use crate::{BLOCK_SIZE, traits::BufferMut};

pub fn analyse_buffer_by_stepped_windows<B: BufferMut<(usize, u16)>>(
    threshold: u16,
    buf: &[u16],
    average: u16,
    peaks: &mut B,
) -> u16 {
    const CHUNK_SIZE: usize = BLOCK_SIZE / 32;
    const CHUNK_STEP: usize = CHUNK_SIZE / 2;

    let mut total = 0u32;
    let mut len = 0u32;

    for (i, window) in buf
        .array_windows::<CHUNK_SIZE>()
        .enumerate()
        .step_by(CHUNK_STEP)
    {
        let (window_total, window_diff) =
            window
                .iter()
                .copied()
                .fold((0, 0), |(total, diff), sample| {
                    (
                        total + sample,
                        diff + ((average as i16) - sample as i16).unsigned_abs(),
                    )
                });

        let diff = window_diff / CHUNK_SIZE as u16;

        if diff > threshold {
            peaks.push((i, diff));
        } else {
            total += window_total as u32;
            len += CHUNK_SIZE as u32;
        }
    }

    (total / len) as u16
}