use crate::domain::entities::Project;
use crate::domain::value_objects::TrackId;
use anyhow::{Result, anyhow};

/// Ajusta o fator de escala temporal (drift) de uma faixa externa pelo TrackId.
///
/// Um `scale != 1.0` indica que o projeto precisará usar o pipeline mkvmerge.
#[allow(dead_code)]
pub struct AdjustDrift;

impl AdjustDrift {
    #[allow(dead_code)]
    pub fn execute(project: &mut Project, id: TrackId, scale: f64) -> Result<()> {
        if scale <= 0.0 {
            return Err(anyhow!("O fator de escala deve ser maior que zero: {}", scale));
        }
        let track = project
            .find_track_mut(id)
            .ok_or_else(|| anyhow!("Faixa não encontrada: {:?}", id))?;
        track.set_drift_scale(scale);
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::application::use_cases::add_audio_track::AddAudioTrack;
    use crate::domain::entities::{MkvOutput, VideoFile};
    use crate::domain::value_objects::{FilePath, SyncOffset, TrackLanguage};

    fn make_project() -> Project {
        Project::new(
            VideoFile::new(FilePath::from("input.mkv")),
            MkvOutput::new(FilePath::from("output.mkv")),
        )
        .unwrap()
    }

    #[test]
    fn ajusta_drift_existente() {
        let mut p = make_project();
        let lang = TrackLanguage::new("por").unwrap();
        AddAudioTrack::execute(
            &mut p,
            FilePath::from("audio.aac"),
            SyncOffset::default(),
            lang,
            false,
            String::new(),
            1.0,
        )
        .unwrap();
        let id = p.tracks[0].id();

        AdjustDrift::execute(&mut p, id, 0.99983).unwrap();
        assert!((p.tracks[0].drift_scale() - 0.99983).abs() < 1e-9);
    }

    #[test]
    fn erro_se_id_inexistente() {
        let mut p = make_project();
        let result = AdjustDrift::execute(&mut p, TrackId::new(99), 0.99983);
        assert!(result.is_err());
    }

    #[test]
    fn erro_se_scale_zero() {
        let mut p = make_project();
        let lang = TrackLanguage::new("por").unwrap();
        AddAudioTrack::execute(
            &mut p,
            FilePath::from("audio.aac"),
            SyncOffset::default(),
            lang,
            false,
            String::new(),
            1.0,
        )
        .unwrap();
        let id = p.tracks[0].id();
        let result = AdjustDrift::execute(&mut p, id, 0.0);
        assert!(result.is_err());
    }
}