Zero, del, 0);

            return windows.ToArray();
        }
    }
}