def replace_facets_with_markdown(text, facets):
    if not facets:
        return text
        
    # We need to work with bytes since ATProto facets use UTF-8 byte offsets
    text_bytes = text.encode('utf-8')
    
    # Sort facets by byteStart, descending so we can replace from back to front
    # to avoid messing up the offsets for earlier facets
    
    # Actually, one facet might have multiple features, but usually it's just one Link.
    # Let's extract all links with their offsets.
    links = []
    for facet in facets:
        for feature in getattr(facet, 'features', []):
            if hasattr(feature, 'uri'):
                links.append({
                    'start': facet.index.byte_start,
                    'end': facet.index.byte_end,
                    'uri': feature.uri
                })
                
    links.sort(key=lambda x: x['start'], reverse=True)
    
    for link in links:
        start = link['start']
        end = link['end']
        uri = link['uri']
        
        # Original text for the link
        link_text = text_bytes[start:end].decode('utf-8')
        
        # Replace with markdown link
        markdown_link = f"[{link_text}]({uri})".encode('utf-8')
        
        text_bytes = text_bytes[:start] + markdown_link + text_bytes[end:]
        
    return text_bytes.decode('utf-8')

# test it
import sys
from src.void_tools.client import get_client
client = get_client()
response = client.get_posts(['at://did:plc:gfrmhdmjvxn2sjedzboeudef/app.bsky.feed.post/3mgtyb5h5fc25'])
for post in response.posts:
    text = post.record.text
    facets = getattr(post.record, 'facets', [])
    print(replace_facets_with_markdown(text, facets))