using Pcie8586Probe.Models;

namespace Pcie8586Probe.Acquisition;

public static class SampleBlockAssembler
{
    public static SampleBlock Concat(IEnumerable<SampleBlock> blocks)
    {
        var list = blocks.ToList();
        if (list.Count == 0)
        {
            throw new ArgumentException("At least one block is required.", nameof(blocks));
        }

        var first = list[0];
        var channelCount = first.ChannelCount;
        var totalSamples = list.Sum(static block => block.SamplesPerChannel);
        var channels = new double[channelCount][];

        for (var channel = 0; channel < channelCount; channel++)
        {
            channels[channel] = new double[totalSamples];
            var offset = 0;
            foreach (var block in list)
            {
                if (block.ChannelCount != channelCount)
                {
                    throw new InvalidOperationException("All sample blocks must have the same channel count.");
                }

                Array.Copy(block.Channels[channel], 0, channels[channel], offset, block.SamplesPerChannel);
                offset += block.SamplesPerChannel;
            }
        }

        return new SampleBlock(channels, first.SampleRateHz, first.StartSampleIndex, first.Timestamp);
    }

    public static SampleBlock Slice(SampleBlock block, int start, int count)
    {
        if (start < 0 || count < 0 || start + count > block.SamplesPerChannel)
        {
            throw new ArgumentOutOfRangeException(nameof(start));
        }

        var channels = new double[block.ChannelCount][];
        for (var channel = 0; channel < block.ChannelCount; channel++)
        {
            channels[channel] = new double[count];
            Array.Copy(block.Channels[channel], start, channels[channel], 0, count);
        }

        return new SampleBlock(channels, block.SampleRateHz, block.StartSampleIndex + start, block.Timestamp);
    }
}