oximedia-effects 0.1.0

//! Basic auto-tune / pitch correction effect.

use crate::AudioEffect;

/// Auto-tune configuration.
#[derive(Debug, Clone)]
pub struct AutoTuneConfig {
    /// Correction amount (0.0 = no correction, 1.0 = full correction).
    pub correction: f32,
    /// Scale type (for now, just chromatic).
    pub scale: Scale,
}

/// Musical scale.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Scale {
    /// Chromatic (all semitones).
    Chromatic,
    /// Major scale.
    Major,
    /// Minor scale.
    Minor,
}

impl Default for AutoTuneConfig {
    fn default() -> Self {
        Self {
            correction: 0.5,
            scale: Scale::Chromatic,
        }
    }
}

/// Basic auto-tune effect.
///
/// Note: This is a simplified implementation for demonstration.
/// Real auto-tune requires pitch detection and sophisticated correction.
pub struct AutoTune {
    config: AutoTuneConfig,
    buffer: Vec<f32>,
    write_pos: usize,
}

impl AutoTune {
    /// Create new auto-tune effect.
    #[must_use]
    pub fn new(config: AutoTuneConfig, sample_rate: f32) -> Self {
        #[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)]
        let buffer_size = (sample_rate * 0.05) as usize; // 50ms buffer

        Self {
            config,
            buffer: vec![0.0; buffer_size],
            write_pos: 0,
        }
    }

    /// Set correction amount.
    pub fn set_correction(&mut self, correction: f32) {
        self.config.correction = correction.clamp(0.0, 1.0);
    }

    #[allow(dead_code, clippy::unused_self)]
    fn find_nearest_note(&self, frequency: f32) -> f32 {
        // Simplified: just return input frequency
        // Real implementation would quantize to scale
        frequency
    }
}

impl AudioEffect for AutoTune {
    fn process_sample(&mut self, input: f32) -> f32 {
        // Store in buffer
        self.buffer[self.write_pos] = input;
        self.write_pos = (self.write_pos + 1) % self.buffer.len();

        // For now, just pass through with minimal processing
        // Real implementation would detect pitch and apply correction
        input * (1.0 - self.config.correction * 0.1)
    }

    fn reset(&mut self) {
        self.buffer.fill(0.0);
        self.write_pos = 0;
    }
}

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

    #[test]
    fn test_autotune() {
        let config = AutoTuneConfig::default();
        let mut autotune = AutoTune::new(config, 48000.0);
        let output = autotune.process_sample(0.5);
        assert!(output.is_finite());
    }
}