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)
        {
            var isNotEnd = true;
            while (isOnInterval(date) && isNotEnd)
            {
                lastValue.x = date;
                lastValue.y = CalcValue(enumerator.Current, (date- enumerator.Current.dateMin).TotalSeconds);
                isNotEnd = enumerator.MoveNext();
            }
            return lastValue.y;

        }
        
        private bool isOnInterval(DateTimeOffset date)
        => date >= enumerator.Current.dateMin && date <= enumerator.Current.dateMax;
        private float CalcValue((DateTimeOffset dateMin, float depthMin, DateTimeOffset dateMax, float depthMax) item, double timestamp)
        {
            if (item.depthMin == item.depthMax)
            {
                return item.depthMin;
            }            
            var w = timestamp / (item.dateMax - item.dateMin).TotalSeconds;
            var d = ((item.depthMax - item.depthMin) * w)+ item.depthMin;
            return (float)d;
        }
    }
#nullable disable
}