use crate::*;

pub mod microsecond;  pub(crate) use self::microsecond::*;
pub mod moment;       pub(crate) use self::moment::*;
pub mod perf;         pub(crate) use self::perf::*;
pub mod pulse;        pub(crate) use self::pulse::*;
pub mod sample_count; pub(crate) use self::sample_count::*;
pub mod sample_rate;  pub(crate) use self::sample_rate::*;
pub mod timebase;     pub(crate) use self::timebase::*;
pub mod unit;         pub(crate) use self::unit::*;

pub trait HasClock: Send + Sync {
    fn clock (&self) -> &ClockModel;
}

#[macro_export] macro_rules! has_clock {
    (|$self:ident:$Struct:ident$(<$($L:lifetime),*$($T:ident$(:$U:path)?),*>)?|$cb:expr) => {
        impl $(<$($L),*$($T $(: $U)?),*>)? HasClock for $Struct $(<$($L),*$($T),*>)? {
            fn clock (&$self) -> &ClockModel { $cb }
        }
    }
}

/// Hosts the JACK callback for updating the temporal pointer and playback status.
pub struct ClockAudio<'a, T: HasClock>(pub &'a mut T);

impl<T: HasClock> Audio for ClockAudio<'_, T> {
    #[inline] fn process (&mut self, _: &Client, scope: &ProcessScope) -> Control {
        self.0.clock().update_from_scope(scope).unwrap();
        Control::Continue
    }
}

#[derive(Clone, Debug, PartialEq)]
pub enum ClockCommand {
    Play(Option<u32>),
    Pause(Option<u32>),
    SeekUsec(f64),
    SeekSample(f64),
    SeekPulse(f64),
    SetBpm(f64),
    SetQuant(f64),
    SetSync(f64),
}

impl<T: HasClock> Command<T> for ClockCommand {
    fn execute (self, state: &mut T) -> Perhaps<Self> {
        use ClockCommand::*;
        match self {
            Play(start)        => state.clock().play_from(start)?,
            Pause(pause)       => state.clock().pause_at(pause)?,
            SeekUsec(usec)     => state.clock().playhead.update_from_usec(usec),
            SeekSample(sample) => state.clock().playhead.update_from_sample(sample),
            SeekPulse(pulse)   => state.clock().playhead.update_from_pulse(pulse),
            SetBpm(bpm)        => return Ok(Some(SetBpm(state.clock().timebase().bpm.set(bpm)))),
            SetQuant(quant)    => return Ok(Some(SetQuant(state.clock().quant.set(quant)))),
            SetSync(sync)      => return Ok(Some(SetSync(state.clock().sync.set(sync)))),
        };
        Ok(None)
    }
}

#[derive(Clone)]
pub struct ClockModel {
    /// JACK transport handle.
    pub transport: Arc<Transport>,
    /// Global temporal resolution (shared by [Moment] fields)
    pub timebase:  Arc<Timebase>,
    /// Current global sample and usec (monotonic from JACK clock)
    pub global:    Arc<Moment>,
    /// Global sample and usec at which playback started
    pub started:   Arc<RwLock<Option<Moment>>>,
    /// Playback offset (when playing not from start)
    pub offset:    Arc<Moment>,
    /// Current playhead position
    pub playhead:  Arc<Moment>,
    /// Note quantization factor
    pub quant:     Arc<Quantize>,
    /// Launch quantization factor
    pub sync:      Arc<LaunchSync>,
    /// Size of buffer in samples
    pub chunk:     Arc<AtomicUsize>,
}

from!(|jack: &Arc<RwLock<JackClient>>| ClockModel = {
    let jack      = jack.read().unwrap();
    let chunk     = jack.client().buffer_size();
    let transport = jack.client().transport();
    let timebase  = Arc::new(Timebase::default());
    Self {
        quant:     Arc::new(24.into()),
        sync:      Arc::new(384.into()),
        transport: Arc::new(transport),
        chunk:     Arc::new((chunk as usize).into()),
        global:    Arc::new(Moment::zero(&timebase)),
        playhead:  Arc::new(Moment::zero(&timebase)),
        offset:    Arc::new(Moment::zero(&timebase)),
        started:   RwLock::new(None).into(),
        timebase,
    }
});

impl std::fmt::Debug for ClockModel {
    fn fmt (&self, f: &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
        f.debug_struct("ClockModel")
            .field("timebase", &self.timebase)
            .field("chunk",    &self.chunk)
            .field("quant",    &self.quant)
            .field("sync",     &self.sync)
            .field("global",   &self.global)
            .field("playhead", &self.playhead)
            .field("started",  &self.started)
            .finish()
    }
}

impl ClockModel {
    pub fn timebase (&self) -> &Arc<Timebase> {
        &self.timebase
    }
    /// Current sample rate
    pub fn sr (&self) -> &SampleRate {
        &self.timebase.sr
    }
    /// Current tempo
    pub fn bpm (&self) -> &BeatsPerMinute {
        &self.timebase.bpm
    }
    /// Current MIDI resolution
    pub fn ppq (&self) -> &PulsesPerQuaver {
        &self.timebase.ppq
    }
    /// Next pulse that matches launch sync (for phrase switchover)
    pub fn next_launch_pulse (&self) -> usize {
        let sync  = self.sync.get() as usize;
        let pulse = self.playhead.pulse.get() as usize;
        if pulse % sync == 0 {
            pulse
        } else {
            (pulse / sync + 1) * sync
        }
    }
    /// Start playing, optionally seeking to a given location beforehand
    pub fn play_from (&self, start: Option<u32>) -> Usually<()> {
        if let Some(start) = start {
            self.transport.locate(start)?;
        }
        self.transport.start()?;
        Ok(())
    }
    /// Pause, optionally seeking to a given location afterwards
    pub fn pause_at (&self, pause: Option<u32>) -> Usually<()> {
        self.transport.stop()?;
        if let Some(pause) = pause {
            self.transport.locate(pause)?;
        }
        Ok(())
    }
    /// Is currently paused?
    pub fn is_stopped (&self) -> bool {
        self.started.read().unwrap().is_none()
    }
    /// Is currently playing?
    pub fn is_rolling (&self) -> bool {
        self.started.read().unwrap().is_some()
    }
    /// Update chunk size
    pub fn set_chunk (&self, n_frames: usize) {
        self.chunk.store(n_frames, Relaxed);
    }
    pub fn update_from_scope (&self, scope: &ProcessScope) -> Usually<()> {
        // Store buffer length
        self.set_chunk(scope.n_frames() as usize);

        // Store reported global frame and usec
        let CycleTimes { current_frames, current_usecs, .. } = scope.cycle_times()?;
        self.global.sample.set(current_frames as f64);
        self.global.usec.set(current_usecs as f64);

        // If transport has just started or just stopped,
        // update starting point:
        let mut started = self.started.write().unwrap();
        match (self.transport.query_state()?, started.as_ref()) {
            (TransportState::Rolling, None) => {
                let moment = Moment::zero(&self.timebase);
                moment.sample.set(current_frames as f64);
                moment.usec.set(current_usecs as f64);
                *started = Some(moment);
            },
            (TransportState::Stopped, Some(_)) => {
                *started = None;
            },
            _ => {}
        };

        self.playhead.update_from_sample(started.as_ref()
            .map(|started|current_frames as f64 - started.sample.get())
            .unwrap_or(0.));

        Ok(())
    }
}

//#[cfg(test)]
//mod test {
    //use super::*;
    //#[test]
    //fn test_samples_to_ticks () {
        //let ticks = Ticks(12.3).between_samples(0, 100).collect::<Vec<_>>();
        //println!("{ticks:?}");
    //}
//}