feature: Add MessageFlags and AllowedMentions to message modify (#1724)

* feature: Add MessageFlags and AllowedMentions to Modify

* Change exception message

src/Discord.Net.Core/Entities/Messages/IMessage.cs

@@ -164,6 +164,17 @@ namespace Discord
         /// </summary>
         IReadOnlyDictionary<IEmote, ReactionMetadata> Reactions { get; }
 
+        /// <summary>
+        ///     Gets the flags related to this message.
+        /// </summary>
+        /// <remarks>
+        ///     This value is determined by bitwise OR-ing <see cref="MessageFlags"/> values together.
+        /// </remarks>
+        /// <returns>
+        ///     A message's flags, if any is associated.
+        /// </returns>
+        MessageFlags? Flags { get; }
+
         /// <summary>
         ///     Adds a reaction to this message.
         /// </summary>

src/Discord.Net.Core/Entities/Messages/MessageFlags.cs

@@ -0,0 +1,36 @@
+using System;
+
+namespace Discord
+{
+    [Flags]
+    public enum MessageFlags
+    {
+        /// <summary>
+        ///     Default value for flags, when none are given to a message.
+        /// </summary>
+        None = 0,
+        /// <summary>
+        ///     Flag given to messages that have been published to subscribed
+        ///     channels (via Channel Following).
+        /// </summary>
+        Crossposted = 1 << 0,
+        /// <summary>
+        ///     Flag given to messages that originated from a message in another
+        ///     channel (via Channel Following).
+        /// </summary>
+        IsCrosspost = 1 << 1,
+        /// <summary>
+        ///     Flag given to messages that do not display any embeds.
+        /// </summary>
+        SuppressEmbeds = 1 << 2,
+        /// <summary>
+        ///     Flag given to messages that the source message for this crosspost
+        ///     has been deleted (via Channel Following).
+        /// </summary>
+        SourceMessageDeleted = 1 << 3,
+        /// <summary>
+        ///     Flag given to messages that came from the urgent message system.
+        /// </summary>
+        Urgent = 1 << 4,
+    }
+}

src/Discord.Net.Core/Entities/Messages/MessageProperties.cs

@@ -21,5 +21,17 @@ namespace Discord
         ///     Gets or sets the embed the message should display.
         /// </summary>
         public Optional<Embed> Embed { get; set; }
+        /// <summary>
+        ///     Gets or sets the flags of the message.
+        /// </summary>
+        /// <remarks>
+        ///     Only <see cref="MessageFlags.SuppressEmbeds"/> can be set/unset and you need to be
+        ///     the author of the message.
+        /// </remarks>
+        public Optional<MessageFlags?> Flags { get; set; }
+        /// <summary>
+        ///     Gets or sets the allowed mentions of the message.
+        /// </summary>
+        public Optional<AllowedMentions> AllowedMentions { get; set; }
     }
 }

src/Discord.Net.Rest/API/Common/MessageFlags.cs

@@ -1,10 +0,0 @@
-using System;
-
-namespace Discord.API
-{
-    [Flags]
-    internal enum MessageFlags : byte // probably safe to constrain this to 8 values, if not, it's internal so who cares
-    {
-        Suppressed = 0x04,
-    }
-}

src/Discord.Net.Rest/API/Rest/ModifyMessageParams.cs

@@ -1,4 +1,4 @@
-#pragma warning disable CS1591
+#pragma warning disable CS1591
 using Newtonsoft.Json;
 
 namespace Discord.API.Rest
@@ -10,5 +10,9 @@ namespace Discord.API.Rest
         public Optional<string> Content { get; set; }
         [JsonProperty("embed")]
         public Optional<Embed> Embed { get; set; }
+        [JsonProperty("flags")]
+        public Optional<MessageFlags?> Flags { get; set; }
+        [JsonProperty("allowed_mentions")]
+        public Optional<AllowedMentions> AllowedMentions { get; set; }
     }
 }

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

@@ -27,21 +27,46 @@ namespace Discord.Rest
         public static async Task<Model> ModifyAsync(IMessage msg, BaseDiscordClient client, Action<MessageProperties> func,
             RequestOptions options)
         {
-            if (msg.Author.Id != client.CurrentUser.Id)
-                throw new InvalidOperationException("Only the author of a message may modify the message.");
-
             var args = new MessageProperties();
             func(args);
 
+            if (msg.Author.Id != client.CurrentUser.Id && (args.Content.IsSpecified || args.Embed.IsSpecified || args.AllowedMentions.IsSpecified))
+                throw new InvalidOperationException("Only the author of a message may modify the message content, embed, or allowed mentions.");
+
             bool hasText = args.Content.IsSpecified ? !string.IsNullOrEmpty(args.Content.Value) : !string.IsNullOrEmpty(msg.Content);
             bool hasEmbed = args.Embed.IsSpecified ? args.Embed.Value != null : msg.Embeds.Any();
             if (!hasText && !hasEmbed)
                 Preconditions.NotNullOrEmpty(args.Content.IsSpecified ? args.Content.Value : string.Empty, nameof(args.Content));
 
+            if (args.AllowedMentions.IsSpecified)
+            {
+                AllowedMentions allowedMentions = args.AllowedMentions.Value;
+                Preconditions.AtMost(allowedMentions?.RoleIds?.Count ?? 0, 100, nameof(allowedMentions.RoleIds), "A max of 100 role Ids are allowed.");
+                Preconditions.AtMost(allowedMentions?.UserIds?.Count ?? 0, 100, nameof(allowedMentions.UserIds), "A max of 100 user Ids are allowed.");
+
+                // check that user flag and user Id list are exclusive, same with role flag and role Id list
+                if (allowedMentions != null && allowedMentions.AllowedTypes.HasValue)
+                {
+                    if (allowedMentions.AllowedTypes.Value.HasFlag(AllowedMentionTypes.Users) &&
+                        allowedMentions.UserIds != null && allowedMentions.UserIds.Count > 0)
+                    {
+                        throw new ArgumentException("The Users flag is mutually exclusive with the list of User Ids.", nameof(allowedMentions));
+                    }
+
+                    if (allowedMentions.AllowedTypes.Value.HasFlag(AllowedMentionTypes.Roles) &&
+                        allowedMentions.RoleIds != null && allowedMentions.RoleIds.Count > 0)
+                    {
+                        throw new ArgumentException("The Roles flag is mutually exclusive with the list of Role Ids.", nameof(allowedMentions));
+                    }
+                }
+            }
+
             var apiArgs = new API.Rest.ModifyMessageParams
             {
                 Content = args.Content,
-                Embed = args.Embed.IsSpecified ? args.Embed.Value.ToModel() : Optional.Create<API.Embed>()
+                Embed = args.Embed.IsSpecified ? args.Embed.Value.ToModel() : Optional.Create<API.Embed>(),
+                Flags = args.Flags.IsSpecified ? args.Flags.Value : Optional.Create<MessageFlags?>(),
+                AllowedMentions = args.AllowedMentions.IsSpecified ? args.AllowedMentions.Value.ToModel() : Optional.Create<API.AllowedMentions>(),
             };
             return await client.ApiClient.ModifyMessageAsync(msg.Channel.Id, msg.Id, apiArgs, options).ConfigureAwait(false);
         }

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

@@ -67,6 +67,8 @@ namespace Discord.Rest
         public MessageApplication Application { get; private set; }
         /// <inheritdoc />
         public MessageReference Reference { get; private set; }
+        /// <inheritdoc />
+        public MessageFlags? Flags { get; private set; }
 
         internal RestMessage(BaseDiscordClient discord, ulong id, IMessageChannel channel, IUser author, MessageSource source)
             : base(discord, id)
@@ -124,6 +126,9 @@ namespace Discord.Rest
                 };
             }
 
+            if (model.Flags.IsSpecified)
+                Flags = model.Flags.Value;
+
             if (model.Reactions.IsSpecified)
             {
                 var value = model.Reactions.Value;

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

@@ -13,7 +13,7 @@ namespace Discord.Rest
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
     public class RestUserMessage : RestMessage, IUserMessage
     {
-        private bool _isMentioningEveryone, _isTTS, _isPinned, _isSuppressed;
+        private bool _isMentioningEveryone, _isTTS, _isPinned;
         private long? _editedTimestampTicks;
         private IUserMessage _referencedMessage;
         private ImmutableArray<Attachment> _attachments = ImmutableArray.Create<Attachment>();
@@ -27,7 +27,7 @@ namespace Discord.Rest
         /// <inheritdoc />
         public override bool IsPinned => _isPinned;
         /// <inheritdoc />
-        public override bool IsSuppressed => _isSuppressed;
+        public override bool IsSuppressed => Flags.HasValue && Flags.Value.HasFlag(MessageFlags.SuppressEmbeds);
         /// <inheritdoc />
         public override DateTimeOffset? EditedTimestamp => DateTimeUtils.FromTicks(_editedTimestampTicks);
         /// <inheritdoc />
@@ -70,10 +70,6 @@ namespace Discord.Rest
                 _editedTimestampTicks = model.EditedTimestamp.Value?.UtcTicks;
             if (model.MentionEveryone.IsSpecified)
                 _isMentioningEveryone = model.MentionEveryone.Value;
-            if (model.Flags.IsSpecified)
-            {
-                _isSuppressed = model.Flags.Value.HasFlag(API.MessageFlags.Suppressed);
-            }
             if (model.RoleMentions.IsSpecified)
                 _roleMentionIds = model.RoleMentions.Value.ToImmutableArray();
 

src/Discord.Net.WebSocket/Entities/Messages/SocketMessage.cs

@@ -58,6 +58,9 @@ namespace Discord.WebSocket
         /// <inheritdoc />
         public MessageReference Reference { get; private set; }
 
+        /// <inheritdoc />
+        public MessageFlags? Flags { get; private set; }
+
         /// <summary>
         ///     Returns all attachments included in this message.
         /// </summary>
@@ -156,6 +159,9 @@ namespace Discord.WebSocket
                     MessageId = model.Reference.Value.MessageId
                 };
             }
+
+            if (model.Flags.IsSpecified)
+                Flags = model.Flags.Value;
         }
 
         /// <inheritdoc />

src/Discord.Net.WebSocket/Entities/Messages/SocketUserMessage.cs

@@ -15,7 +15,7 @@ namespace Discord.WebSocket
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
     public class SocketUserMessage : SocketMessage, IUserMessage
     {
-        private bool _isMentioningEveryone, _isTTS, _isPinned, _isSuppressed;
+        private bool _isMentioningEveryone, _isTTS, _isPinned;
         private long? _editedTimestampTicks;
         private IUserMessage _referencedMessage;
         private ImmutableArray<Attachment> _attachments = ImmutableArray.Create<Attachment>();
@@ -29,7 +29,7 @@ namespace Discord.WebSocket
         /// <inheritdoc />
         public override bool IsPinned => _isPinned;
         /// <inheritdoc />
-        public override bool IsSuppressed => _isSuppressed;
+        public override bool IsSuppressed => Flags.HasValue && Flags.Value.HasFlag(MessageFlags.SuppressEmbeds);
         /// <inheritdoc />
         public override DateTimeOffset? EditedTimestamp => DateTimeUtils.FromTicks(_editedTimestampTicks);
         /// <inheritdoc />
@@ -74,10 +74,6 @@ namespace Discord.WebSocket
                 _editedTimestampTicks = model.EditedTimestamp.Value?.UtcTicks;
             if (model.MentionEveryone.IsSpecified)
                 _isMentioningEveryone = model.MentionEveryone.Value;
-            if (model.Flags.IsSpecified)
-            {
-                _isSuppressed = model.Flags.Value.HasFlag(API.MessageFlags.Suppressed);
-            }
             if (model.RoleMentions.IsSpecified)
                 _roleMentions = model.RoleMentions.Value.Select(x => guild.GetRole(x)).ToImmutableArray();