import glob

def add_favicon(files, link_tag):
    for f in files:
        with open(f, 'r', encoding='utf-8') as file:
            content = file.read()
        
        if '<link rel="icon"' not in content:
            content = content.replace('</head>', f'  {link_tag}\n</head>')
            with open(f, 'w', encoding='utf-8') as file:
                file.write(content)

add_favicon(glob.glob('*.html'), '<link rel="icon" href="logo.png" type="image/png">')
add_favicon(glob.glob('blog/*.html'), '<link rel="icon" href="../logo.png" type="image/png">')
print("Favicon added.")