"""
Test fixtures and test cases for normalization pipeline steps.
Covers NORM-16 acceptance criteria: metadata pre-header, report-date line,
repeated headers, trailer row count, whitespace/null tokens, numeric commas.
"""

import pytest


class TestNormalizationFixtures:
    """Test fixtures for various CSV normalization scenarios."""

    @pytest.fixture
    def csv_with_metadata_preamble(self):
        """CSV with metadata lines before header (NORM-8 scenario)."""
        return """REPORT GENERATED: 2024-01-15
SOURCE SYSTEM: Legacy DB
EXTRACT DATE: 2024-01-15 08:30:00

id,name,email,status
1,Alice,alice@example.com,active
2,Bob,bob@example.com,inactive
"""

    @pytest.fixture
    def csv_with_bom(self):
        """CSV with UTF-8 BOM at start (NORM-7 scenario)."""
        return "\ufeffid,name,email\n1,Alice,alice@example.com\n2,Bob,bob@example.com\n"

    @pytest.fixture
    def csv_with_repeated_headers(self):
        """CSV with duplicate header rows mid-file (NORM-10 scenario)."""
        return """id,name,email
1,Alice,alice@example.com
2,Bob,bob@example.com
id,name,email
3,Charlie,charlie@example.com
4,Diana,diana@example.com
"""

    @pytest.fixture
    def csv_with_trailer(self):
        """CSV with trailer/footer row count (NORM-9 scenario)."""
        return """id,name,email
1,Alice,alice@example.com
2,Bob,bob@example.com
3,Charlie,charlie@example.com
TRAILER: ROW_COUNT=3
"""

    @pytest.fixture
    def csv_with_trailer_alternate_format(self):
        """CSV with alternative trailer format."""
        return """id,name,email
1,Alice,alice@example.com
2,Bob,bob@example.com
ROW_COUNT=2
"""

    @pytest.fixture
    def csv_with_messy_whitespace(self):
        """CSV with leading/trailing whitespace around values (NORM-11 scenario)."""
        return """id,name,email,notes
1,  Alice  ,  alice@example.com  , " quoted value "
2,Bob   ,bob@example.com   ,
3,   Charlie,  charlie@example.com,  multiple   spaces
"""

    @pytest.fixture
    def csv_with_null_tokens(self):
        """CSV with various null/missing value representations (NORM-12 scenario)."""
        return """id,name,email,phone,status
1,Alice,alice@example.com,555-1234,active
2,Bob,,NA,inactive
3,Charlie,charlie@example.com,NULL,
4,Diana,diana@example.com,-,N/A
5,Eve,,,nan
"""

    @pytest.fixture
    def csv_with_numeric_commas(self):
        """CSV with comma-formatted numbers (NORM-18 scenario)."""
        return """id,name,salary,revenue
1,Alice,"1,234.56","10,000,000.00"
2,Bob,"2,500.00","5,500,000"
3,Charlie,3000,"1,200,000.50"
"""

    @pytest.fixture
    def csv_complex_scenario(self):
        """Complex CSV combining multiple normalization challenges."""
        return """\ufeffREPORT: Q4 2024 Sales Data
GENERATED: 2024-12-31

id,  customer_name  ,  revenue  ,phone,status
1,  "Acme Corp"  ,"1,250,000.00",555-0100,  active
2,  Beta LLC  ,,"",inactive
id,  customer_name  ,  revenue  ,phone,status
3,Charlie Inc,"500,000",NA,
4,  Delta & Sons  ,"2,100,000.50",555-0200,active
TOTAL RECORDS: 4
"""

    @pytest.fixture
    def csv_with_missing_columns(self):
        """CSV missing expected columns (NORM-14 scenario)."""
        return """id,name
1,Alice
2,Bob
"""

    @pytest.fixture
    def csv_with_extra_columns(self):
        """CSV with extra unexpected columns (NORM-14 scenario)."""
        return """id,name,email,unexpected_col1,unexpected_col2
1,Alice,alice@example.com,extra1,extra2
2,Bob,bob@example.com,extra3,extra4
"""

    @pytest.fixture
    def csv_with_special_characters_in_names(self):
        """CSV with column names requiring normalization (NORM-13 scenario)."""
        return """User ID,First Name,Last Name,E-Mail Address,Phone #,Status (Active/Inactive)
1,Alice,Smith,alice@example.com,555-1234,Active
2,Bob,Jones,bob@example.com,555-5678,Inactive
"""

    @pytest.fixture
    def csv_date_formats(self):
        """CSV with various date formats for type cleanup (NORM-18 scenario)."""
        return """id,name,birth_date,hire_date
1,Alice,01/15/1990,2020-01-15
2,Bob,1985-12-25,12/01/2019
3,Charlie,03-10-1988,2021/03/10
"""

    @pytest.fixture
    def csv_boolean_variants(self):
        """CSV with various boolean representations (NORM-18 scenario)."""
        return """id,name,is_active,verified,subscribed
1,Alice,true,Yes,1
2,Bob,false,No,0
3,Charlie,TRUE,Y,true
4,Diana,FALSE,N,false
5,Eve,T,yes,FALSE
"""

    @pytest.fixture
    def csv_empty_file(self):
        """Empty CSV file (edge case)."""
        return ""

    @pytest.fixture
    def csv_header_only(self):
        """CSV with header but no data rows (edge case)."""
        return "id,name,email\n"

    @pytest.fixture
    def csv_single_row(self):
        """CSV with single data row (edge case)."""
        return """id,name,email
1,Alice,alice@example.com
"""

    @pytest.fixture
    def csv_unicode_content(self):
        """CSV with Unicode characters (edge case)."""
        return """id,name,city,notes
1,José García,São Paulo,Café ☕
2,李明,北京,你好 🌏
3,Müller,München,Schön
"""


class TestRemoveBOMStep:
    """Tests for BOM removal step (NORM-7)."""

    def test_removes_utf8_bom_from_first_line(self):
        """Should detect and remove UTF-8 BOM from first line."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={}, report=report)

        lines = [
            "\ufeffid,name,email\n",
            "1,John,john@example.com\n",
            "2,Jane,jane@example.com\n",
        ]
        result = list(step.process_lines(iter(lines)))

        assert result[0] == "id,name,email\n"
        assert result[1] == "1,John,john@example.com\n"
        assert result[2] == "2,Jane,jane@example.com\n"

    def test_warns_when_bom_detected(self):
        """Should add warning to report when BOM is detected."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={}, report=report)

        lines = ["\ufeffheader\n", "data\n"]
        list(step.process_lines(iter(lines)))

        assert len(report.warnings) == 1
        assert "BOM" in report.warnings[0]

    def test_handles_file_without_bom(self):
        """Should process normally when no BOM present."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={}, report=report)

        lines = ["id,name,email\n", "1,John,john@example.com\n"]
        result = list(step.process_lines(iter(lines)))

        assert result == lines
        assert len(report.warnings) == 0

    def test_configurable_all_lines_mode(self):
        """Should support checking all lines when configured."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={"check_all_lines": True}, report=report)

        lines = ["header\n", "\ufeffdata1\n", "data2\n", "\ufeffdata3\n"]
        result = list(step.process_lines(iter(lines)))

        assert result[0] == "header\n"
        assert result[1] == "data1\n"
        assert result[2] == "data2\n"
        assert result[3] == "data3\n"
        assert len(report.warnings) == 2

    def test_only_checks_first_line_by_default(self):
        """Should only check first line when check_all_lines is False."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={"check_all_lines": False}, report=report)

        lines = ["header\n", "\ufeffdata1\n", "data2\n"]
        result = list(step.process_lines(iter(lines)))

        # BOM should NOT be removed from second line
        assert result[0] == "header\n"
        assert result[1] == "\ufeffdata1\n"
        assert result[2] == "data2\n"
        assert len(report.warnings) == 0

    def test_handles_empty_iterator(self):
        """Should handle empty file gracefully."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={}, report=report)

        lines = []
        result = list(step.process_lines(iter(lines)))

        assert result == []
        assert len(report.warnings) == 0

    def test_handles_single_bom_line(self):
        """Should handle file with only BOM character."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={}, report=report)

        lines = ["\ufeff\n"]
        result = list(step.process_lines(iter(lines)))

        assert result[0] == "\n"
        assert len(report.warnings) == 1

    def test_removes_multiple_boms_from_first_line(self):
        """Should remove multiple BOM characters if present."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={}, report=report)

        lines = ["\ufeff\ufeff\ufeffheader\n", "data\n"]
        result = list(step.process_lines(iter(lines)))

        assert result[0] == "header\n"
        assert len(report.warnings) == 1

    def test_preserves_bom_mid_line(self):
        """Should not remove BOM characters that aren't at the start of a line."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={}, report=report)

        lines = ["header,value\ufeff,extra\n", "data,test\n"]
        result = list(step.process_lines(iter(lines)))

        # BOM in the middle should be preserved
        assert result[0] == "header,value\ufeff,extra\n"
        assert len(report.warnings) == 0

    def test_handles_concatenated_files_with_multiple_boms(self):
        """Should handle concatenated files where each file starts with BOM."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={"check_all_lines": True}, report=report)

        # Simulates two concatenated files, each starting with BOM
        lines = [
            "\ufeffheader\n",
            "data1\n",
            "data2\n",
            "\ufeffheader\n",  # Second file starts here
            "data3\n",
            "data4\n",
        ]
        result = list(step.process_lines(iter(lines)))

        assert result[0] == "header\n"
        assert result[1] == "data1\n"
        assert result[2] == "data2\n"
        assert result[3] == "header\n"
        assert result[4] == "data3\n"
        assert result[5] == "data4\n"
        assert len(report.warnings) == 2

    def test_lazy_evaluation(self):
        """Should process lines lazily without consuming entire iterator."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={}, report=report)

        def line_generator():
            yield "\ufeffline1\n"
            yield "line2\n"
            yield "line3\n"

        result = step.process_lines(line_generator())

        # Should be a generator
        assert hasattr(result, "__iter__")
        assert hasattr(result, "__next__")

        # Consume one at a time
        first = next(result)
        assert first == "line1\n"

    def test_strict_mode_does_not_affect_behavior(self):
        """Strict mode should not change BOM removal behavior."""
        from atomingest.normalization.standard_steps import RemoveBOMStep
        from atomingest.normalization.core import NormalizationReport

        report = NormalizationReport()
        step = RemoveBOMStep(config={}, report=report, strict=True)

        lines = ["\ufeffheader\n", "data\n"]
        result = list(step.process_lines(iter(lines)))

        assert result[0] == "header\n"
        assert result[1] == "data\n"
        assert len(report.warnings) == 1


class TestSkipUntilHeaderStep:
    """Tests for metadata skipping step (NORM-8)."""

    def test_skips_metadata_until_header_by_expected_columns(
        self, csv_with_metadata_preamble
    ):
        """Should skip lines until header matching expected columns is found."""
        pass

    def test_skips_metadata_until_header_by_regex(self):
        """Should skip lines until header matching regex pattern is found."""
        pass

    def test_increments_metadata_lines_skipped_counter(
        self, csv_with_metadata_preamble
    ):
        """Should correctly count skipped metadata lines in report."""
        pass

    def test_respects_max_skip_limit(self):
        """Should raise error if header not found within max_skip lines."""
        pass

    def test_strict_mode_raises_when_header_not_found(self):
        """Should raise exception in strict mode when header cannot be found."""
        pass

    def test_extracts_metadata_when_configured(self, csv_with_metadata_preamble):
        """Should optionally extract metadata values from preamble."""
        pass


class TestDropTrailerLinesStep:
    """Tests for trailer removal step (NORM-9)."""

    def test_removes_trailer_by_prefix(self, csv_with_trailer):
        """Should remove lines matching trailer prefix pattern."""
        pass

    def test_removes_trailer_by_regex(self, csv_with_trailer_alternate_format):
        """Should remove lines matching trailer regex pattern."""
        pass

    def test_extracts_row_count_value(self, csv_with_trailer):
        """Should extract row count value from trailer when present."""
        pass

    def test_increments_trailer_skipped_counter(self, csv_with_trailer):
        """Should correctly count trailer lines in report."""
        pass

    def test_handles_no_trailer_gracefully(self):
        """Should process normally when no trailer lines present."""
        pass


class TestDropRepeatedHeaderRowsStep:
    """Tests for duplicate header removal step (NORM-10)."""

    def test_removes_repeated_header_rows(self, csv_with_repeated_headers):
        """Should detect and remove duplicate header rows mid-file."""
        pass

    def test_increments_duplicate_headers_counter(self, csv_with_repeated_headers):
        """Should correctly count removed duplicate headers in report."""
        pass

    def test_does_not_remove_legitimate_data(self):
        """Should not drop data rows that happen to match header values."""
        pass

    def test_handles_no_duplicates_gracefully(self):
        """Should process normally when no duplicate headers present."""
        pass


class TestTrimWhitespaceStep:
    """Tests for whitespace trimming step (NORM-11)."""

    def test_trims_leading_and_trailing_whitespace(self, csv_with_messy_whitespace):
        """Should remove whitespace around all field values."""
        pass

    def test_configurable_quote_trimming(self, csv_with_messy_whitespace):
        """Should optionally trim whitespace inside quoted values."""
        pass

    def test_configurable_collapse_multiple_spaces(self, csv_with_messy_whitespace):
        """Should optionally collapse multiple internal spaces to single space."""
        pass

    def test_preserves_intentional_whitespace_when_configured(self):
        """Should respect configuration to preserve specific whitespace."""
        pass


class TestNullTokenNormalizationStep:
    """Tests for null token conversion step (NORM-12)."""

    def test_converts_configured_null_tokens_to_none(self, csv_with_null_tokens):
        """Should map configured null tokens to None."""
        pass

    def test_preserves_non_null_values(self, csv_with_null_tokens):
        """Should not modify legitimate values."""
        pass

    def test_case_insensitive_matching_when_configured(self):
        """Should support case-insensitive null token matching."""
        pass

    def test_empty_string_as_null_token(self, csv_with_null_tokens):
        """Should handle empty string as null token."""
        pass

    def test_default_null_tokens(self):
        """Should have sensible default null token set."""
        pass


class TestColumnNameNormalizationStep:
    """Tests for column name normalization step (NORM-13)."""

    def test_strips_whitespace_from_column_names(
        self, csv_with_special_characters_in_names
    ):
        """Should remove leading/trailing whitespace from headers."""
        pass

    def test_converts_to_snake_case(self, csv_with_special_characters_in_names):
        """Should convert column names to snake_case format."""
        pass

    def test_removes_non_alphanumeric_characters(
        self, csv_with_special_characters_in_names
    ):
        """Should remove special characters from column names."""
        pass

    def test_applies_alias_mapping(self):
        """Should apply configured column name aliases."""
        pass

    def test_warns_on_unknown_columns_when_configured(self, csv_with_extra_columns):
        """Should add warning for columns not in expected set."""
        pass

    def test_lowercase_conversion_configurable(self):
        """Should support configurable case conversion."""
        pass


class TestCSVParsingAdapter:
    """Tests for CSV parsing with column contract (NORM-14)."""

    def test_emits_rows_as_dicts(self):
        """Should produce dictionary rows with normalized column names as keys."""
        pass

    def test_handles_missing_required_columns(self, csv_with_missing_columns):
        """Should warn or error when required columns are missing."""
        pass

    def test_handles_extra_columns_drop_mode(self, csv_with_extra_columns):
        """Should drop extra columns when drop_extra_columns=True."""
        pass

    def test_handles_extra_columns_warn_mode(self, csv_with_extra_columns):
        """Should warn about extra columns when drop_extra_columns=False."""
        pass

    def test_strict_mode_raises_on_column_mismatch(self):
        """Should raise exception in strict mode for column mismatches."""
        pass

    def test_collects_warnings_for_column_issues(self):
        """Should add warnings to report for non-critical column issues."""
        pass


class TestBasicTypeCleanupStep:
    """Tests for type conversion and cleanup step (NORM-18)."""

    def test_removes_commas_from_numeric_values(self, csv_with_numeric_commas):
        """Should strip commas from numeric strings."""
        pass

    def test_normalizes_boolean_values(self, csv_boolean_variants):
        """Should convert various boolean representations to standard format."""
        pass

    def test_parses_dates_to_iso_format(self, csv_date_formats):
        """Should parse configured date formats to ISO 8601 strings."""
        pass

    def test_configurable_date_formats(self):
        """Should support multiple input date format patterns."""
        pass

    def test_warns_on_parse_failures(self):
        """Should add warnings to report when type conversion fails."""
        pass

    def test_strict_mode_raises_on_parse_failure(self):
        """Should raise exception in strict mode for parse failures."""
        pass


class TestTrailerRowCountValidation:
    """Tests for trailer validation step (NORM-19)."""

    def test_validates_trailer_matches_emitted_count(self, csv_with_trailer):
        """Should compare trailer row_count with actual rows_emitted."""
        pass

    def test_warns_on_count_mismatch(self):
        """Should add warning when counts don't match."""
        pass

    def test_strict_mode_raises_on_mismatch(self):
        """Should raise exception in strict mode for count mismatch."""
        pass

    def test_skips_validation_when_no_trailer(self):
        """Should not validate when trailer row_count not present."""
        pass


class TestEndToEndNormalizationPipeline:
    """Integration tests for complete normalization pipeline (NORM-16)."""

    def test_complex_scenario_full_pipeline(self, csv_complex_scenario):
        """Should handle complex CSV with multiple normalization needs."""
        pass

    def test_report_counters_accurate(self, csv_with_metadata_preamble):
        """Should produce accurate counters in report for all operations."""
        pass

    def test_preserves_streaming_behavior(self):
        """Should process large files without loading entire content to memory."""
        pass

    def test_all_warnings_collected(self, csv_complex_scenario):
        """Should collect all warnings from all steps into single report."""
        pass

    def test_strict_mode_behavior_consistent(self):
        """Should apply strict mode consistently across all steps."""
        pass

    def test_unicode_content_handled_correctly(self, csv_unicode_content):
        """Should correctly process Unicode characters throughout pipeline."""
        pass

    def test_empty_file_edge_case(self, csv_empty_file):
        """Should handle empty files gracefully."""
        pass

    def test_header_only_edge_case(self, csv_header_only):
        """Should handle files with header but no data."""
        pass

    def test_single_row_edge_case(self, csv_single_row):
        """Should handle files with single data row."""
        pass
