from reportlab.lib import colors
from reportlab.lib.pagesizes import letter
from reportlab.platypus import SimpleDocTemplate, Table, TableStyle, Paragraph, Spacer
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import inch
from datetime import datetime
import os

class PDFGenerator:
    def __init__(self, output_dir="pdfs"):
        self.output_dir = output_dir
        os.makedirs(output_dir, exist_ok=True)
    
    def generate_invoice_pdf(self, invoice_data, client_data):
        """Generate PDF for invoice"""
        filename = f"invoice_{invoice_data['invoice_number']}.pdf"
        filepath = os.path.join(self.output_dir, filename)
        
        # Margins: 0.75 inch
        doc = SimpleDocTemplate(
            filepath, 
            pagesize=letter,
            rightMargin=0.75*inch, 
            leftMargin=0.75*inch,
            topMargin=0.75*inch, 
            bottomMargin=0.75*inch
        )
        
        styles = getSampleStyleSheet()
        story = []
        
        # Custom styles
        title_style = ParagraphStyle(
            'InvoiceTitle',
            parent=styles['Normal'],
            fontName='Helvetica-Bold',
            fontSize=24,
            leading=28,
            textColor=colors.HexColor('#1E293B')
        )
        
        company_style = ParagraphStyle(
            'CompanyHeader',
            parent=styles['Normal'],
            fontName='Helvetica-Bold',
            fontSize=16,
            leading=20,
            textColor=colors.HexColor('#6D28D9')
        )
        
        meta_label_style = ParagraphStyle(
            'MetaLabel',
            parent=styles['Normal'],
            fontName='Helvetica-Bold',
            fontSize=10,
            leading=14,
            textColor=colors.HexColor('#64748B')
        )
        
        meta_val_style = ParagraphStyle(
            'MetaVal',
            parent=styles['Normal'],
            fontName='Helvetica',
            fontSize=10,
            leading=14,
            textColor=colors.HexColor('#1E293B')
        )

        # Header Table: Company name on left, "INVOICE" on right
        header_data = [
            [
                Paragraph("ERHA TECHNOLOGIES", company_style),
                Paragraph("INVOICE", title_style)
            ]
        ]
        header_table = Table(header_data, colWidths=[3.5 * inch, 3.5 * inch])
        header_table.setStyle(TableStyle([
            ('VALIGN', (0, 0), (-1, -1), 'MIDDLE'),
            ('ALIGN', (0, 0), (0, 0), 'LEFT'),
            ('ALIGN', (1, 0), (1, 0), 'RIGHT'),
        ]))
        story.append(header_table)
        story.append(Spacer(1, 0.1 * inch))
        
        # Colored accent bar
        accent_bar = Table([['']], colWidths=[7 * inch], rowHeights=[3])
        accent_bar.setStyle(TableStyle([
            ('BACKGROUND', (0, 0), (-1, -1), colors.HexColor('#6D28D9')),
            ('BOTTOMPADDING', (0, 0), (-1, -1), 0),
            ('TOPPADDING', (0, 0), (-1, -1), 0),
        ]))
        story.append(accent_bar)
        story.append(Spacer(1, 0.3 * inch))
        
        # Invoice metadata grid
        meta_data = [
            [Paragraph("Invoice Number:", meta_label_style), Paragraph(invoice_data['invoice_number'], meta_val_style),
             Paragraph("Issue Date:", meta_label_style), Paragraph(invoice_data['issue_date'].strftime('%b %d, %Y'), meta_val_style)],
            [Paragraph("Client Name:", meta_label_style), Paragraph(client_data['name'], meta_val_style),
             Paragraph("Due Date:", meta_label_style), Paragraph(invoice_data['due_date'].strftime('%b %d, %Y'), meta_val_style)],
            [Paragraph("Client Email:", meta_label_style), Paragraph(client_data.get('email', 'N/A'), meta_val_style),
             Paragraph("Payment Status:", meta_label_style), Paragraph(invoice_data['status'].upper(), ParagraphStyle('Status', parent=meta_val_style, fontName='Helvetica-Bold', textColor=colors.HexColor('#10B981') if invoice_data['status'] == 'Paid' else colors.HexColor('#F59E0B')))]
        ]
        
        meta_table = Table(meta_data, colWidths=[1.3 * inch, 2.2 * inch, 1.3 * inch, 2.2 * inch])
        meta_table.setStyle(TableStyle([
            ('ALIGN', (0, 0), (-1, -1), 'LEFT'),
            ('VALIGN', (0, 0), (-1, -1), 'TOP'),
            ('BOTTOMPADDING', (0, 0), (-1, -1), 8),
        ]))
        story.append(meta_table)
        story.append(Spacer(1, 0.4 * inch))
        
        # Details Header
        details_title = Paragraph("BILLING SUMMARY", ParagraphStyle('Sub', fontName='Helvetica-Bold', fontSize=12, leading=16, textColor=colors.HexColor('#475569')))
        story.append(details_title)
        story.append(Spacer(1, 0.1 * inch))
        
        # Billing details table
        bill_data = [
            ["Description", "Amount"],
            [f"Services rendered for {client_data['name']}", f"PKR {invoice_data['amount']:,.2f}"],
            ["Total Due", f"PKR {invoice_data['amount']:,.2f}"]
        ]
        
        bill_table = Table(bill_data, colWidths=[5 * inch, 2 * inch])
        bill_table.setStyle(TableStyle([
            # Header Row Styling
            ('BACKGROUND', (0, 0), (-1, 0), colors.HexColor('#F8FAFC')),
            ('TEXTCOLOR', (0, 0), (-1, 0), colors.HexColor('#475569')),
            ('FONTNAME', (0, 0), (-1, 0), 'Helvetica-Bold'),
            ('FONTSIZE', (0, 0), (-1, 0), 10),
            ('ALIGN', (0, 0), (-1, 0), 'LEFT'),
            ('ALIGN', (1, 0), (1, 0), 'RIGHT'),
            ('BOTTOMPADDING', (0, 0), (-1, 0), 10),
            ('TOPPADDING', (0, 0), (-1, 0), 10),
            # Line under header
            ('LINEBELOW', (0, 0), (-1, 0), 1.5, colors.HexColor('#E2E8F0')),
            
            # Content Row Styling
            ('FONTNAME', (0, 1), (-1, 1), 'Helvetica'),
            ('FONTSIZE', (0, 1), (-1, 1), 10),
            ('TEXTCOLOR', (0, 1), (-1, 1), colors.HexColor('#1E293B')),
            ('ALIGN', (0, 1), (0, 1), 'LEFT'),
            ('ALIGN', (1, 1), (1, 1), 'RIGHT'),
            ('BOTTOMPADDING', (0, 1), (-1, 1), 12),
            ('TOPPADDING', (0, 1), (-1, 1), 12),
            ('LINEBELOW', (0, 1), (-1, 1), 0.5, colors.HexColor('#F1F5F9')),
            
            # Total Row Styling
            ('FONTNAME', (0, 2), (-1, 2), 'Helvetica-Bold'),
            ('FONTSIZE', (0, 2), (-1, 2), 12),
            ('TEXTCOLOR', (0, 2), (-1, 2), colors.HexColor('#6D28D9')),
            ('ALIGN', (0, 2), (0, 2), 'LEFT'),
            ('ALIGN', (1, 2), (1, 2), 'RIGHT'),
            ('BOTTOMPADDING', (0, 2), (-1, 2), 12),
            ('TOPPADDING', (0, 2), (-1, 2), 12),
            ('LINEABOVE', (0, 2), (-1, 2), 1.5, colors.HexColor('#E2E8F0')),
        ]))
        
        story.append(bill_table)
        doc.build(story)
        return filepath
    
    def generate_payslip_pdf(self, payroll_data, employee_data):
        """Generate PDF for payslip"""
        filename = f"payslip_{payroll_data['employee_name']}_{payroll_data['month']}_{payroll_data['year']}.pdf"
        filepath = os.path.join(self.output_dir, filename)
        
        # Margins: 0.75 inch
        doc = SimpleDocTemplate(
            filepath, 
            pagesize=letter,
            rightMargin=0.75*inch, 
            leftMargin=0.75*inch,
            topMargin=0.75*inch, 
            bottomMargin=0.75*inch
        )
        
        styles = getSampleStyleSheet()
        story = []
        
        # Custom styles
        title_style = ParagraphStyle(
            'PayslipTitle',
            parent=styles['Normal'],
            fontName='Helvetica-Bold',
            fontSize=24,
            leading=28,
            textColor=colors.HexColor('#1E293B')
        )
        
        company_style = ParagraphStyle(
            'CompanyHeader',
            parent=styles['Normal'],
            fontName='Helvetica-Bold',
            fontSize=16,
            leading=20,
            textColor=colors.HexColor('#6D28D9')
        )
        
        meta_label_style = ParagraphStyle(
            'MetaLabel',
            parent=styles['Normal'],
            fontName='Helvetica-Bold',
            fontSize=10,
            leading=14,
            textColor=colors.HexColor('#64748B')
        )
        
        meta_val_style = ParagraphStyle(
            'MetaVal',
            parent=styles['Normal'],
            fontName='Helvetica',
            fontSize=10,
            leading=14,
            textColor=colors.HexColor('#1E293B')
        )

        # Header Table: Company name on left, "PAYSLIP" on right
        header_data = [
            [
                Paragraph("ERHA TECHNOLOGIES", company_style),
                Paragraph("PAYSLIP", title_style)
            ]
        ]
        header_table = Table(header_data, colWidths=[3.5 * inch, 3.5 * inch])
        header_table.setStyle(TableStyle([
            ('VALIGN', (0, 0), (-1, -1), 'MIDDLE'),
            ('ALIGN', (0, 0), (0, 0), 'LEFT'),
            ('ALIGN', (1, 0), (1, 0), 'RIGHT'),
        ]))
        story.append(header_table)
        story.append(Spacer(1, 0.1 * inch))
        
        # Colored accent bar
        accent_bar = Table([['']], colWidths=[7 * inch], rowHeights=[3])
        accent_bar.setStyle(TableStyle([
            ('BACKGROUND', (0, 0), (-1, -1), colors.HexColor('#6D28D9')),
            ('BOTTOMPADDING', (0, 0), (-1, -1), 0),
            ('TOPPADDING', (0, 0), (-1, -1), 0),
        ]))
        story.append(accent_bar)
        story.append(Spacer(1, 0.3 * inch))
        
        # Employee / Period metadata grid
        payment_date_str = "N/A"
        if payroll_data.get('payment_date'):
            if isinstance(payroll_data['payment_date'], str):
                try:
                    payment_date_str = datetime.strptime(payroll_data['payment_date'][:10], '%Y-%m-%d').strftime('%b %d, %Y')
                except:
                    payment_date_str = payroll_data['payment_date']
            elif hasattr(payroll_data['payment_date'], 'strftime'):
                payment_date_str = payroll_data['payment_date'].strftime('%b %d, %Y')

        meta_data = [
            [Paragraph("Employee Name:", meta_label_style), Paragraph(payroll_data['employee_name'], meta_val_style),
             Paragraph("Payroll Period:", meta_label_style), Paragraph(f"{payroll_data['month']} {payroll_data['year']}", meta_val_style)],
            [Paragraph("Designation:", meta_label_style), Paragraph(employee_data.get('role', 'N/A'), meta_val_style),
             Paragraph("Disbursement Date:", meta_label_style), Paragraph(payment_date_str, meta_val_style)],
            [Paragraph("Payment Status:", meta_label_style), Paragraph("PAID" if payroll_data['is_paid'] else "PENDING", ParagraphStyle('Status', parent=meta_val_style, fontName='Helvetica-Bold', textColor=colors.HexColor('#10B981') if payroll_data['is_paid'] else colors.HexColor('#F59E0B'))),
             Paragraph("Employer:", meta_label_style), Paragraph("Spaze", meta_val_style)]
        ]
        
        meta_table = Table(meta_data, colWidths=[1.3 * inch, 2.2 * inch, 1.3 * inch, 2.2 * inch])
        meta_table.setStyle(TableStyle([
            ('ALIGN', (0, 0), (-1, -1), 'LEFT'),
            ('VALIGN', (0, 0), (-1, -1), 'TOP'),
            ('BOTTOMPADDING', (0, 0), (-1, -1), 8),
        ]))
        story.append(meta_table)
        story.append(Spacer(1, 0.4 * inch))
        
        # Details Header
        details_title = Paragraph("EARNINGS & DEDUCTIONS", ParagraphStyle('Sub', fontName='Helvetica-Bold', fontSize=12, leading=16, textColor=colors.HexColor('#475569')))
        story.append(details_title)
        story.append(Spacer(1, 0.1 * inch))
        
        # Salary breakdown list
        salary_breakdown = [
            ["Description", "Amount"],
            ["Base Monthly Salary", f"PKR {payroll_data['base_salary']:,.2f}"]
        ]
        
        # Add Bonus if exists
        if payroll_data.get('bonus', 0.0) > 0.0:
            salary_breakdown.append(["Performance Bonus", f"PKR {payroll_data['bonus']:,.2f}"])
            
        # Add Deductions if exists
        if payroll_data.get('deductions', 0.0) > 0.0:
            salary_breakdown.append(["Salary Advance / Deductions", f"-PKR {payroll_data['deductions']:,.2f}"])
            
        # Final Net Payout row
        salary_breakdown.append(["Net Payout", f"PKR {payroll_data['net_salary']:,.2f}"])
        
        # Build ReportLab TableStyle dynamic ranges based on count of rows
        total_rows = len(salary_breakdown)
        table_style_cmd = [
            # Header Row Styling
            ('BACKGROUND', (0, 0), (-1, 0), colors.HexColor('#F8FAFC')),
            ('TEXTCOLOR', (0, 0), (-1, 0), colors.HexColor('#475569')),
            ('FONTNAME', (0, 0), (-1, 0), 'Helvetica-Bold'),
            ('FONTSIZE', (0, 0), (-1, 0), 10),
            ('ALIGN', (0, 0), (-1, 0), 'LEFT'),
            ('ALIGN', (1, 0), (1, 0), 'RIGHT'),
            ('BOTTOMPADDING', (0, 0), (-1, 0), 10),
            ('TOPPADDING', (0, 0), (-1, 0), 10),
            ('LINEBELOW', (0, 0), (-1, 0), 1.5, colors.HexColor('#E2E8F0')),
        ]
        
        # Content Rows Styling
        for i in range(1, total_rows - 1):
            is_deduction = "-" in salary_breakdown[i][1]
            row_color = colors.HexColor('#EF4444') if is_deduction else colors.HexColor('#1E293B')
            table_style_cmd.extend([
                ('FONTNAME', (0, i), (-1, i), 'Helvetica'),
                ('FONTSIZE', (0, i), (-1, i), 10),
                ('TEXTCOLOR', (0, i), (0, i), colors.HexColor('#1E293B')),
                ('TEXTCOLOR', (1, i), (1, i), row_color),
                ('ALIGN', (0, i), (0, i), 'LEFT'),
                ('ALIGN', (1, i), (1, i), 'RIGHT'),
                ('BOTTOMPADDING', (0, i), (-1, i), 10),
                ('TOPPADDING', (0, i), (-1, i), 10),
                ('LINEBELOW', (0, i), (-1, i), 0.5, colors.HexColor('#F1F5F9')),
            ])
            
        # Total Row Styling (last row)
        last_idx = total_rows - 1
        table_style_cmd.extend([
            ('FONTNAME', (0, last_idx), (-1, last_idx), 'Helvetica-Bold'),
            ('FONTSIZE', (0, last_idx), (-1, last_idx), 12),
            ('TEXTCOLOR', (0, last_idx), (-1, last_idx), colors.HexColor('#6D28D9')),
            ('ALIGN', (0, last_idx), (0, last_idx), 'LEFT'),
            ('ALIGN', (1, last_idx), (1, last_idx), 'RIGHT'),
            ('BOTTOMPADDING', (0, last_idx), (-1, last_idx), 12),
            ('TOPPADDING', (0, last_idx), (-1, last_idx), 12),
            ('LINEABOVE', (0, last_idx), (-1, last_idx), 1.5, colors.HexColor('#E2E8F0')),
        ])
        
        bill_table = Table(salary_breakdown, colWidths=[5 * inch, 2 * inch])
        bill_table.setStyle(TableStyle(table_style_cmd))
        story.append(bill_table)
        
        doc.build(story)
        return filepath