// [[file:../parser.note::99232ff4][99232ff4]]
use gchemol_parser::parsers::*;
use gchemol_parser::GrepReader;
use gut::prelude::*;

/// A minimal representation for chemical atom.
#[derive(Debug)]
struct Atom {
    symbol: String,
    position: [f64; 3],
}

impl Atom {
    fn new(sym: &str, position: [f64; 3]) -> Self {
        Self {
            symbol: sym.into(),
            position,
        }
    }
}

/// Create Atom object from xyz line
///
/// # Example
///
/// C -11.4286  1.7645  0.0000
fn read_atom_xyz(s: &mut &str) -> PResult<Atom> {
    let (symbol, positions, _extra) = (ws(alpha1), ws(xyz_array), rest_line).context(label("xyz line")).parse_next(s)?;
    let atom = Atom::new(symbol, positions);

    Ok(atom)
}

#[test]
fn test_parser_read_atom() -> Result<()> {
    let (_, x) = read_atom_xyz.parse_peek("C -11.4286 -1.3155  0.0000 \n").unwrap();
    assert_eq!("C", x.symbol);
    let (_, x) = read_atom_xyz.parse_peek(" C -11.4286 -1.3155  0.0000 \n").unwrap();
    assert_eq!("C", x.symbol);
    assert_eq!(0.0, x.position[2]);
    Ok(())
}

/// Create a list of atoms from many lines in xyz format
///
/// # Example
///
/// 16
/// comment line
/// C -11.4286  1.7645  0.0000
/// C -10.0949  0.9945  0.0000
/// C -10.0949 -0.5455  0.0000
fn read_xyz_stream(s: &mut &str) -> PResult<Vec<Atom>> {
    let mut read_atoms = repeat(1.., read_atom_xyz);
    let (_, _, atoms) = ((
        read_usize, // natoms
        read_line,  // ignore title
        read_atoms, // many atoms
    ))
        .parse_next(s)?;
    Ok(atoms)
}

#[test]
fn test_parser_read_xyz() {
    let txt = " 16
   Configuration number :        7
   N   1.38635  -0.29197   0.01352
   N  -1.38633   0.29227   0.00681
   C   0.91882   0.97077  -0.01878
   C  -0.44889   1.25897  -0.02208
   C  -0.91881  -0.97095   0.00730
   C   0.44886  -1.25914   0.01058
   H   1.66107   1.76596  -0.02576
   H  -0.80712   2.28604  -0.03176
   H   0.80714  -2.28611   0.02735
   H  -1.66109  -1.76602   0.02139
   O   4.17450  -0.57938  -0.37886
   H   3.20186  -0.81182  -0.38259
   H   4.56688  -0.80173   0.51370
   O  -3.77040   0.96374  -1.49419
   H  -3.35189   1.74003  -1.96565
   H  -3.08717   0.51682  -0.91667

";
    let (_, x) = read_xyz_stream.parse_peek(txt).unwrap();
    assert_eq!(x.len(), 16);
}

#[test]
fn test_text_parser() -> Result<()> {
    let fname = "tests/files/multi.xyz";
    let mut reader = GrepReader::try_from_path(fname.as_ref())?;
    let n = reader.mark(r"^\s*\d+\s*$", None)?;
    assert_eq!(n, 6);
    reader.goto_next_marker()?;
    let parts = (0..n).map(move |i| {
        let mut s = String::new();
        reader.read_until_next_marker(&mut s)?;
        Ok_(s) // anyhow wrapper function for Ok
    });

    let mols: Result<Vec<_>> = parts
        .map(|part| {
            let part = part?;
            let mol = read_xyz_stream
                .parse(&part)
                .map_err(|e| anyhow!("{e}\nstream = {part:?}"))?;
            Ok(mol)
        })
        .collect();
    let mols = mols?;
    assert_eq!(mols.len(), 6);
    assert_eq!(mols[5].len(), 13);

    Ok(())
}
// 99232ff4 ends here