#![warn(missing_docs)]
//! This file implements the interface to turn a parsed representation
//! of a sheet into pulses.

use super::*;

#[allow(unused_imports)]
use crate::instruments::{self, Instrument as IInstrument};

#[derive(Debug, Clone, Copy)]
/// The environment when generating waves from a sheet.
struct SheetEnv {
    volume: Volume,
    bpm: BPM,
    instrument: Instrument,
    duration: Beats,
    octave: usize,
    rate: Samples,
}

impl SheetEnv {
    fn set_volume(&mut self, volume: Volume) {
        self.volume = volume;
    }
    fn set_bpm(&mut self, bpm: BPM) {
        self.bpm = bpm;
    }
    fn set_instrument(&mut self, instrument: Instrument) {
        self.instrument = instrument;
    }
    fn set_duration(&mut self, duration: Beats) {
        self.duration = duration;
    }
    fn set_octave(&mut self, octave: usize) {
        self.octave = octave;
    }
}

impl Default for SheetEnv {
    fn default() -> Self {
        let volume = Volume::default();
        let bpm = BPM::default();
        let instrument = Instrument::default();
        let duration = Beats::default();
        let octave = 4usize;
        let rate = Samples::default();

        Self {
            volume,
            bpm,
            instrument,
            duration,
            octave,
            rate,
        }
    }
}

impl From<(&SheetDuration, Beats)> for Beats {
    fn from((duration, env_duration): (&SheetDuration, Beats)) -> Self {
        let duration_base: Beats = if let Some(base) = duration.beats {
            base
        } else {
            env_duration
        };

        let mut final_duration = duration_base;

        for i in (0..duration.dots).map(|n| n + 1) {
            let power = 2usize.pow(i as u32) as f64;

            final_duration = (*final_duration + *duration_base / power).into();
        }

        final_duration
    }
}

impl From<(&SheetUnit, &mut SheetEnv)> for Wave {
    fn from((unit, env): (&SheetUnit, &mut SheetEnv)) -> Self {
        let mut result = Vec::new();

        // Unfortunately our trait is wrongly designed and that is not
        // dynamically dispatchable, so we need separate variables for
        // each instrument.
        let mut piano = instruments::PianoFromC::default();
        let mut violin = instruments::Violin::default();
        let mut sinus = instruments::Sinus::default();
        let mut tangent = instruments::Tangent::default();

        match unit {
            SheetUnit::Tone(chord, duration) => {
                let mut local_waves = Vec::new();

                for tone in chord.0.iter() {
                    let octave = if let Some(abs_or_rel) = tone.octave {
                        match abs_or_rel {
                            SheetOctave::Absolute(absolute_octave) => absolute_octave,
                            SheetOctave::Relative(relative_octave) => {
                                let result: isize = relative_octave + env.octave as isize;

                                assert!(!result.is_negative());

                                result as usize
                            }
                        }
                    } else {
                        env.octave
                    };

                    env.set_octave(octave);

                    let semitone: Semitones = (octave, tone.semitone).into();

                    let final_duration: Beats = (duration, env.duration).into();

                    env.set_duration(final_duration);

                    let wave = match env.instrument {
                        Instrument::Piano => {
                            piano.play(semitone, env.rate, env.bpm, final_duration, env.volume)
                        }
                        Instrument::Violin => {
                            violin.play(semitone, env.rate, env.bpm, final_duration, env.volume)
                        }
                        Instrument::Sinus => {
                            sinus.play(semitone, env.rate, env.bpm, final_duration, env.volume)
                        }
                        Instrument::Tangent => {
                            tangent.play(semitone, env.rate, env.bpm, final_duration, env.volume)
                        }
                    };

                    local_waves.push(wave);
                }

                let local_result = mix_waves_exact(local_waves);

                result.append(&mut local_result.to_vec());
            }
            SheetUnit::Silence(duration) => {
                let duration_per_beat: Seconds = env.bpm.into();

                let final_duration: Beats = (duration, env.duration).into();

                env.set_duration(final_duration);

                let duration: Seconds = (*final_duration * *duration_per_beat).into();
                let nb_samples = (*duration * *env.rate).floor() as usize;

                result.append(&mut vec![0f64.into(); nb_samples]);
            }
            SheetUnit::Instruction(instruction) => match instruction {
                Instruction::VolumeTo(volume) => {
                    env.set_volume(*volume);
                }
                Instruction::BPMTo(bpm) => {
                    env.set_bpm(*bpm);
                }
                Instruction::InstrumentTo(instrument) => {
                    env.set_instrument(*instrument);
                }
            },
        }

        Wave::new(result)
    }
}

impl From<(&mut SheetGroup, &mut SheetEnv)> for Wave {
    fn from((group, env): (&mut SheetGroup, &mut SheetEnv)) -> Self {
        group.do_cram(&mut env.duration);

        // if group.nodes.len() == 19 {
        //     println!("group={group:?}");
        // }

        // After we crammed the expressions, we are sure that all
        // tones have the correct durations, so we can safely ignore
        // all cram expressions afterwards.

        let mut stack = vec![0usize];
        let mut seen = vec![false; group.nodes.len()];
        let mut stack_args: Vec<Wave> = vec![];

        while let Some(top) = stack.pop() {
            match &group.nodes[top] {
                SheetGroupNode::Intermediate(repetition, _) if *repetition != 0 => {
                    if !seen[top] {
                        stack.push(top);

                        stack.append(
                            &mut group.edges[top]
                                .iter()
                                .copied()
                                .rev()
                                .filter(|child| match group.nodes[*child] {
                                    SheetGroupNode::Intermediate(child_repetition, _)
                                        if child_repetition != 0 =>
                                    {
                                        true
                                    }
                                    SheetGroupNode::Unit(_) => true,
                                    _ => false,
                                })
                                .collect(),
                        );
                    } else {
                        match repetition {
                            0 => {
                                unreachable!()
                            }
                            // 1 => {
                            //     for _ in 0..group.edges[top]
                            //         .iter()
                            //         .filter(|child| match group.nodes[**child] {
                            //             SheetGroupNode::Intermediate(child_repetition, _)
                            //                 if child_repetition != 0 =>
                            //             {
                            //                 true
                            //             }
                            //             SheetGroupNode::Unit(_) => true,
                            //             _ => false,
                            //         })
                            //         .count()
                            //     {
                            //         result.append(&mut stack_args.pop().unwrap().to_vec());
                            //     }
                            // }
                            _ => {
                                let mut local_stack_args = vec![];
                                let mut local_results = vec![];
                                let mut final_local_result = vec![];

                                for _ in 0..group.edges[top]
                                    .iter()
                                    .filter(|child| match group.nodes[**child] {
                                        SheetGroupNode::Intermediate(child_repetition, _)
                                            if child_repetition != 0 =>
                                        {
                                            true
                                        }
                                        SheetGroupNode::Unit(_) => true,
                                        _ => false,
                                    })
                                    .count()
                                {
                                    local_stack_args.push(stack_args.pop().unwrap());
                                }

                                for local_wave in local_stack_args.into_iter().rev() {
                                    local_results.append(&mut local_wave.to_vec());
                                }

                                for _ in 0..(repetition - 1) {
                                    final_local_result.append(&mut local_results.clone());
                                }

                                final_local_result.append(&mut local_results);

                                stack_args.push(Wave::new(final_local_result));
                            }
                        }
                    }
                }
                SheetGroupNode::Unit(unit) => {
                    stack_args.push((unit, &mut *env).into());
                }
                _ => {
                    continue;
                }
            }

            seen[top] = true;
        }

        let result = stack_args
            .iter()
            .flat_map(|vec| vec.iter())
            .copied()
            .collect();

        Wave::new(result)
    }
}

// Note: The rest are but ordinary house-keeping codes to glue
// everything together.

impl From<&mut SheetBlock> for Wave {
    fn from(block: &mut SheetBlock) -> Self {
        let mut result = Vec::new();
        let mut env = SheetEnv::default();

        for group in block.groups.iter_mut() {
            let wave: Wave = (group, &mut env).into();

            result.append(&mut wave.to_vec());
        }

        Self::new(result)
    }
}

impl From<&mut Sheet> for Wave {
    fn from(sheet: &mut Sheet) -> Self {
        mix_waves_exact(sheet.blocks.iter_mut().map(Into::<Wave>::into).collect())
    }
}

#[cfg(test)]
mod tests {
    // use super::*;
}