orgmode_to_anki.py

#!/usr/bin/env python3

"""
orgmode_to_anki.py
Read in an org-mode and convert it to a tab-separated file suitable for use with Anki.
Allows the file to then be imported as a new deck or to update an existing deck.
"""

import argparse


def read_orgmode_file(filename: str) -> list[str]:
    """
    Reads in an org-mode file and returns a list of strings, each containing a note.
    """
    notes = []
    lines = []
    try:
        with open(filename, encoding="utf-8") as inputf:
            lines = [line for line in inputf.readlines()]
    except OSError as err:
        print(f"Problem occured while reading {filename}:", err)
    # Now convert the lines into notes
    current_line = ""
    for line in lines:
        # Org-mode notes start with "*"
        if current_line and line.startswith("*"):
            notes.append(current_line)
            current_line = line
        else:
            current_line += line
    return notes


def format_card(note: str) -> str:
    """Formats a single org-mode note as an HTML card."""
    lines = note.split("\n")
    if lines[0].startswith("* "):
        card_front = f"<br />{lines[0][2:]}<br />"
    else:
        print(f"Received an incorrectly formatted note: {note}")
        return ""
    card_back = "<br />".join(lines[1:])
    return card_front + "\t" + card_back


def write_cards_to_file(cards: list[str], output_file: str, append: bool) -> None:
    """Write the list of cards to file."""
    if append:
        file_args = "a"
    else:
        file_args = "w"
    try:
        with open(output_file, file_args, encoding="utf-8") as outputf:
            for card in cards:
                outputf.write(card + "\n")
    except OSError as err:
        print(f"Encountered issue while writing out file {output_file}", err)


def main() -> None:
    """Use read_orgmode_file() to read in a file, then operate on the resulting notes."""
    parser = argparse.ArgumentParser(
        description="Reads in an org-mode file and generates a "
        + "matching Anki card with HTML formatting."
    )
    parser.add_argument(
        "-i",
        "--input",
        nargs=1,
        type=str,
        required=True,
        dest="input_file",
        help="Location of the org-mode file to consume.",
    )
    parser.add_argument(
        "-o",
        "--output",
        nargs=1,
        type=str,
        required=False,
        dest="output_file",
        help="Output file where HTML-formatted Anki cards are written.",
    )
    parser.add_argument(
        "-a",
        "--append",
        action="store_true",
        help="Append to output file, " + "rather than writing to it.",
    )
    args = parser.parse_args()
    # Argparse guarantees that we don't need to wrap the next two lines in a try-except
    input_file = args.input_file[0].strip()
    if args.output_file is not None:
        output_file = args.output_file[0].strip()
    else:
        # Strip off the input file's filetype; append '.txt'
        output_prefix = input_file.rsplit(".", 1)[0]
        output_file = output_prefix + ".txt"
    try:
        notes = read_orgmode_file(input_file)
        cards = [format_card(note) for note in notes]
        write_cards_to_file(cards, output_file, args.append)
    except UnicodeDecodeError as err:
        print(f"Text in the input file {input_file} was not UTF-8 encoded.", err)
        return
    print(f"Done! Anki cards written to '{output_file}'")


if __name__ == "__main__":
    main()