EndpointCommand.cs

using Newtonsoft.Json;
using TypedRest.CommandLine.IO;
using TypedRest.Endpoints;

namespace TypedRest.CommandLine.Commands;

/// <summary>
/// Command operating on an <see cref="IEndpoint"/>.
/// </summary>
/// <param name="endpoint">The endpoint this command operates on.</param>
/// <typeparam name="TEndpoint">The specific type of <see cref="IEndpoint"/> to operate on.</typeparam>
public abstract class EndpointCommand<TEndpoint>(TEndpoint endpoint) : IEndpointCommand
    where TEndpoint : IEndpoint
{
    /// <summary>
    /// The endpoint this command operates on.
    /// </summary>
    protected readonly TEndpoint Endpoint = endpoint ?? throw new ArgumentNullException(nameof(endpoint));

    /// <summary>
    /// The text input/output device used for user interaction.
    /// </summary>
    public IConsole Console { get; set; } = new JsonConsole();

    public virtual async Task ExecuteAsync(IReadOnlyList<string> args, CancellationToken cancellationToken = default)
    {
        var subCommand = (args.Count == 0) ? null : GetSubCommand(args[0]);
        if (subCommand == null) await ExecuteInnerAsync(args, cancellationToken);
        else await subCommand.ExecuteAsync(args.Skip(1).ToList(), cancellationToken);
    }

    /// <summary>
    /// Creates a sub-<see cref="IEndpointCommand"/> based on the given <paramref name="name"/>.
    /// </summary>
    /// <returns>The <see cref="IEndpointCommand"/> or <c>null</c> if the <paramref name="name"/> does not match.</returns>
    protected virtual IEndpointCommand? GetSubCommand(string name)
        => null;

    /// <summary>
    /// Parses command-line arguments and executes the resulting operation when no additional sub-<see cref="IEndpointCommand"/> is specified.
    /// </summary>
    /// <param name="args">the console arguments.</param>
    /// <param name="cancellationToken">Used to cancel the request.</param>
    protected virtual Task ExecuteInnerAsync(IReadOnlyList<string> args, CancellationToken cancellationToken = default)
        => throw new ArgumentException("Unknown command: " + args[0]);

    /// <summary>
    /// Reads an input object (usually in JSON format) either from the command-line or stdin.
    /// </summary>
    /// <param name="args">The command-line to check for input data.</param>
    /// <typeparam name="T">The type of object to read.</typeparam>
    protected virtual T Input<T>(IReadOnlyList<string> args)
        => ((args.Count == 0)
               ? Console.Read<T>()
               : JsonConvert.DeserializeObject<T>(args[0]))
        ?? throw new InvalidOperationException($"Expected {typeof(T)} but got null as input");
}