"""Convert a UTF-8 id,front,back CSV into a persistent Basic-card APKG."""
import argparse
import csv
from pathlib import Path

from ankiforge import BuildOptions, Note, Project


def build_csv(source: Path, destination: Path, namespace: str, deck: str) -> int:
    if destination.exists():
        raise ValueError('Choose a new output path; keep previously distributed APKGs')
    project = Project(namespace, default_deck=deck)
    seen = set()
    with source.open(encoding='utf-8-sig', newline='') as handle:
        rows = csv.DictReader(handle, strict=True)
        if rows.fieldnames != ['id', 'front', 'back']:
            raise ValueError('Expected the header id,front,back in that order')
        for row in rows:
            if None in row or any(value is None or not value.strip() for value in row.values()):
                raise ValueError(f'Line {rows.line_num}: expected three nonempty fields')
            key = row['id'].strip()
            if key in seen:
                raise ValueError(f'Line {rows.line_num}: duplicate id {key!r}')
            project.add(key, Note.basic(row['front'], row['back']))
            seen.add(key)
    if not seen:
        raise ValueError('The CSV must contain at least one note')
    project.build(BuildOptions.to(destination))
    return len(seen)


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('source', type=Path)
    parser.add_argument('destination', type=Path)
    parser.add_argument('--namespace', default='csv-vocabulary')
    parser.add_argument('--deck', default='Vocabulary')
    args = parser.parse_args()
    count = build_csv(args.source, args.destination, args.namespace, args.deck)
    print(f'{args.destination}: {count} notes, {count} Basic cards')