Implement IMessageChannel#DeleteMessageAsync (#996)

* Implement DeleteMessageAsync

* Refer to MessageHelper instead of duplicating call

* Fix refactor error

src/Discord.Net.Core/Entities/Channels/IMessageChannel.cs

@@ -30,6 +30,11 @@ namespace Discord
         /// <summary> Gets a collection of pinned messages in this channel. </summary>
         Task<IReadOnlyCollection<IMessage>> GetPinnedMessagesAsync(RequestOptions options = null);
 
+        /// <summary> Deletes a message based on the message ID in this channel. </summary>
+        Task DeleteMessageAsync(ulong messageId, RequestOptions options = null);
+        /// <summary> Deletes a message based on the provided message in this channel. </summary>
+        Task DeleteMessageAsync(IMessage message, RequestOptions options = null);
+
         /// <summary> Broadcasts the "user is typing" message to all users in this channel, lasting 10 seconds. </summary>
         Task TriggerTypingAsync(RequestOptions options = null);
         /// <summary> Continuously broadcasts the "user is typing" message to all users in this channel until the returned object is disposed. </summary>

src/Discord.Net.Rest/Entities/Channels/ChannelHelper.cs

@@ -185,6 +185,10 @@ namespace Discord.Rest
             return RestUserMessage.Create(client, channel, client.CurrentUser, model);
         }
 
+        public static Task DeleteMessageAsync(IMessageChannel channel, ulong messageId, BaseDiscordClient client,
+            RequestOptions options)
+            => MessageHelper.DeleteAsync(channel.Id, messageId, client, options);
+
         public static async Task DeleteMessagesAsync(ITextChannel channel, BaseDiscordClient client,
             IEnumerable<ulong> messageIds, RequestOptions options)
         {

src/Discord.Net.Rest/Entities/Channels/RestDMChannel.cs

@@ -72,6 +72,11 @@ namespace Discord.Rest
         public Task<RestUserMessage> SendFileAsync(Stream stream, string filename, string text, bool isTTS = false, Embed embed = null, RequestOptions options = null)
             => ChannelHelper.SendFileAsync(this, Discord, stream, filename, text, isTTS, embed, options);
 
+        public Task DeleteMessageAsync(ulong messageId, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, messageId, Discord, options);
+        public Task DeleteMessageAsync(IMessage message, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, message.Id, Discord, options);
+
         public Task TriggerTypingAsync(RequestOptions options = null)
             => ChannelHelper.TriggerTypingAsync(this, Discord, options);
         public IDisposable EnterTypingState(RequestOptions options = null)

src/Discord.Net.Rest/Entities/Channels/RestGroupChannel.cs

@@ -76,6 +76,11 @@ namespace Discord.Rest
         public Task<IReadOnlyCollection<RestMessage>> GetPinnedMessagesAsync(RequestOptions options = null)
             => ChannelHelper.GetPinnedMessagesAsync(this, Discord, options);
 
+        public Task DeleteMessageAsync(ulong messageId, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, messageId, Discord, options);
+        public Task DeleteMessageAsync(IMessage message, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, message.Id, Discord, options);
+
         public Task<RestUserMessage> SendMessageAsync(string text = null, bool isTTS = false, Embed embed = null, RequestOptions options = null)
             => ChannelHelper.SendMessageAsync(this, Discord, text, isTTS, embed, options);
 #if FILESYSTEM

src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs

@@ -67,6 +67,11 @@ namespace Discord.Rest
         public Task<RestUserMessage> SendFileAsync(Stream stream, string filename, string text, bool isTTS = false, Embed embed = null, RequestOptions options = null)
             => ChannelHelper.SendFileAsync(this, Discord, stream, filename, text, isTTS, embed, options);
 
+        public Task DeleteMessageAsync(ulong messageId, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, messageId, Discord, options);
+        public Task DeleteMessageAsync(IMessage message, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, message.Id, Discord, options);
+
         public Task DeleteMessagesAsync(IEnumerable<IMessage> messages, RequestOptions options = null)
             => ChannelHelper.DeleteMessagesAsync(this, Discord, messages.Select(x => x.Id), options);
         public Task DeleteMessagesAsync(IEnumerable<ulong> messageIds, RequestOptions options = null)

src/Discord.Net.Rest/Entities/Channels/RpcVirtualMessageChannel.cs

@@ -42,6 +42,11 @@ namespace Discord.Rest
         public Task<RestUserMessage> SendFileAsync(Stream stream, string filename, string text, bool isTTS = false, Embed embed = null, RequestOptions options = null)
             => ChannelHelper.SendFileAsync(this, Discord, stream, filename, text, isTTS, embed, options);
 
+        public Task DeleteMessageAsync(ulong messageId, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, messageId, Discord, options);
+        public Task DeleteMessageAsync(IMessage message, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, message.Id, Discord, options);
+
         public Task TriggerTypingAsync(RequestOptions options = null)
             => ChannelHelper.TriggerTypingAsync(this, Discord, options);
         public IDisposable EnterTypingState(RequestOptions options = null)

src/Discord.Net.Rest/Entities/Messages/MessageHelper.cs

@@ -25,10 +25,12 @@ namespace Discord.Rest
             };
             return await client.ApiClient.ModifyMessageAsync(msg.Channel.Id, msg.Id, apiArgs, options).ConfigureAwait(false);
         }
-        public static async Task DeleteAsync(IMessage msg, BaseDiscordClient client,
+        public static Task DeleteAsync(IMessage msg, BaseDiscordClient client, RequestOptions options)
+            => DeleteAsync(msg.Channel.Id, msg.Id, client, options);
+        public static async Task DeleteAsync(ulong channelId, ulong msgId, BaseDiscordClient client,
             RequestOptions options)
         {
-            await client.ApiClient.DeleteMessageAsync(msg.Channel.Id, msg.Id, options).ConfigureAwait(false);
+            await client.ApiClient.DeleteMessageAsync(channelId, msgId, options).ConfigureAwait(false);
         }
 
         public static async Task AddReactionAsync(IMessage msg, IEmote emote, BaseDiscordClient client, RequestOptions options)

src/Discord.Net.WebSocket/Entities/Channels/SocketDMChannel.cs

@@ -76,6 +76,11 @@ namespace Discord.WebSocket
         public Task<RestUserMessage> SendFileAsync(Stream stream, string filename, string text, bool isTTS = false, Embed embed = null, RequestOptions options = null)
             => ChannelHelper.SendFileAsync(this, Discord, stream, filename, text, isTTS, embed, options);
 
+        public Task DeleteMessageAsync(ulong messageId, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, messageId, Discord, options);
+        public Task DeleteMessageAsync(IMessage message, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, message.Id, Discord, options);
+
         public Task TriggerTypingAsync(RequestOptions options = null)
             => ChannelHelper.TriggerTypingAsync(this, Discord, options);
         public IDisposable EnterTypingState(RequestOptions options = null)

src/Discord.Net.WebSocket/Entities/Channels/SocketGroupChannel.cs

@@ -104,6 +104,11 @@ namespace Discord.WebSocket
         public Task<RestUserMessage> SendFileAsync(Stream stream, string filename, string text, bool isTTS = false, Embed embed = null, RequestOptions options = null)
             => ChannelHelper.SendFileAsync(this, Discord, stream, filename, text, isTTS, embed, options);
 
+        public Task DeleteMessageAsync(ulong messageId, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, messageId, Discord, options);
+        public Task DeleteMessageAsync(IMessage message, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, message.Id, Discord, options);
+
         public Task TriggerTypingAsync(RequestOptions options = null)
             => ChannelHelper.TriggerTypingAsync(this, Discord, options);
         public IDisposable EnterTypingState(RequestOptions options = null)

src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs

@@ -89,6 +89,11 @@ namespace Discord.WebSocket
         public Task DeleteMessagesAsync(IEnumerable<ulong> messageIds, RequestOptions options = null)
             => ChannelHelper.DeleteMessagesAsync(this, Discord, messageIds, options);
 
+        public Task DeleteMessageAsync(ulong messageId, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, messageId, Discord, options);
+        public Task DeleteMessageAsync(IMessage message, RequestOptions options = null)
+            => ChannelHelper.DeleteMessageAsync(this, message.Id, Discord, options);
+
         public Task TriggerTypingAsync(RequestOptions options = null)
             => ChannelHelper.TriggerTypingAsync(this, Discord, options);
         public IDisposable EnterTypingState(RequestOptions options = null)