#!/bin/env python3

from typing import List, Optional
import argparse
import sqlite3
import os
import re
import datetime

import csv


TABLES = ['branch', 'wb_gl', 'wb_kg', 'wb_rd', 'wine_attribute', 'wine_cultivation',
          'member', 'member_billing_address', 'contract', 'area_commitment',
          'season', 'modifier', 'delivery', 'delivery_part', 'delivery_part_modifier', ]
# 'payment_variant', 'delivery_payment', 'member_payment']


def get_sql_files() -> List[str]:
    base_dir = '..'
    entries_0 = os.listdir(f'{base_dir}/sql')
    dir_name = [e for e in entries_0 if e.startswith("v") and len(e) == 3][-1]
    entries_data = os.listdir(f'{base_dir}/data')

    files = [f'{base_dir}/sql/{dir_name}/{e}'
             for e in os.listdir(f'{base_dir}/sql/{dir_name}')
             if e.endswith('.sql')] + \
            [f'{base_dir}/data/{e}'
             for e in entries_data
             if e.endswith('.sql')] + \
            [f'{base_dir}/sql/{e}'
             for e in entries_0
             if e.endswith('.sql') and not e.startswith('sample')]

    files.sort(key=lambda f: f.split('/')[-1])
    return files


def sqlite_regexp(pattern: str, value: Optional[str]) -> Optional[bool]:
    if value is None:
        return None
    return re.match(pattern, value) is not None


def import_csv(cur: sqlite3.Cursor, table_name: str) -> None:
    rows = list(csv.parse(f'{args.dir}/{table_name}.csv'))
    if len(rows) == 0:
        return

    names = tuple(rows[0].keys())
    values = [tuple(row.values()) for row in rows]

    sql = f'INSERT INTO {table_name} ({", ".join(names)}) VALUES ({", ".join(["?"] * len(names))})'
    print(sql)
    cur.executemany(sql, values)
    print(f'{len(values)} inserts')

    cur.close()


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('dir', type=str, metavar='DIR',
                        help='The directory where the migrated csv files are stored')
    parser.add_argument('db', type=str, metavar='DB',
                        help='The sqlite database file')
    parser.add_argument('-k', '--keep', action='store_true', default=False,
                        help='Whether the database file should be overwritten or kept')
    args = parser.parse_args()

    if not args.keep:
        try:
            os.remove(args.db)
        except FileNotFoundError:
            pass

    sqlite3.register_adapter(datetime.date, lambda d: str(d))
    sqlite3.register_adapter(datetime.time, lambda t: str(t))

    DB_CNX = sqlite3.connect(args.db)
    DB_CNX.create_function('REGEXP', 2, sqlite_regexp)

    if not args.keep:
        for file_name in get_sql_files():
            with open(file_name, encoding='utf-8') as sql_file:
                print(f'Executing {file_name}')
                DB_CNX.executescript(sql_file.read())

    try:
        DB_CNX.isolation_level = None
        # Member predecessors may refer to a higher MgNr
        DB_CNX.execute("PRAGMA foreign_keys = OFF")
        DB_CNX.execute("BEGIN")
        for table in TABLES:
            import_csv(DB_CNX.cursor(), table)
        DB_CNX.execute("COMMIT")
    except Exception as err:
        DB_CNX.execute("ROLLBACK")
        raise err
    finally:
        DB_CNX.execute("PRAGMA foreign_keys = ON")
        DB_CNX.close()