pdf_generator.py

import io
from reportlab.lib.pagesizes import letter, A4, legal
from reportlab.platypus import SimpleDocTemplate, Table, TableStyle, Paragraph, Spacer, Image
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import inch
from reportlab.lib import colors
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_RIGHT
import pandas as pd
from template_manager import TemplateManager
from datetime import datetime

class PDFGenerator:
    def __init__(self, template_name="default", include_images=True, preserve_formatting=True, page_size="A4"):
        self.template_name = template_name
        self.include_images = include_images
        self.preserve_formatting = preserve_formatting
        self.page_size = self._get_page_size(page_size)
        self.template_manager = TemplateManager()
        self.styles = getSampleStyleSheet()
        self._setup_custom_styles()
    
    def _get_page_size(self, size_name):
        """Convert page size name to reportlab page size"""
        sizes = {
            "A4": A4,
            "Letter": letter,
            "Legal": legal
        }
        return sizes.get(size_name, A4)
    
    def _setup_custom_styles(self):
        """Setup custom paragraph styles"""
        # Title style
        self.styles.add(ParagraphStyle(
            name='CustomTitle',
            parent=self.styles['Heading1'],
            fontSize=18,
            spaceAfter=30,
            alignment=TA_CENTER,
            textColor=colors.darkblue
        ))
        
        # Header style
        self.styles.add(ParagraphStyle(
            name='CustomHeader',
            parent=self.styles['Heading2'],
            fontSize=14,
            spaceAfter=12,
            textColor=colors.darkblue
        ))
        
        # Normal style with spacing
        self.styles.add(ParagraphStyle(
            name='CustomNormal',
            parent=self.styles['Normal'],
            fontSize=10,
            spaceAfter=6
        ))
    
    def generate_pdf(self, data_df):
        """Generate PDF from data using the selected template"""
        buffer = io.BytesIO()
        
        # Create document
        doc = SimpleDocTemplate(
            buffer,
            pagesize=self.page_size,
            rightMargin=72,
            leftMargin=72,
            topMargin=72,
            bottomMargin=18
        )
        
        # Build story (content)
        story = []
        
        # Add title
        title = Paragraph("Bank Operations Verification Report", self.styles['CustomTitle'])
        story.append(title)
        story.append(Spacer(1, 12))
        
        # Add generation info
        generation_info = f"Generated on: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}<br/>"
        generation_info += f"Template: {self.template_name}<br/>"
        generation_info += f"Records: {len(data_df)}"
        info_para = Paragraph(generation_info, self.styles['CustomNormal'])
        story.append(info_para)
        story.append(Spacer(1, 20))
        
        # Add data summary
        summary_header = Paragraph("Data Summary", self.styles['CustomHeader'])
        story.append(summary_header)
        
        # Create summary table
        summary_data = [
            ['Metric', 'Value'],
            ['Total Records', str(len(data_df))],
            ['Columns', str(len(data_df.columns))],
            ['Data Types', ', '.join(data_df.dtypes.astype(str).unique())]
        ]
        
        summary_table = Table(summary_data, colWidths=[2*inch, 3*inch])
        summary_table.setStyle(TableStyle([
            ('BACKGROUND', (0, 0), (-1, 0), colors.grey),
            ('TEXTCOLOR', (0, 0), (-1, 0), colors.whitesmoke),
            ('ALIGN', (0, 0), (-1, -1), 'CENTER'),
            ('FONTNAME', (0, 0), (-1, 0), 'Helvetica-Bold'),
            ('FONTSIZE', (0, 0), (-1, 0), 12),
            ('BOTTOMPADDING', (0, 0), (-1, 0), 12),
            ('BACKGROUND', (0, 1), (-1, -1), colors.beige),
            ('GRID', (0, 0), (-1, -1), 1, colors.black)
        ]))
        
        story.append(summary_table)
        story.append(Spacer(1, 20))
        
        # Add main data table
        data_header = Paragraph("Detailed Data", self.styles['CustomHeader'])
        story.append(data_header)
        
        # Prepare data for table
        table_data = []
        
        # Add headers
        headers = list(data_df.columns)
        table_data.append(headers)
        
        # Add data rows (limit to prevent overly large PDFs)
        max_rows = min(len(data_df), 50)  # Limit to 50 rows for performance
        for i in range(max_rows):
            row = []
            for col in data_df.columns:
                value = str(data_df.iloc[i][col])
                # Truncate long values
                if len(value) > 30:
                    value = value[:27] + "..."
                row.append(value)
            table_data.append(row)
        
        # Add truncation notice if needed
        if len(data_df) > max_rows:
            truncation_notice = Paragraph(
                f"Note: Only showing first {max_rows} rows of {len(data_df)} total records.",
                self.styles['CustomNormal']
            )
            story.append(truncation_notice)
            story.append(Spacer(1, 10))
        
        # Calculate column widths
        page_width = self.page_size[0] - 144  # Account for margins
        num_cols = len(headers)
        col_width = page_width / num_cols
        col_widths = [col_width] * num_cols
        
        # Create main data table
        main_table = Table(table_data, colWidths=col_widths, repeatRows=1)
        
        # Style the main table
        table_style = [
            ('BACKGROUND', (0, 0), (-1, 0), colors.darkblue),
            ('TEXTCOLOR', (0, 0), (-1, 0), colors.whitesmoke),
            ('ALIGN', (0, 0), (-1, -1), 'CENTER'),
            ('FONTNAME', (0, 0), (-1, 0), 'Helvetica-Bold'),
            ('FONTSIZE', (0, 0), (-1, 0), 10),
            ('BOTTOMPADDING', (0, 0), (-1, 0), 12),
            ('FONTSIZE', (0, 1), (-1, -1), 8),
            ('GRID', (0, 0), (-1, -1), 1, colors.black)
        ]
        
        # Alternate row colors
        for i in range(1, len(table_data)):
            if i % 2 == 0:
                table_style.append(('BACKGROUND', (0, i), (-1, i), colors.lightgrey))
            else:
                table_style.append(('BACKGROUND', (0, i), (-1, i), colors.white))
        
        main_table.setStyle(TableStyle(table_style))
        story.append(main_table)
        
        # Add footer
        story.append(Spacer(1, 30))
        footer = Paragraph(
            "This report was automatically generated by the PDF Export System.",
            self.styles['CustomNormal']
        )
        story.append(footer)
        
        # Build PDF
        doc.build(story)
        buffer.seek(0)
        
        return buffer
    
    def _format_value(self, value):
        """Format value for display in PDF"""
        if pd.isna(value):
            return "N/A"
        elif isinstance(value, (int, float)):
            if isinstance(value, float) and value.is_integer():
                return str(int(value))
            elif isinstance(value, float):
                return f"{value:.2f}"
            else:
                return str(value)
        else:
            return str(value)