namespace w4c_workflows.Services.Execution;

/// <summary>
/// A language as exposed by <c>GET /api/languages</c>: identity + whether its
/// runtime is actually executable on this host (availability is probed at
/// startup and cached).
/// </summary>
public sealed record RuntimeInfo(
    string Id,
    string DisplayName,
    string DefaultFunction,
    string Extension,
    bool Available);

/// <summary>
/// Maps each registered language to its <see cref="IScriptExecutor"/>. Built on
/// top of <see cref="LanguageRegistry"/> (the source of truth for known
/// languages); the executor set is DI-injected so new languages/runtimes plug in
/// without touching this class.
/// </summary>
public class RuntimeRegistry
{
    private readonly IReadOnlyDictionary<string, IScriptExecutor> _executors;
    private readonly IReadOnlyList<RuntimeInfo> _all;

    public RuntimeRegistry(LanguageRegistry languages, IEnumerable<IScriptExecutor> executors)
    {
        _executors = executors.ToDictionary(e => e.Language, StringComparer.Ordinal);
        _all = languages.All
            .Select(l => new RuntimeInfo(
                l.Id,
                l.DisplayName,
                l.DefaultFunction,
                l.Extension,
                _executors.TryGetValue(l.Id, out var executor) && executor.IsAvailable()))
            .ToList();
    }

    public IReadOnlyList<RuntimeInfo> All => _all;

    public IScriptExecutor? Resolve(string language)
        => _executors.TryGetValue(language, out var executor) ? executor : null;

    public bool IsAvailable(string language)
        => _executors.TryGetValue(language, out var executor) && executor.IsAvailable();
}