Added channel reordering

src/Discord.Net/API/Requests.cs

@@ -4,6 +4,7 @@
 
 using Newtonsoft.Json;
 using System.Collections.Generic;
+using System.Collections;
 
 namespace Discord.API
 {
@@ -43,6 +44,21 @@ namespace Discord.API
 		[JsonProperty("topic", NullValueHandling = NullValueHandling.Ignore)]
 		public string Topic;
 	}
+	internal sealed class ReorderChannelsRequest : IEnumerable<ReorderChannelsRequest.Channel>
+	{
+		public sealed class Channel
+		{
+			[JsonProperty("id")]
+			public string Id;
+			[JsonProperty("position")]
+			public uint Position;
+		}
+		private IEnumerable<Channel> _channels;
+		public ReorderChannelsRequest(IEnumerable<Channel> channels) { _channels = channels; }
+
+		public IEnumerator<Channel> GetEnumerator() =>_channels.GetEnumerator();
+		IEnumerator IEnumerable.GetEnumerator() => _channels.GetEnumerator();
+	}
 
 	//Invites
 	internal sealed class CreateInviteRequest

src/Discord.Net/DiscordAPIClient.cs

@@ -1,6 +1,7 @@
 using Discord.API;
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -85,6 +86,17 @@ namespace Discord
 			var request = new EditChannelRequest { Name = name, Topic = topic };
 			return _rest.Patch<EditChannelResponse>(Endpoints.Channel(channelId), request);
 		}
+		public Task ReorderChannels(string serverId, int startPos, IEnumerable<string> channelIds)
+		{
+			if (serverId == null) throw new ArgumentNullException(nameof(serverId));
+			if (channelIds == null) throw new ArgumentNullException(nameof(channelIds));
+			if (startPos < 0) throw new ArgumentOutOfRangeException(nameof(startPos), "startPos must be a positive integer.");
+
+			uint pos = (uint)startPos;
+			var channels = channelIds.Select(x => new ReorderChannelsRequest.Channel { Id = x, Position = pos++ });
+			var request = new ReorderChannelsRequest(channels);
+			return _rest.Patch(Endpoints.ServerChannels(serverId), request);
+		}
 		public Task<GetMessagesResponse> GetMessages(string channelId, int count)
 		{
 			if (channelId == null) throw new ArgumentNullException(nameof(channelId));

src/Discord.Net/DiscordClient.API.cs

@@ -108,16 +108,58 @@ namespace Discord
 		}
 
 		/// <summary> Edits the provided channel, changing only non-null attributes. </summary>
-		public Task EditChannel(Channel channel, string name = null, string topic = null)
+		public Task EditChannel(string channelId, string name = null, string topic = null, int? position = null)
-			=> EditChannel(channel?.Id, name: name, topic: topic);
+			=> EditChannel(_channels[channelId], name: name, topic: topic, position: position);
 		/// <summary> Edits the provided channel, changing only non-null attributes. </summary>
-		public Task EditChannel(string channelId, string name = null, string topic = null)
+        public async Task EditChannel(Channel channel, string name = null, string topic = null, int? position = null)
 		{
 			CheckReady();
-			if (channelId == null) throw new ArgumentNullException(nameof(channelId));
+			if (channel == null) throw new ArgumentNullException(nameof(channel));
-			if (topic == null) throw new ArgumentNullException(nameof(topic));
 
-			return _api.EditChannel(channelId, name: name, topic: topic);
+			await _api.EditChannel(channel.Id, name: name, topic: topic);
+
+			if (position != null)
+			{
+				int oldPos = channel.Position;
+				int newPos = position.Value;
+				int minPos;
+				Channel[] channels = channel.Server.Channels.OrderBy(x => x.Position).ToArray();
+
+				if (oldPos < newPos) //Moving Down
+				{
+					minPos = oldPos;
+					for (int i = oldPos; i < newPos; i++)
+						channels[i] = channels[i + 1];
+					channels[newPos] = channel;
+                }
+				else //(oldPos > newPos) Moving Up
+				{
+					minPos = newPos;
+					for (int i = oldPos; i > newPos; i--)
+						channels[i] = channels[i - 1];
+					channels[newPos] = channel;
+				}
+				await _api.ReorderChannels(channel.ServerId, minPos, channels.Skip(minPos).Select(x => x.Id));
+			}
+		}
+
+		public Task ReorderChannels(Server server, int startPos, IEnumerable<object> channels)
+			=> ReorderChannels(server.Id, startPos, channels);
+        public Task ReorderChannels(string serverId, int startPos, IEnumerable<object> channels)
+		{
+			if (serverId == null) throw new ArgumentNullException(nameof(serverId));
+			if (channels == null) throw new ArgumentNullException(nameof(channels));
+			if (startPos < 0) throw new ArgumentOutOfRangeException(nameof(startPos), "startPos must be a positive integer.");
+
+			return _api.ReorderChannels(serverId, startPos, channels.Select(x =>
+			{
+				if (x is string)
+					return x as string;
+				else if (x is Channel)
+					return (x as Role).Id;
+				else
+					throw new ArgumentException("Channels must be a collection of string or Channel.", nameof(channels));
+			}));
 		}
 
 		/// <summary> Destroys the provided channel. </summary>
@@ -243,7 +285,7 @@ namespace Discord
 				else if (x is Role)
 					return (x as Role).Id;
 				else
-					throw new ArgumentException("Roles must be a collection of strings or roles.", nameof(roles));
+					throw new ArgumentException("Roles must be a collection of string or Role.", nameof(roles));
 			});
 
 			return _api.EditMember(serverId, userId, mute, deaf, newRoles);