using System;
using System.Collections.Generic;

namespace Sarand.Net.Standard.Base.Utils
{
	//=======================================================================
	public static class ExceptionUtil
	{
		//-------------------------------------------------------------------
		/// <summary>
		/// Extract and cleanse exception message.
		/// <para>- \r\n replaced with \n</para>
		/// <para>- Duplicate lines removed.</para>
		/// </summary>
		public static String GetMessage(this Exception exc)
		{
			List<String> messageLines = new List<string>();
			foreach (String messageLine in (StringUtil.EmptyOnNull(exc?.Message) ?? "").Trim().ReplaceAll("\r\n", "\n").Split('\n'))
			{
				if (!messageLines.ContainsCI(messageLine))
					messageLines.Add(messageLine);
			}
			return messageLines.Concat("\n");
		}

		//-------------------------------------------------------------------
		/// <summary>
		/// Generate standard exception log message.
		/// <para>[ExceptionType]: [ExceptionMessage]</para>
		/// <para>followed by stack entries on separate lines.</para>
		/// </summary>
		public static String GetErrorStateMessage(this Exception exc, bool includeExceptionType = true)
		{
			return (includeExceptionType ? exc.GetType().Name + ": " : "") + GetMessage(exc);
		}

		//-------------------------------------------------------------------
		/// <summary>
		/// Generate standard exception log message.
		/// <para>[ExceptionType]: [ExceptionMessage]</para>
		/// <para>followed by stack entries on separate lines.</para>
		/// </summary>
		public static String GetLogMessage(this Exception exc, int entries = 8, String stackEntryDelim = "\n\t")
		{
			return exc.GetLogMessage("", entries, stackEntryDelim);
		}
		/// <summary>
		/// Generate standard exception log message.
		/// <para>[ExceptionType] [message]: [ExceptionMessage]</para>
		/// <para>followed by stack entries on separate lines.</para>
		/// </summary>
		public static String GetLogMessage(this Exception exc, String message, int entries = 8, String stackEntryDelim = "\n\t")
		{
			return (exc.GetType().Name + " " + message + ": " + GetMessage(exc) + exc.GetStackEntries(entries).Concat("", stackEntryDelim)).TrimAll();
		}

		//-------------------------------------------------------------------
		/// <summary>Retrieve stack entries, up to maximum number.</summary>
		public static List<String> GetStackEntries(this Exception exc, int entries = 0)
		{
			List<String> stackEntries = new List<string>();
			if (exc.StackTrace != null)
			{
				stackEntries.AddRange(exc.StackTrace.Split(new String[] { "\r\n" }, (entries > 0 ? entries : 999), StringSplitOptions.None));
				for (int idx = 0; idx < stackEntries.Count; idx++)
					stackEntries[idx] = stackEntries[idx].Replace("   at ", "");
			}
			return stackEntries;
		}

		//-------------------------------------------------------------------
	}

	//=======================================================================
	// File handling exceptions.
	public class FileException : Exception
	{
		public FileException(string message) :
			base(message)
		{ }
	}
	public class ArchiveFileException : FileException
	{
		public ArchiveFileException(string message) :
			base(message)
		{ }
	}
	public class FileExistsException : FileException
	{
		public FileExistsException(string message) :
			base(message)
		{ }
	}

	//=======================================================================
}