zettelkasten-index.py

"""Script to create an index file from my Zettelkasten notes (md files)"""
from collections import defaultdict
import os
from pathlib import Path
import re
from typing import NamedTuple

INDEX_NAME = "index.md"
NOTE_FILENAME_REGEX = re.compile(r"^\d.*\.md")
TAG_REGEX = re.compile(r"#\S+")
HEADER = """# Bob's Zettelkasten index

Idea from [this post](https://www.edwinwenink.xyz/posts/42-vim_notetaking/).
This file gets generated by [this script](index.py).

"""


class Note(NamedTuple):
    title: str
    filename: str


def group_notes_by_tag(
    directory: Path = Path.cwd()
) -> defaultdict[str, list[Note]]:
    notes_grouped_by_tags = defaultdict(list)

    filenames = os.listdir(directory)

    for filename in filenames:
        if not NOTE_FILENAME_REGEX.match(filename):
            continue

        note_content = Path(filename).read_text()
        title = note_content.splitlines()[0].strip("# ")
        tag_lines = "\n".join(
            line for line in note_content.splitlines()
            if line.startswith("#")
        )
        tags = re.findall(TAG_REGEX, tag_lines)

        for tag in tags:
            tag = tag.lstrip("#").title()
            notes_grouped_by_tags[tag].append(
                Note(title=title, filename=filename)
            )

    return notes_grouped_by_tags


def create_index(tag_index_tree: defaultdict[str, list[Note]]) -> None:
    output = [HEADER]

    for tag, notes in sorted(tag_index_tree.items()):
        tag = tag.lower().capitalize()
        output.append(f"## {tag}\n\n")

        for note in notes:
            title = note.title.capitalize()
            output.append(f"- [{title}]({note.filename})\n")

        output.append("\n\n")

    with open(INDEX_NAME, "w") as f:
        f.write("".join(output))


if __name__ == "__main__":
    tag_index_tree = group_notes_by_tag()
    create_index(tag_index_tree)