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

namespace AsbCloudInfrastructure.Services.Subsystems.Utils
{
#nullable enable
    internal class DepthInterpolation
    {
        private IEnumerator<(DateTimeOffset dateMin, float depthMin, DateTimeOffset dateMax, float depthMax)> enumerator;
        (DateTimeOffset x, float? y) lastValue = default;

        private DateTimeOffset dateMin;
        public DepthInterpolation(IOrderedEnumerable<(DateTimeOffset dateMin, float depthMin, DateTimeOffset dateMax, float depthMax)> collection)
        {
            enumerator = collection.GetEnumerator();
            enumerator.MoveNext();
            dateMin = enumerator.Current.dateMin;
        }

        public float GetDepth(DateTimeOffset date)
        {            
            {
                while (isLess(date))
                {                    
                   lastValue.x = date;
                   lastValue.y = CalcValue(enumerator.Current, (date - dateMin).TotalSeconds);
                   enumerator.MoveNext();
                }
            }
            return (float)lastValue.y;
        }
        
        private bool isLess(DateTimeOffset date)
        {
           if (date >= enumerator.Current.dateMin)
                return true;
           return false;
        }
        private float CalcValue((DateTimeOffset dateMin, float depthMin, DateTimeOffset dateMax, float depthMax) item, double timestamp)
        {
            var a = (item.depthMax - item.depthMin) / (item.dateMax - item.dateMin).TotalSeconds;
            var b = item.depthMin * (item.dateMax.Second - (item.depthMax - item.depthMin) / (item.dateMax.Second - item.dateMin.Second));
            var resultDepth = a * timestamp + b;
            return (float)resultDepth;
        }

    }
#nullable disable
}