using System;
using System.Reflection;
using RGB.NET.Devices.Novation.Attributes;

namespace RGB.NET.Devices.Novation
{
    /// <summary>
    /// Offers some extensions and helper-methods for enum related things.
    /// </summary>
    internal static class EnumExtension
    {
        /// <summary>
        /// Gets the value of the <see cref="DeviceIdAttribute"/>.
        /// </summary>
        /// <param name="source">The enum value to get the description from.</param>
        /// <returns>The value of the <see cref="DeviceIdAttribute"/> of the source.</returns>
        internal static string? GetDeviceId(this Enum source) => source.GetAttribute<DeviceIdAttribute>()?.Id;

        /// <summary>
        /// Gets the value of the <see cref="ColorCapabilityAttribute"/>.
        /// </summary>
        /// <param name="source">The enum value to get the description from.</param>
        /// <returns>The value of the <see cref="ColorCapabilityAttribute"/> of the source.</returns>
        internal static NovationColorCapabilities GetColorCapability(this Enum source) => source.GetAttribute<ColorCapabilityAttribute>()?.Capability ?? NovationColorCapabilities.None;

        /// <summary>
        /// Gets the value of the <see cref="LedIdMappingAttribute"/>.
        /// </summary>
        /// <param name="source">The enum value to get the description from.</param>
        /// <returns>The value of the <see cref="LedIdMappingAttribute"/> of the source.</returns>
        internal static LedIdMappings GetLedIdMapping(this Enum source) => source.GetAttribute<LedIdMappingAttribute>()?.LedIdMapping ?? LedIdMappings.Current;

        /// <summary>
        /// Gets the attribute of type T.
        /// </summary>
        /// <param name="source">The enum value to get the attribute from</param>
        /// <typeparam name="T">The generic attribute type</typeparam>
        /// <returns>The <see cref="Attribute"/>.</returns>
        private static T? GetAttribute<T>(this Enum source)
            where T : Attribute
        {
            FieldInfo? fi = source.GetType().GetField(source.ToString());
            if (fi == null) return null;
            T[] attributes = (T[])fi.GetCustomAttributes(typeof(T), false);
            return attributes.Length > 0 ? attributes[0] : null;
        }
    }
}