lasprs 0.6.4

use crate::daq::InStreamMsg;
use crate::math::maxabs;
use crate::slm::{self, SLMSettingsBuilder, TimeWeighting, SLM};
use crate::{config::*, FreqWeighting, StandardFilterDescriptor};
use crate::{daq::StreamMgr, Dcol};
use crossbeam::channel::{unbounded, Receiver, Sender};
use crossbeam::utils::Backoff;
use parking_lot::Mutex;
use std::default;
use std::ops::DerefMut;
use std::sync::Arc;
use std::time::{Duration, Instant};

/// When the level reaches ALMOST_CLIPPED_REL_AMP in amplitude, w.r.t. to the
/// full scale, we mark a channel as almost clipped.
const ALMOST_CLIPPED_REL_AMP: Flt = 0.98;

/// If clipping occured, this is the time it keeps saying 'signal is clipped'
const CLIP_INDICATOR_WAIT_S: Duration = Duration::from_secs(2);

/// If the signal level falls below this value, we indicate that the signal level is low.
const LEVEL_THRESHOLD_FOR_LOW_LEVEL: Flt = -50.;

/// If the signal level falls below this value, we indicate that the signal level is low.
const LEVEL_THRESHOLD_FOR_HIGH_LEVEL: Flt = -10.;

type SharedPPMStatus = Arc<Mutex<Vec<PPMChannelStatus>>>;

/// Peak programme meter implementation, including clip detector. Effectively uses a realtime SLM on all
/// input channels. Also includes a clipping detector.
#[derive(Debug)]
#[cfg_attr(feature = "python-bindings", pyclass)]
pub struct PPM {
    // Latest and createst status
    status: SharedPPMStatus,
    sender: Sender<PPMMessage>,
}

impl PPM {
    /// Initialize a new PPM meter.
    ///
    /// Args
    ///
    /// - `mgr`: Stream manager instance.
    pub fn new(mgr: &mut StreamMgr) -> Self {
        let (sender, rxmsg) = unbounded();

        // Shared status object
        let status: SharedPPMStatus = Arc::new(Mutex::new(vec![]));

        // Start the thread that calculates PPM and clip values
        Self::startThread(status.clone(), mgr, rxmsg);

        PPM { status, sender }
    }
    fn startThread(status: SharedPPMStatus, mgr: &mut StreamMgr, rxmsg: Receiver<PPMMessage>) {
        // Obtain messages from stream manager
        let (tx, rxstream) = unbounded();

        // Add queue sender part of queue to stream manager
        mgr.addInQueue(tx);

        rayon::spawn(move || {
            let mut slms: Vec<SLM> = vec![];

            let resetall = |slms: &mut Vec<SLM>| {
                let mut status = status.lock();
                *status = Default::default();
                slms.clear();
            };
            loop {
                if let Some(msg) = rxstream
                    .recv_timeout(std::time::Duration::from_millis(10))
                    .ok()
                {
                    match msg {
                        InStreamMsg::InStreamData(d) => {
                            let mut status = status.lock();
                            let floatdata = d.getFloatData();

                            'channel: for (chno, (slm, ppmstatus)) in
                                slms.iter_mut().zip(status.iter_mut()).enumerate()
                            {
                                let chdata = floatdata.slice(s![.., chno]);
                                let maxabs_new = maxabs(chdata);
                                let chdata = chdata
                                    .as_slice()
                                    .expect("Data not contiguous on sample axis");
                                slm.run(chdata, false);

                                // Update levels
                                let last_level = slm.Ltlast()[0];
                                ppmstatus.level = last_level;

                                // If previous clip is there, and some time has elapsed, we remove the clip state
                                if let Some(moment) = ppmstatus.clip_time {
                                    if moment.elapsed() > CLIP_INDICATOR_WAIT_S {
                                        ppmstatus.clip = ClipState::LevelFine;
                                        ppmstatus.clip_time = None;
                                    }
                                    // Do not update anything else if we are
                                    // still in clipping mode. We are done
                                    // updating PPM status for this channel.
                                    continue 'channel;
                                }

                                // Update clip status, if we were not clipping
                                ppmstatus.clip = if maxabs_new > ALMOST_CLIPPED_REL_AMP {
                                    ppmstatus.clip_time = Some(Instant::now());
                                    ClipState::Clipped
                                } else if last_level > LEVEL_THRESHOLD_FOR_HIGH_LEVEL {
                                    ClipState::HighLevel
                                } else if last_level < LEVEL_THRESHOLD_FOR_LOW_LEVEL {
                                    ClipState::LowLevel
                                } else {
                                    ClipState::LevelFine
                                }
                            }
                        }
                        InStreamMsg::StreamError(_e) => {
                            resetall(&mut slms);
                        }
                        InStreamMsg::StreamStarted(meta) => {
                            // Re-initalize sound level meters
                            slms.clear();
                            let mut s = status.lock();
                            (0..meta.nchannels()).for_each(|_ch_index| {
                                // Create SLM settings. These might be different
                                // depending on channel in future
                                let slmsettings = SLMSettingsBuilder::default()
                                    .fs(meta.samplerate)
                                    .freqWeighting(FreqWeighting::Z)
                                    .Lref(1.0)
                                    .timeWeighting(TimeWeighting::Impulse {})
                                    // .timeWeighting(TimeWeighting::CustomAsymmetric { tup: 0.01, tdown: 1.0 })
                                    // .timeWeighting(TimeWeighting::Fast {})
                                    .filterDescriptors([
                                        StandardFilterDescriptor::Overall().unwrap()
                                    ])
                                    .build()
                                    .unwrap();

                                slms.push(SLM::new(slmsettings.clone()));
                                // Initialize levels at -300 dB, and clip state
                                // at low levels
                                s.push(PPMChannelStatus {
                                    clip: ClipState::LowLevel,
                                    level: -300.,
                                    clip_time: None,
                                });
                            });
                        }
                        InStreamMsg::StreamStopped => {}
                    }
                    // Loop over any messages coming in from main thread
                    for msg in rxmsg.try_iter() {
                        match msg {
                            PPMMessage::ResetClip => {
                                // Reset clip state to not clipped.
                                let mut s = status.lock();
                                s.iter_mut().for_each(|c| c.clip = ClipState::LevelFine);
                            }
                            PPMMessage::StopThread => {
                                resetall(&mut slms);
                                return;
                            }
                        }
                    }
                }
            }
        });
    }

    /// Reset clip state. Used to quickly restore the clipping state.
    pub fn resetClip(&self) {
        self.sender.send(PPMMessage::ResetClip).unwrap();
    }
    /// Returns the current state: levels and clip state
    pub fn getState(&self) -> (Dcol, Vec<ClipState>) {
        let status = self.status.lock();
        let levels = Dcol::from_iter(status.iter().map(|s| s.level));
        let clips = status.iter().map(|s| s.clip).collect();
        (levels, clips)
    }
}
impl Drop for PPM {
    fn drop(&mut self) {
        // Stop the thread
        self.sender.send(PPMMessage::StopThread).unwrap();
    }
}

/// Enumerator denoting, for each channel what the level approximately is. Low,
/// fine, high or clipped.
#[cfg_attr(feature = "python-bindings", pyclass(eq, eq_int))]
#[derive(Copy, Debug, PartialEq, Clone, Default)]
pub enum ClipState {
    /// Level is rather low
    #[default]
    LowLevel,
    /// Default state, fine levels
    LevelFine,
    /// High levels: warning!
    HighLevel,
    /// Signal probably clipped. The instant denotes when in history the clip
    /// happened.
    Clipped,
}

#[derive(Debug, Default)]
struct PPMChannelStatus {
    // Current levels
    level: Flt,
    // If clipped in the past, it gives a timestamp on the time the clip
    // happened. A call to [PPM::resetClip] will reset the clip state.
    clip: ClipState,

    /// Store when clip was
    clip_time: Option<Instant>,
}

enum PPMMessage {
    ResetClip,
    StopThread,
}

#[cfg(feature = "python-bindings")]
#[cfg_attr(feature = "python-bindings", pymethods)]
impl PPM {
    #[new]
    fn new_py(smgr: &mut StreamMgr) -> Self {
        Self::new(smgr)
    }

    #[pyo3(name = "getState")]
    fn getState_py<'py>(&self, py: Python<'py>) -> (Bound<'py, PyArray1<Flt>>, Vec<ClipState>) {
        let (levels, clips) = self.getState();
        let levels = levels.to_pyarray_bound(py);
        (levels, clips)
    }

    #[pyo3(name = "resetClip")]
    fn resetClip_py(&self) {
        self.resetClip()
    }
}