"""
PDF Exporter for YouTube Summaries
Exports summaries to professionally formatted PDF documents
Requires: pip install reportlab
"""

import tempfile
from typing import Dict, Any, Optional, List
from ..export_service import BaseExporter

try:
    from reportlab.lib.pagesizes import letter, A4
    from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
    from reportlab.lib.units import inch
    from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle, PageBreak
    from reportlab.lib import colors
    from reportlab.lib.enums import TA_JUSTIFY, TA_CENTER
    REPORTLAB_AVAILABLE = True
except ImportError:
    REPORTLAB_AVAILABLE = False


class PDFExporter(BaseExporter):
    """Export summaries to PDF format"""
    
    def __init__(self):
        if not REPORTLAB_AVAILABLE:
            raise ImportError("reportlab is required for PDF export. Install with: pip install reportlab")
    
    async def export(
        self, 
        summary_data: Dict[str, Any], 
        template: Optional[str] = None,
        branding: Optional[Dict[str, Any]] = None
    ) -> str:
        """Export to PDF"""
        
        data = self._prepare_summary_data(summary_data)
        
        with tempfile.NamedTemporaryFile(suffix='.pdf', delete=False) as f:
            doc = SimpleDocTemplate(
                f.name, 
                pagesize=A4,
                leftMargin=1*inch, 
                rightMargin=1*inch,
                topMargin=1*inch, 
                bottomMargin=1*inch,
                title=f"YouTube Summary - {data.get('video_metadata', {}).get('title', 'Video')}",
                author="YouTube Summarizer"
            )
            
            story = self._build_pdf_content(data, branding)
            doc.build(story, onFirstPage=self._add_page_number, onLaterPages=self._add_page_number)
            
            return f.name
    
    def _build_pdf_content(self, data: Dict[str, Any], branding: Optional[Dict[str, Any]]) -> List:
        """Build PDF content elements"""
        
        styles = getSampleStyleSheet()
        story = []
        
        # Custom styles
        primary_color = colors.HexColor("#2563eb")
        if branding and branding.get("primary_color"):
            try:
                primary_color = colors.HexColor(branding["primary_color"])
            except:
                pass
        
        title_style = ParagraphStyle(
            'CustomTitle',
            parent=styles['Title'],
            fontSize=24,
            textColor=primary_color,
            spaceAfter=30,
            alignment=TA_CENTER
        )
        
        heading_style = ParagraphStyle(
            'CustomHeading',
            parent=styles['Heading2'],
            fontSize=14,
            textColor=primary_color,
            spaceBefore=20,
            spaceAfter=10,
            leftIndent=0
        )
        
        subheading_style = ParagraphStyle(
            'CustomSubHeading',
            parent=styles['Heading3'],
            fontSize=12,
            textColor=colors.darkgray,
            spaceBefore=15,
            spaceAfter=8
        )
        
        body_style = ParagraphStyle(
            'CustomBody',
            parent=styles['Normal'],
            fontSize=11,
            alignment=TA_JUSTIFY,
            spaceAfter=12
        )
        
        # Title Page
        story.append(Paragraph("YouTube Video Summary", title_style))
        
        # Branding
        if branding and branding.get("company_name"):
            branding_style = ParagraphStyle(
                'Branding',
                parent=styles['Normal'],
                fontSize=10,
                textColor=colors.gray,
                alignment=TA_CENTER
            )
            story.append(Paragraph(f"Generated by {branding['company_name']} using YouTube Summarizer", branding_style))
        
        story.append(Spacer(1, 30))
        
        # Video Information Table
        video_metadata = data.get("video_metadata", {})
        video_info = [
            ["Video Title", self._safe_str(video_metadata.get('title', 'N/A'))],
            ["Channel", self._safe_str(video_metadata.get('channel_name', 'N/A'))],
            ["Duration", self._format_duration(video_metadata.get('duration'))],
            ["Published", self._safe_str(video_metadata.get('published_at', 'N/A'))],
            ["Views", self._format_number(video_metadata.get('view_count'))],
            ["URL", self._safe_str(data.get('video_url', 'N/A'))[:50] + "..."]
        ]
        
        video_table = Table(video_info, colWidths=[2*inch, 4*inch])
        video_table.setStyle(TableStyle([
            ('BACKGROUND', (0, 0), (0, -1), colors.lightgrey),
            ('TEXTCOLOR', (0, 0), (0, -1), colors.black),
            ('ALIGN', (0, 0), (-1, -1), 'LEFT'),
            ('FONTNAME', (0, 0), (0, -1), 'Helvetica-Bold'),
            ('FONTSIZE', (0, 0), (-1, -1), 10),
            ('GRID', (0, 0), (-1, -1), 1, colors.black),
            ('VALIGN', (0, 0), (-1, -1), 'MIDDLE'),
            ('ROWBACKGROUNDS', (0, 0), (-1, -1), [colors.white, colors.whitesmoke])
        ]))
        
        story.append(video_table)
        story.append(Spacer(1, 40))
        
        # Summary
        story.append(Paragraph("Summary", heading_style))
        summary_text = data.get('summary', 'No summary available')
        story.append(Paragraph(self._safe_str(summary_text), body_style))
        story.append(Spacer(1, 20))
        
        # Key Points
        story.append(Paragraph("Key Points", heading_style))
        key_points = data.get('key_points', [])
        if key_points:
            for point in key_points:
                story.append(Paragraph(f"• {self._safe_str(point)}", body_style))
        else:
            story.append(Paragraph("No key points identified", body_style))
        story.append(Spacer(1, 20))
        
        # Main Themes
        story.append(Paragraph("Main Themes", heading_style))
        main_themes = data.get('main_themes', [])
        if main_themes:
            for theme in main_themes:
                story.append(Paragraph(f"• <b>{self._safe_str(theme)}</b>", body_style))
        else:
            story.append(Paragraph("No main themes identified", body_style))
        story.append(Spacer(1, 20))
        
        # Actionable Insights
        story.append(Paragraph("Actionable Insights", heading_style))
        insights = data.get('actionable_insights', [])
        if insights:
            for i, insight in enumerate(insights, 1):
                story.append(Paragraph(f"{i}. {self._safe_str(insight)}", body_style))
        else:
            story.append(Paragraph("No actionable insights identified", body_style))
        
        # Chapters (if available) - New Page
        chapters = data.get('chapters', [])
        if chapters:
            story.append(PageBreak())
            story.append(Paragraph("Chapter Breakdown", heading_style))
            
            for chapter in chapters:
                timestamp = chapter.get('timestamp', '')
                title = chapter.get('title', '')
                summary = chapter.get('summary', '')
                
                story.append(Paragraph(f"<b>[{timestamp}] {self._safe_str(title)}</b>", subheading_style))
                if summary:
                    story.append(Paragraph(self._safe_str(summary), body_style))
                story.append(Spacer(1, 10))
        
        # Footer - Processing Information
        story.append(Spacer(1, 40))
        
        footer_style = ParagraphStyle(
            'Footer',
            parent=styles['Normal'],
            fontSize=8,
            textColor=colors.grey
        )
        
        processing_metadata = data.get("processing_metadata", {})
        footer_data = [
            ["AI Model", self._safe_str(processing_metadata.get('model', 'N/A'))],
            ["Processing Time", self._format_duration(processing_metadata.get('processing_time_seconds'))],
            ["Confidence Score", self._format_percentage(data.get('confidence_score'))],
            ["Token Usage", self._safe_str(processing_metadata.get('tokens_used', 'N/A'))],
            ["Generated", self._safe_str(data.get('export_metadata', {}).get('exported_at', 'N/A'))]
        ]
        
        footer_table = Table(footer_data, colWidths=[1.5*inch, 2*inch])
        footer_table.setStyle(TableStyle([
            ('FONTSIZE', (0, 0), (-1, -1), 8),
            ('TEXTCOLOR', (0, 0), (-1, -1), colors.grey),
            ('ALIGN', (0, 0), (-1, -1), 'LEFT'),
            ('FONTNAME', (0, 0), (0, -1), 'Helvetica-Bold')
        ]))
        
        story.append(footer_table)
        story.append(Spacer(1, 20))
        story.append(Paragraph(
            "Summary generated by YouTube Summarizer - Transform video content into actionable insights", 
            footer_style
        ))
        
        return story
    
    def _add_page_number(self, canvas, doc):
        """Add page numbers to PDF"""
        canvas.saveState()
        canvas.setFont('Helvetica', 9)
        canvas.setFillColor(colors.grey)
        page_num = canvas.getPageNumber()
        text = f"Page {page_num}"
        canvas.drawCentredString(A4[0] / 2, 0.75 * inch, text)
        canvas.restoreState()
    
    def _safe_str(self, value: Any) -> str:
        """Safely convert value to string and escape for PDF"""
        if value is None:
            return 'N/A'
        
        # Convert to string
        str_value = str(value)
        
        # Replace problematic characters for PDF
        replacements = {
            '&': '&amp;',
            '<': '&lt;',
            '>': '&gt;',
            '"': '&quot;',
            "'": '&apos;'
        }
        
        for old, new in replacements.items():
            str_value = str_value.replace(old, new)
        
        return str_value
    
    def _format_duration(self, duration: Optional[Any]) -> str:
        """Format duration from seconds to human-readable format"""
        if not duration:
            return 'N/A'
        
        # Handle string format (e.g., "10:30")
        if isinstance(duration, str):
            return duration
        
        # Handle numeric format (seconds)
        try:
            seconds = int(duration)
        except (ValueError, TypeError):
            return 'N/A'
        
        hours = seconds // 3600
        minutes = (seconds % 3600) // 60
        secs = seconds % 60
        
        if hours > 0:
            return f"{hours}h {minutes}m {secs}s"
        elif minutes > 0:
            return f"{minutes}m {secs}s"
        else:
            return f"{secs}s"
    
    def _format_number(self, number: Optional[int]) -> str:
        """Format large numbers with commas"""
        if number is None:
            return 'N/A'
        return f"{number:,}"
    
    def _format_percentage(self, value: Optional[float]) -> str:
        """Format decimal as percentage"""
        if value is None:
            return 'N/A'
        return f"{value * 100:.1f}%"
    
    def get_file_extension(self) -> str:
        return "pdf"