using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Web;
using System.Xml;
using Common.Logging;
using WebDAVSharp.Server.Adapters;
using WebDAVSharp.Server.Exceptions;
using WebDAVSharp.Server.Stores;
using WebDAVSharp.Server.Utilities;

namespace WebDAVSharp.Server.MethodHandlers {
	/// <summary>
	/// This class implements the <c>PROPFIND</c> HTTP method for WebDAV#.
	/// </summary>
	internal class WebDavPropfindMethodHandler : WebDavMethodHandlerBase, IWebDavMethodHandler {
		private ILog _log;
		private String _requestedFilePath;
		private List<WebDavProperty> _requestedProperties;
		private List<IWebDavStoreItem> _webDavStoreItems;

		/// <summary>
		/// Gets the collection of the names of the HTTP methods handled by this instance.
		/// </summary>
		/// <value>
		/// The names.
		/// </value>
		public IEnumerable<string> Names {
			get {
				return new[] { "PROPFIND" };
			}
		}

		/// <summary>
		/// Processes the request.
		/// </summary>
		/// <param name="server">The <see cref="WebDavServer" /> through which the request came in from the client.</param>
		/// <param name="context">The
		/// <see cref="IHttpListenerContext" /> object containing both the request and response
		/// objects to use.</param>
		/// <param name="store">The <see cref="IWebDavStore" /> that the <see cref="WebDavServer" /> is hosting.</param>
		/// <exception cref="WebDAVSharp.Server.Exceptions.WebDavUnauthorizedException"></exception>
		public void ProcessRequest(WebDavServer server, HttpContext context, IWebDavStore store, String fileName) {
			_log = LogManager.GetLogger<WebDavPropfindMethodHandler>();

			/***************************************************************************************************
			 * Retreive all the information from the request
			 ***************************************************************************************************/

			// Read the headers, ...
			bool isPropname = false;
			int depth = GetDepthHeader(context.Request);
			_requestedFilePath = server.ServiceUrl + fileName;//GetRequestUri(context.Request.Url2.ToString());
																												// make sure _requestedFilePath ends with /
			_requestedFilePath = _requestedFilePath.TrimEnd('/') + '/';

			try {
				_webDavStoreItems = GetWebDavStoreItems(GetItem(server, store, fileName), depth);
			}
			catch (UnauthorizedAccessException) {
				throw new WebDavUnauthorizedException();
			}

			// Get the XmlDocument from the request
			XmlDocument requestDoc = GetXmlDocument(context.Request);

			// See what is requested
			_requestedProperties = new List<WebDavProperty>();
			if (requestDoc.DocumentElement != null) {
				if (requestDoc.DocumentElement.LocalName != "propfind")
					_log.Debug("PROPFIND method without propfind in xml document");
				else {
					XmlNode n = requestDoc.DocumentElement.FirstChild;
					if (n == null)
						_log.Debug("propfind element without children");
					else {
						switch (n.LocalName) {
							case "allprop":
								_requestedProperties = GetAllProperties();
								break;
							case "propname":
								isPropname = true;
								_requestedProperties = GetAllProperties();
								break;
							case "prop":
								foreach (XmlNode child in n.ChildNodes)
									_requestedProperties.Add(new WebDavProperty(child.LocalName, "", child.NamespaceURI));
								break;
							default:
								_requestedProperties.Add(new WebDavProperty(n.LocalName, "", n.NamespaceURI));
								break;
						}
					}
				}
			}
			else
				_requestedProperties = GetAllProperties();

			/***************************************************************************************************
			 * Create the body for the response
			 ***************************************************************************************************/

			XmlDocument responseDoc = ResponseDocument(context, isPropname);

			/***************************************************************************************************
			 * Send the response
			 ***************************************************************************************************/

			SendResponse(context, responseDoc);
		}

		#region RetrieveInformation

		/// <summary>
		/// Get the URI to the location
		/// If no slash at the end of the URI, this method adds one
		/// </summary>
		/// <param name="uri">The <see cref="string" /> that contains the URI</param>
		/// <returns>
		/// The <see cref="Uri" /> that contains the given uri
		/// </returns>
		private static Uri GetRequestUri(string uri) {
			return new Uri(uri.EndsWith("/") ? uri : uri + "/");
		}

		/// <summary>
		/// Convert the given 
		/// <see cref="IWebDavStoreItem" /> to a 
		/// <see cref="List{T}" /> of 
		/// <see cref="IWebDavStoreItem" />
		/// This list depends on the "Depth" header
		/// </summary>
		/// <param name="iWebDavStoreItem">The <see cref="IWebDavStoreItem" /> that needs to be converted</param>
		/// <param name="depth">The "Depth" header</param>
		/// <returns>
		/// A <see cref="List{T}" /> of <see cref="IWebDavStoreItem" />
		/// </returns>
		/// <exception cref="WebDAVSharp.Server.Exceptions.WebDavConflictException"></exception>
		private static List<IWebDavStoreItem> GetWebDavStoreItems(IWebDavStoreItem iWebDavStoreItem, int depth) {
			ILog _log = LogManager.GetLogger<WebDavPropfindMethodHandler>();
			List<IWebDavStoreItem> list = new List<IWebDavStoreItem>();

			//IWebDavStoreCollection
			// if the item is a collection
			IWebDavStoreCollection collection = iWebDavStoreItem as IWebDavStoreCollection;
			if (collection != null) {
				list.Add(collection);
				if (depth == 0)
					return list;
				foreach (IWebDavStoreItem item in collection.Items) {
					try {
						list.Add(item);
					}
					catch (Exception ex) {
						_log.Debug(ex.Message + "\r\n" + ex.StackTrace);
					}
				}
				return list;
			}
			// if the item is not a document, throw conflict exception
			if (!(iWebDavStoreItem is IWebDavStoreDocument))
				throw new WebDavConflictException();

			// add the item to the list
			list.Add(iWebDavStoreItem);

			return list;
		}

		/// <summary>
		/// Reads the XML body of the 
		/// <see cref="IHttpListenerRequest" />
		/// and converts it to an 
		/// <see cref="XmlDocument" />
		/// </summary>
		/// <param name="request">The <see cref="IHttpListenerRequest" /></param>
		/// <returns>
		/// The <see cref="XmlDocument" /> that contains the request body
		/// </returns>
		private XmlDocument GetXmlDocument(HttpRequest request) {
			try {
				StreamReader reader = new StreamReader(request.InputStream, Encoding.UTF8);
				string requestBody = reader.ReadToEnd();
				reader.Close();

				if (!String.IsNullOrEmpty(requestBody)) {
					var xmlDocument = new XmlDocument();
					xmlDocument.LoadXml(requestBody);
					return xmlDocument;
				}
			}
			catch (Exception) {
				_log.Warn("XmlDocument has not been read correctly");
			}

			return new XmlDocument();
		}

		/// <summary>
		/// Adds the standard properties for an Propfind allprop request to a <see cref="List{T}" /> of <see cref="WebDavProperty" />
		/// </summary>
		/// <returns>
		/// The list with all the <see cref="WebDavProperty" />
		/// </returns>
		private List<WebDavProperty> GetAllProperties() {
			List<WebDavProperty> list = new List<WebDavProperty>
			{
								new WebDavProperty("creationdate"),
								new WebDavProperty("displayname"),
								new WebDavProperty("getcontentlength"),
								new WebDavProperty("getcontenttype"),
								new WebDavProperty("getetag"),
								new WebDavProperty("getlastmodified"),
								new WebDavProperty("resourcetype"),
								new WebDavProperty("supportedlock"),
								new WebDavProperty("ishidden")
						};
			//list.Add(new WebDAVProperty("getcontentlanguage"));
			//list.Add(new WebDAVProperty("lockdiscovery"));
			return list;
		}

		#endregion

		#region BuildResponseBody

		/// <summary>
		/// Builds the <see cref="XmlDocument" /> containing the response body
		/// </summary>
		/// <param name="context">The <see cref="IHttpListenerContext" /></param>
		/// <param name="propname">The boolean defining the Propfind propname request</param>
		/// <returns>
		/// The <see cref="XmlDocument" /> containing the response body
		/// </returns>
		private XmlDocument ResponseDocument(HttpContext context, bool propname) {
			// Create the basic response XmlDocument
			XmlDocument responseDoc = new XmlDocument();
			const string responseXml = "<?xml version=\"1.0\"?><D:multistatus xmlns:D=\"DAV:\"></D:multistatus>";
			responseDoc.LoadXml(responseXml);

			// Generate the manager
			XmlNamespaceManager manager = new XmlNamespaceManager(responseDoc.NameTable);
			manager.AddNamespace("D", "DAV:");
			manager.AddNamespace("Office", "schemas-microsoft-com:office:office");
			manager.AddNamespace("Repl", "http://schemas.microsoft.com/repl/");
			manager.AddNamespace("Z", "urn:schemas-microsoft-com:");

			int count = 0;

			foreach (IWebDavStoreItem webDavStoreItem in _webDavStoreItems) {
				// Create the response element
				WebDavProperty responseProperty = new WebDavProperty("response", "");
				XmlElement responseElement = responseProperty.ToXmlElement(responseDoc);

				// The href element
				Uri result;
				//String result;
				if (count == 0) {
					Uri.TryCreate(new Uri(_requestedFilePath), "", out result);
					//result = _requestedFilePath;
				}
				else {
					Uri.TryCreate(new Uri(_requestedFilePath), webDavStoreItem.Name, out result);
					//result = _requestedFilePath + webDavStoreItem.Name;
				}
				WebDavProperty hrefProperty = new WebDavProperty("href", result.AbsoluteUri);
				responseElement.AppendChild(hrefProperty.ToXmlElement(responseDoc));
				count++;

				// The propstat element
				WebDavProperty propstatProperty = new WebDavProperty("propstat", "");
				XmlElement propstatElement = propstatProperty.ToXmlElement(responseDoc);

				// The prop element
				WebDavProperty propProperty = new WebDavProperty("prop", "");
				XmlElement propElement = propProperty.ToXmlElement(responseDoc);

				foreach (WebDavProperty davProperty in _requestedProperties) {
					propElement.AppendChild(PropChildElement(davProperty, responseDoc, webDavStoreItem, propname));
				}

				// Add the prop element to the propstat element
				propstatElement.AppendChild(propElement);

				// The status element
				WebDavProperty statusProperty = new WebDavProperty("status",
						"HTTP/1.1 " + context.Response.StatusCode + " " +
						HttpWorkerRequest.GetStatusDescription(context.Response.StatusCode));
				propstatElement.AppendChild(statusProperty.ToXmlElement(responseDoc));

				// Add the propstat element to the response element
				responseElement.AppendChild(propstatElement);

				// Add the response element to the multistatus element
				responseDoc.DocumentElement.AppendChild(responseElement);
			}

			return responseDoc;
		}

		/// <summary>
		/// Gives the 
		/// <see cref="XmlElement" /> of a 
		/// <see cref="WebDavProperty" />
		/// with or without values
		/// or with or without child elements
		/// </summary>
		/// <param name="webDavProperty">The <see cref="WebDavProperty" /></param>
		/// <param name="xmlDocument">The <see cref="XmlDocument" /> containing the response body</param>
		/// <param name="iWebDavStoreItem">The <see cref="IWebDavStoreItem" /></param>
		/// <param name="isPropname">The boolean defining the Propfind propname request</param>
		/// <returns>
		/// The <see cref="XmlElement" /> of the <see cref="WebDavProperty" /> containing a value or child elements
		/// </returns>
		private XmlElement PropChildElement(WebDavProperty webDavProperty, XmlDocument xmlDocument, IWebDavStoreItem iWebDavStoreItem, bool isPropname) {
			// If Propfind request contains a propname element
			if (isPropname) {
				webDavProperty.Value = String.Empty;
				return webDavProperty.ToXmlElement(xmlDocument);
			}
			// If not, add the values to webDavProperty
			webDavProperty.Value = GetWebDavPropertyValue(iWebDavStoreItem, webDavProperty);
			XmlElement xmlElement = webDavProperty.ToXmlElement(xmlDocument);

			// If the webDavProperty is the resourcetype property
			// and the webDavStoreItem is a collection
			// add the collection XmlElement as a child to the xmlElement
			if (webDavProperty.Name != "resourcetype" || !iWebDavStoreItem.IsCollection)
				return xmlElement;

			WebDavProperty collectionProperty = new WebDavProperty("collection", "");
			xmlElement.AppendChild(collectionProperty.ToXmlElement(xmlDocument));
			return xmlElement;
		}

		/// <summary>
		/// Gets the correct value for a <see cref="WebDavProperty" />
		/// </summary>
		/// <param name="webDavStoreItem">The <see cref="IWebDavStoreItem" /> defines the values</param>
		/// <param name="davProperty">The <see cref="WebDavProperty" /> that needs a value</param>
		/// <returns>
		/// A <see cref="string" /> containing the value
		/// </returns>
		private string GetWebDavPropertyValue(IWebDavStoreItem webDavStoreItem, WebDavProperty davProperty) {
			switch (davProperty.Name) {
				case "creationdate":
					return webDavStoreItem.CreationDate.ToUniversalTime().ToString("s") + "Z";
				case "displayname":
					return webDavStoreItem.Name;
				case "getcontentlanguage":
					// still to implement !!!
					return String.Empty;
				case "getcontentlength":
					return (!webDavStoreItem.IsCollection ? "" + ((IWebDavStoreDocument)webDavStoreItem).Size : "");
				case "getcontenttype":
					return (!webDavStoreItem.IsCollection ? "" + ((IWebDavStoreDocument)webDavStoreItem).MimeType : "");
				case "getetag":
					return (!webDavStoreItem.IsCollection ? "" + ((IWebDavStoreDocument)webDavStoreItem).Etag : "");
				case "getlastmodified":
					return webDavStoreItem.ModificationDate.ToUniversalTime().ToString("R");
				case "lockdiscovery":
					// still to implement !!!
					return String.Empty;
				case "resourcetype":
					return "";
				case "supportedlock":
					// still to implement !!!
					return "";
				//webDavProperty.Value = "<D:lockentry><D:lockscope><D:shared/></D:lockscope><D:locktype><D:write/></D:locktype></D:lockentry>";
				case "ishidden":
					return "" + webDavStoreItem.Hidden;
				default:
					return String.Empty;
			}
		}

		#endregion

		#region SendResponse

		/// <summary>
		/// Sends the response
		/// </summary>
		/// <param name="context">The <see cref="IHttpListenerContext" /> containing the response</param>
		/// <param name="responseDocument">The <see cref="XmlDocument" /> containing the response body</param>
		private static void SendResponse(HttpContext context, XmlDocument responseDocument) {
			// convert the XmlDocument
			byte[] responseBytes = Encoding.UTF8.GetBytes(responseDocument.InnerXml);

			// HttpStatusCode doesn't contain WebDav status codes, but HttpWorkerRequest can handle these WebDav status codes
			context.Response.StatusCode = (int)WebDavStatusCode.MultiStatus;
			context.Response.StatusDescription = HttpWorkerRequest.GetStatusDescription((int)WebDavStatusCode.MultiStatus);

			//context.Response.ContentLength64 = responseBytes.Length;
			//context.Response.AdaptedInstance.ContentType = "text/xml";
			context.Response.ContentType = "text/xml";

			context.Response.OutputStream.Write(responseBytes, 0, responseBytes.Length);

			//context.Response.Close();
		}

		#endregion

	}
}