using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace GB5Shared.Storage
{
    public static class StorageServiceExtensions
    {
        /// <summary>
        /// Registers the GB5 storage abstraction.
        /// Call in Program.cs:
        ///   builder.Services.AddGB5Storage(builder.Configuration.GetSection("StorageConfiguration"));
        /// NetworkBasePath/PathTemplate should come from HashiCorp Vault, not appsettings.json.
        /// The active backend is no longer a single static provider per deployment — it's resolved
        /// per tenant DB at request time via <see cref="IAttachmentStorageResolver"/>, based on that
        /// tenant's own MDBLEVELSETTING.ATTACHMENTOPTION (see AttachmentStorageResolver).
        /// </summary>
        public static IServiceCollection AddGB5Storage(
            this IServiceCollection services,
            IConfiguration configuration)
        {
            services.Configure<StorageConfiguration>(configuration);

            // Fallback provider for the FileBased option — stateless, safe as a singleton.
            // AmazonS3Client/S3StorageProvider are NOT registered here: they're built per-tenant
            // by AttachmentStorageResolver from that tenant's own decrypted MDBLEVELSETTING
            // credentials, since bucket/keys differ per tenant DB.
            services.AddSingleton<NetworkStorageProvider>();
            // Also bind IStorageProvider itself to the same singleton instance — consumers that
            // don't need per-tenant resolution (IceImport's upload staging, DMS's Alfresco
            // migration/ESSDocument BLLs) inject IStorageProvider directly rather than going
            // through IAttachmentStorageResolver.
            services.AddSingleton<IStorageProvider>(sp => sp.GetRequiredService<NetworkStorageProvider>());
            services.AddScoped<IAttachmentStorageResolver, AttachmentStorageResolver>();

            return services;
        }
    }
}