use crate::*;
use std::fmt::Write;

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

impl<T: Has<Clock>> HasClock for T {
    fn clock (&self) -> &Clock { self.get() }
    fn clock_mut (&mut self) -> &mut Clock { self.get_mut() }
}

#[derive(Clone, Default)]
pub struct Clock {
    /// JACK transport handle.
    pub transport: Arc<Option<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>,
    // Cache of formatted strings
    pub view_cache: Arc<RwLock<ViewCache>>,
    /// For syncing the clock to an external source
    #[cfg(feature = "port")] pub midi_in:   Arc<RwLock<Option<MidiInput>>>,
    /// For syncing other devices to this clock
    #[cfg(feature = "port")] pub midi_out:  Arc<RwLock<Option<MidiOutput>>>,
    /// For emitting a metronome
    #[cfg(feature = "port")] pub click_out: Arc<RwLock<Option<AudioOutput>>>,
}

impl std::fmt::Debug for Clock {
    fn fmt (&self, f: &mut Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
        f.debug_struct("Clock")
            .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 Clock {
    pub fn new (jack: &Jack<'static>, bpm: Option<f64>) -> Usually<Self> {
        let (chunk, transport) = jack.with_client(|c|(c.buffer_size(), c.transport()));
        let timebase = Arc::new(Timebase::default());
        let clock = Self {
            quant:     Arc::new(24.into()),
            sync:      Arc::new(384.into()),
            transport: Arc::new(Some(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,
            midi_in:   Arc::new(RwLock::new(Some(MidiInput::new(jack,   &"M/clock", &[])?))),
            midi_out:  Arc::new(RwLock::new(Some(MidiOutput::new(jack,  &"clock/M", &[])?))),
            click_out: Arc::new(RwLock::new(Some(AudioOutput::new(jack, &"click",   &[])?))),
            ..Default::default()
        };
        if let Some(bpm) = bpm {
            clock.timebase.bpm.set(bpm);
        }
        Ok(clock)
    }
    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(transport) = self.transport.as_ref() {
            if let Some(start) = start {
                transport.locate(start)?;
            }
            transport.start()?;
        }
        Ok(())
    }
    /// Pause, optionally seeking to a given location afterwards
    pub fn pause_at (&self, pause: Option<u32>) -> Usually<()> {
        if let Some(transport) = self.transport.as_ref() {
            transport.stop()?;
            if let Some(pause) = pause {
                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);

        let mut started = self.started.write().unwrap();

        // If transport has just started or just stopped,
        // update starting point:
        if let Some(transport) = self.transport.as_ref() {
            match (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(())
    }

    pub fn bbt (&self) -> PositionBBT {
        let pulse = self.playhead.pulse.get() as i32;
        let ppq   = self.timebase.ppq.get() as i32;
        let bpm   = self.timebase.bpm.get();
        let bar   = (pulse / ppq) / 4;
        PositionBBT {
            bar:              1 + bar,
            beat:             1 + (pulse / ppq) % 4,
            tick:             (pulse % ppq),
            bar_start_tick:   (bar * 4 * ppq) as f64,
            beat_type:        4.,
            beats_per_bar:    4.,
            beats_per_minute: bpm,
            ticks_per_beat:   ppq as f64
        }
    }

    pub fn next_launch_instant (&self) -> Moment {
        Moment::from_pulse(self.timebase(), self.next_launch_pulse() as f64)
    }

    /// Get index of first sample to populate.
    ///
    /// Greater than 0 means that the first pulse of the clip
    /// falls somewhere in the middle of the chunk.
    pub fn get_sample_offset (&self, scope: &ProcessScope, started: &Moment) -> usize{
        (scope.last_frame_time() as usize).saturating_sub(
            started.sample.get() as usize +
            self.started.read().unwrap().as_ref().unwrap().sample.get() as usize
        )
    }

    // Get iterator that emits sample paired with pulse.
    //
    // * Sample: index into output buffer at which to write MIDI event
    // * Pulse: index into clip from which to take the MIDI event
    //
    // Emitted for each sample of the output buffer that corresponds to a MIDI pulse.
    pub fn get_pulses (&self, scope: &ProcessScope, offset: usize) -> TicksIterator {
        self.timebase().pulses_between_samples(offset, offset + scope.n_frames() as usize)
    }
}

impl Clock {
    fn _todo_provide_u32 (&self) -> u32 {
        todo!()
    }
    fn _todo_provide_opt_u32 (&self) -> Option<u32> {
        todo!()
    }
    fn _todo_provide_f64 (&self) -> f64 {
        todo!()
    }
}

impl<T: HasClock> Command<T> for ClockCommand {
    fn execute (&self, state: &mut T) -> Perhaps<Self> {
        self.execute(state.clock_mut()) // awesome
    }
}

def_command!(ClockCommand: |clock: Clock| {
    SeekUsec   { usec:   f64 } => {
        clock.playhead.update_from_usec(*usec); Ok(None) },
    SeekSample { sample: f64 } => {
        clock.playhead.update_from_sample(*sample); Ok(None) },
    SeekPulse  { pulse:  f64 } => {
        clock.playhead.update_from_pulse(*pulse); Ok(None) },
    SetBpm     { bpm:    f64 } => Ok(Some(
        Self::SetBpm { bpm: clock.timebase().bpm.set(*bpm) })),
    SetQuant   { quant:  f64 } => Ok(Some(
        Self::SetQuant { quant: clock.quant.set(*quant) })),
    SetSync    { sync:   f64 } => Ok(Some(
        Self::SetSync { sync: clock.sync.set(*sync) })),

    Play  { position: Option<u32> } => {
        clock.play_from(*position)?; Ok(None) /* TODO Some(Pause(previousPosition)) */ },
    Pause { position: Option<u32> } => {
        clock.pause_at(*position)?; Ok(None) },

    TogglePlayback { position: u32 } => Ok(if clock.is_rolling() {
        clock.pause_at(Some(*position))?; None
    } else {
        clock.play_from(Some(*position))?; None
    }),
});

pub fn view_transport (
    play: bool,
    bpm:  Arc<RwLock<String>>,
    beat: Arc<RwLock<String>>,
    time: Arc<RwLock<String>>,
) -> impl Content<TuiOut> {
    let theme = ItemTheme::G[96];
    Tui::bg(Black, row!(Bsp::a(
        Fill::XY(Align::w(button_play_pause(play))),
        Fill::XY(Align::e(row!(
            FieldH(theme, "BPM",  bpm),
            FieldH(theme, "Beat", beat),
            FieldH(theme, "Time", time),
        )))
    )))
}

pub fn view_status (
    sel: Option<Arc<str>>,
    sr:  Arc<RwLock<String>>,
    buf: Arc<RwLock<String>>,
    lat: Arc<RwLock<String>>,
) -> impl Content<TuiOut> {
    let theme = ItemTheme::G[96];
    Tui::bg(Black, row!(Bsp::a(
        Fill::XY(Align::w(sel.map(|sel|FieldH(theme, "Selected", sel)))),
        Fill::XY(Align::e(row!(
            FieldH(theme, "SR",  sr),
            FieldH(theme, "Buf", buf),
            FieldH(theme, "Lat", lat),
        )))
    )))
}

pub(crate) fn button_play_pause (playing: bool) -> impl Content<TuiOut> {
    let compact = true;//self.is_editing();
    Tui::bg(if playing { Rgb(0, 128, 0) } else { Rgb(128, 64, 0) },
        Either::new(compact,
            Thunk::new(move|to: &mut TuiOut|to.place(&Fixed::X(9, Either::new(playing,
                Tui::fg(Rgb(0, 255, 0),   " PLAYING "),
                Tui::fg(Rgb(255, 128, 0), " STOPPED ")))
            )),
            Thunk::new(move|to: &mut TuiOut|to.place(&Fixed::X(5, Either::new(playing,
                Tui::fg(Rgb(0, 255, 0),   Bsp::s(" 🭍🭑🬽 ", " 🭞🭜🭘 ",)),
                Tui::fg(Rgb(255, 128, 0), Bsp::s(" ▗▄▖ ", " ▝▀▘ ",))))
            ))
        )
    )
}

#[derive(Debug)] pub struct ViewCache {
    pub sr:   Memo<Option<(bool, f64)>, String>,
    pub buf:  Memo<Option<f64>, String>,
    pub lat:  Memo<Option<f64>, String>,
    pub bpm:  Memo<Option<f64>, String>,
    pub beat: Memo<Option<f64>, String>,
    pub time: Memo<Option<f64>, String>,
}

impl Default for ViewCache {
    fn default () -> Self {
        let mut beat = String::with_capacity(16);
        let _ = write!(beat, "{}", Self::BEAT_EMPTY);
        let mut time = String::with_capacity(16);
        let _ = write!(time, "{}", Self::TIME_EMPTY);
        let mut bpm  = String::with_capacity(16);
        let _ = write!(bpm,  "{}", Self::BPM_EMPTY);
        Self {
            beat: Memo::new(None, beat),
            time: Memo::new(None, time),
            bpm:  Memo::new(None, bpm),
            sr:   Memo::new(None, String::with_capacity(16)),
            buf:  Memo::new(None, String::with_capacity(16)),
            lat:  Memo::new(None, String::with_capacity(16)),
        }
    }
}

impl ViewCache {
    pub const BEAT_EMPTY: &'static str = "-.-.--";
    pub const TIME_EMPTY: &'static str = "-.---s";
    pub const BPM_EMPTY:  &'static str = "---.---";

    //pub fn track_counter (cache: &Arc<RwLock<Self>>, track: usize, tracks: usize)
        //-> Arc<RwLock<String>>
    //{
        //let data = (track, tracks);
        //cache.write().unwrap().trks.update(Some(data), rewrite!(buf, "{}/{}", data.0, data.1));
        //cache.read().unwrap().trks.view.clone()
    //}

    //pub fn scene_add (cache: &Arc<RwLock<Self>>, scene: usize, scenes: usize, is_editing: bool)
        //-> impl Content<TuiOut>
    //{
        //let data = (scene, scenes);
        //cache.write().unwrap().scns.update(Some(data), rewrite!(buf, "({}/{})", data.0, data.1));
        //button_3("S", "add scene", cache.read().unwrap().scns.view.clone(), is_editing)
    //}

    pub fn update_clock (cache: &Arc<RwLock<Self>>, clock: &Clock, compact: bool) {
        let rate  = clock.timebase.sr.get();
        let chunk = clock.chunk.load(Relaxed) as f64;
        let lat   = chunk / rate * 1000.;
        let delta = |start: &Moment|clock.global.usec.get() - start.usec.get();
        let mut cache = cache.write().unwrap();
        cache.buf.update(Some(chunk), rewrite!(buf, "{chunk}"));
        cache.lat.update(Some(lat),   rewrite!(buf, "{lat:.1}ms"));
        cache.sr.update(Some((compact, rate)), |buf,_,_|{
            buf.clear();
            if compact {
                write!(buf, "{:.1}kHz", rate / 1000.)
            } else {
                write!(buf, "{:.0}Hz", rate)
            }
        });
        if let Some(now) = clock.started.read().unwrap().as_ref().map(delta) {
            let pulse = clock.timebase.usecs_to_pulse(now);
            let time  = now/1000000.;
            let bpm   = clock.timebase.bpm.get();
            cache.beat.update(Some(pulse), |buf, _, _|{
                buf.clear();
                clock.timebase.format_beats_1_to(buf, pulse)
            });
            cache.time.update(Some(time), rewrite!(buf, "{:.3}s", time));
            cache.bpm.update(Some(bpm),   rewrite!(buf, "{:.3}",  bpm));
        } else {
            cache.beat.update(None, rewrite!(buf, "{}", ViewCache::BEAT_EMPTY));
            cache.time.update(None, rewrite!(buf, "{}", ViewCache::TIME_EMPTY));
            cache.bpm.update(None,  rewrite!(buf, "{}", ViewCache::BPM_EMPTY));
        }
    }

    //pub fn view_h2 (&self) -> impl Content<TuiOut> {
        //let cache = self.project.clock.view_cache.clone();
        //let cache = cache.read().unwrap();
        //add(&Fixed::x(15, Align::w(Bsp::s(
            //FieldH(theme, "Beat", cache.beat.view.clone()),
            //FieldH(theme, "Time", cache.time.view.clone()),
        //))));
        //add(&Fixed::x(13, Align::w(Bsp::s(
            //Fill::X(Align::w(FieldH(theme, "BPM", cache.bpm.view.clone()))),
            //Fill::X(Align::w(FieldH(theme, "SR ", cache.sr.view.clone()))),
        //))));
        //add(&Fixed::x(12, Align::w(Bsp::s(
            //Fill::X(Align::w(FieldH(theme, "Buf", cache.buf.view.clone()))),
            //Fill::X(Align::w(FieldH(theme, "Lat", cache.lat.view.clone()))),
        //))));
        //add(&Bsp::s(
            //Fill::X(Align::w(FieldH(theme, "Selected", Align::w(self.selection().describe(
                //self.tracks(),
                //self.scenes()
            //))))),
            //Fill::X(Align::w(FieldH(theme, format!("History ({})", self.history.len()),
                //self.history.last().map(|last|Fill::X(Align::w(format!("{:?}", last.0)))))))
        //));
        ////if let Some(last) = self.history.last() {
            ////add(&FieldV(theme, format!("History ({})", self.history.len()),
                ////Fill::X(Align::w(format!("{:?}", last.0)))));
        ////}
    //}
}