use crate::config::StageConfig;

pub fn generate_nst_content(stage: &StageConfig) -> String {
    let mut line1_parts = vec![
        "ND=50".to_string(),
        "NLAMBD=3".to_string(),
        "VTB=2.".to_string(),
        "ISPODF=1".to_string(),
        "DDNU=50.".to_string(),
        "CNU1=6.".to_string(),
    ];

    if let Some(chmax) = stage.chmax {
        line1_parts.push(format!("CHMAX={}", chmax));
    }
    if let Some(itek) = stage.itek {
        line1_parts.push(format!("ITEK={}", itek));
    }
    line1_parts.push(format!("NITER={}", stage.niter));

    let mut line2_parts = Vec::new();
    if let Some(orelax) = stage.orelax {
        line2_parts.push(format!("ORELAX={}", orelax));
    }
    if let Some(idlte) = stage.idlte {
        line2_parts.push(format!("IDLTE={}", idlte));
    }
    if let Some(iacc) = stage.iacc {
        line2_parts.push(format!("IACC={}", iacc));
    }
    if let Some(ichang) = stage.ichang {
        line2_parts.push(format!("ICHANG={}", ichang));
    }
    line2_parts.push("IELCOR=-1".to_string());

    format!("{}\n{}\n", line1_parts.join(","), line2_parts.join(","))
}

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

    #[test]
    fn test_nst_generation() {
        let stage = StageConfig {
            label: "nc".to_string(),
            lte: "F".to_string(),
            ltgray: "F".to_string(),
            ilvlin: 0,
            require_converged: false,
            niter: 10,
            chmax: None,
            itek: None,
            metals: None,
            ichang: None,
            idlte: None,
            iacc: None,
            orelax: None,
        };
        let content = generate_nst_content(&stage);
        assert!(content.contains("ND=50"));
        assert!(content.contains("NITER=10"));
        assert!(content.contains("IELCOR=-1"));
    }
}