""" Budget Parser """

from collections import namedtuple

from .exceptions import BudgetParserError

EXPECTED_TABLE_HEADERS = [
    "Nr.",
    "Projekt",
    "Laufzeit",
    "BA",
    "Budget",
    "Ausgaben",
    "Rest",
]

BudgetData = namedtuple(
    "BudgetData",
    [
        "row",
        "number",
        "project_name",
        "period",
        "project",
        "budget",
        "expenses",
        "rest",
    ],
)


def _check_table_header(row):
    fields = [c.strip() for c in row[:7]]
    print(fields)
    print(EXPECTED_TABLE_HEADERS)
    if fields != EXPECTED_TABLE_HEADERS:
        raise BudgetParserError(f"unexpected headers: '{row}'")


def _skip_empty_lines(rows, start=0):
    for i, row in enumerate(rows, start=start):
        first_cell = row[0]
        if first_cell is None:
            continue
        if isinstance(first_cell, str) and first_cell.strip() == "":
            continue
        yield i, row


def _parse_data_table(rows, start=2):
    for i, data in _skip_empty_lines(rows, start):
        yield BudgetData(i, *data[:7])


def parse_budget_data(xls_sheet):
    """ parses the budget data """
    rows = xls_sheet.values
    _check_table_header(next(rows))
    return list(_parse_data_table(rows, start=2))