From d82a4d2e5e380e67dbb9212a9edcc654727454ec Mon Sep 17 00:00:00 2001
From: Oliver Booth <me@olivr.me>
Date: Mon, 5 Dec 2022 01:43:40 +0000
Subject: [PATCH] Add pre-execution checks

---
 .../PreExecutionCheckAttribute.cs             | 13 ++++++++
 .../RequireAvatarNameAttribute.cs             | 31 +++++++++++++++++++
 .../ExecutionChecks/RequireBotAttribute.cs    | 14 +++++++++
 .../ExecutionChecks/RequireHumanAttribute.cs  | 14 +++++++++
 .../ExecutionChecks/RequireUserIdAttribute.cs | 31 +++++++++++++++++++
 .../RequireUserNameAttribute.cs               | 31 +++++++++++++++++++
 VpSharp.Commands/CommandsExtension.cs         | 11 ++++++-
 7 files changed, 144 insertions(+), 1 deletion(-)
 create mode 100644 VpSharp.Commands/Attributes/ExecutionChecks/PreExecutionCheckAttribute.cs
 create mode 100644 VpSharp.Commands/Attributes/ExecutionChecks/RequireAvatarNameAttribute.cs
 create mode 100644 VpSharp.Commands/Attributes/ExecutionChecks/RequireBotAttribute.cs
 create mode 100644 VpSharp.Commands/Attributes/ExecutionChecks/RequireHumanAttribute.cs
 create mode 100644 VpSharp.Commands/Attributes/ExecutionChecks/RequireUserIdAttribute.cs
 create mode 100644 VpSharp.Commands/Attributes/ExecutionChecks/RequireUserNameAttribute.cs

diff --git a/VpSharp.Commands/Attributes/ExecutionChecks/PreExecutionCheckAttribute.cs b/VpSharp.Commands/Attributes/ExecutionChecks/PreExecutionCheckAttribute.cs
new file mode 100644
index 0000000..26edd99
--- /dev/null
+++ b/VpSharp.Commands/Attributes/ExecutionChecks/PreExecutionCheckAttribute.cs
@@ -0,0 +1,13 @@
+namespace VpSharp.Commands.Attributes.ExecutionChecks;
+
+/// <summary>
+///     Represents the base class for all execution check attributes.
+/// </summary>
+public abstract class PreExecutionCheckAttribute : Attribute
+{
+    /// <summary>
+    ///     Performs the execution check.
+    /// </summary>
+    /// <returns><see langword="true" /> if the execution check has passed; otherwise, <see langword="false" />.</returns>
+    protected internal abstract Task<bool> PerformAsync(CommandContext context);
+}
diff --git a/VpSharp.Commands/Attributes/ExecutionChecks/RequireAvatarNameAttribute.cs b/VpSharp.Commands/Attributes/ExecutionChecks/RequireAvatarNameAttribute.cs
new file mode 100644
index 0000000..5b851a6
--- /dev/null
+++ b/VpSharp.Commands/Attributes/ExecutionChecks/RequireAvatarNameAttribute.cs
@@ -0,0 +1,31 @@
+namespace VpSharp.Commands.Attributes.ExecutionChecks;
+
+/// <summary>
+///     Specifies that this command can only be run by bots.
+/// </summary>
+public sealed class RequireAvatarNameAttribute : PreExecutionCheckAttribute
+{
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="RequireAvatarNameAttribute" /> class.
+    /// </summary>
+    /// <param name="names">An array of allowed user names.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="names" /> is <see langword="null" />.</exception>
+    public RequireAvatarNameAttribute(params string[] names)
+    {
+        ArgumentNullException.ThrowIfNull(names);
+        Names = names[..];
+    }
+
+    /// <summary>
+    ///     Gets a read-only view of the user names allowed to run this command.
+    /// </summary>
+    /// <value>A <see cref="IReadOnlyList{T}" /> of <see cref="string" /> representing the allowed user names.</value>
+    public IReadOnlyList<string> Names { get; }
+
+    /// <inheritdoc />
+    protected internal override Task<bool> PerformAsync(CommandContext context)
+    {
+        ArgumentNullException.ThrowIfNull(context);
+        return Task.FromResult(Names.Contains(context.Avatar.Name));
+    }
+}
diff --git a/VpSharp.Commands/Attributes/ExecutionChecks/RequireBotAttribute.cs b/VpSharp.Commands/Attributes/ExecutionChecks/RequireBotAttribute.cs
new file mode 100644
index 0000000..3afce7c
--- /dev/null
+++ b/VpSharp.Commands/Attributes/ExecutionChecks/RequireBotAttribute.cs
@@ -0,0 +1,14 @@
+namespace VpSharp.Commands.Attributes.ExecutionChecks;
+
+/// <summary>
+///     Specifies that this command can only be run by bots.
+/// </summary>
+public sealed class RequireBotAttribute : PreExecutionCheckAttribute
+{
+    /// <inheritdoc />
+    protected internal override Task<bool> PerformAsync(CommandContext context)
+    {
+        ArgumentNullException.ThrowIfNull(context);
+        return Task.FromResult(context.Avatar.IsBot);
+    }
+}
diff --git a/VpSharp.Commands/Attributes/ExecutionChecks/RequireHumanAttribute.cs b/VpSharp.Commands/Attributes/ExecutionChecks/RequireHumanAttribute.cs
new file mode 100644
index 0000000..83332a9
--- /dev/null
+++ b/VpSharp.Commands/Attributes/ExecutionChecks/RequireHumanAttribute.cs
@@ -0,0 +1,14 @@
+namespace VpSharp.Commands.Attributes.ExecutionChecks;
+
+/// <summary>
+///     Specifies that this command cannot be run by bots.
+/// </summary>
+public sealed class RequireHumanAttribute : PreExecutionCheckAttribute
+{
+    /// <inheritdoc />
+    protected internal override Task<bool> PerformAsync(CommandContext context)
+    {
+        ArgumentNullException.ThrowIfNull(context);
+        return Task.FromResult(!context.Avatar.IsBot);
+    }
+}
diff --git a/VpSharp.Commands/Attributes/ExecutionChecks/RequireUserIdAttribute.cs b/VpSharp.Commands/Attributes/ExecutionChecks/RequireUserIdAttribute.cs
new file mode 100644
index 0000000..57541b1
--- /dev/null
+++ b/VpSharp.Commands/Attributes/ExecutionChecks/RequireUserIdAttribute.cs
@@ -0,0 +1,31 @@
+namespace VpSharp.Commands.Attributes.ExecutionChecks;
+
+/// <summary>
+///     Specifies that this command can only be run by bots.
+/// </summary>
+public sealed class RequireUserIdAttribute : PreExecutionCheckAttribute
+{
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="RequireUserIdAttribute" /> class.
+    /// </summary>
+    /// <param name="userIds">An array of allowed user IDs.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="userIds" /> is <see langword="null" />.</exception>
+    public RequireUserIdAttribute(params int[] userIds)
+    {
+        ArgumentNullException.ThrowIfNull(userIds);
+        UserIds = userIds[..];
+    }
+
+    /// <summary>
+    ///     Gets a read-only view of the user IDs allowed to run this command.
+    /// </summary>
+    /// <value>A <see cref="IReadOnlyList{T}" /> of <see cref="string" /> representing the allowed user IDs.</value>
+    public IReadOnlyList<int> UserIds { get; }
+
+    /// <inheritdoc />
+    protected internal override Task<bool> PerformAsync(CommandContext context)
+    {
+        ArgumentNullException.ThrowIfNull(context);
+        return Task.FromResult(UserIds.Contains(context.Avatar.User.Id));
+    }
+}
diff --git a/VpSharp.Commands/Attributes/ExecutionChecks/RequireUserNameAttribute.cs b/VpSharp.Commands/Attributes/ExecutionChecks/RequireUserNameAttribute.cs
new file mode 100644
index 0000000..5ccb619
--- /dev/null
+++ b/VpSharp.Commands/Attributes/ExecutionChecks/RequireUserNameAttribute.cs
@@ -0,0 +1,31 @@
+namespace VpSharp.Commands.Attributes.ExecutionChecks;
+
+/// <summary>
+///     Specifies that this command can only be run by bots.
+/// </summary>
+public sealed class RequireUserNameAttribute : PreExecutionCheckAttribute
+{
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="RequireUserNameAttribute" /> class.
+    /// </summary>
+    /// <param name="names">An array of allowed user names.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="names" /> is <see langword="null" />.</exception>
+    public RequireUserNameAttribute(params string[] names)
+    {
+        ArgumentNullException.ThrowIfNull(names);
+        Names = names[..];
+    }
+
+    /// <summary>
+    ///     Gets a read-only view of the user names allowed to run this command.
+    /// </summary>
+    /// <value>A <see cref="IReadOnlyList{T}" /> of <see cref="string" /> representing the allowed user names.</value>
+    public IReadOnlyList<string> Names { get; }
+
+    /// <inheritdoc />
+    protected internal override Task<bool> PerformAsync(CommandContext context)
+    {
+        ArgumentNullException.ThrowIfNull(context);
+        return Task.FromResult(Names.Contains(context.Avatar.User.Name));
+    }
+}
diff --git a/VpSharp.Commands/CommandsExtension.cs b/VpSharp.Commands/CommandsExtension.cs
index 105e73f..fedfe32 100644
--- a/VpSharp.Commands/CommandsExtension.cs
+++ b/VpSharp.Commands/CommandsExtension.cs
@@ -2,6 +2,7 @@ using System.Reflection;
 using Microsoft.Extensions.DependencyInjection;
 using VpSharp.ClientExtensions;
 using VpSharp.Commands.Attributes;
+using VpSharp.Commands.Attributes.ExecutionChecks;
 using VpSharp.Entities;
 using VpSharp.EventData;
 
@@ -218,8 +219,16 @@ public sealed class CommandsExtension : VirtualParadiseClientExtension
             }
 
             var context = new CommandContext(Client, message.Author, command.Name, commandNameString, rawArguments.ToString());
-            object?[] arguments = {context};
 
+            foreach (var attribute in command.Method.GetCustomAttributes<PreExecutionCheckAttribute>())
+            {
+                if (!attribute.PerformAsync(context).ConfigureAwait(false).GetAwaiter().GetResult())
+                {
+                    return base.OnMessageReceived(args);
+                }
+            }
+
+            object?[] arguments = {context};
             if (rawArguments.Length > 0)
             {
                 spaceIndex = rawArguments.IndexOf(' ');