Add base IChannel abstraction

src/Core/ChannelType.cs

@@ -0,0 +1,37 @@
+namespace Discord.Core
+{
+    /// <summary>
+    /// The type of channel a <see cref="IChannel"/> is.
+    /// </summary>
+    public enum ChannelType
+    {
+        /// <summary>
+        /// A guild text channel.
+        /// </summary>
+        GuildText = 0,
+        /// <summary>
+        /// A direct message channel.
+        /// </summary>
+        DirectMessage = 1,
+        /// <summary>
+        /// A guild voice channel.
+        /// </summary>
+        GuildVoice = 2,
+        /// <summary>
+        /// A group direct message channel.
+        /// </summary>
+        GroupDirectMessage = 3,
+        /// <summary>
+        /// A guild category channel.
+        /// </summary>
+        GuildCategory = 4,
+        /// <summary>
+        /// A guild news channel.
+        /// </summary>
+        GuildNews = 5,
+        /// <summary>
+        /// A guild store channel.
+        /// </summary>
+        GuildStore = 6,
+    }
+}

src/Core/Entities/IChannel.cs

@@ -0,0 +1,114 @@
+using System;
+
+namespace Discord.Core
+{
+    /// <summary>
+    /// An interface representing the collection of operations which can be
+    /// performed on a channel.
+    /// </summary>
+    public interface IChannel
+    {
+        /// <summary>
+        /// Gets a value indicating the unique identifier for this channel.
+        /// </summary>
+        ulong Id { get; }
+
+        /// <summary>
+        /// Gets a value indicating the type of the current channel.
+        /// </summary>
+        ChannelType Type { get; }
+
+        /// <summary>
+        /// Gets a value indicating the unique identifier of the guild this
+        /// channel belongs to.
+        /// </summary>
+        ulong? GuildId { get; }
+
+        /// <summary>
+        /// Gets a value indicating the sorting position of the channel, or
+        /// <code>null</code> if one is not present.
+        /// </summary>
+        int? Position { get; }
+
+        // TODO: permission overwrites
+
+        /// <summary>
+        /// Gets a value indicating the name of this channel, or
+        /// <code>null</code> if one is not present.
+        /// </summary>
+        string? Name { get; }
+
+        /// <summary>
+        /// Gets a value indicating the topic of this channel, or
+        /// <code>null</code> if one is not present.
+        /// </summary>
+        string? Topic { get; }
+
+        /// <summary>
+        /// Gets a value indicating the last message sent in this channel, or
+        /// <code>null</code> if one is not present.
+        /// </summary>
+        /// <remarks>
+        /// This identifier may point to a non-existent or invalid message.
+        /// </remarks>
+        ulong? LastMessageId { get; }
+
+        /// <summary>
+        /// Gets a value indicating the bitrate, in bits per second, of the
+        /// voice channel, or <code>null</code> if one is not present.
+        /// </summary>
+        int? Bitrate { get; }
+
+        /// <summary>
+        /// Gets a value indicating the user limit of the voice channel, or
+        /// <code>null</code> if one is not present.
+        /// </summary>
+        int? UserLimit { get; }
+
+        /// <summary>
+        /// Gets a value indicating the rate limit per user of the text
+        /// channel, or <code>null</code> if one is not present.
+        /// </summary>
+        /// <remarks>
+        /// If the current user has the Manage Messages permission or
+        /// Manage Channel permission, this rate limit takes no effect.
+        /// </remarks>
+        int? RateLimit { get; }
+
+        // TODO: recipients
+
+        /// <summary>
+        /// Gets a value indicating the icon of the text channel, or
+        /// <code>null</code> if one is not present.
+        /// </summary>
+        string? Icon { get; }
+
+        /// <summary>
+        /// Gets a value indicating the unique identifier of the owner this
+        /// DM channel belongs to, or <code>null</code> if one is not present.
+        /// </summary>
+        ulong? OwnerId { get; }
+
+        /// <summary>
+        /// Gets a value indicating the unique identifier of the owner this
+        /// DM channel belongs to, or <code>null</code> if one is not present.
+        /// </summary>
+        ulong? ApplicationId { get; }
+
+        /// <summary>
+        /// Gets a value indicating the unique identifier of the parent
+        /// category this channel belongs to, or <code>null</code> if one is
+        /// not present.
+        /// </summary>
+        /// <remarks>
+        /// Each category channel can contain 50 child channels.
+        /// </remarks>
+        ulong? ParentId { get; }
+
+        /// <summary>
+        /// Gets a value indicating the time when the last pinned message was
+        /// pinned, or <code>null</code> if one is not present.
+        /// </summary>
+        DateTimeOffset? LastPinTimestamp { get; }
+    }
+}