using System;
using System.Runtime.InteropServices;
using Unix.Terminal;

namespace Terminal.Gui;

/// <summary>
///  A clipboard implementation for Linux.
///  This implementation uses the xclip command to access the clipboard.
/// </summary>	
/// <remarks>
/// If xclip is not installed, this implementation will not work.
/// </remarks>
class CursesClipboard : ClipboardBase {
	public CursesClipboard ()
	{
		IsSupported = CheckSupport ();
	}

	string _xclipPath = string.Empty;
	public override bool IsSupported { get; }

	bool CheckSupport ()
	{
#pragma warning disable RCS1075 // Avoid empty catch clause that catches System.Exception.
		try {
			var (exitCode, result) = ClipboardProcessRunner.Bash ("which xclip", waitForOutput: true);
			if (exitCode == 0 && result.FileExists ()) {
				_xclipPath = result;
				return true;
			}
		} catch (Exception) {
			// Permissions issue.
		}
#pragma warning restore RCS1075 // Avoid empty catch clause that catches System.Exception.
		return false;
	}

	protected override string GetClipboardDataImpl ()
	{
		var tempFileName = System.IO.Path.GetTempFileName ();
		var xclipargs = "-selection clipboard -o";

		try {
			var (exitCode, result) = ClipboardProcessRunner.Bash ($"{_xclipPath} {xclipargs} > {tempFileName}", waitForOutput: false);
			if (exitCode == 0) {
				if (Application.Driver is CursesDriver) {
					Curses.raw ();
					Curses.noecho ();
				}
				return System.IO.File.ReadAllText (tempFileName);
			}
		} catch (Exception e) {
			throw new NotSupportedException ($"\"{_xclipPath} {xclipargs}\" failed.", e);
		} finally {
			System.IO.File.Delete (tempFileName);
		}
		return string.Empty;
	}

	protected override void SetClipboardDataImpl (string text)
	{
		var xclipargs = "-selection clipboard -i";
		try {
			var (exitCode, _) = ClipboardProcessRunner.Bash ($"{_xclipPath} {xclipargs}", text, waitForOutput: false);
			if (exitCode == 0 && Application.Driver is CursesDriver) {
				Curses.raw ();
				Curses.noecho ();
			}
		} catch (Exception e) {
			throw new NotSupportedException ($"\"{_xclipPath} {xclipargs} < {text}\" failed", e);
		}
	}
}
/// <summary>
///  A clipboard implementation for MacOSX. 
///  This implementation uses the Mac clipboard API (via P/Invoke) to copy/paste.
///  The existance of the Mac pbcopy and pbpaste commands 
///  is used to determine if copy/paste is supported.
/// </summary>	
class MacOSXClipboard : ClipboardBase {
	IntPtr _nsString = objc_getClass ("NSString");
	IntPtr _nsPasteboard = objc_getClass ("NSPasteboard");
	IntPtr _utfTextType;
	IntPtr _generalPasteboard;
	IntPtr _initWithUtf8Register = sel_registerName ("initWithUTF8String:");
	IntPtr _allocRegister = sel_registerName ("alloc");
	IntPtr _setStringRegister = sel_registerName ("setString:forType:");
	IntPtr _stringForTypeRegister = sel_registerName ("stringForType:");
	IntPtr _utf8Register = sel_registerName ("UTF8String");
	IntPtr _nsStringPboardType;
	IntPtr _generalPasteboardRegister = sel_registerName ("generalPasteboard");
	IntPtr _clearContentsRegister = sel_registerName ("clearContents");

	public MacOSXClipboard ()
	{
		_utfTextType = objc_msgSend (objc_msgSend (_nsString, _allocRegister), _initWithUtf8Register, "public.utf8-plain-text");
		_nsStringPboardType = objc_msgSend (objc_msgSend (_nsString, _allocRegister), _initWithUtf8Register, "NSStringPboardType");
		_generalPasteboard = objc_msgSend (_nsPasteboard, _generalPasteboardRegister);
		IsSupported = CheckSupport ();
	}

	public override bool IsSupported { get; }

	bool CheckSupport ()
	{
		var (exitCode, result) = ClipboardProcessRunner.Bash ("which pbcopy", waitForOutput: true);
		if (exitCode != 0 || !result.FileExists ()) {
			return false;
		}
		(exitCode, result) = ClipboardProcessRunner.Bash ("which pbpaste", waitForOutput: true);
		return exitCode == 0 && result.FileExists ();
	}

	protected override string GetClipboardDataImpl ()
	{
		var ptr = objc_msgSend (_generalPasteboard, _stringForTypeRegister, _nsStringPboardType);
		var charArray = objc_msgSend (ptr, _utf8Register);
		return Marshal.PtrToStringAnsi (charArray);
	}

	protected override void SetClipboardDataImpl (string text)
	{
		IntPtr str = default;
		try {
			str = objc_msgSend (objc_msgSend (_nsString, _allocRegister), _initWithUtf8Register, text);
			objc_msgSend (_generalPasteboard, _clearContentsRegister);
			objc_msgSend (_generalPasteboard, _setStringRegister, str, _utfTextType);
		} finally {
			if (str != default) {
				objc_msgSend (str, sel_registerName ("release"));
			}
		}
	}

	[DllImport ("/System/Library/Frameworks/AppKit.framework/AppKit")]
	static extern IntPtr objc_getClass (string className);

	[DllImport ("/System/Library/Frameworks/AppKit.framework/AppKit")]
	static extern IntPtr objc_msgSend (IntPtr receiver, IntPtr selector);

	[DllImport ("/System/Library/Frameworks/AppKit.framework/AppKit")]
	static extern IntPtr objc_msgSend (IntPtr receiver, IntPtr selector, string arg1);

	[DllImport ("/System/Library/Frameworks/AppKit.framework/AppKit")]
	static extern IntPtr objc_msgSend (IntPtr receiver, IntPtr selector, IntPtr arg1);

	[DllImport ("/System/Library/Frameworks/AppKit.framework/AppKit")]
	static extern IntPtr objc_msgSend (IntPtr receiver, IntPtr selector, IntPtr arg1, IntPtr arg2);

	[DllImport ("/System/Library/Frameworks/AppKit.framework/AppKit")]
	static extern IntPtr sel_registerName (string selectorName);
}

/// <summary>
///  A clipboard implementation for Linux, when running under WSL. 
///  This implementation uses the Windows clipboard to store the data, and uses Windows'
///  powershell.exe (launched via WSL interop services) to set/get the Windows
///  clipboard. 
/// </summary>
class WSLClipboard : ClipboardBase {
	public WSLClipboard ()
	{
	}

	public override bool IsSupported {
		get {
			return CheckSupport ();
		}
	}

	private static string _powershellPath = string.Empty;

	bool CheckSupport ()
	{
		if (string.IsNullOrEmpty (_powershellPath)) {
			// Specify pwsh.exe (not pwsh) to ensure we get the Windows version (invoked via WSL)
			var (exitCode, result) = ClipboardProcessRunner.Bash ("which pwsh.exe", waitForOutput: true);
			if (exitCode > 0) {
				(exitCode, result) = ClipboardProcessRunner.Bash ("which powershell.exe", waitForOutput: true);
			}

			if (exitCode == 0) {
				_powershellPath = result;
			}
		}
		return !string.IsNullOrEmpty (_powershellPath);
	}

	protected override string GetClipboardDataImpl ()
	{
		if (!IsSupported) {
			return string.Empty;
		}

		var (exitCode, output) = ClipboardProcessRunner.Process (_powershellPath, "-noprofile -command \"Get-Clipboard\"");
		if (exitCode == 0) {
			if (Application.Driver is CursesDriver) {
				Curses.raw ();
				Curses.noecho ();
			}

			if (output.EndsWith ("\r\n")) {
				output = output.Substring (0, output.Length - 2);
			}
			return output;
		}
		return string.Empty;
	}

	protected override void SetClipboardDataImpl (string text)
	{
		if (!IsSupported) {
			return;
		}

		var (exitCode, output) = ClipboardProcessRunner.Process (_powershellPath, $"-noprofile -command \"Set-Clipboard -Value \\\"{text}\\\"\"");
		if (exitCode == 0) {
			if (Application.Driver is CursesDriver) {
				Curses.raw ();
				Curses.noecho ();
			}
		}
	}
}