using System;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;
using SysClipboard = System.Windows.Clipboard;

/// <summary>
/// 剪贴板帮助类（WinForms / WPF 通用）
/// 解决的问题：
///  1. CLIPBRD_E_CANT_OPEN (0x800401D0) 等 COMException / ExternalException
///     （剪贴板被其他进程占用，如远程桌面、剪贴板管理器、杀毒软件、微信/QQ 等）
///  2. 非 STA 线程调用导致的 ThreadStateException
///  3. 空字符串 / null 导致的 ArgumentNullException
/// </summary>
public static class ClipboardHelper
{
	/// <summary>默认重试次数</summary>
	public static int DefaultRetryCount { get; set; } = 10;

	/// <summary>默认重试间隔（毫秒）</summary>
	public static int DefaultRetryDelayMs { get; set; } = 100;

	#region 同步 API

	/// <summary>复制文本，失败返回 false，不抛异常</summary>
	public static bool TrySetText(string text, int retryCount = -1, int retryDelayMs = -1)
	{
		return TryExecute(() =>
		{
			if (string.IsNullOrEmpty(text))
				SysClipboard.Clear();
			else
				SetDataObjectCore(text);
			return true;
		}, out _, retryCount, retryDelayMs);
	}

	/// <summary>复制任意数据（文本、文件列表、图片、DataObject 等）</summary>
	public static bool TrySetData(object data, int retryCount = -1, int retryDelayMs = -1)
	{
		if (data == null) return false;
		return TryExecute(() =>
		{
			SetDataObjectCore(data);
			return true;
		}, out _, retryCount, retryDelayMs);
	}

	/// <summary>读取文本，失败或无文本返回 null</summary>
	public static string TryGetText(int retryCount = -1, int retryDelayMs = -1)
	{
		TryExecute(() => SysClipboard.ContainsText() ? SysClipboard.GetText() : null,
			out string result, retryCount, retryDelayMs);
		return result;
	}

	/// <summary>清空剪贴板</summary>
	public static bool TryClear(int retryCount = -1, int retryDelayMs = -1)
	{
		return TryExecute(() => { SysClipboard.Clear(); return true; },
			out _, retryCount, retryDelayMs);
	}

	/// <summary>复制文本，失败时抛出最后一次的异常</summary>
	public static void SetText(string text, int retryCount = -1, int retryDelayMs = -1)
	{
		Execute(() =>
		{
			if (string.IsNullOrEmpty(text))
				SysClipboard.Clear();
			else
				SetDataObjectCore(text);
			return true;
		}, retryCount, retryDelayMs);
	}

	#endregion

	#region 异步 API（不阻塞 UI 线程，建议在 UI 线程 await 调用）

	public static async Task<bool> TrySetTextAsync(string text, int retryCount = -1, int retryDelayMs = -1)
	{
		retryCount = retryCount < 0 ? DefaultRetryCount : retryCount;
		retryDelayMs = retryDelayMs < 0 ? DefaultRetryDelayMs : retryDelayMs;

		for (int i = 0; i < retryCount; i++)
		{
			try
			{
				RunSta(() =>
				{
					if (string.IsNullOrEmpty(text))
						SysClipboard.Clear();
					else
						SetDataObjectCore(text);
					return true;
				});
				return true;
			}
			catch (Exception ex) when (IsRetryable(ex))
			{
				if (i < retryCount - 1)
					await Task.Delay(retryDelayMs).ConfigureAwait(true); // 回到 UI 线程
			}
			catch
			{
				return false;
			}
		}
		return false;
	}

	public static async Task<string> TryGetTextAsync(int retryCount = -1, int retryDelayMs = -1)
	{
		retryCount = retryCount < 0 ? DefaultRetryCount : retryCount;
		retryDelayMs = retryDelayMs < 0 ? DefaultRetryDelayMs : retryDelayMs;

		for (int i = 0; i < retryCount; i++)
		{
			try
			{
				return RunSta(() => SysClipboard.ContainsText() ? SysClipboard.GetText() : null);
			}
			catch (Exception ex) when (IsRetryable(ex))
			{
				if (i < retryCount - 1)
					await Task.Delay(retryDelayMs).ConfigureAwait(true);
			}
			catch
			{
				return null;
			}
		}
		return null;
	}

	#endregion

	#region 内部实现

	private static void SetDataObjectCore(object data)
	{
		SysClipboard.SetDataObject(data, true);
	}

	private static T Execute<T>(Func<T> action, int retryCount, int retryDelayMs)
	{
		retryCount = retryCount < 0 ? DefaultRetryCount : retryCount;
		retryDelayMs = retryDelayMs < 0 ? DefaultRetryDelayMs : retryDelayMs;
		if (retryCount < 1) retryCount = 1;

		for (int i = 0; ; i++)
		{
			try
			{
				return RunSta(action);
			}
			catch (Exception ex) when (IsRetryable(ex) && i < retryCount - 1)
			{
				Thread.Sleep(retryDelayMs);
			}
		}
	}

	private static bool TryExecute<T>(Func<T> action, out T result, int retryCount, int retryDelayMs)
	{
		try
		{
			result = Execute(action, retryCount, retryDelayMs);
			return true;
		}
		catch
		{
			result = default(T);
			return false;
		}
	}

	/// <summary>剪贴板必须在 STA 线程访问；当前不是 STA 就新建一个 STA 线程执行</summary>
	private static T RunSta<T>(Func<T> action)
	{
		if (Thread.CurrentThread.GetApartmentState() == ApartmentState.STA)
			return action();

		T result = default(T);
		Exception error = null;
		var thread = new Thread(() =>
		{
			try { result = action(); }
			catch (Exception ex) { error = ex; }
		});
		thread.SetApartmentState(ApartmentState.STA);
		thread.Start();
		thread.Join();

		if (error != null)
		{
			// 保留原始异常类型，便于上层判断
			System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture(error).Throw();
		}
		return result;
	}

	/// <summary>
	/// 判断是否为"剪贴板暂时被占用"类的可重试异常
	/// COMException 继承自 ExternalException，所以一起覆盖
	/// </summary>
	private static bool IsRetryable(Exception ex)
	{
		if (ex is ExternalException)
		{
			// 0x800401D0 CLIPBRD_E_CANT_OPEN
			// 0x800401D1 CLIPBRD_E_CANT_EMPTY
			// 0x800401D2 CLIPBRD_E_CANT_SET
			// 0x800401D3 CLIPBRD_E_BAD_DATA
			// 0x800401D4 CLIPBRD_E_CANT_CLOSE
			// WinForms 的 "Requested Clipboard operation did not succeed" 也是 ExternalException
			return true;
		}
		return false;
	}

	#endregion
}