using InnovEnergy.S3.Metadata;
using InnovEnergy.S3.Records;
using InnovEnergy.S3.Records.Specialized;
using InnovEnergy.Time.Unix;

namespace InnovEnergy.S3.Drivers.Internal.Util;

internal class Sampler
{
    public  Record           CurrentRecord    { get; set; }
    public  UnixTime         CurrentTimeStamp { get; set; }
    public  AggregationLevel AggregationLevel { get; }

    private UnixTimeSpan     SamplePeriod => AggregationLevel.SamplePeriod;

    public Sampler(AggregationLevel aggregationLevel, Record record, UnixTime currentTime)
    {
        AggregationLevel = aggregationLevel;
        CurrentRecord    = record;
        CurrentTimeStamp = aggregationLevel.GetPeriodStartTime(currentTime);
    }


    // TODO: repeat/max age
    public IEnumerable<AggregatedRecord> Sample(Record record, UnixTime timeStamp)
    {
        timeStamp = AggregationLevel.GetPeriodStartTime(timeStamp);

        if (timeStamp < CurrentTimeStamp)
            yield break; //throw new IndexOutOfRangeException(nameof(index));  // TODO: log

        if (timeStamp > CurrentTimeStamp)
            yield return new AggregatedRecord(CurrentRecord, AggregationLevel, CurrentTimeStamp);

        for (var t = CurrentTimeStamp + SamplePeriod; t < timeStamp; t += SamplePeriod)
            yield return new AggregatedRecord(Record.Empty, AggregationLevel, t);

        CurrentTimeStamp = timeStamp;
        CurrentRecord    = record;
    }


}