import os
import re

def generate_index():
    characters = [f.replace('.md', '') for f in os.listdir('characters') if f.endswith('.md')]
    index = {}

    for chapter_file in sorted(os.listdir('chapters')):
        if not chapter_file.endswith('.md'): continue
        with open(os.path.join('chapters', chapter_file), 'r') as f:
            content = f.read()
            for char in characters:
                if re.search(r'\b' + char + r'\b', content, re.IGNORECASE):
                    if char not in index: index[char] = []
                    index[char].append(chapter_file)

    with open('KNOWLEDGE_GRAPH.md', 'w') as f:
        f.write('# Knowledge Graph\n\n')
        for char, chapters in index.items():
            f.write(f'## {char}\n')
            for chap in chapters:
                f.write(f'- [{chap}](chapters/{chap})\n')
            f.write('\n')

if __name__ == "__main__":
    generate_index()