using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using StellaOps.Scanner.Surface.Env;
using StellaOps.Scanner.Surface.Secrets.Providers;

namespace StellaOps.Scanner.Surface.Secrets;

public static class ServiceCollectionExtensions
{
    public static IServiceCollection AddSurfaceSecrets(
        this IServiceCollection services,
        Action<SurfaceSecretsOptions>? configure = null)
    {
        if (services is null)
        {
            throw new ArgumentNullException(nameof(services));
        }

        services.AddOptions<SurfaceSecretsOptions>();
        if (configure is not null)
        {
            services.Configure(configure);
        }

        services.TryAddSingleton<ISurfaceSecretProvider>(sp =>
        {
            var env = sp.GetRequiredService<ISurfaceEnvironment>();
            var options = sp.GetRequiredService<IOptions<SurfaceSecretsOptions>>().Value;
            var logger = sp.GetRequiredService<ILoggerFactory>().CreateLogger("SurfaceSecrets");
            return CreateProvider(env.Settings.Secrets, logger);
        });

        return services;
    }

    private static ISurfaceSecretProvider CreateProvider(SurfaceSecretsConfiguration configuration, ILogger logger)
    {
        var providers = new List<ISurfaceSecretProvider>();

        switch (configuration.Provider.ToLowerInvariant())
        {
            case "kubernetes":
                providers.Add(new KubernetesSurfaceSecretProvider(configuration, logger));
                break;
            case "file":
                providers.Add(new FileSurfaceSecretProvider(configuration.Root ?? throw new ArgumentException("Secrets root is required for file provider.")));
                break;
            case "inline":
                providers.Add(new InlineSurfaceSecretProvider(configuration));
                break;
            default:
                logger.LogWarning("Unknown surface secret provider '{Provider}'. Falling back to inline provider.", configuration.Provider);
                providers.Add(new InlineSurfaceSecretProvider(configuration));
                break;
        }

        if (!string.IsNullOrWhiteSpace(configuration.FallbackProvider))
        {
            providers.Add(new InlineSurfaceSecretProvider(configuration with { Provider = configuration.FallbackProvider }));
        }

        return providers.Count == 1 ? providers[0] : new CompositeSurfaceSecretProvider(providers);
    }
}