"""
Unit tests for DirectExtractionEngine service.

Tests cover:
- Text extraction accuracy
- Structure preservation (headers, lists, sections)
- Coordinate extraction
- Table detection
- Image extraction
"""

import pytest
from pathlib import Path
import fitz
from PIL import Image
import io

from app.services.direct_extraction_engine import DirectExtractionEngine
from app.models.unified_document import (
    ElementType, ProcessingTrack, UnifiedDocument
)


class TestDirectExtractionEngine:
    """Test suite for DirectExtractionEngine."""

    @pytest.fixture
    def engine(self):
        """Create engine with default settings."""
        return DirectExtractionEngine()

    @pytest.fixture
    def engine_no_tables(self):
        """Create engine with table detection disabled."""
        return DirectExtractionEngine(enable_table_detection=False)

    @pytest.fixture
    def engine_no_images(self):
        """Create engine with image extraction disabled."""
        return DirectExtractionEngine(enable_image_extraction=False)

    # ===== Text Extraction Tests =====

    def test_extract_simple_text(self, engine, temp_dir):
        """Test basic text extraction from PDF."""
        pdf_path = temp_dir / "simple.pdf"
        doc = fitz.open()
        page = doc.new_page()

        test_text = "Hello World! This is a test document."
        page.insert_text((50, 50), test_text, fontsize=12)

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        assert isinstance(result, UnifiedDocument)
        assert len(result.pages) == 1
        assert result.metadata.processing_track == ProcessingTrack.DIRECT

        # Check text was extracted
        text_elements = [e for e in result.pages[0].elements if e.is_text]
        assert len(text_elements) > 0

        # Verify text content
        all_text = " ".join(e.content for e in text_elements if isinstance(e.content, str))
        assert "Hello World" in all_text

    def test_extract_multiline_text(self, engine, temp_dir):
        """Test extraction of multiple lines of text."""
        pdf_path = temp_dir / "multiline.pdf"
        doc = fitz.open()
        page = doc.new_page()

        lines = [
            "First line of text",
            "Second line of text",
            "Third line of text"
        ]

        y = 50
        for line in lines:
            page.insert_text((50, y), line, fontsize=12)
            y += 20

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        text_elements = [e for e in result.pages[0].elements if e.is_text]
        all_text = " ".join(e.content for e in text_elements if isinstance(e.content, str))

        for line in lines:
            assert line in all_text

    def test_extract_chinese_text(self, engine, temp_dir):
        """Test extraction of Chinese text."""
        pdf_path = temp_dir / "chinese.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Use a font that supports Chinese if available
        chinese_text = "這是中文測試文字"
        try:
            page.insert_text((50, 50), chinese_text, fontsize=12)
            doc.save(str(pdf_path))
            doc.close()

            result = engine.extract(pdf_path)
            assert len(result.pages) == 1
        except Exception:
            # Skip if font not available
            doc.close()
            pytest.skip("Chinese font not available for test")

    def test_extract_multiple_pages(self, engine, temp_dir):
        """Test extraction from multi-page PDF."""
        pdf_path = temp_dir / "multipage.pdf"
        doc = fitz.open()

        for i in range(5):
            page = doc.new_page()
            page.insert_text((50, 50), f"This is page {i + 1}", fontsize=12)

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        assert len(result.pages) == 5

        for i, page in enumerate(result.pages):
            assert page.page_number == i + 1

    # ===== Coordinate Extraction Tests =====

    def test_bounding_box_accuracy(self, engine, temp_dir):
        """Test that bounding boxes are extracted correctly."""
        pdf_path = temp_dir / "bbox.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Insert text at known position
        x, y = 100, 200
        page.insert_text((x, y), "Positioned Text", fontsize=12)

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        text_elements = [e for e in result.pages[0].elements if e.is_text]
        assert len(text_elements) > 0

        # Check that bbox is near the insertion point
        element = text_elements[0]
        assert element.bbox is not None
        assert element.bbox.x0 >= 0
        assert element.bbox.y0 >= 0
        assert element.bbox.x1 > element.bbox.x0
        assert element.bbox.y1 > element.bbox.y0

    def test_page_dimensions(self, engine, temp_dir):
        """Test that page dimensions are extracted correctly."""
        pdf_path = temp_dir / "dimensions.pdf"
        doc = fitz.open()

        # Create A4 page (595.28 x 841.89 points)
        page = doc.new_page(width=595.28, height=841.89)
        page.insert_text((50, 50), "Test", fontsize=12)

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        dimensions = result.pages[0].dimensions
        assert abs(dimensions.width - 595.28) < 1
        assert abs(dimensions.height - 841.89) < 1

    # ===== Structure Preservation Tests =====

    def test_detect_title_by_font_size(self, engine, temp_dir):
        """Test title detection based on font size."""
        pdf_path = temp_dir / "title.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Large text for title
        page.insert_text((50, 50), "Document Title", fontsize=24)
        # Normal text for content
        page.insert_text((50, 100), "This is regular content.", fontsize=12)

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        elements = result.pages[0].elements

        # Should have extracted text elements
        text_elements = [e for e in elements if e.is_text]
        assert len(text_elements) >= 1

        # Check that elements with larger fonts have different types or metadata
        # Note: Title detection depends on font size thresholds and may vary
        font_sizes = []
        for e in text_elements:
            if e.style and e.style.font_size:
                font_sizes.append(e.style.font_size)

        # Should have captured different font sizes
        if len(font_sizes) >= 2:
            assert max(font_sizes) > min(font_sizes)

    def test_detect_list_items(self, engine, temp_dir):
        """Test detection of list items."""
        pdf_path = temp_dir / "list.pdf"
        doc = fitz.open()
        page = doc.new_page()

        y = 50
        list_items = [
            "• First item",
            "• Second item",
            "• Third item"
        ]

        for item in list_items:
            page.insert_text((50, y), item, fontsize=12)
            y += 20

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        list_elements = [e for e in result.pages[0].elements
                        if e.type == ElementType.LIST_ITEM]

        # Should detect list items
        assert len(list_elements) >= 1

    def test_detect_headers_footers(self, engine, temp_dir):
        """Test header/footer detection by position."""
        pdf_path = temp_dir / "header_footer.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Header at top
        page.insert_text((50, 30), "Document Header", fontsize=10)

        # Content in middle
        page.insert_text((50, 400), "Main content of the document.", fontsize=12)

        # Footer at bottom
        page.insert_text((50, 800), "Page 1", fontsize=10)

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        elements = result.pages[0].elements

        # Check for header/footer metadata
        headers = [e for e in elements if e.metadata.get('is_page_header')]
        footers = [e for e in elements if e.metadata.get('is_page_footer')]

        # At least one should be detected
        assert len(headers) + len(footers) >= 1

    def test_section_hierarchy(self, engine, temp_dir):
        """Test section hierarchy building."""
        pdf_path = temp_dir / "sections.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Create hierarchical headers
        page.insert_text((50, 50), "Main Title", fontsize=20)
        page.insert_text((50, 100), "Section 1", fontsize=16)
        page.insert_text((50, 150), "Subsection 1.1", fontsize=14)
        page.insert_text((50, 200), "Content text", fontsize=12)

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        elements = result.pages[0].elements

        # Check for section levels
        headers = [e for e in elements
                  if e.type in [ElementType.TITLE, ElementType.HEADER]]

        levels = [e.metadata.get('section_level') for e in headers
                 if e.metadata.get('section_level')]

        if levels:
            # Should have multiple levels
            assert len(set(levels)) >= 1

    # ===== Table Detection Tests =====

    def test_detect_simple_table(self, engine, temp_dir):
        """Test detection of a simple table."""
        pdf_path = temp_dir / "table.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Create a simple table layout
        table_data = [
            ["Name", "Age", "City"],
            ["Alice", "30", "Tokyo"],
            ["Bob", "25", "Paris"]
        ]

        y = 100
        for row in table_data:
            x = 50
            for cell in row:
                page.insert_text((x, y), cell, fontsize=10)
                x += 100
            y += 20

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        table_elements = [e for e in result.pages[0].elements
                        if e.type == ElementType.TABLE]

        # Table detection may or may not succeed depending on layout
        # Just verify the extraction completed without error
        assert result.pages[0].elements is not None

    def test_table_detection_disabled(self, engine_no_tables, temp_dir):
        """Test that table detection can be disabled."""
        pdf_path = temp_dir / "no_table.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Create table-like layout
        for i in range(3):
            page.insert_text((50 + i*100, 100), f"Col{i}", fontsize=10)
            page.insert_text((50 + i*100, 120), f"Val{i}", fontsize=10)

        doc.save(str(pdf_path))
        doc.close()

        result = engine_no_tables.extract(pdf_path)

        # With table detection disabled, should not find tables
        table_elements = [e for e in result.pages[0].elements
                        if e.type == ElementType.TABLE]

        assert len(table_elements) == 0

    # ===== Image Extraction Tests =====

    def test_extract_embedded_image(self, engine, temp_dir):
        """Test extraction of embedded images."""
        pdf_path = temp_dir / "with_image.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Create and embed an image
        img = Image.new('RGB', (100, 100), color='red')
        img_bytes = io.BytesIO()
        img.save(img_bytes, format='PNG')
        img_bytes.seek(0)

        # Insert image into PDF
        rect = fitz.Rect(100, 100, 300, 300)
        page.insert_image(rect, stream=img_bytes.read())

        doc.save(str(pdf_path))
        doc.close()

        # Create output directory for images
        output_dir = temp_dir / "images"

        result = engine.extract(pdf_path, output_dir)

        image_elements = [e for e in result.pages[0].elements
                        if e.type == ElementType.IMAGE]

        assert len(image_elements) >= 1

        # Check image has bbox
        if image_elements:
            img_elem = image_elements[0]
            assert img_elem.bbox is not None

    def test_image_extraction_disabled(self, engine_no_images, temp_dir):
        """Test that image extraction can be disabled."""
        pdf_path = temp_dir / "no_image.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Add image
        img = Image.new('RGB', (50, 50), color='blue')
        img_bytes = io.BytesIO()
        img.save(img_bytes, format='PNG')
        img_bytes.seek(0)

        rect = fitz.Rect(100, 100, 200, 200)
        page.insert_image(rect, stream=img_bytes.read())

        doc.save(str(pdf_path))
        doc.close()

        result = engine_no_images.extract(pdf_path)

        image_elements = [e for e in result.pages[0].elements
                        if e.type == ElementType.IMAGE]

        assert len(image_elements) == 0

    # ===== Metadata Tests =====

    def test_extract_pdf_metadata(self, engine, temp_dir):
        """Test extraction of PDF metadata."""
        pdf_path = temp_dir / "metadata.pdf"
        doc = fitz.open()

        # Set metadata
        doc.set_metadata({
            "title": "Test Document",
            "author": "Test Author",
            "subject": "Testing"
        })

        page = doc.new_page()
        page.insert_text((50, 50), "Content", fontsize=12)

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        assert result.metadata.title == "Test Document"
        assert result.metadata.author == "Test Author"
        assert result.metadata.subject == "Testing"

    def test_processing_track_is_direct(self, engine, temp_dir):
        """Test that processing track is set to DIRECT."""
        pdf_path = temp_dir / "track.pdf"
        doc = fitz.open()
        page = doc.new_page()
        page.insert_text((50, 50), "Test", fontsize=12)
        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        assert result.metadata.processing_track == ProcessingTrack.DIRECT

    def test_confidence_is_perfect(self, engine, temp_dir):
        """Test that direct extraction has confidence 1.0."""
        pdf_path = temp_dir / "confidence.pdf"
        doc = fitz.open()
        page = doc.new_page()
        page.insert_text((50, 50), "High confidence text", fontsize=12)
        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        text_elements = [e for e in result.pages[0].elements if e.is_text]

        for element in text_elements:
            assert element.confidence == 1.0

    # ===== Style Extraction Tests =====

    def test_extract_font_info(self, engine, temp_dir):
        """Test extraction of font information."""
        pdf_path = temp_dir / "fonts.pdf"
        doc = fitz.open()
        page = doc.new_page()

        page.insert_text((50, 50), "Normal text", fontsize=12)
        page.insert_text((50, 80), "Large text", fontsize=20)

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        text_elements = [e for e in result.pages[0].elements
                        if e.is_text and e.style]

        # Should have style information
        assert len(text_elements) > 0

        # Check font sizes are different
        font_sizes = [e.style.font_size for e in text_elements if e.style.font_size]
        if len(font_sizes) >= 2:
            assert max(font_sizes) > min(font_sizes)

    # ===== Error Handling Tests =====

    def test_nonexistent_file(self, engine, temp_dir):
        """Test handling of non-existent file."""
        pdf_path = temp_dir / "nonexistent.pdf"

        result = engine.extract(pdf_path)

        # Should return document with errors
        assert result.processing_errors is not None
        assert len(result.processing_errors) > 0

    def test_corrupted_pdf(self, engine, temp_dir):
        """Test handling of corrupted PDF."""
        pdf_path = temp_dir / "corrupted.pdf"

        # Create invalid PDF file
        pdf_path.write_bytes(b"This is not a valid PDF file")

        result = engine.extract(pdf_path)

        # Should return document with errors
        assert result.processing_errors is not None

    def test_empty_pdf_page(self, engine, temp_dir):
        """Test handling of PDF with empty pages."""
        pdf_path = temp_dir / "empty_page.pdf"
        doc = fitz.open()
        doc.new_page()  # Empty page
        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        assert len(result.pages) == 1
        # May or may not have elements

    # ===== Link Extraction Tests =====

    def test_extract_hyperlinks(self, engine, temp_dir):
        """Test extraction of hyperlinks."""
        pdf_path = temp_dir / "links.pdf"
        doc = fitz.open()
        page = doc.new_page()

        # Add text and link
        page.insert_text((50, 50), "Click here", fontsize=12)

        # Add hyperlink
        link_rect = fitz.Rect(50, 40, 120, 60)
        page.insert_link({
            'kind': fitz.LINK_URI,
            'from': link_rect,
            'uri': 'https://example.com'
        })

        doc.save(str(pdf_path))
        doc.close()

        result = engine.extract(pdf_path)

        reference_elements = [e for e in result.pages[0].elements
                            if e.type == ElementType.REFERENCE]

        assert len(reference_elements) >= 1

        # Check URI is extracted
        if reference_elements:
            link = reference_elements[0]
            assert link.content.get('uri') == 'https://example.com'

    # ===== Performance Tests =====

    def test_large_document_performance(self, engine, temp_dir):
        """Test extraction performance on larger document."""
        import time

        pdf_path = temp_dir / "large.pdf"
        doc = fitz.open()

        # Create 20 pages with content
        for i in range(20):
            page = doc.new_page()
            for j in range(10):
                page.insert_text((50, 50 + j*20),
                               f"Page {i+1} Line {j+1}: Lorem ipsum dolor sit amet",
                               fontsize=10)

        doc.save(str(pdf_path))
        doc.close()

        start_time = time.time()
        result = engine.extract(pdf_path)
        elapsed = time.time() - start_time

        assert len(result.pages) == 20
        assert elapsed < 30  # Should complete within 30 seconds

        # Check processing time is recorded
        assert result.metadata.processing_time > 0