use anyhow::{Result, anyhow};
use macroquad::color::*;
use serialport::SerialPortType;

#[derive(Clone, Copy, Debug)]
pub enum Instruction {
    NoteOn(u8),
    NoteOff,
    Modulation { depth: u8, rate: u8 },
    Frequency(u16),
}

pub struct SerialDevice {
    port: Box<dyn serialport::SerialPort>,
}

const CHANNEL_COUNT: u8 = 4;

impl SerialDevice {
    pub fn new() -> Result<Self> {
        let ports = serialport::available_ports()?;
        let mut this: anyhow::Result<Self> = Err(anyhow!("No serial port found"));
        for port in ports {
            match port.port_type {
                SerialPortType::UsbPort(_) => {
                    this = Ok(Self {
                        port: serialport::new(port.port_name, 115200).open()?,
                    });
                    break;
                }
                _ => {}
            };
        }
        this
    }

    fn note_off(&mut self, ch: u8) -> Result<()> {
        assert!((0..CHANNEL_COUNT).contains(&ch));
        let bytes: Vec<u8> = vec![0x80 + ch];
        self.port.write(&bytes)?;
        Ok(())
    }

    fn note_on(&mut self, ch: u8, note: u8) -> Result<()> {
        assert!((0..CHANNEL_COUNT).contains(&ch));
        assert!((0..=127).contains(&note));
        let bytes: Vec<u8> = vec![0x90 + ch, note];
        self.port.write(&bytes)?;
        Ok(())
    }

    fn modulation(&mut self, ch: u8, depth: u8, rate: u8) -> Result<()> {
        assert!((0..CHANNEL_COUNT).contains(&ch));
        assert!((0..=127).contains(&depth));
        let bytes: Vec<u8> = vec![0xA0 + ch, depth, rate];
        self.port.write(&bytes)?;
        Ok(())
    }

    fn frequency_on(&mut self, ch: u8, freq: u16) -> Result<()> {
        assert!((0..CHANNEL_COUNT).contains(&ch));
        let bytes: Vec<u8> = vec![0xB0 + ch, (freq & 0xff) as u8, (freq >> 8) as u8];
        self.port.write(&bytes)?;
        Ok(())
    }

    pub fn stop(&mut self) -> Result<()> {
        let bytes: Vec<u8> = vec![0xff];
        self.port.write(&bytes)?;
        Ok(())
    }

    pub fn execute(&mut self, ch: u8, instruction: Instruction) -> Result<()> {
        match instruction {
            Instruction::NoteOn(note) => self.note_on(ch, note),
            Instruction::NoteOff => self.note_off(ch),
            Instruction::Modulation { depth, rate } => self.modulation(ch, depth, rate),
            Instruction::Frequency(freq) => self.frequency_on(ch, freq),
        }
    }
}

pub struct Pattern {
    pub rows: Vec<[Option<Instruction>; CHANNEL_COUNT as usize]>,
}

impl Pattern {
    pub fn new() -> Self {
        let mut rows = Vec::new();
        rows.resize_with(256, || [None; CHANNEL_COUNT as usize]);
        Self { rows }
    }
}

pub struct TimeSignature {
    pub numerator: u8,
    pub denominator: u8,
}

impl Default for TimeSignature {
    fn default() -> Self {
        Self {
            numerator: 4,
            denominator: 4,
        }
    }
}

pub struct Song {
    pub bpm: f64,
    pub time_signature: TimeSignature,
    pub patterns: Vec<Pattern>,
    pub pattern_order: Vec<usize>, // index into patterns
}

impl Song {
    const DEFAULT_BPM: f64 = 120.0;

    pub fn new(bpm: Option<f64>, time_signature: Option<TimeSignature>) -> Self {
        Self {
            bpm: bpm.unwrap_or(Self::DEFAULT_BPM),
            time_signature: time_signature.unwrap_or_default(),
            patterns: vec![Pattern::new()],
            pattern_order: vec![0],
        }
    }

    pub fn empty(bpm: Option<f64>, time_signature: Option<TimeSignature>) -> Self {
        Self {
            bpm: bpm.unwrap_or(Self::DEFAULT_BPM),
            time_signature: time_signature.unwrap_or_default(),
            patterns: Vec::new(),
            pattern_order: Vec::new(),
        }
    }
}

#[derive(Default)]
struct App {}

impl App {
    pub fn new() -> Self {
        Self { ..App::default() }
    }

    pub async fn run(&self) {
        loop {
            self.update().await;
        }
    }

    async fn update(&self) {
        macroquad::window::clear_background(WHITE);

        macroquad::shapes::draw_line(40.0, 40.0, 100.0, 200.0, 15.0, BLUE);
        macroquad::shapes::draw_rectangle(
            macroquad::window::screen_width() / 2.0 - 60.0,
            100.0,
            120.0,
            60.0,
            GREEN,
        );

        macroquad::text::draw_text("Hello, Macroquad!", 20.0, 20.0, 30.0, DARKGRAY);

        macroquad::window::next_frame().await
    }
}

#[macroquad::main("singer")]
async fn main() {
    let app = App::new();
    app.run().await;
}