from __future__ import annotations

import re
import unittest
from dataclasses import replace
from io import BytesIO
from unittest.mock import patch
from zipfile import ZipFile

from openpyxl import Workbook

from govoplan_core.core.tabular_sources import TabularSourceValidationError
from govoplan_connectors.backend import tabular_adapters as adapters


def workbook_bytes(*, dimension: str | None = None, last_cell: str = "A2") -> bytes:
    workbook = Workbook()
    workbook.active.append(["name"])
    workbook.active.append(["Ada"])
    output = BytesIO()
    workbook.save(output)
    workbook.close()
    result = BytesIO()
    with ZipFile(BytesIO(output.getvalue())) as original, ZipFile(result, "w") as modified:
        for entry in original.infolist():
            content = original.read(entry)
            if entry.filename == "xl/worksheets/sheet1.xml":
                xml = content.decode()
                if dimension is not None:
                    xml = re.sub(r'<dimension ref="[^"]+"\s*/>', f'<dimension ref="{dimension}"/>', xml)
                xml = xml.replace('r="A2"', f'r="{last_cell}"')
                xml = xml.replace('<row r="2">', f'<row r="{re.search(r"[0-9]+$", last_cell).group()}">')
                content = xml.encode()
            modified.writestr(entry, content)
    return result.getvalue()


def parse(payload: bytes):
    return adapters.parse_managed_tabular_content(payload, filename="fixture.xlsx", content_type=None, delimiter=",", sheet_name=None)


class XlsxSafetyBoundsTests(unittest.TestCase):
    def test_sparse_rows_cannot_bypass_limit_by_not_counting_as_data(self):
        with self.assertRaisesRegex(TabularSourceValidationError, "row"):
            parse(workbook_bytes(last_cell=f"A{adapters.MAX_FILE_ROWS + 2}"))

    def test_forged_small_dimensions_cannot_hide_far_away_cells(self):
        with self.assertRaisesRegex(TabularSourceValidationError, "row"):
            parse(workbook_bytes(dimension="A1:A2", last_cell="A1000000"))

    def test_forged_small_dimensions_cannot_hide_out_of_range_columns(self):
        with self.assertRaisesRegex(TabularSourceValidationError, "column"):
            parse(workbook_bytes(dimension="A1:A2", last_cell="XFD2"))

    def test_declared_dimensions_do_not_expand_or_truncate_real_rows(self):
        for dimension in ("A1:XFD1048576", "A1:A1"):
            with self.subTest(dimension=dimension):
                rows, sheet = parse(workbook_bytes(dimension=dimension))
                self.assertEqual(({"name": "Ada"},), rows)
                self.assertEqual("Sheet", sheet)

    def test_small_blank_gaps_and_exact_limit_remain_usable(self):
        for cell in ("A4", f"A{adapters.MAX_FILE_ROWS + 1}"):
            rows, _sheet = parse(workbook_bytes(last_cell=cell))
            self.assertEqual(({"name": "Ada"},), rows)

    def test_workbook_is_parsed_in_a_fresh_child_not_the_parent(self):
        with patch.object(adapters, "_parse_xlsx_content", side_effect=AssertionError("parent parser ran")):
            rows, sheet = parse(workbook_bytes())
        self.assertEqual(({"name": "Ada"},), rows)
        self.assertEqual("Sheet", sheet)

    def test_real_worker_timeout_fails_without_parent_fallback(self):
        limits = replace(adapters.XLSX_PROCESS_LIMITS, wall_seconds=0.001)
        with patch.object(adapters, "XLSX_PROCESS_LIMITS", limits), patch.object(
            adapters, "_parse_xlsx_content", side_effect=AssertionError("parent parser ran")
        ):
            with self.assertRaisesRegex(TabularSourceValidationError, "timeout"):
                parse(workbook_bytes())

    def test_child_validation_keeps_missing_sheet_message(self):
        with self.assertRaisesRegex(TabularSourceValidationError, "worksheet 'Missing' was not found"):
            adapters.parse_managed_tabular_content(
                workbook_bytes(), filename="fixture.xlsx", content_type=None,
                delimiter=",", sheet_name="Missing",
            )


if __name__ == "__main__":
    unittest.main()