from django.core.exceptions import ValidationError
from django.core.files.uploadedfile import SimpleUploadedFile
from django.test import TestCase, override_settings

from .validators import validate_receipt_file
from .views import SubmitClaimView


class ReceiptValidatorTests(TestCase):
    def test_accepts_valid_pdf(self):
        file_obj = SimpleUploadedFile(
            "receipt.pdf",
            b"%PDF-1.4\nsample",
            content_type="application/pdf",
        )
        try:
            validate_receipt_file(file_obj)
        except ValidationError as exc:  # pragma: no cover - explicit failure message
            self.fail(f"Valid PDF rejected: {exc}")

    def test_rejects_disallowed_extension(self):
        file_obj = SimpleUploadedFile(
            "script.exe",
            b"MZ fake exe",
            content_type="application/octet-stream",
        )
        with self.assertRaises(ValidationError):
            validate_receipt_file(file_obj)

    @override_settings(CLAIMS_MAX_RECEIPT_BYTES=1024)
    def test_rejects_too_large_file(self):
        big_payload = b"%PDF-1.4\n" + b"a" * 2048
        file_obj = SimpleUploadedFile(
            "large.pdf",
            big_payload,
            content_type="application/pdf",
        )
        with self.assertRaises(ValidationError):
            validate_receipt_file(file_obj)

    def test_rejects_signature_mismatch(self):
        file_obj = SimpleUploadedFile(
            "fake.pdf",
            b"\x89PNG\r\n\x1a\nnot a pdf",
            content_type="application/pdf",
        )
        with self.assertRaises(ValidationError):
            validate_receipt_file(file_obj)


class ClaimFormsetLimitTests(TestCase):
    def test_default_formset_has_single_row(self):
        view = SubmitClaimView()
        formset = view.build_formset(extra=1)
        self.assertEqual(formset.total_form_count(), 1)

    def test_cannot_submit_more_than_max_forms(self):
        view = SubmitClaimView()
        data = {
            "claim_lines-TOTAL_FORMS": "6",
            "claim_lines-INITIAL_FORMS": "0",
            "claim_lines-MIN_NUM_FORMS": "1",
            "claim_lines-MAX_NUM_FORMS": "5",
        }
        formset = view.build_formset(data=data)
        self.assertFalse(formset.is_valid())
        self.assertTrue(formset.non_form_errors())