using System;
using System.Collections.Generic;
using System.Web;
using WebDAVSharp.Server.Adapters;
using WebDAVSharp.Server.Stores;

namespace WebDAVSharp.Server.MethodHandlers {
	/// <summary>
	/// This class implements the <c>OPTIONS</c> HTTP method for WebDAV#.
	/// </summary>
	internal class WebDavOptionsMethodHandler : WebDavMethodHandlerBase, IWebDavMethodHandler {
		/// <summary>
		/// Gets the collection of the names of the HTTP methods handled by this instance.
		/// </summary>
		public IEnumerable<string> Names {
			get {
				return new[] { "OPTIONS" };
			}
		}

		/// <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>
		public void ProcessRequest(WebDavServer server, HttpContext context, IWebDavStore store, String fileName) {

			List<string> verbsAllowed = new List<string> { "OPTIONS", "TRACE", "GET", "HEAD", "POST", "COPY", "PROPFIND", "LOCK", "UNLOCK" };
			List<string> verbsPublic = new List<string> { "OPTIONS", "GET", "HEAD", "PROPFIND", "PROPPATCH", "MKCOL", "PUT", "DELETE", "COPY", "MOVE", "LOCK", "UNLOCK" };

			foreach (string verb in verbsAllowed)
				context.Response.AppendHeader("Allow", verb);

			foreach (string verb in verbsPublic)
				context.Response.AppendHeader("Public", verb);

			//tell MS Office specifically: yes, this is a WebDAV Server, and yes, we want you to use WebDAV to edit documents
			//see. https://msdn.microsoft.com/en-us/library/cc250217.aspx
			//and: http://stackoverflow.com/questions/40460818/ms-office-opens-documents-readonly-with-webdav
			// or: https://answers.microsoft.com/en-us/msoffice/forum/msoffice_word-mso_winother/office-opens-documents-readonly-with-webdav/a1a6dbb6-4041-41a6-9701-8c70343da6ce 
			context.Response.AppendHeader("MS-Author-Via", "DAV");

			// Sends 200 OK
			context.SendSimpleResponse();
		}
	}
}