using System;
using System.Collections.Generic;
using System.Linq;
using LCU.Shared.Collections.RepoApiLib.Models;
using LCU.Shared.Collections.RepoApiLib.WebServices.NADA;
using Microsoft.EntityFrameworkCore.Internal;
using Enumerable = System.Linq.Enumerable;

namespace LCU.API.Collections.RepoApi.Domain.FloorPricing.Strategies
{
	/**
     * This strategy uses the AutoIms MMR values, the values from Nada, and the condition from AutoIms along
     * with a specific formula, to calculate a floor.
     */
	public class NadaMmrConditionValue : IFloorPricingStrategy
	{

		public FloorPriceCalculationResult CalculateFloorPrice(FloorPriceCalculationParams fpcParams)
		{
			var result = new FloorPriceCalculationResult()
			{
				StrategyName = this.GetType().FullName,
				Success = false,
				ResultWeight = -1
			};

			if (fpcParams?.CollateralValuation == null || fpcParams?.ImsAutoFileData == null ||
				fpcParams?.VehicleFloorPricingParameters == null
				|| fpcParams?.VehicleFloorPricingParameters?.Any() == false)
			{
				// May want to log here, or set a reason code on the result.
				result.FailureReason = "Missing ImsAuto File, Pricing Parameters, or Collateral Valuation";
				return result;
			}

			// 1. use condition to find the correct params.
			//    + VehicleDemicalGradeCode is ignored, ApprovedVehicleGrade is preferred, and Vehicle Grade is the fallback.
			var condition = fpcParams.ImsAutoFileData.ApprovedVehicleGrade ?? fpcParams.ImsAutoFileData.VehicleGrade;

			if (condition <= 0 || condition == null)
			{
				result.FailureReason = "No Condition In AutoIMS File Data";
				return result;
			}

			// 2. Get the matching floor pricing calculation row.
			var floorPricing = Enumerable.First(Enumerable.Where(fpcParams.VehicleFloorPricingParameters,
				x => condition >= x.LowCondition && condition <= x.HighCondition));

			// 3. Get the floor pricing params based on matching condition.
			var mmrValue = GetMMRValueByParam(floorPricing.MMRAdjustedValue, fpcParams.ImsAutoFileData,
				fpcParams.ImsAutoFileData.AuctionGuideBookPrice ?? 0);

			List<Decimal> nadaValues = new List<decimal>();

			nadaValues.Add(GetNadaValueByParam(floorPricing.NADAFirstValue, fpcParams.CollateralValuation));
			nadaValues.Add(GetNadaValueByParam(floorPricing.NADASecondValue, fpcParams.CollateralValuation));

			bool onlyZeroNadaValues = nadaValues.TrueForAll(x => x == 0);

			if (fpcParams.CollateralValuation.Year <= (DateTime.Now.AddYears(-7).Year) || onlyZeroNadaValues)
			{
				nadaValues.Add(fpcParams.CollateralValuation.TradeIn);
				onlyZeroNadaValues = nadaValues.TrueForAll(x => x == 0);
			}

			// If there are no NADA or MMR prices, fail the strategy
			if (onlyZeroNadaValues && (mmrValue == 0 || mmrValue == fpcParams.ImsAutoFileData.AuctionGuideBookPrice))
			{
				result.FailureReason = "No NADA or MMR prices returned";
				return result;
			}

			// 4. Run the formula
			var nadaValue = GetNadaAvgValue(nadaValues);

			var divisor = mmrValue == 0 || nadaValue == 0
				? 1
				: 2;

			var baseResult = (mmrValue + nadaValue) / divisor;
			baseResult = (baseResult * floorPricing.PercentageOf) / 100;
			baseResult = Math.Round(baseResult / 5.0m) * 5;

			result.FloorPrice = baseResult;
			result.Success = true;
			result.ResultWeight = GetStrategyWeight();
			return result;
		}

		public decimal GetNadaAvgValue(List<Decimal> nadaValues)
		{
			Decimal aggregateValue = 0;
			int valueCount = 0;
			Decimal aggregateAvgValue = 0;
			if (nadaValues.Count() > 0)
			{
				foreach (var nadaVal in nadaValues)
				{
					if (nadaVal > 0)
					{
						aggregateValue += nadaVal;
						valueCount++;
					}
				}
				aggregateAvgValue = aggregateValue / valueCount;
			}

			return aggregateAvgValue;
		}

		private decimal GetNadaValueByParam(string floorPricingNadaFirstValue,
			CollateralValuation fpcParamsCollateralValuation)
		{
			if (floorPricingNadaFirstValue.ToLower().StartsWith("low"))
			{
				return fpcParamsCollateralValuation.LowAdjustedAuctionValue;
			}

			if (floorPricingNadaFirstValue.ToLower().StartsWith("avg"))
			{
				return fpcParamsCollateralValuation.AverageAdjustedAuctionValue;
			}

			return fpcParamsCollateralValuation.HighAdjustedAuctionValue;
		}

		private decimal GetMMRValueByParam(string floorPricingMmrValue, ImsAutoFileData fpcParamsImsAutoFileData,
			decimal defaultValue)
		{
			if (floorPricingMmrValue.ToLower().StartsWith("regional"))
			{
				return fpcParamsImsAutoFileData.MMRRegionalAdjustedPrice ?? defaultValue;
			}

			return fpcParamsImsAutoFileData.MMRNationalAdjustedPrice ?? defaultValue;
		}

		public int GetStrategyWeight()
		{
			return 99; // This is the preferred strategy.
		}
	}
}