Squashed commit of the following:

commit dca41a348e
Author: quin lynch <lynchquin@gmail.com>
Date:   Thu Sep 23 07:02:19 2021 -0300

    Autocomplete commands

src/Discord.Net.Core/Discord.Net.Core.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <Import Project="../../Discord.Net.targets" />
   <Import Project="../../StyleAnalyzer.targets" />
   <PropertyGroup>

src/Discord.Net.Core/Discord.Net.Core.xml

@@ -4508,37 +4508,42 @@
         </member>
         <member name="P:Discord.ApplicationCommandOptionProperties.Name">
             <summary>
-                The name of this option.
+                Gets or sets the name of this option.
             </summary>
         </member>
         <member name="P:Discord.ApplicationCommandOptionProperties.Description">
             <summary>
-                The description of this option.
+                Gets or sets the description of this option.
             </summary>
         </member>
         <member name="P:Discord.ApplicationCommandOptionProperties.Type">
             <summary>
-                The type of this option.
+                Gets or sets the type of this option.
             </summary>
         </member>
         <member name="P:Discord.ApplicationCommandOptionProperties.Default">
             <summary>
-                The first required option for the user to complete. only one option can be default.
+                Gets or sets whether or not this options is the first required option for the user to complete. only one option can be default.
             </summary>
         </member>
         <member name="P:Discord.ApplicationCommandOptionProperties.Required">
             <summary>
-                <see langword="true"/> if this option is required for this command, otherwise <see langword="false"/>.
+                Gets or sets if the option is required.
+            </summary>
+        </member>
+        <member name="P:Discord.ApplicationCommandOptionProperties.Autocomplete">
+            <summary>
+                Gets or sets whether or not this option supports autocomplete
             </summary>
         </member>
         <member name="P:Discord.ApplicationCommandOptionProperties.Choices">
             <summary>
-                choices for string and int types for the user to pick from.
+                Gets or sets the choices for string and int types for the user to pick from.
             </summary>
         </member>
         <member name="P:Discord.ApplicationCommandOptionProperties.Options">
             <summary>
-                If the option is a subcommand or subcommand group type, this nested options will be the parameters.
+                Gets or sets if this option is a subcommand or subcommand group type, these nested options will be the parameters.
             </summary>
         </member>
         <member name="T:Discord.ApplicationCommandOptionChoiceProperties">
@@ -4649,6 +4654,68 @@
                 ApplicationCommandType.Message is Context Menu Message command type
             </summary>
         </member>
+        <member name="T:Discord.AutocompleteOption">
+            <summary>
+                Represents an autocomplete option.
+            </summary>
+        </member>
+        <member name="P:Discord.AutocompleteOption.Type">
+            <summary>
+                Gets the type of this option
+            </summary>
+        </member>
+        <member name="P:Discord.AutocompleteOption.Name">
+            <summary>
+                Gets the name of the option.
+            </summary>
+        </member>
+        <member name="P:Discord.AutocompleteOption.Value">
+            <summary>
+                Gets the value of the option.
+            </summary>
+        </member>
+        <member name="P:Discord.AutocompleteOption.Focused">
+            <summary>
+                Gets whether or not this option is focused by the executing user.
+            </summary>
+        </member>
+        <member name="T:Discord.AutocompleteResult">
+            <summary>
+                Represents a result to an autocomplete interaction.
+            </summary>
+        </member>
+        <member name="P:Discord.AutocompleteResult.Name">
+            <summary>
+                Gets or sets the name of the result.
+            </summary>
+            <remarks>
+                Name cannot be null and has to be between 1-100 characters in length.
+            </remarks>
+            <exception cref="T:System.ArgumentNullException"/>
+            <exception cref="T:System.ArgumentException"/>
+        </member>
+        <member name="P:Discord.AutocompleteResult.Value">
+            <summary>
+                Gets or sets the value of the result.
+            </summary>
+            <remarks>
+                Only <see cref="T:System.String"/>, <see cref="T:System.Int32"/>, and <see cref="T:System.Double"/> are allowed for a value.
+            </remarks>
+            <exception cref="T:System.ArgumentNullException"/>
+            <exception cref="T:System.ArgumentException"/>
+        </member>
+        <member name="M:Discord.AutocompleteResult.#ctor">
+            <summary>
+                Creates a new <see cref="T:Discord.AutocompleteResult"/>.
+            </summary>
+        </member>
+        <member name="M:Discord.AutocompleteResult.#ctor(System.String,System.Object)">
+            <summary>
+                Creates a new <see cref="T:Discord.AutocompleteResult"/> with the passed in <paramref name="name"/> and <paramref name="value"/>.
+            </summary>
+            <exception cref="T:System.ArgumentNullException"/>
+            <exception cref="T:System.ArgumentException"/>
+        </member>
         <member name="T:Discord.MessageCommandBuilder">
             <summary>
                 A class used to build Message commands.
@@ -5029,12 +5096,17 @@
         </member>
         <member name="F:Discord.InteractionResponseType.DeferredUpdateMessage">
             <summary>
-                for components: ACK an interaction and edit the original message later; the user does not see a loading state
+                For components: ACK an interaction and edit the original message later; the user does not see a loading state
             </summary>
         </member>
         <member name="F:Discord.InteractionResponseType.UpdateMessage">
             <summary>
-                for components: edit the message the component was attached to
+                For components: edit the message the component was attached to
+            </summary>
+        </member>
+        <member name="F:Discord.InteractionResponseType.ApplicationCommandAutocompleteResult">
+            <summary>
+                Respond with a set of choices to a autocomplete interaction
             </summary>
         </member>
         <member name="T:Discord.InteractionType">
@@ -5057,6 +5129,11 @@
                 A <see cref="T:Discord.IMessageComponent"/> sent from discord.
             </summary>
         </member>
+        <member name="F:Discord.InteractionType.ApplicationCommandAutocomplete">
+            <summary>
+                An autocomplete request sent from discord.
+            </summary>
+        </member>
         <member name="T:Discord.ActionRowComponent">
             <summary>
                 Represents a <see cref="T:Discord.IMessageComponent"/> Row for child components to live in. 
@@ -5934,7 +6011,7 @@
             <param name="value">The default permission value to set.</param>
             <returns>The current builder.</returns>
         </member>
-        <member name="M:Discord.SlashCommandBuilder.AddOption(System.String,Discord.ApplicationCommandOptionType,System.String,System.Boolean,System.Boolean,System.Collections.Generic.List{Discord.SlashCommandOptionBuilder},Discord.ApplicationCommandOptionChoiceProperties[])">
+        <member name="M:Discord.SlashCommandBuilder.AddOption(System.String,Discord.ApplicationCommandOptionType,System.String,System.Boolean,System.Boolean,System.Boolean,System.Collections.Generic.List{Discord.SlashCommandOptionBuilder},Discord.ApplicationCommandOptionChoiceProperties[])">
             <summary>
                 Adds an option to the current slash command.
             </summary>
@@ -5987,37 +6064,42 @@
         </member>
         <member name="P:Discord.SlashCommandOptionBuilder.Name">
             <summary>
-                The name of this option.
+                Gets or sets the name of this option.
             </summary>
         </member>
         <member name="P:Discord.SlashCommandOptionBuilder.Description">
             <summary>
-                The description of this option.
+                Gets or sets the description of this option.
             </summary>
         </member>
         <member name="P:Discord.SlashCommandOptionBuilder.Type">
             <summary>
-                The type of this option.
+                Gets or sets the type of this option.
             </summary>
         </member>
         <member name="P:Discord.SlashCommandOptionBuilder.Default">
             <summary>
-                The first required option for the user to complete. only one option can be default.
+                Gets or sets whether or not this options is the first required option for the user to complete. only one option can be default.
             </summary>
         </member>
         <member name="P:Discord.SlashCommandOptionBuilder.Required">
             <summary>
-                <see langword="true"/> if this option is required for this command, otherwise <see langword="false"/>.
+                Gets or sets if the option is required.
+            </summary>
+        </member>
+        <member name="P:Discord.SlashCommandOptionBuilder.Autocomplete">
+            <summary>
+                Gets or sets whether or not this option supports autocomplete.
             </summary>
         </member>
         <member name="P:Discord.SlashCommandOptionBuilder.Choices">
             <summary>
-                choices for string and int types for the user to pick from.
+                Gets or sets the choices for string and int types for the user to pick from.
             </summary>
         </member>
         <member name="P:Discord.SlashCommandOptionBuilder.Options">
             <summary>
-                If the option is a subcommand or subcommand group type, this nested options will be the parameters.
+                Gets or sets if this option is a subcommand or subcommand group type, these nested options will be the parameters.
             </summary>
         </member>
         <member name="M:Discord.SlashCommandOptionBuilder.Build">
@@ -8876,14 +8958,24 @@
                 authentication when used on a guild that has server-wide 2FA enabled.
             </remarks>
         </member>
+        <member name="F:Discord.GuildPermission.CreatePublicThreads">
+            <summary>
+                Allows for creating public threads.
+            </summary>
+        </member>
+        <member name="F:Discord.GuildPermission.CreatePrivateThreads">
+            <summary>
+                Allows for creating private threads.
+            </summary>
+        </member>
         <member name="F:Discord.GuildPermission.UsePublicThreads">
             <summary>
-            Allows for creating and participating in threads.
+                Allows for creating public threads.
             </summary>
         </member>
         <member name="F:Discord.GuildPermission.UsePrivateThreads">
             <summary>
-                Allows for creating and participating in private threads.
+                Allows for creating private threads.
             </summary>
         </member>
         <member name="F:Discord.GuildPermission.UseExternalStickers">
@@ -8891,6 +8983,16 @@
                 Allows the usage of custom stickers from other servers.
             </summary>
         </member>
+        <member name="F:Discord.GuildPermission.SendMessagesInThreads">
+            <summary>
+                Allows for sending messages in threads.
+            </summary>
+        </member>
+        <member name="F:Discord.GuildPermission.StartEmbeddedActivities">
+            <summary>
+                Allows for launching activities (applications with the EMBEDDED flag) in a voice channel.
+            </summary>
+        </member>
         <member name="F:Discord.GuildPermissions.None">
             <summary> Gets a blank <see cref="T:Discord.GuildPermissions"/> that grants no permissions. </summary>
         </member>
@@ -9005,25 +9107,31 @@
         <member name="P:Discord.GuildPermissions.ManageThreads">
             <summary> If <c>true</c>, a user may manage threads in this guild. </summary>
         </member>
-        <member name="P:Discord.GuildPermissions.UsePublicThreads">
+        <member name="P:Discord.GuildPermissions.CreatePublicThreads">
             <summary> If <c>true</c>, a user may create public threads in this guild. </summary>
         </member>
-        <member name="P:Discord.GuildPermissions.UsePrivateThreads">
+        <member name="P:Discord.GuildPermissions.CreatePrivateThreads">
             <summary> If <c>true</c>, a user may create private threads in this guild. </summary>
         </member>
         <member name="P:Discord.GuildPermissions.UseExternalStickers">
             <summary> If <c>true</c>, a user may use external stickers in this guild. </summary>
         </member>
+        <member name="P:Discord.GuildPermissions.SendMessagesInThreads">
+            <summary> If <c>true</c>, a user may send messages in threads in this guild. </summary>
+        </member>
+        <member name="P:Discord.GuildPermissions.StartEmbeddedActivities">
+            <summary> If <c>true</c>, a user launch application activites in voice channels in this guild. </summary>
+        </member>
         <member name="M:Discord.GuildPermissions.#ctor(System.UInt64)">
             <summary> Creates a new <see cref="T:Discord.GuildPermissions"/> with the provided packed value. </summary>
         </member>
         <member name="M:Discord.GuildPermissions.#ctor(System.String)">
             <summary> Creates a new <see cref="T:Discord.GuildPermissions"/> with the provided packed value after converting to ulong. </summary>
         </member>
-        <member name="M:Discord.GuildPermissions.#ctor(System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean)">
+        <member name="M:Discord.GuildPermissions.#ctor(System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean,System.Boolean)">
             <summary> Creates a new <see cref="T:Discord.GuildPermissions"/> structure with the provided permissions. </summary>
         </member>
-        <member name="M:Discord.GuildPermissions.Modify(System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean})">
+        <member name="M:Discord.GuildPermissions.Modify(System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean},System.Nullable{System.Boolean})">
             <summary> Creates a new <see cref="T:Discord.GuildPermissions"/> from this one, changing the provided non-null permissions. </summary>
         </member>
         <member name="M:Discord.GuildPermissions.Has(Discord.GuildPermission)">

src/Discord.Net.Core/Entities/Interactions/ApplicationCommandOption.cs

@@ -16,7 +16,7 @@ namespace Discord
         private string _description;
 
         /// <summary>
-        ///     The name of this option.
+        ///     Gets or sets the name of this option.
         /// </summary>
         public string Name
         {
@@ -37,7 +37,7 @@ namespace Discord
         }
 
         /// <summary>
-        ///     The description of this option.
+        ///     Gets or sets the description of this option.
         /// </summary>
         public string Description
         {
@@ -53,27 +53,31 @@ namespace Discord
         }
 
         /// <summary>
-        ///     The type of this option.
+        ///     Gets or sets the type of this option.
         /// </summary>
         public ApplicationCommandOptionType Type { get; set; }
 
         /// <summary>
-        ///     The first required option for the user to complete. only one option can be default.
+        ///     Gets or sets whether or not this options is the first required option for the user to complete. only one option can be default.
         /// </summary>
         public bool? Default { get; set; }
 
         /// <summary>
-        ///     <see langword="true"/> if this option is required for this command, otherwise <see langword="false"/>.
+        ///     Gets or sets if the option is required.
         /// </summary>
         public bool? Required { get; set; }
 
         /// <summary>
-        ///     choices for string and int types for the user to pick from.
+        ///     Gets or sets whether or not this option supports autocomplete.
+        /// </summary>
+        public bool Autocomplete { get; set; }
+        /// <summary>
+        ///     Gets or sets the choices for string and int types for the user to pick from.
         /// </summary>
         public List<ApplicationCommandOptionChoiceProperties> Choices { get; set; }
 
         /// <summary>
-        ///     If the option is a subcommand or subcommand group type, this nested options will be the parameters.
+        ///     Gets or sets if this option is a subcommand or subcommand group type, these nested options will be the parameters.
         /// </summary>
         public List<ApplicationCommandOptionProperties> Options { get; set; }
 

src/Discord.Net.Core/Entities/Interactions/AutocompleteOption.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Discord
+{
+    /// <summary>
+    ///     Represents an autocomplete option.
+    /// </summary>
+    public class AutocompleteOption
+    {
+        /// <summary>
+        ///     Gets the type of this option
+        /// </summary>
+        public ApplicationCommandOptionType Type { get; }
+
+        /// <summary>
+        ///     Gets the name of the option.
+        /// </summary>
+        public string Name { get; }
+
+        /// <summary>
+        ///     Gets the value of the option.
+        /// </summary>
+        public object Value { get; }
+
+        /// <summary>
+        ///     Gets whether or not this option is focused by the executing user.
+        /// </summary>
+        public bool Focused { get; }
+
+        internal AutocompleteOption(ApplicationCommandOptionType type, string name, object value, bool focused)
+        {
+            this.Type = type;
+            this.Name = name;
+            this.Value = value;
+            this.Focused = focused;
+        }
+    }
+}

src/Discord.Net.Core/Entities/Interactions/AutocompleteResult.cs

@@ -0,0 +1,90 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Discord
+{
+    /// <summary>
+    ///     Represents a result to an autocomplete interaction.
+    /// </summary>
+    public class AutocompleteResult
+    {
+        private object _value { get; set; }
+        private string _name { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the name of the result.
+        /// </summary>
+        /// <remarks>
+        ///     Name cannot be null and has to be between 1-100 characters in length.
+        /// </remarks>
+        /// <exception cref="ArgumentNullException"/>
+        /// <exception cref="ArgumentException"/>
+        public string Name
+        {
+            get => _name;
+            set
+            {
+                if (value == null)
+                    throw new ArgumentException("Name cannot be null!");
+                if (value.Length > 100)
+                    throw new ArgumentException("Name length must be less than or equal to 100 characters in length!");
+                if (value.Length < 1)
+                    throw new ArgumentException("Name length must at least 1 character in length!");
+                _name = value;
+            }
+        }
+
+        /// <summary>
+        ///     Gets or sets the value of the result.
+        /// </summary>
+        /// <remarks>
+        ///     Only <see cref="string"/>, <see cref="int"/>, and <see cref="double"/> are allowed for a value.
+        /// </remarks>
+        /// <exception cref="ArgumentNullException"/>
+        /// <exception cref="ArgumentException"/>
+        public object Value
+        {
+            get => _value;
+            set
+            {
+                if (value == null)
+                    throw new ArgumentNullException("Value cannot be null");
+
+                switch (value)
+                {
+                    case string str:
+                        _value = str;
+                        break;
+                    case int integer:
+                        _value = integer;
+                        break;
+                    case double number:
+                        _value = number;
+                        break;
+
+                    default:
+                        throw new ArgumentException($"Type {value.GetType().Name} cannot be set as a value! Only string, int, and double allowed!");
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Creates a new <see cref="AutocompleteResult"/>.
+        /// </summary>
+        public AutocompleteResult() { }
+
+        /// <summary>
+        ///     Creates a new <see cref="AutocompleteResult"/> with the passed in <paramref name="name"/> and <paramref name="value"/>.
+        /// </summary>
+        /// <exception cref="ArgumentNullException"/>
+        /// <exception cref="ArgumentException"/>
+        public AutocompleteResult(string name, object value)
+        {
+            this.Name = name;
+            this.Value = value;
+        }
+    }
+}

src/Discord.Net.Core/Entities/Interactions/InteractionResponseType.cs

@@ -45,13 +45,18 @@ namespace Discord
         DeferredChannelMessageWithSource = 5,
 
         /// <summary>
-        ///     for components: ACK an interaction and edit the original message later; the user does not see a loading state
+        ///     For components: ACK an interaction and edit the original message later; the user does not see a loading state
         /// </summary>
         DeferredUpdateMessage = 6,
 
         /// <summary>
-        ///     for components: edit the message the component was attached to
+        ///     For components: edit the message the component was attached to
         /// </summary>
-        UpdateMessage = 7
+        UpdateMessage = 7,
+
+        /// <summary>
+        ///     Respond with a set of choices to a autocomplete interaction
+        /// </summary>
+        ApplicationCommandAutocompleteResult = 8
     }
 }

src/Discord.Net.Core/Entities/Interactions/InteractionType.cs

@@ -25,5 +25,10 @@ namespace Discord
         ///     A <see cref="IMessageComponent"/> sent from discord.
         /// </summary>
         MessageComponent = 3,
+
+        /// <summary>
+        ///     An autocomplete request sent from discord.
+        /// </summary>
+        ApplicationCommandAutocomplete = 4,
     }
 }

src/Discord.Net.Core/Entities/Interactions/SlashCommandBuilder.cs → src/Discord.Net.Core/Entities/Interactions/Slash Commands/SlashCommandBuilder.cs

@@ -165,7 +165,7 @@ namespace Discord
         /// <param name="choices">The choices of this option.</param>
         /// <returns>The current builder.</returns>
         public SlashCommandBuilder AddOption(string name, ApplicationCommandOptionType type,
-           string description, bool required = true, bool isDefault = false, List<SlashCommandOptionBuilder> options = null, params ApplicationCommandOptionChoiceProperties[] choices)
+           string description, bool required = true, bool isDefault = false, bool isAutocomplete = false, List<SlashCommandOptionBuilder> options = null, params ApplicationCommandOptionChoiceProperties[] choices)
         {
             // Make sure the name matches the requirements from discord
             Preconditions.NotNullOrEmpty(name, nameof(name));
@@ -197,6 +197,7 @@ namespace Discord
             option.Default = isDefault;
             option.Options = options;
             option.Type = type;
+            option.Autocomplete = isAutocomplete;
             option.Choices = choices != null ? new List<ApplicationCommandOptionChoiceProperties>(choices) : null;
 
             return AddOption(option);
@@ -288,7 +289,7 @@ namespace Discord
         private string _description;
 
         /// <summary>
-        ///     The name of this option.
+        ///     Gets or sets the name of this option.
         /// </summary>
         public string Name
         {
@@ -309,7 +310,7 @@ namespace Discord
         }
 
         /// <summary>
-        ///     The description of this option.
+        ///     Gets or sets the description of this option.
         /// </summary>
         public string Description
         {
@@ -326,27 +327,32 @@ namespace Discord
         }
 
         /// <summary>
-        ///     The type of this option.
+        ///     Gets or sets the type of this option.
         /// </summary>
         public ApplicationCommandOptionType Type { get; set; }
 
         /// <summary>
-        ///     The first required option for the user to complete. only one option can be default.
+        ///     Gets or sets whether or not this options is the first required option for the user to complete. only one option can be default.
         /// </summary>
         public bool? Default { get; set; }
 
         /// <summary>
-        ///     <see langword="true"/> if this option is required for this command, otherwise <see langword="false"/>.
+        ///     Gets or sets if the option is required.
         /// </summary>
         public bool Required { get; set; }
 
         /// <summary>
-        ///     choices for string and int types for the user to pick from.
+        ///     Gets or sets whether or not this option supports autocomplete.
+        /// </summary>
+        public bool Autocomplete { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the choices for string and int types for the user to pick from.
         /// </summary>
         public List<ApplicationCommandOptionChoiceProperties> Choices { get; set; }
 
         /// <summary>
-        ///     If the option is a subcommand or subcommand group type, this nested options will be the parameters.
+        ///     Gets or sets if this option is a subcommand or subcommand group type, these nested options will be the parameters.
         /// </summary>
         public List<SlashCommandOptionBuilder> Options { get; set; }
 
@@ -372,7 +378,8 @@ namespace Discord
                 Required = this.Required,
                 Type = this.Type,
                 Options = this.Options?.Count > 0 ? new List<ApplicationCommandOptionProperties>(this.Options.Select(x => x.Build())) : null,
-                Choices = this.Choices
+                Choices = this.Choices,
+                Autocomplete = this.Autocomplete
             };
         }
 

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

@@ -30,6 +30,9 @@ namespace Discord.API
         [JsonProperty("options")]
         public Optional<ApplicationCommandOption[]> Options { get; set; }
 
+        [JsonProperty("autocomplete")]
+        public Optional<bool> Autocomplete { get; set; }
+
         public ApplicationCommandOption() { }
 
         public ApplicationCommandOption(IApplicationCommandOption cmd)
@@ -78,6 +81,7 @@ namespace Discord.API
             this.Name = option.Name;
             this.Type = option.Type;
             this.Description = option.Description;
+            this.Autocomplete = option.Autocomplete;
         }
     }
 }

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

@@ -0,0 +1,27 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Discord.API
+{
+    internal class AutocompleteInteractionData : IDiscordInteractionData
+    {
+        [JsonProperty("id")]
+        public ulong Id { get; set; }
+
+        [JsonProperty("name")]
+        public string Name { get; set; }
+
+        [JsonProperty("type")]
+        public ApplicationCommandType Type { get; set; }
+
+        [JsonProperty("version")]
+        public ulong Version { get; set; }
+
+        [JsonProperty("options")]
+        public AutocompleteInteractionDataOption[] Options { get; set; }
+    }
+}

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

@@ -0,0 +1,24 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Discord.API
+{
+    internal class AutocompleteInteractionDataOption
+    {
+        [JsonProperty("type")]
+        public ApplicationCommandOptionType Type { get; set; }
+
+        [JsonProperty("name")]
+        public string Name { get; set; }
+
+        [JsonProperty("value")]
+        public object Value { get; set; }
+
+        [JsonProperty("focused")]
+        public bool Focused { get; set; }
+    }
+}

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

@@ -21,5 +21,8 @@ namespace Discord.API
 
         [JsonProperty("components")]
         public Optional<API.ActionRowComponent[]> Components { get; set; }
+
+        [JsonProperty("choices")]
+        public Optional<API.ApplicationCommandOptionChoice[]> Choices { get; set; }
     }
 }

src/Discord.Net.Rest/Entities/Interactions/InteractionHelper.cs

@@ -418,6 +418,28 @@ namespace Discord.Rest
 
         public static async Task DeletedInteractionResponse(BaseDiscordClient client, RestInteractionMessage message, RequestOptions options = null)
             => await client.ApiClient.DeleteInteractionFollowupMessageAsync(message.Id, message.Token, options);
+
+        public static Task SendAutocompleteResult(BaseDiscordClient client, IEnumerable<AutocompleteResult> result, ulong interactionId,
+            string interactionToken, RequestOptions options)
+        {
+            if (result == null)
+                result = new AutocompleteResult[0];
+
+            Preconditions.AtMost(result.Count(), 20, nameof(result), "A maximum of 20 choices are allowed!");
+
+            var apiArgs = new InteractionResponse()
+            {
+                Type = InteractionResponseType.ApplicationCommandAutocompleteResult,
+                Data = new InteractionCallbackData()
+                {
+                    Choices = result.Any()
+                        ? result.Select(x => new API.ApplicationCommandOptionChoice() { Name = x.Name, Value = x.Value }).ToArray()
+                        : new ApplicationCommandOptionChoice[0]
+                }
+            };
+
+            return client.ApiClient.CreateInteractionResponseAsync(apiArgs, interactionId, interactionToken, options);
+        }
         #endregion
 
         #region Guild permissions

src/Discord.Net.Rest/Net/Converters/InteractionConverter.cs

@@ -53,6 +53,13 @@ namespace Discord.Net.Converters
                             interaction.Data = messageComponent;
                         }
                         break;
+                    case InteractionType.ApplicationCommandAutocomplete:
+                        {
+                            var autocompleteData = new API.AutocompleteInteractionData();
+                            serializer.Populate(result.CreateReader(), autocompleteData);
+                            interaction.Data = autocompleteData;
+                        }
+                        break;
                 }
             }
             else

src/Discord.Net.WebSocket/Discord.Net.WebSocket.xml

@@ -3961,6 +3961,98 @@
                 The value(s) of a <see cref="T:Discord.SelectMenuComponent"/> interaction response.
             </summary>
         </member>
+        <member name="T:Discord.WebSocket.SocketAutocompleteInteraction">
+            <summary>
+                Represents a <see cref="F:Discord.InteractionType.ApplicationCommandAutocomplete"/> received over the gateway.
+            </summary>
+        </member>
+        <member name="P:Discord.WebSocket.SocketAutocompleteInteraction.Data">
+            <summary>
+                The autocomplete data of this interaction.
+            </summary>
+        </member>
+        <member name="M:Discord.WebSocket.SocketAutocompleteInteraction.RespondAsync(System.Collections.Generic.IEnumerable{Discord.AutocompleteResult},Discord.RequestOptions)">
+            <summary>
+                Responds to this interaction with a set of choices.
+            </summary>
+            <param name="result">
+                The set of choices for the user to pick from.
+                <remarks>
+                    A max of 20 choices are allowed. Passing <see langword="null"/> for this argument will show the executing user that
+                    there is no choices for their autocompleted input.
+                </remarks>
+            </param>
+            <param name="options">The request options for this response.</param>
+            <returns>
+                A task that represents the asynchronous operation of responding to this interaction.
+            </returns>
+        </member>
+        <member name="M:Discord.WebSocket.SocketAutocompleteInteraction.RespondAsync(Discord.RequestOptions,Discord.AutocompleteResult[])">
+            <summary>
+                Responds to this interaction with a set of choices.
+            </summary>
+            <param name="options">The request options for this response.</param>
+            <param name="result">
+             The set of choices for the user to pick from.
+                <remarks>
+                    A max of 20 choices are allowed. Passing <see langword="null"/> for this argument will show the executing user that
+                    there is no choices for their autocompleted input.
+                </remarks>
+            </param>
+            <returns>
+                A task that represents the asynchronous operation of responding to this interaction.
+            </returns>
+        </member>
+        <member name="M:Discord.WebSocket.SocketAutocompleteInteraction.DeferAsync(System.Boolean,Discord.RequestOptions)">
+            <inheritdoc/>
+        </member>
+        <member name="M:Discord.WebSocket.SocketAutocompleteInteraction.FollowupAsync(System.String,Discord.Embed[],System.Boolean,System.Boolean,Discord.AllowedMentions,Discord.RequestOptions,Discord.MessageComponent,Discord.Embed)">
+            <inheritdoc/>
+        </member>
+        <member name="M:Discord.WebSocket.SocketAutocompleteInteraction.FollowupWithFileAsync(System.String,System.IO.Stream,System.String,Discord.Embed[],System.Boolean,System.Boolean,Discord.AllowedMentions,Discord.RequestOptions,Discord.MessageComponent,Discord.Embed)">
+            <inheritdoc/>
+        </member>
+        <member name="M:Discord.WebSocket.SocketAutocompleteInteraction.FollowupWithFileAsync(System.String,System.String,System.String,Discord.Embed[],System.Boolean,System.Boolean,Discord.AllowedMentions,Discord.RequestOptions,Discord.MessageComponent,Discord.Embed)">
+            <inheritdoc/>
+        </member>
+        <member name="M:Discord.WebSocket.SocketAutocompleteInteraction.RespondAsync(System.String,Discord.Embed[],System.Boolean,System.Boolean,Discord.AllowedMentions,Discord.RequestOptions,Discord.MessageComponent,Discord.Embed)">
+            <inheritdoc/>
+        </member>
+        <member name="T:Discord.WebSocket.SocketAutocompleteInteractionData">
+            <summary>
+                Represents data for a slash commands autocomplete interaction.
+            </summary>
+        </member>
+        <member name="P:Discord.WebSocket.SocketAutocompleteInteractionData.CommandName">
+            <summary>
+                Gets the name of the invoked command.
+            </summary>
+        </member>
+        <member name="P:Discord.WebSocket.SocketAutocompleteInteractionData.CommandId">
+            <summary>
+                Gets the id of the invoked command.
+            </summary>
+        </member>
+        <member name="P:Discord.WebSocket.SocketAutocompleteInteractionData.Type">
+            <summary>
+                Gets the type of the invoked command.
+            </summary>
+        </member>
+        <member name="P:Discord.WebSocket.SocketAutocompleteInteractionData.Version">
+            <summary>
+                Gets the version of the invoked command.
+            </summary>
+        </member>
+        <member name="P:Discord.WebSocket.SocketAutocompleteInteractionData.Current">
+            <summary>
+                Gets the current autocomplete option that is activly being filled out.
+            </summary>
+        </member>
+        <member name="P:Discord.WebSocket.SocketAutocompleteInteractionData.Options">
+            <summary>
+                Gets a collection of all the other options the executing users has filled out.
+            </summary>
+        </member>
         <member name="T:Discord.WebSocket.SocketSlashCommand">
             <summary>
                 Represents a Websocket-based slash command received over the gateway.
@@ -4088,7 +4180,17 @@
         </member>
         <member name="T:Discord.WebSocket.SocketCommandBase">
             <summary>
-                Base class for User, Message, and Slash command interactions
+                Base class for User, Message, and Slash command interactions.
+            </summary>
+        </member>
+        <member name="P:Discord.WebSocket.SocketCommandBase.CommandName">
+            <summary>
+                Gets the name of the invoked command.
+            </summary>
+        </member>
+        <member name="P:Discord.WebSocket.SocketCommandBase.CommandId">
+            <summary>
+                Gets the id of the invoked command.
             </summary>
         </member>
         <member name="P:Discord.WebSocket.SocketCommandBase.Data">

src/Discord.Net.WebSocket/Entities/Interaction/Slash Commands/SocketAutocompleteInteraction.cs

@@ -0,0 +1,97 @@
+using Discord.Rest;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Model = Discord.API.Interaction;
+using DataModel = Discord.API.AutocompleteInteractionData;
+
+
+namespace Discord.WebSocket
+{
+    /// <summary>
+    ///     Represents a <see cref="InteractionType.ApplicationCommandAutocomplete"/> received over the gateway.
+    /// </summary>
+    public class SocketAutocompleteInteraction : SocketInteraction
+    {
+        /// <summary>
+        ///     The autocomplete data of this interaction.
+        /// </summary>
+        public new SocketAutocompleteInteractionData Data { get; }
+
+        internal SocketAutocompleteInteraction(DiscordSocketClient client, Model model, ISocketMessageChannel channel)
+            : base(client, model.Id, channel)
+        {
+            var dataModel = model.Data.IsSpecified
+                ? (DataModel)model.Data.Value
+                : null;
+
+            if (dataModel != null)
+                Data = new SocketAutocompleteInteractionData(dataModel);
+        }
+
+        internal new static SocketAutocompleteInteraction Create(DiscordSocketClient client, Model model, ISocketMessageChannel channel)
+        {
+            var entity =  new SocketAutocompleteInteraction(client, model, channel);
+            entity.Update(model);
+            return entity;
+        }
+
+        /// <summary>
+        ///     Responds to this interaction with a set of choices.
+        /// </summary>
+        /// <param name="result">
+        ///     The set of choices for the user to pick from.
+        ///     <remarks>
+        ///         A max of 20 choices are allowed. Passing <see langword="null"/> for this argument will show the executing user that
+        ///         there is no choices for their autocompleted input.
+        ///     </remarks>
+        /// </param>
+        /// <param name="options">The request options for this response.</param>
+        /// <returns>
+        ///     A task that represents the asynchronous operation of responding to this interaction.
+        /// </returns>
+        public Task RespondAsync(IEnumerable<AutocompleteResult> result, RequestOptions options = null)
+            => InteractionHelper.SendAutocompleteResult(Discord, result, this.Id, this.Token, options);
+
+        /// <summary>
+        ///     Responds to this interaction with a set of choices.
+        /// </summary>
+        /// <param name="options">The request options for this response.</param>
+        /// <param name="result">
+        ///  The set of choices for the user to pick from.
+        ///     <remarks>
+        ///         A max of 20 choices are allowed. Passing <see langword="null"/> for this argument will show the executing user that
+        ///         there is no choices for their autocompleted input.
+        ///     </remarks>
+        /// </param>
+        /// <returns>
+        ///     A task that represents the asynchronous operation of responding to this interaction.
+        /// </returns>
+        public Task RespondAsync(RequestOptions options = null, params AutocompleteResult[] result)
+            => InteractionHelper.SendAutocompleteResult(Discord, result, this.Id, this.Token, options);
+
+
+        /// <inheritdoc/>
+        [Obsolete("Autocomplete interactions cannot be defered!", true)]
+        public override Task DeferAsync(bool ephemeral = false, RequestOptions options = null) => throw new NotSupportedException();
+
+        /// <inheritdoc/>
+        [Obsolete("Autocomplete interactions cannot have followups!", true)]
+        public override Task<RestFollowupMessage> FollowupAsync(string text = null, Embed[] embeds = null, bool isTTS = false, bool ephemeral = false, AllowedMentions allowedMentions = null, RequestOptions options = null, MessageComponent component = null, Embed embed = null) => throw new NotSupportedException();
+
+        /// <inheritdoc/>
+        [Obsolete("Autocomplete interactions cannot have followups!", true)]
+        public override Task<RestFollowupMessage> FollowupWithFileAsync(string text = null, Stream fileStream = null, string fileName = null, Embed[] embeds = null, bool isTTS = false, bool ephemeral = false, AllowedMentions allowedMentions = null, RequestOptions options = null, MessageComponent component = null, Embed embed = null) => throw new NotSupportedException();
+
+        /// <inheritdoc/>
+        [Obsolete("Autocomplete interactions cannot have followups!", true)]
+        public override Task<RestFollowupMessage> FollowupWithFileAsync(string text = null, string filePath = null, string fileName = null, Embed[] embeds = null, bool isTTS = false, bool ephemeral = false, AllowedMentions allowedMentions = null, RequestOptions options = null, MessageComponent component = null, Embed embed = null) => throw new NotSupportedException();
+
+        /// <inheritdoc/>
+        [Obsolete("Autocomplete interactions cannot have normal responses!", true)]
+        public override Task RespondAsync(string text = null, Embed[] embeds = null, bool isTTS = false, bool ephemeral = false, AllowedMentions allowedMentions = null, RequestOptions options = null, MessageComponent component = null, Embed embed = null) => throw new NotSupportedException();
+    }
+}

src/Discord.Net.WebSocket/Entities/Interaction/Slash Commands/SocketAutocompleteInteractionData.cs

@@ -0,0 +1,60 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using DataModel = Discord.API.AutocompleteInteractionData;
+
+
+namespace Discord.WebSocket
+{
+    /// <summary>
+    ///     Represents data for a slash commands autocomplete interaction.
+    /// </summary>
+    public class SocketAutocompleteInteractionData
+    {
+        /// <summary>
+        ///     Gets the name of the invoked command.
+        /// </summary>
+        public string CommandName { get; }
+
+        /// <summary>
+        ///     Gets the id of the invoked command.
+        /// </summary>
+        public ulong CommandId { get; }
+
+        /// <summary>
+        ///     Gets the type of the invoked command.
+        /// </summary>
+        public ApplicationCommandType Type { get; }
+
+        /// <summary>
+        ///     Gets the version of the invoked command.
+        /// </summary>
+        public ulong Version { get; }
+
+        /// <summary>
+        ///     Gets the current autocomplete option that is activly being filled out.
+        /// </summary>
+        public AutocompleteOption Current { get; }
+
+        /// <summary>
+        ///     Gets a collection of all the other options the executing users has filled out.
+        /// </summary>
+        public IReadOnlyCollection<AutocompleteOption> Options { get; }
+
+        internal SocketAutocompleteInteractionData(DataModel model)
+        {
+            var options = model.Options.Select(x => new AutocompleteOption(x.Type, x.Name, x.Value, x.Focused));
+
+            this.Current = options.FirstOrDefault(x => x.Focused);
+            this.Options = options.ToImmutableArray();
+
+            this.CommandName = model.Name;
+            this.CommandId = model.Id;
+            this.Type = model.Type;
+            this.Version = model.Version;
+        }
+    }
+}

src/Discord.Net.WebSocket/Entities/Interaction/SocketBaseCommand/SocketCommandBase.cs

@@ -12,10 +12,22 @@ using Model = Discord.API.Interaction;
 namespace Discord.WebSocket
 {
     /// <summary>
-    ///     Base class for User, Message, and Slash command interactions
+    ///     Base class for User, Message, and Slash command interactions.
     /// </summary>
     public class SocketCommandBase : SocketInteraction
     {
+        /// <summary>
+        ///     Gets the name of the invoked command.
+        /// </summary>
+        public string CommandName
+            => Data.Name;
+
+        /// <summary>
+        ///     Gets the id of the invoked command.
+        /// </summary>
+        public ulong CommandId
+            => Data.Id;
+
         /// <summary>
         ///     The data associated with this interaction.
         /// </summary>

src/Discord.Net.WebSocket/Entities/Interaction/SocketInteraction.cs

@@ -65,23 +65,28 @@ namespace Discord.WebSocket
         {
             if (model.Type == InteractionType.ApplicationCommand)
             {
-                if (model.ApplicationId != null)
-                {
-                    var dataModel = model.Data.IsSpecified ?
+                var dataModel = model.Data.IsSpecified ?
                         (DataModel)model.Data.Value
                         : null;
-                    if (dataModel != null)
-                    {
-                        if (dataModel.Type.Equals(ApplicationCommandType.User))
-                            return SocketUserCommand.Create(client, model, channel);
-                        if (dataModel.Type.Equals(ApplicationCommandType.Message))
-                            return SocketMessageCommand.Create(client, model, channel);
-                    }
+
+                if (dataModel == null)
+                    return null;
+
+                switch (dataModel.Type)
+                {
+                    case ApplicationCommandType.Slash:
+                        return SocketSlashCommand.Create(client, model, channel);
+                    case ApplicationCommandType.Message:
+                        return SocketMessageCommand.Create(client, model, channel);
+                    case ApplicationCommandType.User:
+                        return SocketUserCommand.Create(client, model, channel);
+                    default: return null;
                 }
-                return SocketSlashCommand.Create(client, model, channel);
             }
-            if (model.Type == InteractionType.MessageComponent)
+            else if (model.Type == InteractionType.MessageComponent)
                 return SocketMessageComponent.Create(client, model, channel);
+            else if (model.Type == InteractionType.ApplicationCommandAutocomplete)
+                return SocketAutocompleteInteraction.Create(client, model, channel);
             else
                 return null;
         }