aprender-core 0.29.2

pub(crate) use super::*;

// ========== NG21: Stereo output has correct frequency difference ==========

#[test]
fn test_ng21_frequency_offset_stored() {
    let config = NoiseConfig::brown();
    let gen = BinauralGenerator::new(config, 4.0).unwrap();
    assert!((gen.frequency_offset() - 4.0).abs() < f32::EPSILON);
}

#[test]
fn test_ng21_frequency_offset_from_preset() {
    let config = NoiseConfig::brown();
    let gen = BinauralGenerator::from_preset(config, BinauralPreset::Delta).unwrap();
    assert!((gen.frequency_offset() - 2.0).abs() < f32::EPSILON);
}

#[test]
fn test_ng21_frequency_offset_update() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();
    gen.set_frequency_offset(10.0);
    assert!((gen.frequency_offset() - 10.0).abs() < f32::EPSILON);
}

#[test]
fn test_ng21_negative_offset_becomes_positive() {
    let config = NoiseConfig::brown();
    let gen = BinauralGenerator::new(config, -4.0).unwrap();
    assert!((gen.frequency_offset() - 4.0).abs() < f32::EPSILON);
}

// ========== NG22: Left and right channels are phase-coherent with noise ==========

#[test]
fn test_ng22_channels_coherent() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();

    let mut left = vec![0.0; 1024];
    let mut right = vec![0.0; 1024];
    gen.generate_stereo(&mut left, &mut right).unwrap();

    // Both channels should have similar overall characteristics
    let left_energy: f32 = left.iter().map(|x| x * x).sum();
    let right_energy: f32 = right.iter().map(|x| x * x).sum();

    // Energy should be similar (within 50%)
    let ratio = left_energy / right_energy;
    assert!(
        ratio > 0.5 && ratio < 2.0,
        "Channel energies too different: L={}, R={}, ratio={}",
        left_energy,
        right_energy,
        ratio
    );
}

#[test]
fn test_ng22_channels_correlated() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();

    let mut left = vec![0.0; 1024];
    let mut right = vec![0.0; 1024];
    gen.generate_stereo(&mut left, &mut right).unwrap();

    // Compute correlation
    let mean_l: f32 = left.iter().sum::<f32>() / left.len() as f32;
    let mean_r: f32 = right.iter().sum::<f32>() / right.len() as f32;

    let mut cov = 0.0;
    let mut var_l = 0.0;
    let mut var_r = 0.0;

    for i in 0..left.len() {
        let dl = left[i] - mean_l;
        let dr = right[i] - mean_r;
        cov += dl * dr;
        var_l += dl * dl;
        var_r += dr * dr;
    }

    let correlation = cov / (var_l.sqrt() * var_r.sqrt());

    // Should be highly correlated (same base noise)
    assert!(
        correlation > 0.8,
        "Channels not correlated enough: {}",
        correlation
    );
}

// ========== NG23: Frequency offset=0 produces mono-equivalent stereo ==========

#[test]
fn test_ng23_zero_offset_similar_channels() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 0.0).unwrap();

    let mut left = vec![0.0; 1024];
    let mut right = vec![0.0; 1024];
    gen.generate_stereo(&mut left, &mut right).unwrap();

    // With zero offset, channels should be nearly identical
    // (small differences due to modulation phase)
    let max_diff: f32 = left
        .iter()
        .zip(right.iter())
        .map(|(l, r)| (l - r).abs())
        .fold(0.0, f32::max);

    // With 0 offset, channels are modulated at the same frequency
    // but may start at different phases, so allow small difference
    assert!(
        max_diff < 0.3,
        "Channels too different with zero offset: max_diff={}",
        max_diff
    );
}

#[test]
fn test_ng23_zero_offset_same_energy() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 0.0).unwrap();

    let mut left = vec![0.0; 1024];
    let mut right = vec![0.0; 1024];
    gen.generate_stereo(&mut left, &mut right).unwrap();

    let left_energy: f32 = left.iter().map(|x| x * x).sum();
    let right_energy: f32 = right.iter().map(|x| x * x).sum();

    let diff = (left_energy - right_energy).abs();
    let avg = (left_energy + right_energy) / 2.0;

    assert!(
        diff / avg < 0.1,
        "Energy differs too much: L={}, R={}",
        left_energy,
        right_energy
    );
}

// ========== NG24: Preset frequencies match brainwave ranges ==========

#[test]
fn test_ng24_delta_preset_in_range() {
    let (min, max) = BinauralPreset::Delta.frequency_range();
    let freq = BinauralPreset::Delta.frequency();
    assert!(
        freq >= min && freq <= max,
        "Delta frequency {} not in range [{}, {}]",
        freq,
        min,
        max
    );
}

#[test]
fn test_ng24_theta_preset_in_range() {
    let (min, max) = BinauralPreset::Theta.frequency_range();
    let freq = BinauralPreset::Theta.frequency();
    assert!(
        freq >= min && freq <= max,
        "Theta frequency {} not in range [{}, {}]",
        freq,
        min,
        max
    );
}

#[test]
fn test_ng24_alpha_preset_in_range() {
    let (min, max) = BinauralPreset::Alpha.frequency_range();
    let freq = BinauralPreset::Alpha.frequency();
    assert!(
        freq >= min && freq <= max,
        "Alpha frequency {} not in range [{}, {}]",
        freq,
        min,
        max
    );
}

#[test]
fn test_ng24_beta_preset_in_range() {
    let (min, max) = BinauralPreset::Beta.frequency_range();
    let freq = BinauralPreset::Beta.frequency();
    assert!(
        freq >= min && freq <= max,
        "Beta frequency {} not in range [{}, {}]",
        freq,
        min,
        max
    );
}

#[test]
fn test_ng24_gamma_preset_in_range() {
    let (min, max) = BinauralPreset::Gamma.frequency_range();
    let freq = BinauralPreset::Gamma.frequency();
    assert!(
        freq >= min && freq <= max,
        "Gamma frequency {} not in range [{}, {}]",
        freq,
        min,
        max
    );
}

// ========== NG-F6: Left/right channels cannot be identical when binaural enabled ==========

#[test]
fn test_ng_f6_channels_differ_with_offset() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();

    let mut left = vec![0.0; 1024];
    let mut right = vec![0.0; 1024];
    gen.generate_stereo(&mut left, &mut right).unwrap();

    // Channels should NOT be identical
    assert_ne!(left, right, "Binaural channels should differ");
}

#[test]
fn test_ng_f6_channels_differ_measurably() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 10.0).unwrap();

    let mut left = vec![0.0; 1024];
    let mut right = vec![0.0; 1024];
    gen.generate_stereo(&mut left, &mut right).unwrap();

    // Count differences
    let diff_count = left
        .iter()
        .zip(right.iter())
        .filter(|(l, r)| (*l - *r).abs() > 0.001)
        .count();

    assert!(
        diff_count > left.len() / 2,
        "Not enough channel differences: {}/{}",
        diff_count,
        left.len()
    );
}

// ========== Additional binaural tests ==========

#[test]
fn test_generate_interleaved() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();

    let mut interleaved = vec![0.0; 2048]; // 1024 * 2
    gen.generate_interleaved(&mut interleaved).unwrap();

    // Verify interleaving pattern
    let mut left = vec![0.0; 1024];
    let mut right = vec![0.0; 1024];

    // Reset and generate again
    gen.reset();
    gen.generate_stereo(&mut left, &mut right).unwrap();

    // Reset and compare with interleaved
    gen.reset();
    let mut interleaved2 = vec![0.0; 2048];
    gen.generate_interleaved(&mut interleaved2).unwrap();

    // Interleaved should match
    for i in 0..1024 {
        assert!((interleaved2[i * 2] - left[i]).abs() < f32::EPSILON);
        assert!((interleaved2[i * 2 + 1] - right[i]).abs() < f32::EPSILON);
    }
}

#[test]
fn test_interleaved_wrong_size() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();

    let mut interleaved = vec![0.0; 1024]; // Wrong size
    let result = gen.generate_interleaved(&mut interleaved);
    assert!(result.is_err());
}

#[test]
fn test_stereo_buffer_mismatch() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();

    let mut left = vec![0.0; 1024];
    let mut right = vec![0.0; 512]; // Wrong size
    let result = gen.generate_stereo(&mut left, &mut right);
    assert!(result.is_err());
}

#[test]
fn test_stereo_wrong_buffer_size() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();

    let mut left = vec![0.0; 512]; // Wrong size
    let mut right = vec![0.0; 512]; // Wrong size
    let result = gen.generate_stereo(&mut left, &mut right);
    assert!(result.is_err());
}

#[test]
fn test_update_config() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();

    let new_config = NoiseConfig::pink();
    gen.update_config(new_config).unwrap();

    assert_eq!(
        gen.config().noise_type,
        super::super::config::NoiseType::Pink
    );
}

#[test]
fn test_reset() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 4.0).unwrap();

    // Advance state
    let mut left = vec![0.0; 1024];
    let mut right = vec![0.0; 1024];
    for _ in 0..10 {
        gen.generate_stereo(&mut left, &mut right).unwrap();
    }

    assert!(gen.time() > 0.0);

    gen.reset();

    assert!((gen.time() - 0.0).abs() < f64::EPSILON);
}

#[test]
fn test_output_bounded() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 10.0).unwrap();

    for _ in 0..50 {
        let mut left = vec![0.0; 1024];
        let mut right = vec![0.0; 1024];
        gen.generate_stereo(&mut left, &mut right).unwrap();

        for &sample in left.iter().chain(right.iter()) {
            assert!(sample >= -1.0 && sample <= 1.0);
        }
    }
}

#[test]
fn test_no_nan_inf() {
    let config = NoiseConfig::brown();
    let mut gen = BinauralGenerator::new(config, 40.0).unwrap();

    for _ in 0..50 {
        let mut left = vec![0.0; 1024];
        let mut right = vec![0.0; 1024];
        gen.generate_stereo(&mut left, &mut right).unwrap();

        for &sample in left.iter().chain(right.iter()) {
            assert!(!sample.is_nan());
            assert!(!sample.is_infinite());
        }
    }
}