Medusa System Added

Read about the medusa system [here](https://nadekobot.readthedocs.io/en/latest/medusa/creating-a-medusa/)

src/Nadeko.Medusa/Attributes/FilterAttribute.cs

@@ -0,0 +1,10 @@
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Overridden to implement custom checks which commands have to pass in order to be executed.
+/// </summary>
+[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = true)]
+public abstract class FilterAttribute : Attribute
+{
+    public abstract ValueTask<bool> CheckAsync(AnyContext ctx);
+}

src/Nadeko.Medusa/Attributes/cmdAttribute.cs

@@ -0,0 +1,37 @@
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Marks a method as a snek command
+/// </summary>
+[AttributeUsage(AttributeTargets.Method)]
+public class cmdAttribute : Attribute
+{
+    /// <summary>
+    /// Command description. Avoid using, as cmds.yml is preferred
+    /// </summary>
+    public string? desc { get; set; }
+    
+    /// <summary>
+    /// Command args examples. Avoid using, as cmds.yml is preferred
+    /// </summary>
+    public string[]? args { get; set; }
+    
+    /// <summary>
+    /// Command aliases
+    /// </summary>
+    public string[] Aliases { get; }
+
+    public cmdAttribute()
+    {
+        desc = null;
+        args = null;
+        Aliases = Array.Empty<string>();
+    }
+    
+    public cmdAttribute(params string[] aliases)
+    {
+        Aliases = aliases;
+        desc = null;
+        args = null;
+    }
+}

src/Nadeko.Medusa/Attributes/injectAttribute.cs

@@ -0,0 +1,10 @@
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Marks services in command arguments for injection.
+/// The injected services must come after the context and before any input parameters.
+/// </summary>
+public class injectAttribute : Attribute
+{
+    
+}

src/Nadeko.Medusa/Attributes/leftoverAttribute.cs

@@ -0,0 +1,10 @@
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Marks the parameter to take 
+/// </summary>
+[AttributeUsage(AttributeTargets.Parameter)]
+public class leftoverAttribute : Attribute
+{
+    
+}

src/Nadeko.Medusa/Attributes/prioAttribute.cs

@@ -0,0 +1,20 @@
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Sets the priority of a command in case there are multiple commands with the same name but different parameters.
+/// Higher value means higher priority.
+/// </summary>
+[AttributeUsage(AttributeTargets.Method)]
+public class prioAttribute : Attribute
+{
+    public int Priority { get; }
+
+    /// <summary>
+    /// Snek command priority
+    /// </summary>
+    /// <param name="priority">Priority value. The higher the value, the higher the priority</param>
+    public prioAttribute(int priority)
+    {
+        Priority = priority;
+    }
+}

src/Nadeko.Medusa/Attributes/svcAttribute.cs

@@ -0,0 +1,23 @@
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Marks the class as a service which can be used within the same Medusa
+/// </summary>
+[AttributeUsage(AttributeTargets.Class)]
+public class svcAttribute : Attribute
+{
+    public Lifetime Lifetime { get; }
+    public svcAttribute(Lifetime lifetime)
+    {
+        Lifetime = lifetime;
+    }
+}
+
+/// <summary>
+/// Lifetime for <see cref="svcAttribute"/>
+/// </summary>
+public enum Lifetime
+{
+    Singleton,
+    Transient
+}

src/Nadeko.Medusa/Context/AnyContext.cs

@@ -0,0 +1,47 @@
+using Discord;
+using NadekoBot;
+
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Commands which take this class as a first parameter can be executed in both DMs and Servers 
+/// </summary>
+public abstract class AnyContext
+{
+    /// <summary>
+    /// Channel from the which the command is invoked
+    /// </summary>
+    public abstract IMessageChannel Channel { get; }
+    
+    /// <summary>
+    /// Message which triggered the command
+    /// </summary>
+    public abstract IUserMessage Message { get; }
+    
+    /// <summary>
+    /// The user who invoked the command
+    /// </summary>
+    public abstract IUser User { get; }
+
+    /// <summary>
+    /// Provides access to strings used by this medusa
+    /// </summary>
+    public abstract IMedusaStrings Strings { get; } 
+    
+    /// <summary>
+    /// Gets a formatted localized string using a key and arguments which should be formatted in
+    /// </summary>
+    /// <param name="key">The key of the string as specified in localization files</param>
+    /// <param name="args">Arguments (if any) to format in</param>
+    /// <returns>A formatted localized string</returns>
+    public abstract string GetText(string key, object[]? args = null);
+    
+    /// <summary>
+    /// Creates a context-aware <see cref="IEmbedBuilder"/> instance
+    /// (future feature for guild-based embed colors)
+    /// Any code dealing with embeds should use it for future-proofness
+    /// instead of manually creating embedbuilder instances
+    /// </summary>
+    /// <returns>A context-aware <see cref="IEmbedBuilder"/> instance </returns>
+    public abstract IEmbedBuilder Embed();
+}

src/Nadeko.Medusa/Context/DmContext.cs

@@ -0,0 +1,11 @@
+using Discord;
+
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Commands which take this type as the first parameter can only be executed in DMs
+/// </summary>
+public abstract class DmContext : AnyContext
+{
+    public abstract override IDMChannel Channel { get; }
+}

src/Nadeko.Medusa/Context/GuildContext.cs

@@ -0,0 +1,12 @@
+using Discord;
+
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Commands which take this type as a first parameter can only be executed in a server
+/// </summary>
+public abstract class GuildContext : AnyContext
+{
+   public abstract override ITextChannel Channel { get; }
+   public abstract IGuild Guild { get; }
+}

src/Nadeko.Medusa/EmbedColor.cs

@@ -0,0 +1,8 @@
+namespace NadekoBot;
+
+public enum EmbedColor
+{
+    Ok,
+    Pending,
+    Error
+}

src/Nadeko.Medusa/Extensions/EmbedBuilderExtensions.cs

@@ -0,0 +1,14 @@
+namespace NadekoBot;
+
+public static class EmbedBuilderExtensions
+{
+    public static IEmbedBuilder WithOkColor(this IEmbedBuilder eb)
+        => eb.WithColor(EmbedColor.Ok);
+    
+    public static IEmbedBuilder WithPendingColor(this IEmbedBuilder eb)
+        => eb.WithColor(EmbedColor.Pending);
+    
+    public static IEmbedBuilder WithErrorColor(this IEmbedBuilder eb)
+        => eb.WithColor(EmbedColor.Error);
+    
+}

src/Nadeko.Medusa/Extensions/MedusaExtensions.cs

@@ -0,0 +1,66 @@
+using Discord;
+using Nadeko.Snake;
+
+namespace NadekoBot;
+
+public static class MedusaExtensions
+{
+    public static Task<IUserMessage> EmbedAsync(this IMessageChannel ch, IEmbedBuilder embed, string msg = "")
+        => ch.SendMessageAsync(msg,
+            embed: embed.Build(),
+            options: new()
+            {
+                RetryMode = RetryMode.AlwaysRetry
+            });
+
+    // unlocalized
+    public static Task<IUserMessage> SendConfirmAsync(this IMessageChannel ch, AnyContext ctx, string msg)
+        => ch.EmbedAsync(ctx.Embed().WithOkColor().WithDescription(msg));
+
+    public static Task<IUserMessage> SendPendingAsync(this IMessageChannel ch, AnyContext ctx, string msg)
+        => ch.EmbedAsync(ctx.Embed().WithPendingColor().WithDescription(msg));
+
+    public static Task<IUserMessage> SendErrorAsync(this IMessageChannel ch, AnyContext ctx, string msg)
+        => ch.EmbedAsync(ctx.Embed().WithErrorColor().WithDescription(msg));
+
+    // unlocalized
+    public static Task<IUserMessage> SendConfirmAsync(this AnyContext ctx, string msg)
+        => ctx.Channel.SendConfirmAsync(ctx, msg);
+
+    public static Task<IUserMessage> SendPendingAsync(this AnyContext ctx, string msg)
+        => ctx.Channel.SendPendingAsync(ctx, msg);
+
+    public static Task<IUserMessage> SendErrorAsync(this AnyContext ctx, string msg)
+        => ctx.Channel.SendErrorAsync(ctx, msg);
+
+    // localized
+    public static Task ConfirmAsync(this AnyContext ctx)
+        => ctx.Message.AddReactionAsync(new Emoji("✅"));
+
+    public static Task ErrorAsync(this AnyContext ctx)
+        => ctx.Message.AddReactionAsync(new Emoji("❌"));
+
+    public static Task WarningAsync(this AnyContext ctx)
+        => ctx.Message.AddReactionAsync(new Emoji("⚠️"));
+
+    public static Task WaitAsync(this AnyContext ctx)
+        => ctx.Message.AddReactionAsync(new Emoji("🤔"));
+
+    public static Task<IUserMessage> ErrorLocalizedAsync(this AnyContext ctx, string key, params object[]? args)
+        => ctx.SendErrorAsync(ctx.GetText(key));
+
+    public static Task<IUserMessage> PendingLocalizedAsync(this AnyContext ctx, string key, params object[]? args)
+        => ctx.SendPendingAsync(ctx.GetText(key, args));
+
+    public static Task<IUserMessage> ConfirmLocalizedAsync(this AnyContext ctx, string key, params object[]? args)
+        => ctx.SendConfirmAsync(ctx.GetText(key, args));
+
+    public static Task<IUserMessage> ReplyErrorLocalizedAsync(this AnyContext ctx, string key, params object[]? args)
+        => ctx.SendErrorAsync($"{Format.Bold(ctx.User.ToString())} {ctx.GetText(key)}");
+
+    public static Task<IUserMessage> ReplyPendingLocalizedAsync(this AnyContext ctx, string key, params object[]? args)
+        => ctx.SendPendingAsync($"{Format.Bold(ctx.User.ToString())} {ctx.GetText(key)}");
+
+    public static Task<IUserMessage> ReplyConfirmLocalizedAsync(this AnyContext ctx, string key, params object[]? args)
+        => ctx.SendConfirmAsync($"{Format.Bold(ctx.User.ToString())} {ctx.GetText(key)}");
+}

src/Nadeko.Medusa/IEmbedBuilder.cs

@@ -0,0 +1,17 @@
+using Discord;
+
+namespace NadekoBot;
+
+public interface IEmbedBuilder
+{
+    IEmbedBuilder WithDescription(string? desc);
+    IEmbedBuilder WithTitle(string title);
+    IEmbedBuilder AddField(string title, object value, bool isInline = false);
+    IEmbedBuilder WithFooter(string text, string? iconUrl = null);
+    IEmbedBuilder WithAuthor(string name, string? iconUrl = null, string? url = null);
+    IEmbedBuilder WithColor(EmbedColor color);
+    Embed Build();
+    IEmbedBuilder WithUrl(string url);
+    IEmbedBuilder WithImageUrl(string url);
+    IEmbedBuilder WithThumbnailUrl(string url);
+}

src/Nadeko.Medusa/Nadeko.Medusa.csproj

@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net6.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <LangVersion>preview</LangVersion>
+        <EnablePreviewFeatures>true</EnablePreviewFeatures>
+        <RootNamespace>Nadeko.Snake</RootNamespace>
+        
+        <Authors>The NadekoBot Team</Authors>
+        <Version>1.0.2</Version>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <PackageReference Include="Discord.Net.Core" Version="3.5.0" />
+      <PackageReference Include="Serilog" Version="2.10.0" />
+      <PackageReference Include="YamlDotNet" Version="11.2.1" />
+    </ItemGroup>
+
+</Project>

src/Nadeko.Medusa/ParamParser/ParamParser.cs

@@ -0,0 +1,16 @@
+namespace Nadeko.Snake;
+
+/// <summary>
+/// Overridden to implement parsers for custom types 
+/// </summary>
+/// <typeparam name="T">Type into which to parse the input</typeparam>
+public abstract class ParamParser<T>
+{
+    /// <summary>
+    /// Overridden to implement parsing logic
+    /// </summary>
+    /// <param name="ctx">Context</param>
+    /// <param name="input">Input to parse</param>
+    /// <returns>A <see cref="ParseResult{T}"/> with successful or failed status</returns>
+    public abstract ValueTask<ParseResult<T>> TryParseAsync(AnyContext ctx, string input);
+}

src/Nadeko.Medusa/ParamParser/ParseResult.cs

@@ -0,0 +1,48 @@
+namespace Nadeko.Snake;
+
+public readonly struct ParseResult<T>
+{
+    /// <summary>
+    /// Whether the parsing was successful
+    /// </summary>
+    public bool IsSuccess { get; private init; }
+    
+    /// <summary>
+    /// Parsed value. It should only have value if <see cref="IsSuccess"/> is set to true
+    /// </summary>
+    public T? Data { get; private init;  }
+
+    /// <summary>
+    /// Instantiate a **successful** parse result
+    /// </summary>
+    /// <param name="data">Parsed value</param>
+    public ParseResult(T data)
+    {
+        Data = data;
+        IsSuccess = true;
+    }
+    
+
+    /// <summary>
+    /// Create a new <see cref="ParseResult{T}"/> with IsSuccess = false
+    /// </summary>
+    /// <returns>A new <see cref="ParseResult{T}"/></returns>
+    public static ParseResult<T> Fail()
+        => new ParseResult<T>
+        {
+            IsSuccess = false,
+            Data = default,
+        };
+
+    /// <summary>
+    /// Create a new <see cref="ParseResult{T}"/> with IsSuccess = true
+    /// </summary>
+    /// <param name="obj">Value of the parsed object</param>
+    /// <returns>A new <see cref="ParseResult{T}"/></returns>
+    public static ParseResult<T> Success(T obj)
+        => new ParseResult<T>
+        {
+            IsSuccess = true,
+            Data = obj,
+        };
+}

src/Nadeko.Medusa/README.md

@@ -0,0 +1 @@
+This is the library which is the base of any medusa.

src/Nadeko.Medusa/Snek.cs

@@ -0,0 +1,143 @@
+using Discord;
+
+namespace Nadeko.Snake;
+
+/// <summary>
+/// The base class which will be loaded as a module into NadekoBot
+/// Any user-defined snek has to inherit from this class.
+/// Sneks get instantiated ONLY ONCE during the loading,
+/// and any snek commands will be executed on the same instance.
+/// </summary>
+public abstract class Snek : IAsyncDisposable
+{
+    /// <summary>
+    /// Name of the snek. Defaults to the lowercase class name
+    /// </summary>
+    public virtual string Name
+        => GetType().Name.ToLowerInvariant();
+
+    /// <summary>
+    /// The prefix required before the command name. For example
+    /// if you set this to 'test' then a command called 'cmd' will have to be invoked by using
+    /// '.test cmd' instead of `.cmd` 
+    /// </summary>
+    public virtual string Prefix
+        => string.Empty;
+
+    /// <summary>
+    /// Executed once this snek has been instantiated and before any command is executed.
+    /// </summary>
+    /// <returns>A <see cref="ValueTask"/> representing completion</returns>
+    public virtual ValueTask InitializeAsync()
+        => default;
+
+    /// <summary>
+    /// Override to cleanup any resources or references which might hold this snek in memory
+    /// </summary>
+    /// <returns></returns>
+    public virtual ValueTask DisposeAsync()
+        => default;
+
+    /// <summary>
+    /// This method is called right after the message was received by the bot.
+    /// You can use this method to make the bot conditionally ignore some messages and prevent further processing.
+    /// <para>Execution order:</para>
+    /// <para>
+    /// *<see cref="ExecOnMessageAsync"/>* →
+    /// <see cref="ExecInputTransformAsync"/> →
+    /// <see cref="ExecPreCommandAsync"/> →
+    /// <see cref="ExecPostCommandAsync"/> OR <see cref="ExecOnNoCommandAsync"/>
+    /// </para>
+    /// </summary>
+    /// <param name="guild">Guild in which the message was sent</param>
+    /// <param name="msg">Message received by the bot</param>
+    /// <returns>A <see cref="ValueTask"/> representing whether the message should be ignored and not processed further</returns>
+    public virtual ValueTask<bool> ExecOnMessageAsync(IGuild? guild, IUserMessage msg)
+        => default;
+
+    /// <summary>
+    /// Override this method to modify input before the bot searches for any commands matching the input
+    /// Executed after <see cref="ExecOnMessageAsync"/>
+    /// This is useful if you want to reinterpret the message under some conditions
+    /// <para>Execution order:</para>
+    /// <para>
+    /// <see cref="ExecOnMessageAsync"/> →
+    /// *<see cref="ExecInputTransformAsync"/>* →
+    /// <see cref="ExecPreCommandAsync"/> →
+    /// <see cref="ExecPostCommandAsync"/> OR <see cref="ExecOnNoCommandAsync"/>
+    /// </para> 
+    /// </summary>
+    /// <param name="guild">Guild in which the message was sent</param>
+    /// <param name="channel">Channel in which the message was sent</param>
+    /// <param name="user">User who sent the message</param>
+    /// <param name="input">Content of the message</param>
+    /// <returns>A <see cref="ValueTask"/> representing new, potentially modified content</returns>
+    public virtual ValueTask<string?> ExecInputTransformAsync(
+        IGuild? guild,
+        IMessageChannel channel,
+        IUser user,
+        string input
+    )
+        => default;
+
+    /// <summary>
+    /// This method is called after the command was found but not executed,
+    /// and can be used to prevent the command's execution.
+    /// The command information doesn't have to be from this snek as this method
+    /// will be called when *any* command from any module or snek was found.
+    /// You can choose to prevent the execution of the command by returning "true" value.
+    /// <para>Execution order:</para>
+    /// <para>
+    /// <see cref="ExecOnMessageAsync"/> →
+    /// <see cref="ExecInputTransformAsync"/> →
+    /// *<see cref="ExecPreCommandAsync"/>* →
+    /// <see cref="ExecPostCommandAsync"/> OR <see cref="ExecOnNoCommandAsync"/>
+    /// </para>
+    /// </summary>
+    /// <param name="context">Command context</param>
+    /// <param name="moduleName">Name of the snek or module from which the command originates</param>
+    /// <param name="commandName">Name of the command which is about to be executed</param>
+    /// <returns>A <see cref="ValueTask"/> representing whether the execution should be blocked</returns>
+    public virtual ValueTask<bool> ExecPreCommandAsync(
+        AnyContext context,
+        string moduleName,
+        string commandName
+    )
+        => default;
+
+    /// <summary>
+    /// This method is called after the command was succesfully executed.
+    /// If this method was called, then <see cref="ExecOnNoCommandAsync"/> will not be executed
+    /// <para>Execution order:</para>
+    /// <para>
+    /// <see cref="ExecOnMessageAsync"/> →
+    /// <see cref="ExecInputTransformAsync"/> →
+    /// <see cref="ExecPreCommandAsync"/> →
+    /// *<see cref="ExecPostCommandAsync"/>* OR <see cref="ExecOnNoCommandAsync"/>
+    /// </para>
+    /// </summary>
+    /// <returns>A <see cref="ValueTask"/> representing completion</returns>
+    public virtual ValueTask ExecPostCommandAsync(AnyContext ctx, string moduleName, string commandName)
+        => default;
+
+    /// <summary>
+    /// This method is called if no command was found for the input.
+    /// Useful if you want to have games or features which take arbitrary input
+    /// but ignore any messages which were blocked or caused a command execution
+    /// If this method was called, then <see cref="ExecPostCommandAsync"/> will not be executed
+    /// <para>Execution order:</para>
+    /// <para>
+    /// <see cref="ExecOnMessageAsync"/> →
+    /// <see cref="ExecInputTransformAsync"/> →
+    /// <see cref="ExecPreCommandAsync"/> →
+    /// <see cref="ExecPostCommandAsync"/> OR *<see cref="ExecOnNoCommandAsync"/>*
+    /// </para>
+    /// </summary>
+    /// <returns>A <see cref="ValueTask"/> representing completion</returns>
+    public virtual ValueTask ExecOnNoCommandAsync(IGuild? guild, IUserMessage msg)
+        => default;
+}
+
+public readonly struct ExecResponse
+{
+}

src/Nadeko.Medusa/Strings/CommandStrings.cs

@@ -0,0 +1,24 @@
+using YamlDotNet.Serialization;
+
+namespace Nadeko.Snake;
+
+public readonly struct CommandStrings
+{
+    public CommandStrings(string? desc, string[]? args)
+    {
+        Desc = desc;
+        Args = args;
+    }
+
+    [YamlMember(Alias = "desc")]
+    public string? Desc { get; init; }
+    
+    [YamlMember(Alias = "args")]
+    public string[]? Args { get; init; }
+
+    public void Deconstruct(out string? desc, out string[]? args)
+    {
+        desc = Desc;
+        args = Args;
+    }
+}

src/Nadeko.Medusa/Strings/IMedusaStrings.cs

@@ -0,0 +1,15 @@
+using System.Globalization;
+
+namespace Nadeko.Snake;
+
+/// <summary>
+///     Defines methods to retrieve and reload medusa strings
+/// </summary>
+public interface IMedusaStrings
+{
+    // string GetText(string key, ulong? guildId = null, params object[] data);
+    string? GetText(string key, CultureInfo locale, params object[] data);
+    void Reload();
+    CommandStrings GetCommandStrings(string commandName, CultureInfo cultureInfo);
+    string? GetDescription(CultureInfo? locale);
+}

src/Nadeko.Medusa/Strings/IMedusaStringsProvider.cs

@@ -0,0 +1,28 @@
+namespace Nadeko.Snake;
+
+/// <summary>
+///     Implemented by classes which provide localized strings in their own ways
+/// </summary>
+public interface IMedusaStringsProvider
+{
+    /// <summary>
+    ///     Gets localized string
+    /// </summary>
+    /// <param name="localeName">Language name</param>
+    /// <param name="key">String key</param>
+    /// <returns>Localized string</returns>
+    string? GetText(string localeName, string key);
+
+    /// <summary>
+    ///     Reloads string cache
+    /// </summary>
+    void Reload();
+
+    // /// <summary>
+    // ///     Gets command arg examples and description
+    // /// </summary>
+    // /// <param name="localeName">Language name</param>
+    // /// <param name="commandName">Command name</param>
+    // CommandStrings GetCommandStrings(string localeName, string commandName);
+    CommandStrings? GetCommandStrings(string localeName, string commandName);
+}

src/Nadeko.Medusa/Strings/LocalMedusaStringsProvider.cs

@@ -0,0 +1,40 @@
+namespace Nadeko.Snake;
+
+public class LocalMedusaStringsProvider : IMedusaStringsProvider
+{
+    private readonly StringsLoader _source;
+    private IReadOnlyDictionary<string, IReadOnlyDictionary<string, string>> _responseStrings;
+    private IReadOnlyDictionary<string, IReadOnlyDictionary<string, CommandStrings>> _commandStrings;
+
+    public LocalMedusaStringsProvider(StringsLoader source)
+    {
+        _source = source;
+        _responseStrings = _source.GetResponseStrings();
+        _commandStrings = _source.GetCommandStrings();
+    }
+
+    public void Reload()
+    {
+        _responseStrings = _source.GetResponseStrings();
+        _commandStrings = _source.GetCommandStrings();
+    }
+    
+
+    public string? GetText(string localeName, string key)
+    {
+        if (_responseStrings.TryGetValue(localeName.ToLowerInvariant(), out var langStrings)
+            && langStrings.TryGetValue(key.ToLowerInvariant(), out var text))
+            return text;
+
+        return null;
+    }
+
+    public CommandStrings? GetCommandStrings(string localeName, string commandName)
+    {
+        if (_commandStrings.TryGetValue(localeName.ToLowerInvariant(), out var langStrings)
+            && langStrings.TryGetValue(commandName.ToLowerInvariant(), out var strings))
+            return strings;
+    
+        return null;
+    }
+} 

src/Nadeko.Medusa/Strings/MedusaStrings.cs

@@ -0,0 +1,79 @@
+using System.Globalization;
+using Serilog;
+
+namespace Nadeko.Snake;
+
+public class MedusaStrings : IMedusaStrings
+{
+    /// <summary>
+    ///     Used as failsafe in case response key doesn't exist in the selected or default language.
+    /// </summary>
+    private readonly CultureInfo _usCultureInfo = new("en-US");
+    
+    private readonly IMedusaStringsProvider _stringsProvider;
+
+    public MedusaStrings(IMedusaStringsProvider stringsProvider)
+    {
+        _stringsProvider = stringsProvider;
+    }
+
+    private string? GetString(string key, CultureInfo cultureInfo)
+        => _stringsProvider.GetText(cultureInfo.Name, key);
+
+    public string? GetText(string key, CultureInfo cultureInfo)
+        => GetString(key, cultureInfo)
+           ?? GetString(key, _usCultureInfo);
+
+    public string? GetText(string key, CultureInfo cultureInfo, params object[] data)
+    {
+        var text = GetText(key, cultureInfo);
+
+        if (string.IsNullOrWhiteSpace(text))
+            return null;
+        
+        try
+        {
+            return string.Format(text, data);
+        }
+        catch (FormatException)
+        {
+            Log.Warning(" Key '{Key}' is not properly formatted in '{LanguageName}' response strings",
+                key,
+                cultureInfo.Name);
+            
+            return $"⚠️ Response string key '{key}' is not properly formatted. Please report this.\n\n{text}";
+        }
+    }
+    
+    public CommandStrings GetCommandStrings(string commandName, CultureInfo cultureInfo)
+    {
+        var cmdStrings = _stringsProvider.GetCommandStrings(cultureInfo.Name, commandName);
+        if (cmdStrings is null)
+        {
+            if (cultureInfo.Name == _usCultureInfo.Name)
+            {
+                Log.Warning("'{CommandName}' doesn't exist in 'en-US' command strings for one of the medusae",
+                    commandName);
+
+                return new(null, null);
+            }
+
+            Log.Information("Missing '{CommandName}' command strings for the '{LocaleName}' locale",
+                commandName,
+                cultureInfo.Name);
+            
+            return GetCommandStrings(commandName, _usCultureInfo);
+        }
+
+        return cmdStrings.Value;
+    }
+
+    public string? GetDescription(CultureInfo? locale = null)
+        => GetText("medusa.description", locale ?? _usCultureInfo);
+
+    public static MedusaStrings CreateDefault(string basePath)
+        => new MedusaStrings(new LocalMedusaStringsProvider(new(basePath)));
+    
+    public void Reload()
+        => _stringsProvider.Reload();
+}

src/Nadeko.Medusa/Strings/StringsLoader.cs

@@ -0,0 +1,137 @@
+using System.Diagnostics.CodeAnalysis;
+using Serilog;
+using YamlDotNet.Serialization;
+
+namespace Nadeko.Snake;
+
+/// <summary>
+///     Loads strings from the shortcut or localizable path
+/// </summary>
+public class StringsLoader
+{
+    private readonly string _localizableResponsesPath;
+    private readonly string _shortcutResponsesFile;
+    
+    private readonly string _localizableCommandsPath;
+    private readonly string _shortcutCommandsFile;
+
+    public StringsLoader(string basePath)
+    {
+        _localizableResponsesPath = Path.Join(basePath, "strings/res");
+        _shortcutResponsesFile = Path.Join(basePath, "res.yml");
+        
+        _localizableCommandsPath = Path.Join(basePath, "strings/cmds");
+        _shortcutCommandsFile = Path.Join(basePath, "cmds.yml");
+    }
+
+    public IReadOnlyDictionary<string, IReadOnlyDictionary<string, CommandStrings>> GetCommandStrings()
+    {
+        var outputDict = new Dictionary<string, IReadOnlyDictionary<string, CommandStrings>>();
+
+        if (File.Exists(_shortcutCommandsFile))
+        {
+            if (TryLoadCommandsFromFile(_shortcutCommandsFile, out var dict, out _))
+            {
+                outputDict["en-us"] = dict;
+            }
+
+            return outputDict;
+        }
+
+        if (Directory.Exists(_localizableCommandsPath))
+        {
+            foreach (var cmdsFile in Directory.EnumerateFiles(_localizableCommandsPath))
+            {
+                if (TryLoadCommandsFromFile(cmdsFile, out var dict, out var locale) && locale is not null)
+                {
+                    outputDict[locale.ToLowerInvariant()] = dict;
+                }
+            }
+        }
+
+        return outputDict;
+    }
+
+    
+    private static readonly IDeserializer _deserializer = new DeserializerBuilder().Build();
+    private static bool TryLoadCommandsFromFile(string file,
+        [NotNullWhen(true)] out IReadOnlyDictionary<string, CommandStrings>? strings,
+        out string? localeName)
+    {
+        try
+        {
+            var text = File.ReadAllText(file);
+            strings = _deserializer.Deserialize<Dictionary<string, CommandStrings>?>(text)
+                      ?? new();
+            localeName = GetLocaleName(file);
+            return true;
+        }
+        catch (Exception ex)
+        {
+            Log.Error(ex, "Error loading {FileName} command strings: {ErrorMessage}", file, ex.Message);
+        }
+
+        strings = null;
+        localeName = null;
+        return false;
+    }
+
+
+    public IReadOnlyDictionary<string, IReadOnlyDictionary<string, string>> GetResponseStrings()
+    {
+        var outputDict = new Dictionary<string, IReadOnlyDictionary<string, string>>();
+
+        // try to load a shortcut file
+        if (File.Exists(_shortcutResponsesFile))
+        {
+            if (TryLoadResponsesFromFile(_shortcutResponsesFile, out var dict, out _))
+            {
+                outputDict["en-us"] = dict;
+            }
+
+            return outputDict;
+        }
+
+        if (!Directory.Exists(_localizableResponsesPath))
+            return outputDict;
+        
+        // if shortcut file doesn't exist, try to load localizable files
+        foreach (var file in Directory.GetFiles(_localizableResponsesPath))
+        {
+            if (TryLoadResponsesFromFile(file, out var strings, out var localeName) && localeName is not null)
+            {
+                outputDict[localeName.ToLowerInvariant()] = strings;
+            }
+        }
+
+        return outputDict;
+    }
+
+    private static bool TryLoadResponsesFromFile(string file,
+        [NotNullWhen(true)] out IReadOnlyDictionary<string, string>? strings,
+        out string? localeName)
+    {
+        try
+        {
+            strings = _deserializer.Deserialize<Dictionary<string, string>?>(File.ReadAllText(file));
+            if (strings is null)
+            {
+                localeName = null;
+                return false;
+            }
+
+            localeName = GetLocaleName(file).ToLowerInvariant();
+            return true;
+        }
+        catch (Exception ex)
+        {
+            Log.Error(ex, "Error loading {FileName} response strings: {ErrorMessage}", file, ex.Message);
+            strings = null;
+            localeName = null;
+            return false;
+        }
+    }
+
+    private static string GetLocaleName(string fileName)
+        => Path.GetFileNameWithoutExtension(fileName);
+}

src/Nadeko.Medusa/pack-and-push.ps1

@@ -0,0 +1,2 @@
+dotnet pack -o bin/Release/packed
+dotnet nuget push bin/Release/packed/ --api-key $env:nadeko_myget_api_key --source https://www.myget.org/F/nadeko/api/v2/package