using Microsoft.Extensions.Configuration;

namespace DigitalData.Core.Abstractions
{
    /// <summary>
    /// Extension methods for the <see cref="IConfiguration"/> interface, providing 
    /// additional functionality for retrieving configuration values with default behavior.
    /// </summary>
    public static class ConfigurationExtension
    {
        /// <summary>
        /// Retrieves a configuration value for the specified key, or returns a default value 
        /// of type <typeparamref name="T"/> if the configuration is not found or the key is null.
        /// </summary>
        /// <typeparam name="T">The type of the object to retrieve from the configuration.</typeparam>
        /// <param name="configuration">The <see cref="IConfiguration"/> instance.</param>
        /// <param name="key">The optional key to look for in the configuration. If null, the method 
        /// retrieves the root configuration.</param>
        /// <returns>
        /// An instance of <typeparamref name="T"/> populated from the configuration values, or 
        /// a new instance of <typeparamref name="T"/> if no matching configuration is found.
        /// </returns>
        public static T GetOrDefault<T>(this IConfiguration configuration, string? key = null)
            where T : new()
            => (key is null
                ? configuration.Get<T>()
                : configuration.GetSection(key).Get<T>())
            ?? new T();
    }
}