use crate::*;

pub trait TransportModelApi: JackModelApi + ClockModelApi {
    fn transport (&self) -> &jack::Transport;
    fn metronome (&self) -> bool;
}

impl JackModelApi for TransportModel {
    fn jack (&self) -> &Arc<RwLock<JackClient>> {
        &self.jack
    }
}

impl ClockModelApi for TransportModel {
    fn clock (&self) -> &Arc<Clock> {
        &self.clock
    }
}

impl TransportModelApi for TransportModel {
    fn transport (&self) -> &jack::Transport {
        &self.transport
    }
    fn metronome (&self) -> bool {
        self.metronome
    }
}

pub struct TransportModel {
    jack:      Arc<RwLock<JackClient>>,
    /// Current sample rate, tempo, and PPQ.
    clock:     Arc<Clock>,
    /// JACK transport handle.
    transport: jack::Transport,
    /// Enable metronome?
    metronome: bool,
}

impl Debug for TransportModel {
    fn fmt (&self, f: &mut Formatter<'_>) -> std::result::Result<(), Error> {
        f.debug_struct("transport")
            .field("jack",      &self.jack)
            .field("transport", &"(JACK transport)")
            .field("clock",     &self.clock)
            .field("metronome", &self.metronome)
            .finish()
    }
}

impl TransportModel {
    pub fn toggle_play (&mut self) -> Usually<()> {
        let playing = self.clock.playing.read().unwrap().expect("1st sample has not been processed yet");
        let playing = match playing {
            TransportState::Stopped => {
                self.transport.start()?;
                Some(TransportState::Starting)
            },
            _ => {
                self.transport.stop()?;
                self.transport.locate(0)?;
                Some(TransportState::Stopped)
            },
        };
        *self.clock.playing.write().unwrap() = playing;
        Ok(())
    }
}

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

impl<T: TransportModelApi> Command<T> for TransportCommand {
    fn execute (self, state: &mut T) -> Perhaps<Self> {
        use TransportCommand::*;
        match self {
            Play(start)        => {todo!()},
            Pause(start)       => {todo!()},
            SeekUsec(usec)     => {state.clock().current.update_from_usec(usec);},
            SeekSample(sample) => {state.clock().current.update_from_sample(sample);},
            SeekPulse(pulse)   => {state.clock().current.update_from_pulse(pulse);},
            SetBpm(bpm)        => {return Ok(Some(Self::SetBpm(state.clock().timebase().bpm.set(bpm))))},
            SetQuant(quant)    => {return Ok(Some(Self::SetQuant(state.clock().quant.set(quant))))},
            SetSync(sync)      => {return Ok(Some(Self::SetSync(state.clock().sync.set(sync))))},
            _ => { unreachable!() }
        }
        Ok(None)
    }
}