//! Example: render a simple melody (pulse lead + triangle bass + noise hihat) to WAV.

use soundgen_core::{
    voice::{DutyCycle, NoiseChannel, NoiseMode, PulseChannel, TriangleChannel},
    ChannelRenderer, Envelope, VoiceKind,
};
use soundgen_io::write_wav;

fn note_freq(n: &str) -> f32 {
    // Note name to frequency: e.g., "A4" = 440 Hz
    let notes = [
        "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B",
    ];
    let note = &n[..n.len() - 1];
    let octave: i32 = n[n.len() - 1..].parse().unwrap();
    let semitone = notes.iter().position(|&x| x == note).unwrap() as i32;
    let midi = 12 * (octave + 1) + semitone;
    440.0 * 2.0f32.powf((midi - 69) as f32 / 12.0)
}

fn main() {
    let sr = 44100u32;
    let bpm = 120.0;
    let beat = 60.0 / bpm; // seconds per beat
    let total_beats = 8.0;
    let total_samples = (beat * total_beats * sr as f32) as usize;

    // Melody: C4 E4 G4 C5 G4 E4 C4 G3
    let melody = ["C4", "E4", "G4", "C5", "G4", "E4", "C4", "G3"];
    // Bass: C3 C3 G3 G3 A2 A2 F2 F2
    let bass = ["C3", "C3", "G3", "G3", "A2", "A2", "F2", "F2"];

    let samples_per_note = (beat * sr as f32) as usize;

    let mut stereo = Vec::with_capacity(total_samples * 2);

    for i in 0..8 {
        // Lead: pulse wave
        let mut lead = ChannelRenderer::new(
            VoiceKind::Pulse(PulseChannel::new(sr as f32, DutyCycle::D50)),
            sr as f32,
        )
        .with_envelope(Envelope::adsr(sr as f32, 0.01, 0.05, 0.6, 0.08))
        .with_volume(0.3)
        .with_pan(-0.3);

        lead.trigger();
        lead.set_frequency(note_freq(melody[i]));

        // Bass: triangle
        let mut bass_ch = ChannelRenderer::new(
            VoiceKind::Triangle(TriangleChannel::new(sr as f32)),
            sr as f32,
        )
        .with_envelope(Envelope::adsr(sr as f32, 0.02, 0.1, 0.5, 0.1))
        .with_volume(0.35)
        .with_pan(0.3);

        bass_ch.trigger();
        bass_ch.set_frequency(note_freq(bass[i]));

        // Hihat: noise on offbeats
        let has_hihat = i % 2 == 1;
        let mut hihat = ChannelRenderer::new(
            VoiceKind::Noise(NoiseChannel::new(sr as f32, NoiseMode::White)),
            sr as f32,
        )
        .with_envelope(Envelope::adsr(sr as f32, 0.0, 0.02, 0.0, 0.03))
        .with_volume(0.15)
        .with_pan(0.0);

        if has_hihat {
            hihat.trigger();
            hihat.set_frequency(10000.0);
        }

        for _ in 0..samples_per_note {
            let (ll, lr) = lead.tick();
            let (bl, br) = bass_ch.tick();
            let (hl, hr) = hihat.tick();
            let l = (ll + bl + hl).tanh();
            let r = (lr + br + hr).tanh();
            stereo.push(l);
            stereo.push(r);
        }
    }

    let out = std::path::Path::new("play_melody.wav");
    write_wav(out, &stereo, sr).expect("failed to write WAV");
    eprintln!("Wrote {} ({} notes, {:.1}s)", out.display(), 8, beat * 8.0);
}