#!/bin/env python
import re
import shutil
import sys
def doit(filename):
if not filename.endswith(".html"):
# nothing to do here
sys.exit(f"skipping {filename}\n")
alt_define = re.compile(r'.*#\s*alt-text:\s*([^<]+)')
img_define = re.compile(r'(]*\balt=")[^"]*(")')
empty_span = re.compile(r'<\s*span\b[^>]*>\s*')
# back up the original file
backup = f"{filename}.backup"
try:
shutil.copy(filename, backup)
except OSError:
sys.exit(f"unable to work on {filename}\n")
# now overwrite the original with the new version with the alt
# text substituted
with open(backup, encoding='utf-8') as fin, open(filename, "w", encoding='utf-8') as fout:
current_alt = None
for line in fin:
# check if we define an alt?
if g := alt_define.match(line):
current_alt = g.group(1)
print(f"{current_alt=}")
# now remove the comment
line = line.replace(f"# alt-text: {current_alt}", "")
# it the line is now just an empty then skip
if empty_span.match(line.strip()):
continue
# check if we are defining an image
if current_alt:
line, n = img_define.subn(rf'\g<1>{current_alt}\g<2>', line)
if n > 0:
current_alt = None
fout.write(line)
if current_alt:
# something back happened
sys.exit("Error: alt text without associated img tag\n")
if __name__ == "__main__":
filename = sys.argv[1]
doit(filename)