using InnovEnergy.S3.Drivers.Internal.Delegates;
using InnovEnergy.S3.Metadata;
using InnovEnergy.S3.Records.Specialized;
using InnovEnergy.Time.Unix;
using InnovEnergy.Lib.Utils;

namespace InnovEnergy.S3.Drivers.Internal;

public partial class Reader
{
    public IReadOnlyList<AggregationLevel> AggregationLevels { get; }
    public UnixTimeSpan SamplePeriod => AggregationLevels[0].SamplePeriod;

    private readonly ReadRecord _ReadRecord;

    internal Reader(IReadOnlyList<AggregationLevel> levels, ReadRecord readRecord)
    {
        _ReadRecord       = readRecord;
        AggregationLevels = InitLevels(levels);
    }

    public Task<TimeStampedRecord> ReadRecord(AggregationLevel level, UInt32 index)
    {
        return _ReadRecord(level, index);
    }

    private static IReadOnlyList<AggregationLevel> InitLevels(IReadOnlyList<AggregationLevel> levels)
    {
        if (!levels.Any())
            throw new ArgumentOutOfRangeException(nameof(levels));

        levels = levels
            .OrderBy(l => l.SamplePeriod.Ticks)
            .ToReadOnlyList(levels.Count);

        var pairwise = levels
            .Select(l => l.SamplePeriod)
            .Pairwise()
            .ToReadOnlyList(levels.Count - 1);

        var greater   = pairwise.Any(ls => ls.right <= ls.left);
        var multiple  = pairwise.Any(ls => ls.right % ls.left != 0 );
        var retention = levels  .Any(l => l.RetentionPeriod % l.SamplePeriod  != 0);

        if (greater || multiple || retention)
            throw new ArgumentException(nameof(levels));  // TODO: error messages

        return levels;
    }
}