Playa/extensions/Volcanic.AgenticCore.Extensions.OpenAI/OpenAIProviderExtension.cs

using Volcanic.AgenticCore.Abstractions.Extensions;
using Volcanic.AgenticCore.Abstractions.Providers;

namespace Volcanic.AgenticCore.Extensions.OpenAI;

/// <summary>
/// Registers one OpenAI-compatible provider. With no options this is OpenAI itself
/// (<c>openai</c>, key from <c>OPENAI_API_KEY</c>, the <see cref="OpenAIModels"/> catalogue);
/// pass <see cref="OpenAIProviderOptions"/> to target OpenRouter, Ollama or any other compatible server.
/// </summary>
public sealed class OpenAIProviderExtension : IExtension
{
    private readonly HttpClient? _http;

    public OpenAIProviderExtension() : this(null, null) { }

    public OpenAIProviderExtension(OpenAIProviderOptions? options = null, HttpClient? http = null)
    {
        Options = options ?? new OpenAIProviderOptions();
        _http = http;
    }

    public OpenAIProviderOptions Options { get; }

    public string Name => $"{Options.ProviderId}-provider";

    public ValueTask ActivateAsync(IExtensionApi api, CancellationToken cancellationToken)
    {
        ArgumentNullException.ThrowIfNull(api);
        api.RegisterProvider(CreateRegistration());
        return ValueTask.CompletedTask;
    }

    /// <summary>The registration handed to <see cref="IExtensionApi.RegisterProvider"/>; also usable directly with a model registry.</summary>
    public ProviderRegistration CreateRegistration() => new()
    {
        Id = Options.ProviderId,
        Name = Options.EffectiveName,
        Api = OpenAIModels.ApiId,
        BaseUrl = Options.BaseUrl,
        ApiKey = Options.EffectiveApiKeySpec,
        Headers = Options.Headers,
        Models = Options.EffectiveModels,
        RequiresApiKey = Options.RequiresApiKey,
        Stream = new OpenAICompletionsApi(Options, _http).StreamAsync,
    };
}