use crate::*;

pub trait HasPlayPhrase: HasClock {
    fn reset (&self) -> bool;
    fn reset_mut (&mut self) -> &mut bool;
    fn play_phrase (&self) -> &Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>;
    fn play_phrase_mut (&mut self) -> &mut Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>;
    fn next_phrase (&self) -> &Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>;
    fn next_phrase_mut (&mut self) -> &mut Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>;
    fn pulses_since_start (&self) -> Option<f64> {
        if let Some((started, Some(_))) = self.play_phrase().as_ref() {
            let elapsed = self.clock().playhead.pulse.get() - started.pulse.get();
            Some(elapsed)
        } else {
            None
        }
    }
    fn pulses_since_start_looped (&self) -> Option<f64> {
        if let Some((started, Some(phrase))) = self.play_phrase().as_ref() {
            let elapsed = self.clock().playhead.pulse.get() - started.pulse.get();
            let length  = phrase.read().unwrap().length.max(1); // prevent div0 on empty phrase
            let elapsed = (elapsed as usize % length) as f64;
            Some(elapsed)
        } else {
            None
        }
    }
    fn enqueue_next (&mut self, phrase: Option<&Arc<RwLock<MidiClip>>>) {
        let start   = self.clock().next_launch_pulse() as f64;
        let instant = Moment::from_pulse(self.clock().timebase(), start);
        *self.next_phrase_mut() = Some((instant, phrase.cloned()));
        *self.reset_mut() = true;
    }
}