using System;
using System.Text.RegularExpressions;
using DPumpHydr.WinFrmUI.WenSkin.Json.Bson;
using DPumpHydr.WinFrmUI.WenSkin.Json.Serialization;

namespace DPumpHydr.WinFrmUI.WenSkin.Json.Converters
{
	/// <summary>
	/// Converts a <see cref="T:System.Text.RegularExpressions.Regex" /> to and from JSON and BSON.
	/// </summary>
	public class RegexConverter : JsonConverter
	{
		private const string PatternName = "Pattern";

		private const string OptionsName = "Options";

		/// <summary>
		/// Writes the JSON representation of the object.
		/// </summary>
		/// <param name="writer">The <see cref="T:Newtonsoft.Json.JsonWriter" /> to write to.</param>
		/// <param name="value">The value.</param>
		/// <param name="serializer">The calling serializer.</param>
		public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
		{
			Regex regex = (Regex)value;
			BsonWriter bsonWriter = writer as BsonWriter;
			if (bsonWriter != null)
			{
				WriteBson(bsonWriter, regex);
			}
			else
			{
				WriteJson(writer, regex, serializer);
			}
		}

		private bool HasFlag(RegexOptions options, RegexOptions flag)
		{
			return (options & flag) == flag;
		}

		private void WriteBson(BsonWriter writer, Regex regex)
		{
			string text = null;
			if (HasFlag(regex.Options, RegexOptions.IgnoreCase))
			{
				text += "i";
			}
			if (HasFlag(regex.Options, RegexOptions.Multiline))
			{
				text += "m";
			}
			if (HasFlag(regex.Options, RegexOptions.Singleline))
			{
				text += "s";
			}
			text += "u";
			if (HasFlag(regex.Options, RegexOptions.ExplicitCapture))
			{
				text += "x";
			}
			writer.WriteRegex(regex.ToString(), text);
		}

		private void WriteJson(JsonWriter writer, Regex regex, JsonSerializer serializer)
		{
			DefaultContractResolver defaultContractResolver = serializer.ContractResolver as DefaultContractResolver;
			writer.WriteStartObject();
			writer.WritePropertyName((defaultContractResolver != null) ? defaultContractResolver.GetResolvedPropertyName("Pattern") : "Pattern");
			writer.WriteValue(regex.ToString());
			writer.WritePropertyName((defaultContractResolver != null) ? defaultContractResolver.GetResolvedPropertyName("Options") : "Options");
			serializer.Serialize(writer, regex.Options);
			writer.WriteEndObject();
		}

		/// <summary>
		/// Reads the JSON representation of the object.
		/// </summary>
		/// <param name="reader">The <see cref="T:Newtonsoft.Json.JsonReader" /> to read from.</param>
		/// <param name="objectType">Type of the object.</param>
		/// <param name="existingValue">The existing value of object being read.</param>
		/// <param name="serializer">The calling serializer.</param>
		/// <returns>The object value.</returns>
		public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
		{
			if (reader.TokenType == JsonToken.StartObject)
			{
				return ReadRegexObject(reader, serializer);
			}
			if (reader.TokenType == JsonToken.String)
			{
				return ReadRegexString(reader);
			}
			throw JsonSerializationException.Create(reader, "Unexpected token when reading Regex.");
		}

		private object ReadRegexString(JsonReader reader)
		{
			string obj = (string)reader.Value;
			int num = obj.LastIndexOf('/');
			string pattern = obj.Substring(1, num - 1);
			string text = obj.Substring(num + 1);
			RegexOptions regexOptions = RegexOptions.None;
			string text2 = text;
			for (int i = 0; i < text2.Length; i++)
			{
				switch (text2[i])
				{
				case 'i':
					regexOptions |= RegexOptions.IgnoreCase;
					break;
				case 'm':
					regexOptions |= RegexOptions.Multiline;
					break;
				case 's':
					regexOptions |= RegexOptions.Singleline;
					break;
				case 'x':
					regexOptions |= RegexOptions.ExplicitCapture;
					break;
				}
			}
			return new Regex(pattern, regexOptions);
		}

		private Regex ReadRegexObject(JsonReader reader, JsonSerializer serializer)
		{
			string text = null;
			RegexOptions? regexOptions = null;
			while (reader.Read())
			{
				switch (reader.TokenType)
				{
				case JsonToken.PropertyName:
				{
					string a = reader.Value.ToString();
					if (!reader.Read())
					{
						throw JsonSerializationException.Create(reader, "Unexpected end when reading Regex.");
					}
					if (string.Equals(a, "Pattern", StringComparison.OrdinalIgnoreCase))
					{
						text = (string)reader.Value;
					}
					else if (string.Equals(a, "Options", StringComparison.OrdinalIgnoreCase))
					{
						regexOptions = serializer.Deserialize<RegexOptions>(reader);
					}
					else
					{
						reader.Skip();
					}
					break;
				}
				case JsonToken.EndObject:
					if (text == null)
					{
						throw JsonSerializationException.Create(reader, "Error deserializing Regex. No pattern found.");
					}
					return new Regex(text, regexOptions ?? RegexOptions.None);
				}
			}
			throw JsonSerializationException.Create(reader, "Unexpected end when reading Regex.");
		}

		/// <summary>
		/// Determines whether this instance can convert the specified object type.
		/// </summary>
		/// <param name="objectType">Type of the object.</param>
		/// <returns>
		/// 	<c>true</c> if this instance can convert the specified object type; otherwise, <c>false</c>.
		/// </returns>
		public override bool CanConvert(Type objectType)
		{
			return objectType == typeof(Regex);
		}
	}
}