Migrate neuron zettelkastens to the new hash ID format

migrate.py

#!/usr/bin/env python3.8

import re
import sys
import os
import uuid
from pathlib import Path
import glob
import time
import datetime
from collections import namedtuple

SRC_ZK, DEST_ZK = map(Path, sys.argv[1:])

Zettel = namedtuple('Zettel', ['id', 'date', 'content'])

SHORT_LINK = re.compile(r"<([A-Za-z-_0-9]+)>")
MARKDOWN_LINK = re.compile(r"\[([A-Z-a-z-_0-9]+)\]\(((?:z(?:cf)?).*?)\)")

# date-id => hash id
remap = {}

def generate_new_id():
    zid = '0'
    while zid.isdigit(): 
        zid = str(uuid.uuid4())[:8]
    return zid

def replace_links(md):
    repl_short_link = lambda match: f"<{remap[match.group(1)]}>"
    repl_markdown_link = lambda match: f"[{remap[match.group(1)]}]({match.group(2)})"
    step1 = re.sub(SHORT_LINK, repl_short_link, md)
    step2 = re.sub(MARKDOWN_LINK, repl_markdown_link, step1)
    return step2

def migrate_zettel(zettel):
    new_id = remap[zettel.id]
    with (DEST_ZK / f"{new_id}.md").open('w') as file:
        lines = replace_links(zettel.content).split('\n')
        file.writelines('\n'.join(lines[:2]))
        if zettel.date is not None:
            file.write(f"\ndate: {zettel.date.strftime('%Y-%m-%d')}")
        file.write('\n')
        file.writelines('\n'.join(lines[2:]))

def make_zettel_from_path(path):
    with (SRC_ZK / path).open() as file:
        zid = path.stem
        content = file.read()

        # Extract date from ID
        if re.match('\d{7}', zid):
            date_id = zid[:4] + str(int(zid[4]) - 1)
            date = datetime.datetime.strptime(date_id, "%y%W%w")
        else:
            date = None
            
        return Zettel(zid, date, content)

def main():
    zettels = []
    for zettel_path in map(Path, glob.glob(str(SRC_ZK / f"[A-Za-z-_0-9]*.md"))):
        zettel = make_zettel_from_path(zettel_path)

        if zettel.date is not None:
            remap[zettel.id] = generate_new_id() 
        else:
            # Keep non-date IDs since they can be meaningful
            remap[zettel.id] = zettel.id
            
        print(f"{zettel.id:<10} => {remap[zettel.id]}")
        zettels.append(zettel)

    for zettel in zettels:
        migrate_zettel(zettel)

if __name__ == '__main__':
    main()