from psycopg.rows import dict_row, Row
from .connection import g_conn_dict as conn
from .operation import *
from .change_set import ChangeSet


def read(name: str, sql: str) -> Row | None:
    with conn[name].cursor(row_factory=dict_row) as cur:
        cur.execute(sql)
        return cur.fetchone()


def write(name: str, sql: str) -> None:
    with conn[name].cursor() as cur:
        cur.execute(sql)


def decorate(value: str | None, type: str, optional: bool) -> str:
    if optional:
        value = 'NULL' if value == None else value
        if type == 'str':
            value = f'"{value}"' if value != 'NULL' else value
    return value


def update(name: str, type: str, table: str, id_key: str, id_value: str, key: str, key_type: str, raw_old_value: str, value: str, optional: bool = False) -> ChangeSet:
    value = f"'{value}'" if key_type is 'str' else value
    old = decorate(raw_old_value, key_type, optional)

    with conn[name].cursor() as cur:
        sql = f"update {table} set {key} = {value} where {id_key} = '{id_value}'"
        cur.execute(sql)
        redo = sql.replace("'", '"')
        undo = f'update {table} set {key} = {old} where {id_key} = "{id_value}"'
        add_operation(name, redo, undo)

    change = ChangeSet()
    change.update(type, id_value, key)
    return change