#!/usr/bin/env python3
"""v6 T3c - replace scientific-notation COORDINATES with exact 0.

Float accumulation in the T3a/T3b generators emitted coordinates like 3.552713679e-15
(i.e. zero). KiCad's s-expression parser is not guaranteed to accept exponent notation.

!! LESSON (2026-08-24): a first attempt used a bare numeric regex over the whole file and
   corrupted 264 UUIDs - segments such as "895e-4153" parse as scientific notation.
   This version ONLY touches tokens inside an (at ...) form, only when the token is a
   complete float in exponent form, and only when |value| < 1e-9. It also refuses to run
   if any UUID would change.

Usage: python3 2026-08-24_v6_T3c_fix_sci_notation.py [--apply]
"""
import re, sys, os, shutil

KI = os.path.join(os.path.dirname(os.path.abspath(__file__)), '..', '03-Architecture-Hardware', 'kicad')
FILES = [os.path.join(KI, 'Drogheda-sym.kicad_sym'), os.path.join(KI, 'hbox-watchdog-v6.kicad_sch')]
APPLY = '--apply' in sys.argv
AT   = re.compile(r'\(at ([^()]*)\)')
NUM  = re.compile(r'^[+-]?(?:\d+\.?\d*|\.\d+)[eE][+-]?\d+$')
UUID = re.compile(r'\(uuid "([^"]*)"\)')

total = 0
for f in FILES:
    src = open(f, encoding='utf-8').read()
    changed = []
    def fix(m):
        toks = m.group(1).split()
        out = []
        for t in toks:
            if NUM.fullmatch(t):
                v = float(t)
                if abs(v) >= 1e-9:
                    sys.exit('REFUSING: non-negligible exponent coordinate %s' % t)
                changed.append((m.group(0), t)); out.append('0')
            else:
                out.append(t)
        return '(at ' + ' '.join(out) + ')'
    new = AT.sub(fix, src)
    if UUID.findall(new) != UUID.findall(src):
        sys.exit('REFUSING: a UUID would change - aborting')
    print('%-30s %d coordinate(s) fixed' % (os.path.basename(f), len(changed)))
    for before, tok in changed:
        print('    %s   (token %s -> 0)' % (before, tok))
    total += len(changed)
    if APPLY and changed:
        shutil.copy2(f, f + '.T3cbak'); open(f, 'w', encoding='utf-8').write(new)
print('total: %d' % total)
print('APPLIED' if APPLY else '\nDRY RUN - nothing written. Re-run with --apply.')