using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.BL.Entities;
using System.Reflection;
using Tango.BL.Enumerations;

namespace Tango.BL.Dispensing
{
    /// <summary>
    /// IDS pack dispensing calculators resolver used to inquire the proper calculator instance.
    /// </summary>
    public static class DispensingCalcResolver
    {
        private static List<KeyValuePair<IdsPackFormulas, IDispensingCalc>> _calculators { get; set; }

        /// <summary>
        /// Initializes the <see cref="DispensingCalcResolver"/> class.
        /// </summary>
        static DispensingCalcResolver()
        {
            _calculators = new List<KeyValuePair<IdsPackFormulas, IDispensingCalc>>();

            foreach (var type in typeof(DispensingCalcResolver).Assembly.GetTypes().Where(x => x.GetCustomAttribute<DispensingCalcAttribute>() != null))
            {
                _calculators.Add(new KeyValuePair<IdsPackFormulas, IDispensingCalc>(type.GetCustomAttribute<DispensingCalcAttribute>().Formula, Activator.CreateInstance(type) as IDispensingCalc));
            }
        }

        /// <summary>
        /// Returns an IDS pack dispensing calculator instance by the specified <see cref="LiquidVolume"/>.
        /// </summary>
        /// <param name="liquidVolume">The liquid volume.</param>
        /// <returns></returns>
        public static IDispensingCalc Resolve(LiquidVolume liquidVolume)
        {
            return _calculators.SingleOrDefault(x => x.Key == (IdsPackFormulas)liquidVolume.IdsPack.IdsPackFormula.Code).Value;
        }

        /// <summary>
        /// Returns an IDS pack dispensing calculator instance by the specified <see cref="IdsPackFormula"/>.
        /// </summary>
        /// <param name="formulaCode">The formula code.</param>
        /// <returns></returns>
        public static IDispensingCalc Resolve(IdsPackFormulas formulaCode)
        {
            return _calculators.SingleOrDefault(x => x.Key == formulaCode).Value;
        }
    }
}