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fusion_authorizer_portal/utils/pdf_filler.py

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+# -*- coding: utf-8 -*-
+# Fusion PDF Template Filler
+# Generic utility for filling any PDF template with data overlays.
+# Uses the same pattern as Odoo Enterprise Sign module (sign/utils/pdf_handling.py):
+#   - Read original PDF page dimensions from mediaBox
+#   - Create reportlab Canvas overlay at the same page size
+#   - Convert percentage positions (0.0-1.0) to absolute PDF coordinates
+#   - Merge overlay onto original page via mergePage()
+
+import logging
+from io import BytesIO
+
+from reportlab.pdfgen import canvas
+from reportlab.lib.utils import ImageReader
+
+from odoo.tools.pdf import PdfFileReader, PdfFileWriter
+
+_logger = logging.getLogger(__name__)
+
+
+class PDFTemplateFiller:
+    """Generic PDF template filler. Works with any template, any number of pages."""
+
+    @staticmethod
+    def fill_template(template_pdf_bytes, fields_by_page, context, signatures=None):
+        """Fill a PDF template by overlaying text/checkmarks/signatures at configured positions.
+
+        Args:
+            template_pdf_bytes: bytes of the original PDF
+            fields_by_page: {page_num: [field_dicts]} where page_num is 1-based
+                Each field_dict has: field_key, pos_x, pos_y, width, height,
+                                     field_type, font_size, font_name
+            context: flat dict of {field_key: value} with all available data
+            signatures: dict of {field_key: binary_png} for signature image fields
+
+        Returns:
+            bytes of the filled PDF (all pages preserved)
+        """
+        if signatures is None:
+            signatures = {}
+
+        try:
+            original = PdfFileReader(BytesIO(template_pdf_bytes))
+        except Exception as e:
+            _logger.error("Failed to read template PDF: %s", e)
+            raise
+
+        output = PdfFileWriter()
+        num_pages = original.getNumPages()
+
+        for page_idx in range(num_pages):
+            page = original.getPage(page_idx)
+            page_num = page_idx + 1  # 1-based page number
+            page_w = float(page.mediaBox.getWidth())
+            page_h = float(page.mediaBox.getHeight())
+
+            fields = fields_by_page.get(page_num, [])
+
+            if fields:
+                # Create a transparent overlay for this page
+                overlay_buf = BytesIO()
+                c = canvas.Canvas(overlay_buf, pagesize=(page_w, page_h))
+
+                for field in fields:
+                    PDFTemplateFiller._draw_field(
+                        c, field, context, signatures, page_w, page_h
+                    )
+
+                c.save()
+                overlay_buf.seek(0)
+
+                # Merge overlay onto original page (same as sign module)
+                overlay_pdf = PdfFileReader(overlay_buf)
+                page.mergePage(overlay_pdf.getPage(0))
+
+            output.addPage(page)
+
+        result = BytesIO()
+        output.write(result)
+        return result.getvalue()
+
+    @staticmethod
+    def _draw_field(c, field, context, signatures, page_w, page_h):
+        """Draw a single field onto the reportlab canvas.
+
+        Args:
+            c: reportlab Canvas
+            field: dict with field_key, pos_x, pos_y, width, height, field_type, etc.
+            context: data context dict
+            signatures: dict of {field_key: binary} for signature fields
+            page_w: page width in PDF points
+            page_h: page height in PDF points
+        """
+        field_key = field.get('field_key') or field.get('field_name', '')
+        field_type = field.get('field_type', 'text')
+        value = context.get(field_key, field.get('default_value', ''))
+
+        if not value and field_type != 'signature':
+            return
+
+        # Convert percentage positions to absolute PDF coordinates
+        # pos_x/pos_y are 0.0-1.0 ratios from top-left
+        # PDF coordinate system: origin at bottom-left, Y goes up
+        abs_x = field['pos_x'] * page_w
+        abs_y = page_h - (field['pos_y'] * page_h)  # flip Y axis
+
+        font_name = field.get('font_name', 'Helvetica')
+        font_size = field.get('font_size', 10.0)
+
+        if field_type in ('text', 'date'):
+            c.setFont(font_name, font_size)
+            c.drawString(abs_x, abs_y, str(value))
+
+        elif field_type == 'checkbox':
+            if value:  # Only draw if truthy
+                # Checkmark using ZapfDingbats (same as sign module)
+                c.setFont('ZapfDingbats', font_size)
+                c.drawString(abs_x, abs_y, '4')  # checkmark character
+
+        elif field_type == 'signature':
+            sig_data = signatures.get(field_key)
+            if sig_data:
+                try:
+                    img = ImageReader(BytesIO(sig_data))
+                    sig_w = field.get('width', 0.15) * page_w
+                    sig_h = field.get('height', 0.05) * page_h
+                    # Draw signature image (position from top, so adjust Y)
+                    c.drawImage(
+                        img, abs_x, abs_y - sig_h,
+                        width=sig_w, height=sig_h,
+                        mask='auto',
+                    )
+                except Exception as e:
+                    _logger.warning("Failed to draw signature for %s: %s", field_key, e)