//! 音频重采样模块

use anyhow::Result;

/// 重采样音频
///
/// 使用线性插值进行重采样
pub fn resample_audio(samples: &[f32], from_rate: u32, to_rate: u32) -> Result<Vec<f32>> {
    if from_rate == to_rate {
        return Ok(samples.to_vec());
    }

    let ratio = to_rate as f32 / from_rate as f32;
    let new_len = (samples.len() as f32 * ratio) as usize;

    if new_len == 0 {
        return Ok(vec![]);
    }

    let mut resampled = Vec::with_capacity(new_len);

    for i in 0..new_len {
        let src_idx = i as f32 / ratio;
        let src_idx_floor = src_idx.floor() as usize;
        let src_idx_ceil = src_idx.ceil() as usize;

        if src_idx_ceil >= samples.len() {
            resampled.push(*samples.last().unwrap_or(&0.0));
        } else if src_idx_floor >= samples.len() {
            resampled.push(*samples.first().unwrap_or(&0.0));
        } else {
            let frac = src_idx - src_idx_floor as f32;
            let sample = samples[src_idx_floor] * (1.0 - frac) + samples[src_idx_ceil] * frac;
            resampled.push(sample);
        }
    }

    Ok(resampled)
}

/// 使用更高品质的重采样算法 (可选)
pub fn resample_audio_high_quality(_samples: &[f32], _from_rate: u32, _to_rate: u32) -> Result<Vec<f32>> {
    // TODO: 实现基于 sinc 插值的高品质重采样
    // 可以使用 rubato crate 实现
    todo!("高品质重采样待实现")
}