#!/usr/bin/env python3
"""Build an SQLite database from definition files."""

import gzip
import lzma
import os
import sqlite3
import sys
from pathlib import Path


def main():
    tlfi_root = os.environ.get("TLFI_ROOT")
    if not tlfi_root:
        sys.exit("No TLFI_ROOT environment variable.")
    tlfi_root_path = Path(tlfi_root)
    lexical_forms_path = tlfi_root_path / "lexical_forms.txt"
    definitions_path = tlfi_root_path / "definitions"

    db_path = Path.cwd() / "tlfi.db"
    conn = sqlite3.connect(db_path)
    create_database(conn)
    fill_database(conn, lexical_forms_path, definitions_path)
    conn.commit()
    conn.close()


def create_database(conn: sqlite3.Connection):
    cursor = conn.cursor()
    cursor.execute(
        "create table if not exists definitions ("
        "  id integer primary key,"
        "  lexical_form text,"
        "  definition blob not null"
        ");"
    )
    cursor.execute(
        "create index if not exists idx_forms on definitions(lexical_form);"
    )


def fill_database(
    conn: sqlite3.Connection,
    lexical_forms_path: Path,
    definitions_path: Path
):
    with open(lexical_forms_path, "rt") as lexical_forms_file:
        forms = [form.rstrip() for form in lexical_forms_file.readlines()]
    print(f"{len(forms)} forms in the lexical forms file.")
    cursor = conn.cursor()
    for letter in definitions_path.iterdir():
        if not letter.is_dir():
            continue
        for form_dir in letter.iterdir():
            form = form_dir.name
            print(form)
            insert_forms(cursor, form, form_dir)


def insert_forms(cursor: sqlite3.Cursor, form: str, form_dir: Path):
    for gz_file in form_dir.iterdir():
        with gzip.open(gz_file, "rt") as form_file:
            html = form_file.read()
        def_data = lzma.compress(html.encode())
        cursor.execute(
            "insert into definitions (lexical_form, definition) values (?, ?)",
            (form, def_data)
        )


if __name__ == "__main__":
    main()