Implement PDF renderer with WeasyPrint

src/py_dvt_ate/reporting/renderers/pdf.py

@@ -0,0 +1,83 @@
+"""PDF renderer using WeasyPrint.
+
+This module provides PDF rendering from HTML content using WeasyPrint.
+"""
+
+from pathlib import Path
+
+from py_dvt_ate.reporting.exceptions import PDFConversionError
+
+
+class PDFRenderer:
+    """Renders PDF documents from HTML content using WeasyPrint.
+
+    WeasyPrint converts HTML/CSS to PDF with support for page layout,
+    headers/footers, and professional typography.
+    """
+
+    def __init__(self) -> None:
+        """Initialise the PDF renderer."""
+        self._weasyprint: type | None = None
+
+    def _get_weasyprint(self) -> type:
+        """Lazy-load WeasyPrint to avoid import errors when not installed.
+
+        Returns:
+            The WeasyPrint HTML class.
+
+        Raises:
+            PDFConversionError: If WeasyPrint is not installed.
+        """
+        if self._weasyprint is None:
+            try:
+                from weasyprint import HTML
+
+                self._weasyprint = HTML
+            except ImportError as e:
+                msg = (
+                    "WeasyPrint is required for PDF generation. "
+                    "Install it with: pip install py_dvt_ate[reports]"
+                )
+                raise PDFConversionError(msg) from e
+        return self._weasyprint
+
+    def render_to_file(self, html: str, path: Path) -> None:
+        """Render HTML content to a PDF file.
+
+        Args:
+            html: HTML content to convert.
+            path: Output path for the PDF file.
+
+        Raises:
+            PDFConversionError: If PDF conversion fails.
+        """
+        try:
+            HTML = self._get_weasyprint()
+            path.parent.mkdir(parents=True, exist_ok=True)
+            HTML(string=html).write_pdf(path)
+        except PDFConversionError:
+            raise
+        except Exception as e:
+            msg = f"Failed to convert HTML to PDF: {e}"
+            raise PDFConversionError(msg) from e
+
+    def render_to_bytes(self, html: str) -> bytes:
+        """Render HTML content to PDF bytes.
+
+        Args:
+            html: HTML content to convert.
+
+        Returns:
+            PDF document as bytes.
+
+        Raises:
+            PDFConversionError: If PDF conversion fails.
+        """
+        try:
+            HTML = self._get_weasyprint()
+            return HTML(string=html).write_pdf()
+        except PDFConversionError:
+            raise
+        except Exception as e:
+            msg = f"Failed to convert HTML to PDF: {e}"
+            raise PDFConversionError(msg) from e