using System;
using System.Net;
using System.Runtime.Serialization;
using System.Security.Permissions;
using System.Web;

namespace WebDAVSharp.Server.Exceptions {
	/// <summary>
	/// This exception, or a descendant, is thrown when requests fail, specifying the status code
	/// that the server should return back to the client.
	/// </summary>
	[Serializable]
	public class WebDavException : HttpException {
		private const string StatusCodeKey = "StatusCode";
		private const string StatusDescriptionKey = "StatusDescription";

		/// <summary>
		/// Initializes a new instance of the <see cref="WebDavException" /> class.
		/// </summary>
		public WebDavException()
				: this(HttpStatusCode.InternalServerError) {
			// Do nothing here
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="WebDavException" /> class.
		/// </summary>
		/// <param name="message">The exception message stating the reason for the exception being thrown.</param>
		public WebDavException(string message)
				: this(HttpStatusCode.InternalServerError, message) {
			// Do nothing here
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="WebDavException" /> class.
		/// </summary>
		/// <param name="message">The exception message stating the reason for the exception being thrown.</param>
		/// <param name="innerException">The 
		/// <see cref="Exception" /> that is the cause for this exception;
		/// or 
		/// <c>null</c> if no inner exception is specified.</param>
		public WebDavException(string message, Exception innerException)
				: this(HttpStatusCode.InternalServerError, message, innerException) {
			// Do nothing here
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="WebDavException" /> class.
		/// </summary>
		/// <param name="info">The <see cref="T:System.Runtime.Serialization.SerializationInfo" /> that holds the serialized object data about the exception being thrown.</param>
		/// <param name="context">The <see cref="T:System.Runtime.Serialization.StreamingContext" /> that contains contextual information about the source or destination.</param>
		/// <exception cref="T:System.ArgumentNullException">The <paramref name="info" /> parameter is null.</exception>
		/// <exception cref="T:System.Runtime.Serialization.SerializationException">The class name is null or <see cref="P:System.Exception.HResult" /> is zero (0).</exception>
		protected WebDavException(SerializationInfo info, StreamingContext context)
				: base(info, context) {
			StatusCode = info.GetInt32(StatusCodeKey);
			StatusDescription = info.GetString(StatusDescriptionKey);
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="WebDavException" /> class.
		/// </summary>
		/// <param name="statusCode">The HTTP status code that this <see cref="WebDavException" /> maps to.</param>
		/// <param name="message">The exception message stating the reason for the exception being thrown.</param>
		/// <param name="innerException">The 
		/// <see cref="Exception" /> that is the cause for this exception;
		/// or 
		/// <c>null</c> if no inner exception is specified.</param>
		public WebDavException(HttpStatusCode statusCode, string message = null, Exception innerException = null)
				: base(GetMessage(statusCode, message), innerException) {
			StatusCode = (int)statusCode;
			StatusDescription = HttpWorkerRequest.GetStatusDescription((int)statusCode);
		}

		/// <summary>
		/// Gets the HTTP status code that this <see cref="WebDavException" /> maps to.
		/// </summary>
		/// <value>
		/// The status code.
		/// </value>
		public int StatusCode {
			get;
			private set;
		}

		/// <summary>
		/// Gets the status description for the HTTP <see cref="StatusCode" />.
		/// </summary>
		/// <value>
		/// The status description.
		/// </value>
		public string StatusDescription {
			get;
			private set;
		}

		/// <summary>
		/// When overridden in a derived class, sets the <see cref="T:System.Runtime.Serialization.SerializationInfo" /> with information about the exception.
		/// </summary>
		/// <param name="info">The <see cref="T:System.Runtime.Serialization.SerializationInfo" /> that holds the serialized object data about the exception being thrown.</param>
		/// <param name="context">The <see cref="T:System.Runtime.Serialization.StreamingContext" /> that contains contextual information about the source or destination.</param>
		/// <exception cref="T:System.ArgumentNullException">The <paramref name="info" /> parameter is a null reference (Nothing in Visual Basic).</exception>
		[SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.SerializationFormatter)]
		public override void GetObjectData(SerializationInfo info, StreamingContext context) {
			base.GetObjectData(info, context);
			info.AddValue(StatusCodeKey, StatusCode);
			info.AddValue(StatusDescriptionKey, StatusDescription);
		}

		/// <summary>
		/// Gets the message.
		/// </summary>
		/// <param name="statusCode">The status code.</param>
		/// <param name="message">The message.</param>
		/// <returns>The message and the status description.</returns>
		private static string GetMessage(HttpStatusCode statusCode, string message) {
			string format = "%s";
			if (!String.IsNullOrWhiteSpace(message))
				format = message;

			return format.Replace("%s", HttpWorkerRequest.GetStatusDescription((int)statusCode));
		}
	}
}