#!/usr/bin/env python3
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"""Code snippet for ring perception."""

from openeye import oechem, oedepict

from oecookbook.scripts.ring_perception import atoms_in_same_ring

mol = oechem.OEGraphMol()
oechem.OESmilesToMol(mol, "CC1CCC23C1C(C(C2)C(C3)CC4CCC5(C4)CCCC5)C(=O)C")
oedepict.OEPrepareDepiction(mol)

width, height = 400, 300
image = oedepict.OEImage(width, height)


class IsSpiroAtom(oechem.OEUnaryAtomPred):
    """
    Predicate class to identify spiro atoms.

    Spiro atoms are the single, central atom that connects more distinct molecular rings.
    """

    def __call__(self, atom: oechem.OEAtomBase) -> bool:
        """Evaluate the atom."""
        spiro_atom_hvy_degree = 4
        if not atom.IsInRing() or atom.GetHvyDegree() != spiro_atom_hvy_degree:
            return False
        ring_neighs = [nbr for nbr in atom.GetAtoms() if nbr.IsInRing()]
        if len(ring_neighs) != spiro_atom_hvy_degree:
            # spiro atom have to have 4 ring neighbors
            return False

        # spiro atom has to have to 2 pairs of neighbors in 2 different rings)
        for neigh in ring_neighs:

            num_neighs_in_same_ring = 0
            for other_neigh in ring_neighs:
                if neigh.GetIdx() == other_neigh.GetIdx():
                    continue
                if atoms_in_same_ring(neigh, other_neigh):
                    num_neighs_in_same_ring += 1
            if num_neighs_in_same_ring != 1:
                #  bridgehead atom not a spiro atom
                return False
        return True


scale = oedepict.OEScale_AutoScale
opts = oedepict.OE2DMolDisplayOptions(width, height, scale)

disp = oedepict.OE2DMolDisplay(mol, opts)
highlight = oedepict.OEHighlightByBallAndStick(oechem.OEBlueTint)
oedepict.OEAddHighlighting(disp, highlight, IsSpiroAtom())
oedepict.OERenderMolecule(image, disp)
oedepict.OEWriteImage("depict_spiro_atoms.svg", image)