"""Emit state-only LSTP event descriptors for both native lowering paths."""
from .compiler import _number


def contact_table(contacts):
    """Rows: velocity indices, gap, stiffness, damping, depth, force option,
    subtract-first flag. Keep the force expression's floating operation order.
    Position follows velocity in each reviewed mechanical state pair.
    """
    rows = []
    for v1, v2, gap, stiffness, damping, depth, option, subtract_first in contacts:
        rows.append('{' + ','.join((str(v1), str(v2), _number(gap),
            _number(stiffness), _number(damping), _number(depth),
            str(option), str(subtract_first))) + '}')
    count = len(rows)
    header = f'''#define NCONTACTS {count}
typedef struct {{
    int velocity1, velocity2;
    double gap0, stiffness, damping, depth;
    int signed_force, subtract_first;
}} NativeContact;
extern const NativeContact model_contacts[{max(1, count)}];'''
    source = f'const NativeContact model_contacts[{max(1, count)}] = {{' + (','.join(rows) or '{0,0,0,0,0,0,0,0}') + '};'
    return source, header