import csv
from typing import Iterable, Optional, Sequence


def csv_as_dicts(
    lines: Iterable[str], types: Sequence[type], headers: Optional[Sequence[str]] = None
):
    records = []
    rows = csv.reader(lines)
    if headers is None:
        headers = next(rows)
    for row in rows:
        record = {name: func(val) for name, func, val in zip(headers, types, row)}
        records.append(record)
    return records


def read_csv_as_dicts(
    filename: str, types: Sequence[type], headers: Optional[Sequence[str]] = None
):
    """
    Read CSV data into list of dictionaries with optional type conversion.
    """
    with open(filename) as file:
        return csv_as_dicts(file, types, headers)


def csv_as_instances(lines: Iterable[str], cls: type, has_headers: bool = True):
    records = []
    rows = csv.reader(lines)
    if has_headers:
        next(rows)
    for row in rows:
        record = cls.from_row(row)
        records.append(record)
    return records


def read_csv_as_instances(filename: str, cls: type, has_headers: bool = True):
    """
    Read CSV data into list of instances.
    """
    with open(filename) as file:
        return csv_as_instances(file, cls, has_headers)