from io import BytesIO
from types import SimpleNamespace

import openpyxl
from django.test import SimpleTestCase

from artifacts.views import XLSX_CONTENT_TYPE, is_xlsx_upload, xlsx_to_csv_text


class IsXlsxUploadTestCase(SimpleTestCase):
    def test_matches_exact_content_type(self):
        upload = SimpleNamespace(name="whatever.bin")
        self.assertTrue(is_xlsx_upload(upload, XLSX_CONTENT_TYPE))

    def test_matches_by_extension_regardless_of_content_type(self):
        upload = SimpleNamespace(name="sheet.xlsx")
        self.assertTrue(is_xlsx_upload(upload, "application/octet-stream"))
        self.assertTrue(is_xlsx_upload(upload, ""))

    def test_extension_match_is_case_insensitive(self):
        upload = SimpleNamespace(name="SHEET.XLSX")
        self.assertTrue(is_xlsx_upload(upload, ""))

    def test_rejects_other_files(self):
        upload = SimpleNamespace(name="report.pdf")
        self.assertFalse(is_xlsx_upload(upload, "application/pdf"))


class XlsxToCsvTextTestCase(SimpleTestCase):
    def make_xlsx(self, rows):
        workbook = openpyxl.Workbook()
        sheet = workbook.active
        for row in rows:
            sheet.append(row)
        buffer = BytesIO()
        workbook.save(buffer)
        buffer.seek(0)
        return buffer

    def test_converts_active_sheet_to_csv(self):
        upload = self.make_xlsx([["Item", "Q1", "Q2"], ["Cash", 1000, 1200]])
        content = xlsx_to_csv_text(upload)
        self.assertEqual(content, "Item,Q1,Q2\nCash,1000,1200\n")

    def test_uses_single_line_terminator_not_doubled(self):
        """Regression test: csv.writer's default "\\r\\n" gets a second
        newline translation from Path.write_text()'s text-mode handling when
        this string is later saved to disk, producing a blank line between
        every row on Windows - lineterminator="\\n" avoids embedding "\\r\\n"
        in the string in the first place, leaving the OS-level text-mode
        write as the only place "\\n" becomes "\\r\\n"."""
        upload = self.make_xlsx([["a"], ["b"], ["c"]])
        content = xlsx_to_csv_text(upload)
        self.assertNotIn("\r", content)
        self.assertEqual(content.count("\n"), 3)

    def test_empty_cells_become_empty_strings(self):
        upload = self.make_xlsx([["a", "b"], ["x", None]])
        content = xlsx_to_csv_text(upload)
        self.assertEqual(content, "a,b\nx,\n")