using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text.RegularExpressions;

namespace LeafWeb.Core.Utility
{
	public static class StringExtensions
	{
		public static string SplitCamelCase(this string str)
		{
			return str.Aggregate(
				string.Empty,
				(current, c) =>
				current + (char.IsUpper(c) && current.Length > 0 ? " " + c : c.ToString(CultureInfo.InvariantCulture)));
		}

		public static string LowercaseFirst(string s)
		{
			// Check for empty string.
			if (string.IsNullOrEmpty(s))
			{
				return string.Empty;
			}
			// Return char and concat substring.
			return char.ToLowerInvariant(s[0]) + s.Substring(1);
		}

		public static byte[] GetBytes(this string str)
		{
			var bytes = new byte[str.Length * sizeof(char)];
			Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
			return bytes;
		}

		public static string GetString(this byte[] bytes)
		{
			var chars = new char[bytes.Length / sizeof(char)];
			Buffer.BlockCopy(bytes, 0, chars, 0, bytes.Length);
			return new string(chars);
		}

		public static Dictionary<string, string> SplitConnectionString(this string connectionString)
		{
			return connectionString.Split(';')
				.Select(t => t.Split(new[] { '=' }, 2))
				.ToDictionary(t => t[0].Trim(), t => t[1].Trim(), StringComparer.InvariantCultureIgnoreCase);
		}

		public static string FilterAlphaNumeric(this string input)
		{
			return Regex.Replace(input, @"[^\w_]", "");
		}
	}
}