using Microsoft.Extensions.DependencyInjection;

namespace FrameworkBLL.GOP.Transform
{
    /// <summary>
    /// Extension methods for registering ITransformExpression implementations.
    ///
    /// Usage in Program.cs (or wherever SL DI is configured):
    ///
    ///     builder.Services.AddMappingTransforms();          // registers all built-in transforms
    ///     builder.Services.AddTransformExpression&lt;MyCustomTransform&gt;();   // add a custom one
    ///
    /// Built-in transforms registered by AddMappingTransforms():
    ///   UPPER, LOWER, TRIM, NULL_TO_EMPTY, CONST, ROUND, FORMAT_DATE, TO_NUMBER, TO_DATETIME
    /// </summary>
    public static class TransformExpressionExtensions
    {
        /// <summary>Registers a single ITransformExpression implementation as Singleton.</summary>
        public static IServiceCollection AddTransformExpression<T>(this IServiceCollection services)
            where T : class, ITransformExpression
        {
            services.AddSingleton<ITransformExpression, T>();
            return services;
        }

        /// <summary>
        /// Registers all built-in ITransformExpression implementations.
        /// Call this once from Program.cs in any SL project that uses the mapping engine.
        /// </summary>
        public static IServiceCollection AddMappingTransforms(this IServiceCollection services)
        {
            services
                .AddTransformExpression<UpperTransform>()
                .AddTransformExpression<LowerTransform>()
                .AddTransformExpression<TrimTransform>()
                .AddTransformExpression<NullToEmptyTransform>()
                .AddTransformExpression<ConstTransform>()
                .AddTransformExpression<RoundTransform>()
                .AddTransformExpression<FormatDateTransform>()
                .AddTransformExpression<ToNumberTransform>()
                .AddTransformExpression<ToDateTimeTransform>();

            return services;
        }
    }
}