from reportlab.lib import colors
from reportlab.lib.pagesizes import A4
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle, Image
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import inch
from datetime import datetime
import logging
import os
from reportlab.pdfgen import canvas

logger = logging.getLogger(__name__)

# Thomas-Krenn Farbschema
TK_ORANGE = colors.HexColor('#F7941D')
TK_DARK_GRAY = colors.HexColor('#333333')
TK_LIGHT_GRAY = colors.HexColor('#F5F5F5')
TK_WHITE = colors.white
TK_GREEN = colors.HexColor('#059669')
TK_RED = colors.HexColor('#dc2626')

def validate_data(data):
    """Checks if all required data is present."""
    required_fields = ['replication_type', 'nodes', 'result']
    for field in required_fields:
        if field not in data:
            raise ValueError(f"Missing field: {field}")
    
    if not data['nodes']:
        raise ValueError("No nodes defined")
    
    if not data['result'].get('raw_total'):
        raise ValueError("No calculation results available")

def safe_int(value, default=0):
    """Safely converts a value to an integer."""
    if value is None:
        return default
    try:
        return int(str(value).strip())
    except (ValueError, TypeError):
        logger.warning(f"Could not convert value '{value}' to integer. Using default value {default}")
        return default

def safe_float(value, default=0.0):
    """Safely converts a value to a float."""
    if value is None:
        return default
    try:
        return float(str(value).strip())
    except (ValueError, TypeError):
        logger.warning(f"Could not convert value '{value}' to float. Using default value {default}")
        return default

def generate_pdf_report(data):
    """
    Generates a PDF report with Ceph configuration data and results.
    
    Args:
        data (dict): Dictionary with configuration and result data
        
    Returns:
        bytes: PDF file as bytes
        
    Raises:
        ValueError: If required data is missing
    """
    try:
        # Validate input data
        validate_data(data)
        
        # Create a temporary buffer for the PDF
        from io import BytesIO
        buffer = BytesIO()
        
        # Create the PDF document
        doc = SimpleDocTemplate(
            buffer,
            pagesize=A4,
            rightMargin=72,
            leftMargin=72,
            topMargin=72,
            bottomMargin=72,
            title="Ceph Storage Capacity Report"
        )
        
        # Define styles
        styles = getSampleStyleSheet()
        
        # Custom styles mit weißer Textfarbe aufgrund des grauen Hintergrunds
        title_style = ParagraphStyle(
            'CustomTitle',
            parent=styles['Heading1'],
            fontSize=24,
            spaceAfter=30,
            textColor=TK_WHITE
        )
        
        heading_style = ParagraphStyle(
            'CustomHeading',
            parent=styles['Heading2'],
            fontSize=16,
            spaceAfter=12,
            textColor=TK_ORANGE
        )
        
        normal_style = ParagraphStyle(
            'CustomNormal',
            parent=styles['Normal'],
            fontSize=10,
            spaceAfter=6,
            textColor=TK_WHITE
        )
        
        # Custom Style for warnings
        warning_style = ParagraphStyle(
            'Warning',
            parent=styles['Normal'],
            textColor=TK_RED,
            fontSize=10,
            spaceAfter=6
        )
        
        # Create story (content)
        story = []
        
        # Hintergrundfarbe und Canvas-Anpassung
        # Definiere die Hintergrundfarbe
        TK_BACKGROUND_GRAY = colors.HexColor('#1f2937')  # Dunkelgrau wie in der Website (dark-bg)
        
        # Funktion zum Zeichnen des Hintergrunds
        def add_page_background(canvas, doc):
            canvas.saveState()
            canvas.setFillColor(TK_BACKGROUND_GRAY)
            canvas.rect(0, 0, doc.pagesize[0], doc.pagesize[1], fill=True, stroke=False)
            canvas.restoreState()
        
        # Title with modern styling
        story.append(Paragraph("Ceph Storage Capacity Report", title_style))
        story.append(Paragraph(f"Generated on: {datetime.now().strftime('%d.%m.%Y %H:%M')}", normal_style))
        story.append(Spacer(1, 20))
        
        # Configuration overview with modern styling
        story.append(Paragraph("Configuration Overview", heading_style))
        story.append(Spacer(1, 12))
        
        # Replication type with modern table style
        config_data = [
            ["Replication Type", data['replication_type']],
            ["Storage Unit", data.get('storage_unit', 'GB')]
        ]
        
        # Add replication-specific parameters
        if data['replication_type'] == 'replication':
            config_data.extend([
                ["Number of Replicas", str(data.get('replicas', 3))],
                ["Minimum Size", str(data.get('min_size', 2))]
            ])
        else:  # Erasure Coding
            config_data.extend([
                ["Data Chunks (k)", str(data.get('k', 4))],
                ["Coding Chunks (m)", str(data.get('m', 2))]
            ])
        
        # Modern table style for configurations
        t = Table(config_data, colWidths=[3*inch, 3*inch])
        t.setStyle(TableStyle([
            ('BACKGROUND', (0, 0), (-1, 0), TK_ORANGE),
            ('TEXTCOLOR', (0, 0), (-1, 0), TK_WHITE),
            ('ALIGN', (0, 0), (-1, -1), 'LEFT'),
            ('FONTNAME', (0, 0), (-1, 0), 'Helvetica-Bold'),
            ('FONTSIZE', (0, 0), (-1, 0), 12),
            ('BOTTOMPADDING', (0, 0), (-1, 0), 12),
            ('BACKGROUND', (0, 1), (-1, -1), TK_DARK_GRAY),
            ('TEXTCOLOR', (0, 1), (-1, -1), TK_WHITE),
            ('FONTNAME', (0, 1), (-1, -1), 'Helvetica'),
            ('FONTSIZE', (0, 1), (-1, -1), 10),
            ('ALIGN', (0, 1), (-1, -1), 'LEFT'),
            ('GRID', (0, 0), (-1, -1), 1, TK_LIGHT_GRAY)
        ]))
        story.append(t)
        
        # Add nodes information with modern styling
        story.append(Spacer(1, 20))
        story.append(Paragraph("Nodes Configuration", heading_style))
        story.append(Spacer(1, 12))
        
        nodes_data = [["Node", "OSD Count", f"OSD Size ({data.get('storage_unit', 'GB')})"]]
        for i, node in enumerate(data.get('nodes', []), 1):
            osd_size = safe_float(node.get('osd_size_gb', 0))
            if data.get('storage_unit') == 'TB':
                osd_size = osd_size / 1024  # Convert GB to TB for display
            nodes_data.append([
                f"Node {i}",
                str(node.get('osd_count', 0)),
                f"{osd_size:.2f}"
            ])
        
        # Nodes table
        t = Table(nodes_data, colWidths=[2*inch, 2*inch, 2*inch])
        t.setStyle(TableStyle([
            ('BACKGROUND', (0, 0), (-1, 0), TK_ORANGE),
            ('TEXTCOLOR', (0, 0), (-1, 0), TK_WHITE),
            ('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), TK_DARK_GRAY),
            ('TEXTCOLOR', (0, 1), (-1, -1), TK_WHITE),
            ('FONTNAME', (0, 1), (-1, -1), 'Helvetica'),
            ('FONTSIZE', (0, 1), (-1, -1), 10),
            ('ALIGN', (0, 1), (-1, -1), 'CENTER'),
            ('GRID', (0, 0), (-1, -1), 1, TK_LIGHT_GRAY)
        ]))
        story.append(t)
        
        # Results with modern styling
        story.append(Spacer(1, 20))
        story.append(Paragraph("Results", heading_style))
        story.append(Spacer(1, 12))
        
        result_data = [
            ["Total Raw Storage", f"{safe_float(data['result']['raw_total'])} {data.get('storage_unit', 'GB')}"],
            ["Max. Recommended Usage", f"{safe_float(data['result'].get('max_usage_percent', 0))}%"],
            ["Max. Usable Storage", f"{safe_float(data['result'].get('max_usage_tb' if data.get('storage_unit') == 'TB' else 'max_usage_gb', 0))} {data.get('storage_unit', 'GB')}"]
        ]
        
        # Results table
        t = Table(result_data, colWidths=[3*inch, 3*inch])
        t.setStyle(TableStyle([
            ('BACKGROUND', (0, 0), (-1, 0), TK_ORANGE),
            ('TEXTCOLOR', (0, 0), (-1, 0), TK_WHITE),
            ('ALIGN', (0, 0), (-1, -1), 'LEFT'),
            ('FONTNAME', (0, 0), (-1, 0), 'Helvetica-Bold'),
            ('FONTSIZE', (0, 0), (-1, 0), 12),
            ('BOTTOMPADDING', (0, 0), (-1, 0), 12),
            ('BACKGROUND', (0, 1), (-1, -1), TK_DARK_GRAY),
            ('TEXTCOLOR', (0, 1), (-1, -1), TK_WHITE),
            ('FONTNAME', (0, 1), (-1, -1), 'Helvetica'),
            ('FONTSIZE', (0, 1), (-1, -1), 10),
            ('ALIGN', (0, 1), (-1, -1), 'LEFT'),
            ('GRID', (0, 0), (-1, -1), 1, TK_LIGHT_GRAY)
        ]))
        story.append(t)
        
        # Fault tolerance with modern styling
        story.append(Spacer(1, 20))
        story.append(Paragraph("Fault Tolerance Analysis", heading_style))
        story.append(Spacer(1, 12))
        
        # Node fault tolerance with status indicator
        node_tolerance = "Available" if data['result'].get('node_failure_tolerance', False) else "Not Available"
        status_color = TK_GREEN if node_tolerance == "Available" else TK_RED
        status_style = ParagraphStyle(
            'Status',
            parent=normal_style,
            textColor=status_color,
            fontSize=12,
            spaceAfter=6
        )
        story.append(Paragraph(f"Node Fault Tolerance: {node_tolerance}", status_style))
        story.append(Paragraph(data['result'].get('node_failure_info', 'No information available'), normal_style))
        
        if data['result'].get('multi_failure_tolerance', False):
            story.append(Paragraph(f"Multi-Node Fault Tolerance: {safe_int(data['result'].get('max_failure_nodes', 0))} Nodes", normal_style))
        
        # OSD fault tolerance with status indicator
        story.append(Spacer(1, 12))
        osd_tolerance = "Available" if data['result'].get('osd_failure_tolerance', False) else "Limited"
        status_color = TK_GREEN if osd_tolerance == "Available" else TK_RED
        status_style = ParagraphStyle(
            'Status',
            parent=normal_style,
            textColor=status_color,
            fontSize=12,
            spaceAfter=6
        )
        story.append(Paragraph(f"OSD Fault Tolerance: {osd_tolerance}", status_style))
        story.append(Paragraph(data['result'].get('osd_failure_info', 'No information available'), normal_style))
        
        # Recommendations mit besserem Kontrast für den dunklen Hintergrund
        story.append(Spacer(1, 20))
        story.append(Paragraph("Recommendations", heading_style))
        story.append(Spacer(1, 12))
        
        recommendations = [
            "Ensure that after node failures, enough capacity is available to avoid reaching the 'full ratio'.",
            "For replication, the number of nodes should be greater than the replication factor.",
            "For erasure coding, the number of nodes should be greater than k+m (data chunks + coding chunks).",
            "Recovery performance depends on network and storage speed.",
            "Note that after a node failure, rebalancing the cluster takes longer the larger the failed node is."
        ]
        
        # Erstelle Box für Empfehlungen mit besserer Lesbarkeit
        recommendations_text = []
        for rec in recommendations:
            recommendations_text.append(Paragraph(f"• {rec}", normal_style))
        
        recommendation_table = Table([[item] for item in recommendations_text], colWidths=[6*inch])
        recommendation_table.setStyle(TableStyle([
            ('BACKGROUND', (0, 0), (-1, -1), TK_DARK_GRAY),
            ('TEXTCOLOR', (0, 0), (-1, -1), TK_WHITE),
            ('ALIGN', (0, 0), (-1, -1), 'LEFT'),
            ('VALIGN', (0, 0), (-1, -1), 'TOP'),
            ('GRID', (0, 0), (-1, -1), 1, TK_LIGHT_GRAY)
        ]))
        story.append(recommendation_table)
        
        # Footer with Thomas-Krenn.AG branding
        story.append(Spacer(1, 30))
        footer_style = ParagraphStyle(
            'Footer',
            parent=normal_style,
            fontSize=8,
            textColor=colors.HexColor('#9ca3af')  # Helleres Grau für bessere Lesbarkeit auf dunklem Hintergrund
        )
        story.append(Paragraph("Generated by Thomas-Krenn.AG Ceph Storage Calculator", footer_style))
        
        # Generate PDF with background
        doc.build(story, onFirstPage=add_page_background, onLaterPages=add_page_background)
        
        # Return PDF bytes
        return buffer.getvalue()
        
    except Exception as e:
        logger.error(f"Error during PDF generation: {str(e)}")
        raise