#pragma warning disable CS1591 // Missing XML comment for publicly visible type or member

using System;
using System.Text;
using System.Threading;

namespace Cysharp.Threading.Tasks
{
    // UniTask has no scheduler like TaskScheduler.
    // Only handle unobserved exception.

    public static class UniTaskScheduler
    {
        /// <summary>
        /// 安全清理异常消息字符串，防止日志注入攻击
        /// 清理控制字符、限制长度、转义特殊字符
        /// </summary>
        /// <param name="message">原始异常消息</param>
        /// <param name="maxLength">最大长度限制，默认1000字符</param>
        /// <returns>清理后的安全消息字符串</returns>
        static string SanitizeExceptionMessage(string message, int maxLength = 1000)
        {
            if (string.IsNullOrEmpty(message))
            {
                return string.Empty;
            }

            // 创建StringBuilder用于构建清理后的消息
            var sanitized = new StringBuilder(message.Length);
            
            // 遍历每个字符进行清理
            for (int i = 0; i < message.Length && sanitized.Length < maxLength; i++)
            {
                char c = message[i];
                
                // 保留可打印字符（ASCII 32-126）和常见的Unicode字符
                // 移除控制字符（ASCII 0-31，除了换行符和制表符）
                if (char.IsControl(c) && c != '\n' && c != '\r' && c != '\t')
                {
                    // 将控制字符替换为安全的转义表示
                    sanitized.Append($"\\u{(int)c:X4}");
                }
                else if (c == '\n')
                {
                    // 将换行符替换为安全表示，防止日志注入
                    sanitized.Append("\\n");
                }
                else if (c == '\r')
                {
                    // 将回车符替换为安全表示
                    sanitized.Append("\\r");
                }
                else if (c == '\t')
                {
                    // 将制表符替换为空格
                    sanitized.Append("    ");
                }
                else
                {
                    // 保留正常的可打印字符
                    sanitized.Append(c);
                }
            }
            
            // 如果消息被截断，添加截断标记
            if (message.Length > maxLength)
            {
                sanitized.Append("...[消息已截断]");
            }
            
            return sanitized.ToString();
        }
        public static event Action<Exception> UnobservedTaskException;

        /// <summary>
        /// Propagate OperationCanceledException to UnobservedTaskException when true. Default is false.
        /// </summary>
        public static bool PropagateOperationCanceledException = false;

#if UNITY_2018_3_OR_NEWER

        /// <summary>
        /// Write log type when catch unobserved exception and not registered UnobservedTaskException. Default is Exception.
        /// </summary>
        public static UnityEngine.LogType UnobservedExceptionWriteLogType = UnityEngine.LogType.Exception;

        /// <summary>
        /// Dispatch exception event to Unity MainThread. Default is true.
        /// </summary>
        public static bool DispatchUnityMainThread = true;
        
        // cache delegate.
        static readonly SendOrPostCallback handleExceptionInvoke = InvokeUnobservedTaskException;

        static void InvokeUnobservedTaskException(object state)
        {
            UnobservedTaskException((Exception)state);
        }
#endif

        internal static void PublishUnobservedTaskException(Exception ex)
        {
            if (ex != null)
            {
                if (!PropagateOperationCanceledException && ex is OperationCanceledException)
                {
                    return;
                }

                if (UnobservedTaskException != null)
                {
#if UNITY_2018_3_OR_NEWER
                    if (!DispatchUnityMainThread || Thread.CurrentThread.ManagedThreadId == PlayerLoopHelper.MainThreadId)
                    {
                        // allows inlining call.
                        UnobservedTaskException.Invoke(ex);
                    }
                    else
                    {
                        // Post to MainThread.
                        PlayerLoopHelper.UnitySynchronizationContext.Post(handleExceptionInvoke, ex);
                    }
#else
                    UnobservedTaskException.Invoke(ex);
#endif
                }
                else
                {
#if UNITY_2018_3_OR_NEWER
                    string msg = null;
                    if (UnobservedExceptionWriteLogType != UnityEngine.LogType.Exception)
                    {
                        // 使用安全清理方法处理异常消息，防止日志注入攻击
                        string safeExceptionMessage = SanitizeExceptionMessage(ex.ToString());
                        msg = "UnobservedTaskException: " + safeExceptionMessage;
                    }
                    switch (UnobservedExceptionWriteLogType)
                    {
                        case UnityEngine.LogType.Error:
                            UnityEngine.Debug.LogError(msg);
                            break;
                        case UnityEngine.LogType.Assert:
                            UnityEngine.Debug.LogAssertion(msg);
                            break;
                        case UnityEngine.LogType.Warning:
                            UnityEngine.Debug.LogWarning(msg);
                            break;
                        case UnityEngine.LogType.Log:
                            UnityEngine.Debug.Log(msg);
                            break;
                        case UnityEngine.LogType.Exception:
                            UnityEngine.Debug.LogException(ex);
                            break;
                        default:
                            break;
                    }
#else
                    // 使用安全清理方法处理异常消息，防止日志注入攻击
                    string safeMessage = SanitizeExceptionMessage(ex.ToString());
                    Console.WriteLine("UnobservedTaskException: " + safeMessage);
#endif
                }
            }
        }
    }
}