using JetBrains.Annotations;
using SJZY.Track.Domain.Aggregates.ForewarningAggregate;

namespace SJZY.Track.Application.Helpers;

public class ForewarningFactorHelper
{
    public static RuleCollectEntity[] GetFactorItem([NotNull]RuleFactorEntity ruleFactors)
    {
        var total = Factorial(ruleFactors);
        var ruleCollect = AllocateFactor(total,ruleFactors.RuleId);
        Assignment(ruleCollect,total,ruleFactors.CargoTypes,(item,value)=>item.CargoType=value);
        Assignment(ruleCollect,total,ruleFactors.Months,(item,value)=>item.Month=value);
        Assignment(ruleCollect,total,ruleFactors.Areas,(item,value)=>item.Area=value);
        Assignment(ruleCollect,total,ruleFactors.IsTransit,(item,value)=>item.IsTransit=value);
        Assignment(ruleCollect,total,ruleFactors.DeparturePorts,(item,value)=>item.DeparturePort=value);
        Assignment(ruleCollect,total,ruleFactors.ProductCodes,(item,value)=>item.ProductCode=value);
        return ruleCollect.ToArray();
    }
    
    private static void Assignment<T>(Span<RuleCollectEntity> ruleCollect,int total,IReadOnlyList<T> values,Action<RuleCollectEntity,T> action)
    {
        if (values.Count == 0)
        {
            return;
        }
        
        var segment = total / values.Count;
        for(int index=0;index<values.Count;index++)
        {
            var start = index * segment;
            var assignmentSlice = ruleCollect.Slice(start, segment);
            foreach (var item in assignmentSlice)
            {
                action(item,values[index]);
            }
        }
    }
    
    private static Span<RuleCollectEntity> AllocateFactor(int total,int ruleId)
    {
        
        Span<RuleCollectEntity> factors = new RuleCollectEntity[total];
        for (int index = 0; index < total; index++)
        {
            factors[index] = new RuleCollectEntity()
            {
                RuleId = ruleId
            };
        }
        return factors;
    }
    
    internal static int Factorial(RuleFactorEntity ruleFactors)
    {
        return ruleFactors.CargoTypes.Count*ruleFactors.Months.Count*ruleFactors.Areas.Count*ruleFactors.IsTransit.Count*ruleFactors.DeparturePorts.Count*ruleFactors.ProductCodes.Count;
    }
}