using System;
using System.Collections.Generic;
using System.Linq;

namespace LCU.Library.Internal.LoanRateModels.Responses.Validation.RateSheetValidations;
public static class RateSheetValidation
{
    public static RateSheetValidationItem IsWithinTrendRange(decimal oldValue, decimal newValue, List<decimal> history)
    {
        var validation = new RateSheetValidationItem
        {
            Label = "Within Trend Range",
            Description = "If there is a history of change, is the current trend within the trend history's max and min values.",
            RateSheetValidationType = RateSheetValidationTypes.IsWithinTrendRange
        };
        
        if (newValue == 0 || oldValue == 0)
        {
            validation.Pass = false;
            validation.Message = $"Values cannot be zero. OldValue: {oldValue} | NewValue: {newValue}";
            return validation;
        }

        var currentTrend = oldValue / newValue;
        var trends = history.Zip(history.Skip(1), (x, y) => y / x).ToList();

        var currentTrendString = Math.Round(currentTrend * 100, 2).ToString("0.##");
        var minTrendString = Math.Round(trends.Min() * 100, 2).ToString("0.##");
        var maxTrendString = Math.Round(trends.Max() * 100, 2).ToString("0.##");

        validation.Value = currentTrendString;
        validation.Formula = trends.Count == 0
                                ? "No history found"
                                : $"{currentTrendString} >= {minTrendString} && {currentTrendString} <= {maxTrendString}";
        validation.Criteria = trends.Count == 0
                                ? "No history found"
                                : $"{minTrendString}% - {maxTrendString}%";
        validation.Pass = trends.Count == 0 || currentTrend >= trends.Min() && currentTrend <= trends.Max();
        return validation;
    }

    public static RateSheetValidationItem IsWithinRange(decimal value, decimal min, decimal max)
        => new()
        {
            Label = "Within Range",
            Description = "Value is within the min and max values.",
            Value = value.ToString("0.##"),
            Formula = $"{value:0.##} >= {min:0.##} && {value:0.##} <= {max:0.##}",
            Criteria = $"{min:0.##} - {max:0.##}",
            Pass = value >= min && value <= max,
            RateSheetValidationType = RateSheetValidationTypes.IsWithinRange
        };
}