"""
Tests for Inference Pipeline

Tests the cross-validation logic between payment_line and detected fields:
- OCR override from payment_line
- Amount override from payment_line
- Bankgiro/Plusgiro comparison (no override)
- Validation scoring
"""

import pytest
from unittest.mock import MagicMock, patch
from backend.pipeline.pipeline import InferencePipeline, InferenceResult, CrossValidationResult


class TestCrossValidationResult:
    """Tests for CrossValidationResult dataclass."""

    def test_default_values(self):
        """Test default values."""
        cv = CrossValidationResult()
        assert cv.ocr_match is None
        assert cv.amount_match is None
        assert cv.bankgiro_match is None
        assert cv.plusgiro_match is None
        assert cv.payment_line_ocr is None
        assert cv.payment_line_amount is None
        assert cv.payment_line_account is None
        assert cv.payment_line_account_type is None

    def test_attributes(self):
        """Test setting attributes."""
        cv = CrossValidationResult()
        cv.ocr_match = True
        cv.amount_match = True
        cv.payment_line_ocr = '12345678901'
        cv.payment_line_amount = '100'
        cv.details = ['OCR match', 'Amount match']

        assert cv.ocr_match is True
        assert cv.amount_match is True
        assert cv.payment_line_ocr == '12345678901'
        assert 'OCR match' in cv.details


class TestInferenceResult:
    """Tests for InferenceResult dataclass."""

    def test_default_fields(self):
        """Test default field values."""
        result = InferenceResult()
        assert result.fields == {}
        assert result.confidence == {}
        assert result.errors == []

    def test_set_fields(self):
        """Test setting field values."""
        result = InferenceResult()
        result.fields = {
            'OCR': '12345678901',
            'Amount': '100',
            'Bankgiro': '782-1713'
        }
        result.confidence = {
            'OCR': 0.95,
            'Amount': 0.90,
            'Bankgiro': 0.88
        }

        assert result.fields['OCR'] == '12345678901'
        assert result.fields['Amount'] == '100'
        assert result.fields['Bankgiro'] == '782-1713'

    def test_cross_validation_assignment(self):
        """Test cross validation assignment."""
        result = InferenceResult()
        result.fields = {'OCR': '12345678901'}

        cv = CrossValidationResult()
        cv.ocr_match = True
        cv.payment_line_ocr = '12345678901'
        result.cross_validation = cv

        assert result.cross_validation is not None
        assert result.cross_validation.ocr_match is True


class TestPaymentLineParsingInPipeline:
    """Tests for payment_line parsing in cross-validation."""

    def test_parse_payment_line_format(self):
        """Test parsing of payment_line format: OCR:xxx Amount:xxx BG:xxx"""
        # Simulate the parsing logic from pipeline
        payment_line = "OCR:310196187399952 Amount:11699 BG:782-1713"

        pl_parts = {}
        for part in payment_line.split():
            if ':' in part:
                key, value = part.split(':', 1)
                pl_parts[key.upper()] = value

        assert pl_parts.get('OCR') == '310196187399952'
        assert pl_parts.get('AMOUNT') == '11699'
        assert pl_parts.get('BG') == '782-1713'

    def test_parse_payment_line_with_plusgiro(self):
        """Test parsing with Plusgiro."""
        payment_line = "OCR:12345678901 Amount:500 PG:1234567-8"

        pl_parts = {}
        for part in payment_line.split():
            if ':' in part:
                key, value = part.split(':', 1)
                pl_parts[key.upper()] = value

        assert pl_parts.get('OCR') == '12345678901'
        assert pl_parts.get('PG') == '1234567-8'
        assert pl_parts.get('BG') is None

    def test_parse_empty_payment_line(self):
        """Test parsing empty payment_line."""
        payment_line = ""

        pl_parts = {}
        for part in payment_line.split():
            if ':' in part:
                key, value = part.split(':', 1)
                pl_parts[key.upper()] = value

        assert pl_parts.get('OCR') is None
        assert pl_parts.get('AMOUNT') is None


class TestOCROverride:
    """Tests for OCR override logic."""

    def test_ocr_override_when_different(self):
        """Test OCR is overridden when payment_line value differs."""
        result = InferenceResult()
        result.fields = {'OCR': 'wrong_ocr_12345', 'payment_line': 'OCR:correct_ocr_67890 Amount:100 BG:782-1713'}

        # Simulate the override logic
        payment_line = result.fields.get('payment_line')
        pl_parts = {}
        for part in str(payment_line).split():
            if ':' in part:
                key, value = part.split(':', 1)
                pl_parts[key.upper()] = value

        payment_line_ocr = pl_parts.get('OCR')

        # Override detected OCR with payment_line OCR
        if payment_line_ocr:
            result.fields['OCR'] = payment_line_ocr

        assert result.fields['OCR'] == 'correct_ocr_67890'

    def test_ocr_no_override_when_no_payment_line(self):
        """Test OCR is not overridden when no payment_line."""
        result = InferenceResult()
        result.fields = {'OCR': 'original_ocr_12345'}

        # No payment_line, no override
        assert result.fields['OCR'] == 'original_ocr_12345'


class TestAmountOverride:
    """Tests for Amount override logic."""

    def test_amount_override(self):
        """Test Amount is overridden from payment_line."""
        result = InferenceResult()
        result.fields = {
            'Amount': '999.00',
            'payment_line': 'OCR:12345 Amount:11699 BG:782-1713'
        }

        payment_line = result.fields.get('payment_line')
        pl_parts = {}
        for part in str(payment_line).split():
            if ':' in part:
                key, value = part.split(':', 1)
                pl_parts[key.upper()] = value

        payment_line_amount = pl_parts.get('AMOUNT')

        if payment_line_amount:
            result.fields['Amount'] = payment_line_amount

        assert result.fields['Amount'] == '11699'


class TestBankgiroComparison:
    """Tests for Bankgiro comparison (no override)."""

    def test_bankgiro_match(self):
        """Test Bankgiro match detection."""
        import re

        detected_bankgiro = '782-1713'
        payment_line_account = '782-1713'

        det_digits = re.sub(r'\D', '', detected_bankgiro)
        pl_digits = re.sub(r'\D', '', payment_line_account)

        assert det_digits == pl_digits
        assert det_digits == '7821713'

    def test_bankgiro_mismatch(self):
        """Test Bankgiro mismatch detection."""
        import re

        detected_bankgiro = '782-1713'
        payment_line_account = '123-4567'

        det_digits = re.sub(r'\D', '', detected_bankgiro)
        pl_digits = re.sub(r'\D', '', payment_line_account)

        assert det_digits != pl_digits

    def test_bankgiro_not_overridden(self):
        """Test that Bankgiro is NOT overridden from payment_line."""
        result = InferenceResult()
        result.fields = {
            'Bankgiro': '999-9999',  # Different value
            'payment_line': 'OCR:12345 Amount:100 BG:782-1713'
        }

        # Bankgiro should NOT be overridden (per current logic)
        # Only compared for validation
        original_bankgiro = result.fields['Bankgiro']

        # The override logic explicitly skips Bankgiro
        # So we verify it remains unchanged
        assert result.fields['Bankgiro'] == '999-9999'
        assert result.fields['Bankgiro'] == original_bankgiro


class TestValidationScoring:
    """Tests for validation scoring logic."""

    def test_all_fields_match(self):
        """Test score when all fields match."""
        matches = [True, True, True]  # OCR, Amount, Bankgiro
        match_count = sum(1 for m in matches if m)
        total = len(matches)

        assert match_count == 3
        assert total == 3

    def test_partial_match(self):
        """Test score with partial matches."""
        matches = [True, True, False]  # OCR match, Amount match, Bankgiro mismatch
        match_count = sum(1 for m in matches if m)

        assert match_count == 2

    def test_no_matches(self):
        """Test score when nothing matches."""
        matches = [False, False, False]
        match_count = sum(1 for m in matches if m)

        assert match_count == 0

    def test_only_count_present_fields(self):
        """Test that only present fields are counted."""
        # When invoice has both BG and PG but payment_line only has BG,
        # we should only count BG in validation

        payment_line_account_type = 'bankgiro'
        bankgiro_match = True
        plusgiro_match = None  # Not compared because payment_line doesn't have PG

        matches = []
        if payment_line_account_type == 'bankgiro' and bankgiro_match is not None:
            matches.append(bankgiro_match)
        elif payment_line_account_type == 'plusgiro' and plusgiro_match is not None:
            matches.append(plusgiro_match)

        assert len(matches) == 1
        assert matches[0] is True


class TestAmountNormalization:
    """Tests for amount normalization for comparison."""

    def test_normalize_amount_with_comma(self):
        """Test normalizing amount with comma decimal."""
        import re

        amount = "11699,00"
        normalized = re.sub(r'[^\d]', '', amount)

        # Remove trailing zeros for öre
        if len(normalized) > 2 and normalized[-2:] == '00':
            normalized = normalized[:-2]

        assert normalized == '11699'

    def test_normalize_amount_with_dot(self):
        """Test normalizing amount with dot decimal."""
        import re

        amount = "11699.00"
        normalized = re.sub(r'[^\d]', '', amount)

        if len(normalized) > 2 and normalized[-2:] == '00':
            normalized = normalized[:-2]

        assert normalized == '11699'

    def test_normalize_amount_with_space_separator(self):
        """Test normalizing amount with space thousand separator."""
        import re

        amount = "11 699,00"
        normalized = re.sub(r'[^\d]', '', amount)

        if len(normalized) > 2 and normalized[-2:] == '00':
            normalized = normalized[:-2]

        assert normalized == '11699'


class TestBusinessFeatures:
    """Tests for business invoice features (line items, VAT, validation)."""

    def test_inference_result_has_business_fields(self):
        """Test that InferenceResult has business feature fields."""
        result = InferenceResult()
        assert result.line_items is None
        assert result.vat_summary is None
        assert result.vat_validation is None

    def test_to_json_without_business_features(self):
        """Test to_json works without business features."""
        result = InferenceResult()
        result.fields = {'InvoiceNumber': '12345'}
        result.confidence = {'InvoiceNumber': 0.95}

        json_result = result.to_json()

        assert json_result['InvoiceNumber'] == '12345'
        assert 'line_items' not in json_result
        assert 'vat_summary' not in json_result
        assert 'vat_validation' not in json_result

    def test_to_json_with_line_items(self):
        """Test to_json includes line items when present."""
        from backend.table.line_items_extractor import LineItem, LineItemsResult

        result = InferenceResult()
        result.fields = {'Amount': '12500.00'}
        result.line_items = LineItemsResult(
            items=[
                LineItem(
                    row_index=0,
                    description="Product A",
                    quantity="2",
                    unit_price="5000,00",
                    amount="10000,00",
                    vat_rate="25",
                    confidence=0.9
                )
            ],
            header_row=["Beskrivning", "Antal", "Pris", "Belopp", "Moms"],
            raw_html="<table>...</table>"
        )

        json_result = result.to_json()

        assert 'line_items' in json_result
        assert len(json_result['line_items']['items']) == 1
        assert json_result['line_items']['items'][0]['description'] == "Product A"
        assert json_result['line_items']['items'][0]['amount'] == "10000,00"

    def test_to_json_with_vat_summary(self):
        """Test to_json includes VAT summary when present."""
        from backend.vat.vat_extractor import VATBreakdown, VATSummary

        result = InferenceResult()
        result.vat_summary = VATSummary(
            breakdowns=[
                VATBreakdown(rate=25.0, base_amount="10000,00", vat_amount="2500,00", source="regex")
            ],
            total_excl_vat="10000,00",
            total_vat="2500,00",
            total_incl_vat="12500,00",
            confidence=0.9
        )

        json_result = result.to_json()

        assert 'vat_summary' in json_result
        assert len(json_result['vat_summary']['breakdowns']) == 1
        assert json_result['vat_summary']['breakdowns'][0]['rate'] == 25.0
        assert json_result['vat_summary']['total_incl_vat'] == "12500,00"

    def test_to_json_with_vat_validation(self):
        """Test to_json includes VAT validation when present."""
        from backend.validation.vat_validator import VATValidationResult, MathCheckResult

        result = InferenceResult()
        result.vat_validation = VATValidationResult(
            is_valid=True,
            confidence_score=0.95,
            math_checks=[
                MathCheckResult(
                    rate=25.0,
                    base_amount=10000.0,
                    expected_vat=2500.0,
                    actual_vat=2500.0,
                    is_valid=True,
                    tolerance=0.5
                )
            ],
            total_check=True,
            line_items_vs_summary=True,
            amount_consistency=True,
            needs_review=False,
            review_reasons=[]
        )

        json_result = result.to_json()

        assert 'vat_validation' in json_result
        assert json_result['vat_validation']['is_valid'] is True
        assert json_result['vat_validation']['confidence_score'] == 0.95
        assert len(json_result['vat_validation']['math_checks']) == 1


class TestBusinessFeaturesAvailable:
    """Tests for BUSINESS_FEATURES_AVAILABLE flag."""

    def test_business_features_available(self):
        """Test that business features are available."""
        from backend.pipeline import BUSINESS_FEATURES_AVAILABLE
        assert BUSINESS_FEATURES_AVAILABLE is True


class TestExtractBusinessFeaturesErrorHandling:
    """Tests for _extract_business_features error handling."""

    def test_pipeline_module_has_logger(self):
        """Test that pipeline module defines logger correctly."""
        from backend.pipeline import pipeline
        assert hasattr(pipeline, 'logger')
        assert pipeline.logger is not None

    def test_extract_business_features_logs_errors(self):
        """Test that _extract_business_features logs detailed errors."""
        from backend.pipeline.pipeline import InferencePipeline, InferenceResult

        # Create a pipeline with mocked extractors that raise an exception
        with patch.object(InferencePipeline, '__init__', lambda self, **kwargs: None):
            pipeline = InferencePipeline()
            pipeline.line_items_extractor = MagicMock()
            pipeline.vat_extractor = MagicMock()
            pipeline.vat_validator = MagicMock()

            # Make line_items_extractor raise an exception
            test_error = ValueError("Test error message")
            pipeline.line_items_extractor.extract_from_pdf.side_effect = test_error

            result = InferenceResult()

            # Call the method
            pipeline._extract_business_features("/fake/path.pdf", result, "full text")

            # Verify error was captured with type info
            assert len(result.errors) == 1
            assert "ValueError" in result.errors[0]
            assert "Test error message" in result.errors[0]

    def test_extract_business_features_handles_numeric_exceptions(self):
        """Test that _extract_business_features handles non-standard exceptions."""
        from backend.pipeline.pipeline import InferencePipeline, InferenceResult

        with patch.object(InferencePipeline, '__init__', lambda self, **kwargs: None):
            pipeline = InferencePipeline()
            pipeline.line_items_extractor = MagicMock()
            pipeline.vat_extractor = MagicMock()
            pipeline.vat_validator = MagicMock()

            # Simulate an exception that might have a numeric value (like exit codes)
            class NumericException(Exception):
                def __str__(self):
                    return "0"

            pipeline.line_items_extractor.extract_from_pdf.side_effect = NumericException()

            result = InferenceResult()
            pipeline._extract_business_features("/fake/path.pdf", result, "full text")

            # Should include type name even when str(e) is just "0"
            assert len(result.errors) == 1
            assert "NumericException" in result.errors[0]


class TestProcessPdfTokenPath:
    """Tests for PDF text token extraction path in process_pdf()."""

    def _make_pipeline(self):
        """Create pipeline with mocked internals, bypassing __init__."""
        with patch.object(InferencePipeline, '__init__', lambda self, **kw: None):
            p = InferencePipeline()
        p.detector = MagicMock()
        p.extractor = MagicMock()
        p.payment_line_parser = MagicMock()
        p.dpi = 300
        p.enable_fallback = False
        p.enable_business_features = False
        p.vat_tolerance = 0.5
        p.line_items_extractor = None
        p.vat_extractor = None
        p.vat_validator = None
        p._business_ocr_engine = None
        p._table_detector = None
        return p

    def _make_detection(self, class_name='Amount', confidence=0.85, page_no=0):
        """Create a Detection object."""
        from backend.pipeline.yolo_detector import Detection
        return Detection(
            class_id=6,
            class_name=class_name,
            confidence=confidence,
            bbox=(100.0, 200.0, 300.0, 250.0),
            page_no=page_no,
        )

    def _make_extracted_field(self, field_name='Amount', raw_text='2.254,50',
                              normalized='2254.50', confidence=0.85):
        """Create an ExtractedField object."""
        from backend.pipeline.field_extractor import ExtractedField
        return ExtractedField(
            field_name=field_name,
            raw_text=raw_text,
            normalized_value=normalized,
            confidence=confidence,
            detection_confidence=confidence,
            ocr_confidence=1.0,
            bbox=(100.0, 200.0, 300.0, 250.0),
            page_no=0,
        )

    def _make_image_bytes(self):
        """Create minimal valid PNG bytes (100x100 white image)."""
        from PIL import Image as PILImage
        import io as _io
        img = PILImage.new('RGB', (100, 100), color='white')
        buf = _io.BytesIO()
        img.save(buf, format='PNG')
        return buf.getvalue()

    @patch('shared.pdf.extractor.PDFDocument')
    @patch('shared.pdf.renderer.render_pdf_to_images')
    def test_text_pdf_uses_pdf_tokens(self, mock_render, mock_pdf_doc_cls):
        """When PDF is text-based, extract_from_detection_with_pdf is used."""
        from shared.pdf.extractor import Token

        pipeline = self._make_pipeline()
        detection = self._make_detection()
        image_bytes = self._make_image_bytes()

        # Setup PDFDocument mock - text PDF with tokens
        mock_pdf_doc = MagicMock()
        mock_pdf_doc.is_text_pdf.return_value = True
        mock_pdf_doc.page_count = 1
        tokens = [Token(text="2.254,50", bbox=(100, 200, 200, 220), page_no=0)]
        mock_pdf_doc.extract_text_tokens.return_value = iter(tokens)
        mock_pdf_doc_cls.return_value.__enter__ = MagicMock(return_value=mock_pdf_doc)
        mock_pdf_doc_cls.return_value.__exit__ = MagicMock(return_value=False)

        pipeline.detector.detect.return_value = [detection]
        pipeline.extractor.extract_from_detection_with_pdf.return_value = (
            self._make_extracted_field()
        )

        mock_render.return_value = iter([(0, image_bytes)])
        result = pipeline.process_pdf('/fake/invoice.pdf')

        pipeline.extractor.extract_from_detection_with_pdf.assert_called_once()
        pipeline.extractor.extract_from_detection.assert_not_called()
        assert result.fields.get('Amount') == '2254.50'
        assert result.success is True

    @patch('shared.pdf.extractor.PDFDocument')
    @patch('shared.pdf.renderer.render_pdf_to_images')
    def test_scanned_pdf_uses_ocr(self, mock_render, mock_pdf_doc_cls):
        """When PDF is scanned, extract_from_detection (OCR) is used."""
        pipeline = self._make_pipeline()
        detection = self._make_detection()
        image_bytes = self._make_image_bytes()

        mock_pdf_doc = MagicMock()
        mock_pdf_doc.is_text_pdf.return_value = False
        mock_pdf_doc_cls.return_value.__enter__ = MagicMock(return_value=mock_pdf_doc)
        mock_pdf_doc_cls.return_value.__exit__ = MagicMock(return_value=False)

        pipeline.detector.detect.return_value = [detection]
        pipeline.extractor.extract_from_detection.return_value = (
            self._make_extracted_field(raw_text='4.50', normalized='4.50', confidence=0.75)
        )

        mock_render.return_value = iter([(0, image_bytes)])
        result = pipeline.process_pdf('/fake/invoice.pdf')

        pipeline.extractor.extract_from_detection.assert_called_once()
        pipeline.extractor.extract_from_detection_with_pdf.assert_not_called()

    @patch('shared.pdf.extractor.PDFDocument')
    @patch('shared.pdf.renderer.render_pdf_to_images')
    def test_pdf_detection_error_falls_back_to_ocr(self, mock_render, mock_pdf_doc_cls):
        """When PDF text detection throws, fall back to OCR."""
        pipeline = self._make_pipeline()
        detection = self._make_detection()
        image_bytes = self._make_image_bytes()

        mock_ctx = MagicMock()
        mock_ctx.__enter__ = MagicMock(side_effect=Exception("corrupt PDF"))
        mock_ctx.__exit__ = MagicMock(return_value=False)
        mock_pdf_doc_cls.return_value = mock_ctx

        pipeline.detector.detect.return_value = [detection]
        pipeline.extractor.extract_from_detection.return_value = (
            self._make_extracted_field(raw_text='4.50', normalized='4.50', confidence=0.75)
        )

        mock_render.return_value = iter([(0, image_bytes)])
        result = pipeline.process_pdf('/fake/invoice.pdf')

        pipeline.extractor.extract_from_detection.assert_called_once()
        pipeline.extractor.extract_from_detection_with_pdf.assert_not_called()

    @patch('shared.pdf.extractor.PDFDocument')
    @patch('shared.pdf.renderer.render_pdf_to_images')
    def test_text_pdf_passes_correct_args(self, mock_render, mock_pdf_doc_cls):
        """Verify correct token list and image dimensions are passed."""
        from shared.pdf.extractor import Token

        pipeline = self._make_pipeline()
        detection = self._make_detection()
        image_bytes = self._make_image_bytes()  # 100x100 PNG

        mock_pdf_doc = MagicMock()
        mock_pdf_doc.is_text_pdf.return_value = True
        mock_pdf_doc.page_count = 1
        tokens = [
            Token(text="Fakturabelopp:", bbox=(50, 190, 100, 210), page_no=0),
            Token(text="2.254,50", bbox=(105, 190, 180, 210), page_no=0),
            Token(text="SEK", bbox=(185, 190, 210, 210), page_no=0),
        ]
        mock_pdf_doc.extract_text_tokens.return_value = iter(tokens)
        mock_pdf_doc_cls.return_value.__enter__ = MagicMock(return_value=mock_pdf_doc)
        mock_pdf_doc_cls.return_value.__exit__ = MagicMock(return_value=False)

        pipeline.detector.detect.return_value = [detection]
        pipeline.extractor.extract_from_detection_with_pdf.return_value = (
            self._make_extracted_field()
        )

        mock_render.return_value = iter([(0, image_bytes)])
        pipeline.process_pdf('/fake/invoice.pdf')

        call_args = pipeline.extractor.extract_from_detection_with_pdf.call_args[0]
        assert call_args[0] == detection
        assert len(call_args[1]) == 3  # 3 tokens passed
        assert call_args[2] == 100  # image width
        assert call_args[3] == 100  # image height


class TestDpiPassthrough:
    """Tests for DPI being passed from pipeline to FieldExtractor (Bug 1)."""

    def test_field_extractor_receives_pipeline_dpi(self):
        """FieldExtractor should receive the pipeline's DPI, not default to 300."""
        with patch('backend.pipeline.pipeline.YOLODetector'):
            with patch('backend.pipeline.pipeline.FieldExtractor') as mock_fe_cls:
                InferencePipeline(
                    model_path='/fake/model.pt',
                    dpi=150,
                    use_gpu=False,
                )
                mock_fe_cls.assert_called_once_with(
                    ocr_lang='en', use_gpu=False, dpi=150
                )

    def test_field_extractor_receives_default_dpi(self):
        """When dpi=300 (default), FieldExtractor should also get 300."""
        with patch('backend.pipeline.pipeline.YOLODetector'):
            with patch('backend.pipeline.pipeline.FieldExtractor') as mock_fe_cls:
                InferencePipeline(
                    model_path='/fake/model.pt',
                    dpi=300,
                    use_gpu=False,
                )
                mock_fe_cls.assert_called_once_with(
                    ocr_lang='en', use_gpu=False, dpi=300
                )


class TestFallbackPatternExtraction:
    """Tests for _extract_with_patterns fallback regex (Bugs 2, 3)."""

    def _make_pipeline_with_patterns(self):
        """Create pipeline with mocked internals for pattern testing."""
        with patch.object(InferencePipeline, '__init__', lambda self, **kw: None):
            p = InferencePipeline()
        p.dpi = 150
        p.enable_fallback = True
        return p

    def test_bankgiro_no_match_in_org_number(self):
        """Bankgiro regex must NOT match digits embedded in an org number."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Org.nr 802546-1610", result)
        assert 'Bankgiro' not in result.fields

    def test_bankgiro_matches_labeled(self):
        """Bankgiro regex should match when preceded by 'Bankgiro' label."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Bankgiro 5393-9484", result)
        assert result.fields.get('Bankgiro') == '5393-9484'

    def test_bankgiro_matches_standalone(self):
        """Bankgiro regex should match a standalone 4-4 digit pattern."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Betala till 5393-9484 senast", result)
        assert result.fields.get('Bankgiro') == '5393-9484'

    def test_amount_rejects_bare_integer(self):
        """Amount regex must NOT match bare integers like 'Summa 1'."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Summa 1 Medlemsavgift", result)
        assert 'Amount' not in result.fields

    def test_amount_requires_decimal(self):
        """Amount regex should require a decimal separator."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Total 5 items", result)
        assert 'Amount' not in result.fields

    def test_amount_with_decimal_works(self):
        """Amount regex should match Swedish decimal amounts."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Att betala 1 234,56 SEK", result)
        assert 'Amount' in result.fields
        assert float(result.fields['Amount']) == pytest.approx(1234.56, abs=0.01)

    def test_amount_with_sek_suffix(self):
        """Amount regex should match amounts ending with SEK."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("7 500,00 SEK", result)
        assert 'Amount' in result.fields
        assert float(result.fields['Amount']) == pytest.approx(7500.00, abs=0.01)

    def test_fallback_extracts_invoice_date(self):
        """Fallback should extract InvoiceDate from Swedish text."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Fakturadatum 2025-01-15 Referens ABC", result)
        assert result.fields.get('InvoiceDate') == '2025-01-15'

    def test_fallback_extracts_due_date(self):
        """Fallback should extract InvoiceDueDate from Swedish text."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Forfallodag 2025-02-15 Belopp", result)
        assert result.fields.get('InvoiceDueDate') == '2025-02-15'

    def test_fallback_extracts_supplier_org(self):
        """Fallback should extract supplier_organisation_number."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Org.nr 556123-4567 Stockholm", result)
        assert result.fields.get('supplier_organisation_number') == '556123-4567'

    def test_fallback_extracts_plusgiro(self):
        """Fallback should extract Plusgiro number."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Plusgiro 12 34 56-7 betalning", result)
        assert 'Plusgiro' in result.fields

    def test_fallback_skips_year_as_invoice_number(self):
        """Fallback should NOT extract year-like value as InvoiceNumber."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Fakturanr 2025 Datum 2025-01-15", result)
        assert 'InvoiceNumber' not in result.fields

    def test_fallback_accepts_valid_invoice_number(self):
        """Fallback should extract valid non-year InvoiceNumber."""
        p = self._make_pipeline_with_patterns()
        result = InferenceResult()
        p._extract_with_patterns("Fakturanr 12345 Summa", result)
        assert result.fields.get('InvoiceNumber') == '12345'


class TestDateValidation:
    """Tests for InvoiceDueDate < InvoiceDate validation (Bug 6)."""

    def _make_pipeline_for_merge(self):
        """Create pipeline with mocked internals for merge testing."""
        with patch.object(InferencePipeline, '__init__', lambda self, **kw: None):
            p = InferencePipeline()
        p.payment_line_parser = MagicMock()
        p.payment_line_parser.parse.return_value = MagicMock(is_valid=False)
        return p

    def test_due_date_before_invoice_date_dropped(self):
        """DueDate earlier than InvoiceDate should be removed."""
        from backend.pipeline.field_extractor import ExtractedField

        p = self._make_pipeline_for_merge()
        result = InferenceResult()
        result.extracted_fields = [
            ExtractedField(
                field_name='InvoiceDate', raw_text='2026-01-16',
                normalized_value='2026-01-16', confidence=0.9,
                detection_confidence=0.9, ocr_confidence=1.0,
                bbox=(0, 0, 100, 50), page_no=0,
            ),
            ExtractedField(
                field_name='InvoiceDueDate', raw_text='2025-12-01',
                normalized_value='2025-12-01', confidence=0.9,
                detection_confidence=0.9, ocr_confidence=1.0,
                bbox=(0, 60, 100, 110), page_no=0,
            ),
        ]
        p._merge_fields(result)
        assert 'InvoiceDate' in result.fields
        assert 'InvoiceDueDate' not in result.fields

    def test_valid_dates_preserved(self):
        """Both dates kept when DueDate >= InvoiceDate."""
        from backend.pipeline.field_extractor import ExtractedField

        p = self._make_pipeline_for_merge()
        result = InferenceResult()
        result.extracted_fields = [
            ExtractedField(
                field_name='InvoiceDate', raw_text='2026-01-16',
                normalized_value='2026-01-16', confidence=0.9,
                detection_confidence=0.9, ocr_confidence=1.0,
                bbox=(0, 0, 100, 50), page_no=0,
            ),
            ExtractedField(
                field_name='InvoiceDueDate', raw_text='2026-02-15',
                normalized_value='2026-02-15', confidence=0.9,
                detection_confidence=0.9, ocr_confidence=1.0,
                bbox=(0, 60, 100, 110), page_no=0,
            ),
        ]
        p._merge_fields(result)
        assert result.fields['InvoiceDate'] == '2026-01-16'
        assert result.fields['InvoiceDueDate'] == '2026-02-15'

    def test_same_dates_preserved(self):
        """Same InvoiceDate and DueDate should both be kept."""
        from backend.pipeline.field_extractor import ExtractedField

        p = self._make_pipeline_for_merge()
        result = InferenceResult()
        result.extracted_fields = [
            ExtractedField(
                field_name='InvoiceDate', raw_text='2026-01-16',
                normalized_value='2026-01-16', confidence=0.9,
                detection_confidence=0.9, ocr_confidence=1.0,
                bbox=(0, 0, 100, 50), page_no=0,
            ),
            ExtractedField(
                field_name='InvoiceDueDate', raw_text='2026-01-16',
                normalized_value='2026-01-16', confidence=0.9,
                detection_confidence=0.9, ocr_confidence=1.0,
                bbox=(0, 60, 100, 110), page_no=0,
            ),
        ]
        p._merge_fields(result)
        assert result.fields['InvoiceDate'] == '2026-01-16'
        assert result.fields['InvoiceDueDate'] == '2026-01-16'


class TestCrossFieldDedup:
    """Tests for cross-field deduplication of InvoiceNumber vs OCR/Bankgiro."""

    def _make_pipeline_for_merge(self):
        """Create pipeline with mocked internals for merge testing."""
        with patch.object(InferencePipeline, '__init__', lambda self, **kw: None):
            p = InferencePipeline()
        p.payment_line_parser = MagicMock()
        p.payment_line_parser.parse.return_value = MagicMock(is_valid=False)
        return p

    def _make_extracted_field(self, field_name, raw_text, normalized, confidence=0.9):
        from backend.pipeline.field_extractor import ExtractedField
        return ExtractedField(
            field_name=field_name,
            raw_text=raw_text,
            normalized_value=normalized,
            confidence=confidence,
            detection_confidence=confidence,
            ocr_confidence=1.0,
            bbox=(0, 0, 100, 50),
            page_no=0,
        )

    def test_invoice_number_not_same_as_ocr(self):
        """When InvoiceNumber == OCR, InvoiceNumber should be dropped."""
        p = self._make_pipeline_for_merge()
        result = InferenceResult()
        result.extracted_fields = [
            self._make_extracted_field('InvoiceNumber', '9179845608', '9179845608'),
            self._make_extracted_field('OCR', '9179845608', '9179845608'),
            self._make_extracted_field('Amount', '1234,56', '1234.56'),
        ]
        p._merge_fields(result)
        assert 'OCR' in result.fields
        assert result.fields['OCR'] == '9179845608'
        assert 'InvoiceNumber' not in result.fields

    def test_invoice_number_not_same_as_bankgiro_digits(self):
        """When InvoiceNumber digits == Bankgiro digits, InvoiceNumber should be dropped."""
        p = self._make_pipeline_for_merge()
        result = InferenceResult()
        result.extracted_fields = [
            self._make_extracted_field('InvoiceNumber', '53939484', '53939484'),
            self._make_extracted_field('Bankgiro', '5393-9484', '5393-9484'),
            self._make_extracted_field('Amount', '500,00', '500.00'),
        ]
        p._merge_fields(result)
        assert 'Bankgiro' in result.fields
        assert result.fields['Bankgiro'] == '5393-9484'
        assert 'InvoiceNumber' not in result.fields

    def test_unrelated_values_kept(self):
        """When InvoiceNumber, OCR, and Bankgiro are all different, keep all."""
        p = self._make_pipeline_for_merge()
        result = InferenceResult()
        result.extracted_fields = [
            self._make_extracted_field('InvoiceNumber', '19061', '19061'),
            self._make_extracted_field('OCR', '9179845608', '9179845608'),
            self._make_extracted_field('Bankgiro', '5393-9484', '5393-9484'),
        ]
        p._merge_fields(result)
        assert result.fields['InvoiceNumber'] == '19061'
        assert result.fields['OCR'] == '9179845608'
        assert result.fields['Bankgiro'] == '5393-9484'

    def test_dedup_after_fallback_re_add(self):
        """Dedup should remove InvoiceNumber re-added by fallback if it matches OCR."""
        p = self._make_pipeline_for_merge()
        result = InferenceResult()
        # Simulate state after fallback re-adds InvoiceNumber = OCR
        result.fields = {
            'OCR': '758200602426',
            'Amount': '164.00',
            'InvoiceNumber': '758200602426',  # re-added by fallback
        }
        result.confidence = {
            'OCR': 0.9,
            'Amount': 0.9,
            'InvoiceNumber': 0.5,  # fallback confidence
        }
        result.bboxes = {}
        p._dedup_invoice_number(result)
        assert 'InvoiceNumber' not in result.fields
        assert 'OCR' in result.fields

    def test_invoice_number_substring_of_bankgiro(self):
        """When InvoiceNumber digits are a substring of Bankgiro digits, drop InvoiceNumber."""
        p = self._make_pipeline_for_merge()
        result = InferenceResult()
        result.extracted_fields = [
            self._make_extracted_field('InvoiceNumber', '4639', '4639'),
            self._make_extracted_field('Bankgiro', '134-4639', '134-4639'),
            self._make_extracted_field('Amount', '500,00', '500.00'),
        ]
        p._merge_fields(result)
        assert 'Bankgiro' in result.fields
        assert result.fields['Bankgiro'] == '134-4639'
        assert 'InvoiceNumber' not in result.fields

    def test_invoice_number_not_substring_of_unrelated_bankgiro(self):
        """When InvoiceNumber is NOT a substring of Bankgiro, keep both."""
        p = self._make_pipeline_for_merge()
        result = InferenceResult()
        result.extracted_fields = [
            self._make_extracted_field('InvoiceNumber', '19061', '19061'),
            self._make_extracted_field('Bankgiro', '5393-9484', '5393-9484'),
            self._make_extracted_field('Amount', '500,00', '500.00'),
        ]
        p._merge_fields(result)
        assert result.fields['InvoiceNumber'] == '19061'
        assert result.fields['Bankgiro'] == '5393-9484'


class TestFallbackTrigger:
    """Tests for _needs_fallback trigger threshold."""

    def _make_pipeline(self):
        with patch.object(InferencePipeline, '__init__', lambda self, **kw: None):
            p = InferencePipeline()
        return p

    def test_fallback_triggers_when_1_key_field_missing(self):
        """Should trigger when only 1 key field (e.g. InvoiceNumber) is missing."""
        p = self._make_pipeline()
        result = InferenceResult()
        result.fields = {
            'Amount': '1234.56',
            'OCR': '12345678901',
            'InvoiceDate': '2025-01-15',
            'InvoiceDueDate': '2025-02-15',
            'supplier_organisation_number': '556123-4567',
        }
        # InvoiceNumber missing -> should trigger
        assert p._needs_fallback(result) is True

    def test_fallback_triggers_when_dates_missing(self):
        """Should trigger when all key fields present but 2+ important fields missing."""
        p = self._make_pipeline()
        result = InferenceResult()
        result.fields = {
            'Amount': '1234.56',
            'InvoiceNumber': '12345',
            'OCR': '12345678901',
        }
        # InvoiceDate, InvoiceDueDate, supplier_org all missing -> should trigger
        assert p._needs_fallback(result) is True

    def test_no_fallback_when_all_fields_present(self):
        """Should NOT trigger when all key and important fields present."""
        p = self._make_pipeline()
        result = InferenceResult()
        result.fields = {
            'Amount': '1234.56',
            'InvoiceNumber': '12345',
            'OCR': '12345678901',
            'InvoiceDate': '2025-01-15',
            'InvoiceDueDate': '2025-02-15',
            'supplier_organisation_number': '556123-4567',
        }
        assert p._needs_fallback(result) is False


if __name__ == '__main__':
    pytest.main([__file__, '-v'])