oximedia-mir 0.1.8

//! Chord progression analysis.

use crate::types::ChordLabel;

/// Chord progression analyzer.
pub struct ProgressionAnalyzer;

impl ProgressionAnalyzer {
    /// Create a new progression analyzer.
    #[must_use]
    pub fn new() -> Self {
        Self
    }

    /// Analyze chord progressions.
    #[must_use]
    pub fn analyze(&self, chords: &[ChordLabel]) -> Vec<String> {
        let mut progressions = Vec::new();

        // Extract common progression patterns
        for window in chords.windows(4) {
            let pattern = self.classify_progression(window);
            if !pattern.is_empty() {
                progressions.push(pattern);
            }
        }

        progressions
    }

    /// Classify a chord progression pattern.
    fn classify_progression(&self, chords: &[ChordLabel]) -> String {
        let labels: Vec<&str> = chords.iter().map(|c| c.label.as_str()).collect();

        // Check for common patterns
        if self.is_twelve_bar_blues(&labels) {
            "12-bar blues".to_string()
        } else if self.is_ii_v_i(&labels) {
            "II-V-I".to_string()
        } else if self.is_i_iv_v(&labels) {
            "I-IV-V".to_string()
        } else {
            labels.join(" - ")
        }
    }

    /// Check if pattern is 12-bar blues.
    fn is_twelve_bar_blues(&self, _chords: &[&str]) -> bool {
        // Simplified check - could be more sophisticated
        false
    }

    /// Check if pattern is II-V-I.
    fn is_ii_v_i(&self, chords: &[&str]) -> bool {
        chords.len() >= 3 && {
            // Simplified check - would need key context
            chords.len() == 3
        }
    }

    /// Check if pattern is I-IV-V.
    fn is_i_iv_v(&self, chords: &[&str]) -> bool {
        chords.len() >= 3 && {
            // Simplified check - would need key context
            chords.len() == 3
        }
    }
}

impl Default for ProgressionAnalyzer {
    fn default() -> Self {
        Self::new()
    }
}

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

    #[test]
    fn test_progression_analyzer_creation() {
        let _analyzer = ProgressionAnalyzer::new();
    }
}