using System;
using System.Runtime.InteropServices;
using System.Text;

namespace PDFPatcher.Common
{
	/// <summary>用于创建或管理快捷方式文件的类。</summary>
	public sealed class ShortcutFile
	{
		readonly IShellLink _link;

		/// <summary>获取或设置快捷方式的目标路径。</summary>
		public string Destination { get; private set; }
		/// <summary>获取或设置快捷方式的工作目录。</summary>
		public string WorkingDirectory { get; set; }
		/// <summary>获取或设置快捷方式的描述文本。</summary>
		public string Description { get; set; }
		/// <summary>获取或设置快捷方式的启动参数。</summary>
		public string Arguments { get; set; }
		/// <summary>获取或设置快捷方式的图标文件位置。</summary>
		public string IconLocation { get; set; }
		/// <summary>获取或设置快捷方式的图标文件索引。</summary>
		public int IconIndex { get; set; }

		private ShortcutFile() {
			_link = (IShellLink)new ShellLink();
		}

		/// <summary>创建快捷方式。</summary>
		/// <param name="destination">快捷方式指向的目标文件路径。</param>
		public ShortcutFile(string destination) {
			_link = (IShellLink)new ShellLink();
			Destination = destination;
			_link.SetPath(destination);
		}

		/// <summary>加载快捷方式。</summary>
		/// <param name="shortcutFilePath">快捷方式文件的位置。</param>
		/// <returns><see cref="ShortcutFile"/> 实例。</returns>
		public static ShortcutFile Load(string shortcutFilePath) {
			var s = new ShortcutFile();
			var l = s._link;
			var file = (System.Runtime.InteropServices.ComTypes.IPersistFile)s._link;
			file.Load(shortcutFilePath, 0);
			s.Destination = shortcutFilePath;
			var sb = new StringBuilder();
			l.GetDescription(sb, 512);
			s.Description = sb.ToString();
			sb.Length = 0;
			l.GetWorkingDirectory(sb, 256);
			s.WorkingDirectory = sb.ToString();
			int ii;
			sb.Length = 0;
			l.GetIconLocation(sb, 256, out ii);
			s.IconLocation = sb.ToString();
			sb.Length = 0;
			l.GetArguments(sb, 256);
			s.Arguments = sb.ToString();
			return s;
		}

		/// <summary>将快捷方式保存到目标位置。</summary>
		/// <param name="position">快捷方式文件的位置。</param>
		public void Save(string position) {
			if (String.IsNullOrEmpty(WorkingDirectory) == false) {
				_link.SetWorkingDirectory(WorkingDirectory);
			}
			if (String.IsNullOrEmpty(Description) == false) {
				_link.SetDescription(Description);
			}
			if (String.IsNullOrEmpty(Arguments) == false) {
				_link.SetArguments(Arguments);
			}
			if (String.IsNullOrEmpty(IconLocation) == false) {
				_link.SetIconLocation(IconLocation, IconIndex >= 0 ? IconIndex : 0);
			}
			var file = (System.Runtime.InteropServices.ComTypes.IPersistFile)_link;
			file.Save(position, false);
		}

		#region COM Interops
		[ComImport]
		[Guid("00021401-0000-0000-C000-000000000046")]
		class ShellLink
		{
		}

		[ComImport]
		[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
		[Guid("000214F9-0000-0000-C000-000000000046")]
		interface IShellLink
		{
			void GetPath([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszFile, int cchMaxPath, out IntPtr pfd, int fFlags);
			void GetIDList(out IntPtr ppidl);
			void SetIDList(IntPtr pidl);
			void GetDescription([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszName, int cchMaxName);
			void SetDescription([MarshalAs(UnmanagedType.LPWStr)] string pszName);
			void GetWorkingDirectory([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszDir, int cchMaxPath);
			void SetWorkingDirectory([MarshalAs(UnmanagedType.LPWStr)] string pszDir);
			void GetArguments([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszArgs, int cchMaxPath);
			void SetArguments([MarshalAs(UnmanagedType.LPWStr)] string pszArgs);
			void GetHotkey(out short pwHotkey);
			void SetHotkey(short wHotkey);
			void GetShowCmd(out int piShowCmd);
			void SetShowCmd(int iShowCmd);
			void GetIconLocation([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszIconPath, int cchIconPath, out int piIcon);
			void SetIconLocation([MarshalAs(UnmanagedType.LPWStr)] string pszIconPath, int iIcon);
			void SetRelativePath([MarshalAs(UnmanagedType.LPWStr)] string pszPathRel, int dwReserved);
			void Resolve(IntPtr hwnd, int fFlags);
			void SetPath([MarshalAs(UnmanagedType.LPWStr)] string pszFile);
		}
		#endregion
	}

}