using Pcie8586Probe.Models;

namespace Pcie8586Probe.Acquisition;

public sealed class Recorder
{
    private readonly object _gate = new();
    private readonly List<SampleBlock> _blocks = new();
    private long _targetSamplesPerChannel;
    private bool _armed;
    private bool _completed;
    private double _sampleRateHz;

    public bool IsRecording
    {
        get
        {
            lock (_gate)
            {
                return _armed && !_completed;
            }
        }
    }

    public double Progress
    {
        get
        {
            lock (_gate)
            {
                if (_targetSamplesPerChannel <= 0)
                {
                    return 0;
                }

                var count = _blocks.Sum(static block => (long)block.SamplesPerChannel);
                return Math.Clamp((double)count / _targetSamplesPerChannel, 0, 1);
            }
        }
    }

    public void Start(TimeSpan duration, double sampleRateHz)
    {
        if (duration <= TimeSpan.Zero) throw new ArgumentOutOfRangeException(nameof(duration));
        if (sampleRateHz <= 0) throw new ArgumentOutOfRangeException(nameof(sampleRateHz));

        lock (_gate)
        {
            _blocks.Clear();
            _sampleRateHz = sampleRateHz;
            _targetSamplesPerChannel = Math.Max(1, (long)Math.Round(sampleRateHz * duration.TotalSeconds));
            _armed = true;
            _completed = false;
        }
    }

    public SampleBlock? Add(SampleBlock block)
    {
        lock (_gate)
        {
            if (!_armed || _completed)
            {
                return null;
            }

            _blocks.Add(block);
            var count = _blocks.Sum(static item => (long)item.SamplesPerChannel);
            if (count < _targetSamplesPerChannel)
            {
                return null;
            }

            _completed = true;
            _armed = false;
            var merged = SampleBlockAssembler.Concat(_blocks);
            return SampleBlockAssembler.Slice(merged, 0, (int)_targetSamplesPerChannel) with { SampleRateHz = _sampleRateHz };
        }
    }
}