using MarketData.MarketDataModel;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MarketData.Generator.Indicators
{
  public class NarrowRangeIndicator
  {
    private NarrowRangeIndicator()
    {
    }
// It is assumed that prices are in descending date order.  (i.e.) The most recent price is in the lowest index position
    public static bool IsNarrowRangeEntry(DateTime date,Prices prices,int dayCount)
    {
      if(!IsInsideDay(date,prices))return false;
      if(!IsNarrowestRange(date,prices,dayCount))return false;
      return true;
    }
    private static bool IsInsideDay(DateTime date,Prices prices)
    {
      int index=prices.FindIndex(x=>x.Date.Date.Equals(date));
      if(-1==index||index+1>=prices.Count)return false;
      if(!(prices[index].High<=prices[index+1].High&&prices[index].Low>=prices[index+1].Low))return false;
      return true;
    }
    private static bool IsNarrowestRange(DateTime date,Prices prices,int dayCount)
    {
      int index=prices.FindIndex(x => x.Date.Date.Equals(date));
      double range=GetRange(prices,index);
      if(index+dayCount>=prices.Count-1)return false;
      for(int dayIndex=index+1;dayIndex<index+dayCount;dayIndex++)
      {
        double nextRange=GetRange(prices,dayIndex);
        if(nextRange<range)return false;
      }
      return true;
    }
    private static double GetRange(Prices prices,int index)
    {
      double range=prices[index].High-prices[index].Low;
      return Math.Abs(range);
    }
  }
}