"""
Экспортеры отчетов в PDF и Excel.
"""
import io
from datetime import datetime
from decimal import Decimal
import logging

logger = logging.getLogger(__name__)


class PDFExporter:
    """Экспорт отчетов в PDF."""
    
    @staticmethod
    def generate_report(mentor, start_date, end_date, report_type='overview'):
        """
        Генерация PDF отчета.
        
        Args:
            mentor: Пользователь-ментор
            start_date: Начало периода
            end_date: Конец периода
            report_type: Тип отчета ('overview', 'detailed', 'revenue')
        
        Returns:
            io.BytesIO: Буфер с PDF файлом
        """
        try:
            from reportlab.lib import colors
            from reportlab.lib.pagesizes import A4, letter
            from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
            from reportlab.lib.units import inch
            from reportlab.platypus import SimpleDocTemplate, Table, TableStyle, Paragraph, Spacer, PageBreak
            from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_RIGHT
            from .services import AnalyticsService
            
            buffer = io.BytesIO()
            doc = SimpleDocTemplate(buffer, pagesize=A4, rightMargin=72, leftMargin=72, topMargin=72, bottomMargin=18)
            story = []
            styles = getSampleStyleSheet()
            
            # Заголовок
            title_style = ParagraphStyle(
                'CustomTitle',
                parent=styles['Heading1'],
                fontSize=24,
                textColor=colors.HexColor('#1f2937'),
                spaceAfter=30,
                alignment=TA_CENTER
            )
            
            story.append(Paragraph('Отчет по аналитике', title_style))
            story.append(Spacer(1, 0.2 * inch))
            
            # Информация о менторе и периоде
            info_style = ParagraphStyle(
                'Info',
                parent=styles['Normal'],
                fontSize=10,
                textColor=colors.HexColor('#6b7280'),
            )
            
            story.append(Paragraph(f'<b>Ментор:</b> {mentor.get_full_name() or mentor.email}', info_style))
            story.append(Paragraph(f'<b>Период:</b> {start_date.strftime("%d.%m.%Y")} - {end_date.strftime("%d.%m.%Y")}', info_style))
            story.append(Paragraph(f'<b>Дата формирования:</b> {datetime.now().strftime("%d.%m.%Y %H:%M")}', info_style))
            story.append(Spacer(1, 0.3 * inch))
            
            # Получаем данные
            if report_type == 'overview':
                from django.utils import timezone
                from datetime import timedelta
                
                # Вычисляем период
                now = timezone.now()
                if (end_date - start_date).days <= 1:
                    period = 'day'
                elif (end_date - start_date).days <= 7:
                    period = 'week'
                elif (end_date - start_date).days <= 31:
                    period = 'month'
                else:
                    period = 'year'
                
                # Используем сервис напрямую для получения данных
                from .services import AnalyticsService
                
                service = AnalyticsService()
                overview_data = service.get_overview_data(mentor, start_date, end_date)
                revenue_data = service.get_revenue_data(mentor, start_date, end_date)
                
                # Общая статистика
                story.append(Paragraph('<b>Общая статистика</b>', styles['Heading2']))
                story.append(Spacer(1, 0.1 * inch))
                
                overview_table_data = [
                    ['Метрика', 'Значение'],
                    ['Всего занятий', str(overview_data['lessons']['total'])],
                    ['Завершено', str(overview_data['lessons']['completed'])],
                    ['Отменено', str(overview_data['lessons']['cancelled'])],
                    ['Активных учеников', str(overview_data['students']['active'])],
                    ['Общий доход', f"{overview_data['revenue']['total']:.2f} ₽"],
                    ['Средний доход за занятие', f"{overview_data['revenue']['average_per_lesson']:.2f} ₽"],
                    ['Средний балл', f"{overview_data['grades']['average']}"],
                ]
                
                overview_table = Table(overview_table_data, colWidths=[4 * inch, 2 * inch])
                overview_table.setStyle(TableStyle([
                    ('BACKGROUND', (0, 0), (-1, 0), colors.HexColor('#3b82f6')),
                    ('TEXTCOLOR', (0, 0), (-1, 0), colors.whitesmoke),
                    ('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), colors.beige),
                    ('GRID', (0, 0), (-1, -1), 1, colors.black),
                ]))
                story.append(overview_table)
                story.append(Spacer(1, 0.3 * inch))
                
                # Доходы
                story.append(Paragraph('<b>Доходы</b>', styles['Heading2']))
                story.append(Spacer(1, 0.1 * inch))
                
                revenue_table_data = [['Дата', 'Доход (₽)', 'Занятий']]
                for item in revenue_data.get('by_day', [])[:30]:  # Ограничиваем 30 записями
                    revenue_table_data.append([
                        item['date'],
                        f"{item['revenue']:.2f}",
                        str(item['lessons_count'])
                    ])
                
                if len(revenue_table_data) > 1:
                    revenue_table = Table(revenue_table_data, colWidths=[2 * inch, 2 * inch, 2 * inch])
                    revenue_table.setStyle(TableStyle([
                        ('BACKGROUND', (0, 0), (-1, 0), colors.HexColor('#10b981')),
                        ('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), 11),
                        ('BOTTOMPADDING', (0, 0), (-1, 0), 12),
                        ('BACKGROUND', (0, 1), (-1, -1), colors.lightgrey),
                        ('GRID', (0, 0), (-1, -1), 1, colors.black),
                    ]))
                    story.append(revenue_table)
            
            elif report_type == 'detailed':
                stats = AnalyticsService.get_detailed_lesson_stats(mentor, start_date, end_date)
                
                story.append(Paragraph('<b>Детальная статистика</b>', styles['Heading2']))
                story.append(Spacer(1, 0.1 * inch))
                
                detailed_table_data = [
                    ['Метрика', 'Значение'],
                    ['Всего занятий', str(stats['summary']['total_lessons'])],
                    ['Завершено', str(stats['summary']['completed'])],
                    ['Процент завершения', f"{stats['summary']['completion_rate']}%"],
                    ['Общее время (часы)', f"{stats['time']['total_duration_hours']}"],
                    ['Средняя длительность (мин)', f"{stats['time']['average_duration_minutes']}"],
                    ['Общий доход', f"{stats['revenue']['total']:.2f} ₽"],
                    ['Средний доход за занятие', f"{stats['revenue']['average_per_lesson']:.2f} ₽"],
                    ['Средний балл', f"{stats['grades']['average']}"],
                ]
                
                detailed_table = Table(detailed_table_data, colWidths=[4 * inch, 2 * inch])
                detailed_table.setStyle(TableStyle([
                    ('BACKGROUND', (0, 0), (-1, 0), colors.HexColor('#8b5cf6')),
                    ('TEXTCOLOR', (0, 0), (-1, 0), colors.whitesmoke),
                    ('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), colors.beige),
                    ('GRID', (0, 0), (-1, -1), 1, colors.black),
                ]))
                story.append(detailed_table)
                story.append(Spacer(1, 0.3 * inch))
                
                # Топ клиентов
                if stats.get('top_clients'):
                    story.append(Paragraph('<b>Топ клиентов</b>', styles['Heading2']))
                    story.append(Spacer(1, 0.1 * inch))
                    
                    clients_table_data = [['Клиент', 'Занятий', 'Доход (₽)', 'Средний балл']]
                    for client in stats['top_clients'][:10]:
                        clients_table_data.append([
                            client['name'],
                            str(client['lessons_count']),
                            f"{client['total_revenue']:.2f}",
                            f"{client['average_grade']}"
                        ])
                    
                    clients_table = Table(clients_table_data, colWidths=[2.5 * inch, 1 * inch, 1.5 * inch, 1 * inch])
                    clients_table.setStyle(TableStyle([
                        ('BACKGROUND', (0, 0), (-1, 0), colors.HexColor('#f59e0b')),
                        ('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),
                        ('BACKGROUND', (0, 1), (-1, -1), colors.lightgrey),
                        ('GRID', (0, 0), (-1, -1), 1, colors.black),
                    ]))
                    story.append(clients_table)
            
            # Генерируем PDF
            doc.build(story)
            buffer.seek(0)
            return buffer
            
        except ImportError:
            logger.error("reportlab not installed. Install it with: pip install reportlab")
            raise Exception("PDF export requires reportlab library. Install it with: pip install reportlab")
        except Exception as e:
            logger.error(f"Error generating PDF: {e}", exc_info=True)
            raise


class ExcelExporter:
    """Экспорт отчетов в Excel."""
    
    @staticmethod
    def generate_report(mentor, start_date, end_date, report_type='overview'):
        """
        Генерация Excel отчета.
        
        Args:
            mentor: Пользователь-ментор
            start_date: Начало периода
            end_date: Конец периода
            report_type: Тип отчета ('overview', 'detailed', 'revenue', 'lessons')
        
        Returns:
            io.BytesIO: Буфер с Excel файлом
        """
        try:
            from openpyxl import Workbook
            from openpyxl.styles import Font, PatternFill, Alignment, Border, Side
            from openpyxl.utils import get_column_letter
            from .services import AnalyticsService
            
            wb = Workbook()
            ws = wb.active
            ws.title = "Отчет"
            
            # Стили
            header_fill = PatternFill(start_color="366092", end_color="366092", fill_type="solid")
            header_font = Font(bold=True, color="FFFFFF", size=12)
            title_font = Font(bold=True, size=16)
            border = Border(
                left=Side(style='thin'),
                right=Side(style='thin'),
                top=Side(style='thin'),
                bottom=Side(style='thin')
            )
            
            # Заголовок
            ws['A1'] = 'Отчет по аналитике'
            ws['A1'].font = title_font
            ws.merge_cells('A1:D1')
            
            ws['A2'] = f'Ментор: {mentor.get_full_name() or mentor.email}'
            ws['A3'] = f'Период: {start_date.strftime("%d.%m.%Y")} - {end_date.strftime("%d.%m.%Y")}'
            ws['A4'] = f'Дата формирования: {datetime.now().strftime("%d.%m.%Y %H:%M")}'
            
            row = 6
            
            if report_type == 'overview':
                # Используем сервис напрямую для получения данных
                from .services import AnalyticsService
                
                service = AnalyticsService()
                overview_data = service.get_overview_data(mentor, start_date, end_date)
                revenue_data = service.get_revenue_data(mentor, start_date, end_date)
                
                # Общая статистика
                ws[f'A{row}'] = 'Общая статистика'
                ws[f'A{row}'].font = Font(bold=True, size=14)
                row += 1
                
                stats_data = [
                    ['Метрика', 'Значение'],
                    ['Всего занятий', overview_data['lessons']['total']],
                    ['Завершено', overview_data['lessons']['completed']],
                    ['Отменено', overview_data['lessons']['cancelled']],
                    ['Активных учеников', overview_data['students']['active']],
                    ['Общий доход', f"{overview_data['revenue']['total']:.2f} ₽"],
                    ['Средний доход за занятие', f"{overview_data['revenue']['average_per_lesson']:.2f} ₽"],
                    ['Средний балл', overview_data['grades']['average']],
                ]
                
                for i, (metric, value) in enumerate(stats_data):
                    ws[f'A{row}'] = metric
                    ws[f'B{row}'] = value
                    if i == 0:  # Заголовок
                        ws[f'A{row}'].fill = header_fill
                        ws[f'A{row}'].font = header_font
                        ws[f'B{row}'].fill = header_fill
                        ws[f'B{row}'].font = header_font
                    ws[f'A{row}'].border = border
                    ws[f'B{row}'].border = border
                    row += 1
                
                row += 2
                
                # Доходы по дням
                ws[f'A{row}'] = 'Доходы по дням'
                ws[f'A{row}'].font = Font(bold=True, size=14)
                row += 1
                
                revenue_headers = ['Дата', 'Доход (₽)', 'Занятий']
                for col, header in enumerate(revenue_headers, 1):
                    cell = ws.cell(row=row, column=col, value=header)
                    cell.fill = header_fill
                    cell.font = header_font
                    cell.border = border
                    cell.alignment = Alignment(horizontal='center', vertical='center')
                
                row += 1
                for item in revenue_data.get('by_day', []):
                    ws.cell(row=row, column=1, value=item['date']).border = border
                    ws.cell(row=row, column=2, value=round(item['revenue'], 2)).border = border
                    ws.cell(row=row, column=3, value=item['lessons_count']).border = border
                    row += 1
                
                # Доходы по предметам
                row += 2
                ws[f'A{row}'] = 'Доходы по предметам'
                ws[f'A{row}'].font = Font(bold=True, size=14)
                row += 1
                
                subject_headers = ['Предмет', 'Доход (₽)', 'Занятий']
                for col, header in enumerate(subject_headers, 1):
                    cell = ws.cell(row=row, column=col, value=header)
                    cell.fill = header_fill
                    cell.font = header_font
                    cell.border = border
                    cell.alignment = Alignment(horizontal='center', vertical='center')
                
                row += 1
                for item in revenue_data.get('by_subject', []):
                    ws.cell(row=row, column=1, value=item['subject']).border = border
                    ws.cell(row=row, column=2, value=round(item['revenue'], 2)).border = border
                    ws.cell(row=row, column=3, value=item['lessons_count']).border = border
                    row += 1
            
            elif report_type == 'detailed':
                stats = AnalyticsService.get_detailed_lesson_stats(mentor, start_date, end_date)
                
                ws[f'A{row}'] = 'Детальная статистика'
                ws[f'A{row}'].font = Font(bold=True, size=14)
                row += 1
                
                detailed_data = [
                    ['Метрика', 'Значение'],
                    ['Всего занятий', stats['summary']['total_lessons']],
                    ['Завершено', stats['summary']['completed']],
                    ['Процент завершения', f"{stats['summary']['completion_rate']}%"],
                    ['Общее время (часы)', stats['time']['total_duration_hours']],
                    ['Средняя длительность (мин)', stats['time']['average_duration_minutes']],
                    ['Общий доход', f"{stats['revenue']['total']:.2f} ₽"],
                    ['Средний доход за занятие', f"{stats['revenue']['average_per_lesson']:.2f} ₽"],
                    ['Средний балл', stats['grades']['average']],
                ]
                
                for i, (metric, value) in enumerate(detailed_data):
                    ws.cell(row=row, column=1, value=metric).border = border
                    ws.cell(row=row, column=2, value=value).border = border
                    if i == 0:
                        ws.cell(row=row, column=1).fill = header_fill
                        ws.cell(row=row, column=1).font = header_font
                        ws.cell(row=row, column=2).fill = header_fill
                        ws.cell(row=row, column=2).font = header_font
                    row += 1
                
                # Топ клиентов
                if stats.get('top_clients'):
                    row += 2
                    ws[f'A{row}'] = 'Топ клиентов'
                    ws[f'A{row}'].font = Font(bold=True, size=14)
                    row += 1
                    
                    clients_headers = ['Клиент', 'Занятий', 'Доход (₽)', 'Средний балл']
                    for col, header in enumerate(clients_headers, 1):
                        cell = ws.cell(row=row, column=col, value=header)
                        cell.fill = header_fill
                        cell.font = header_font
                        cell.border = border
                        cell.alignment = Alignment(horizontal='center', vertical='center')
                    
                    row += 1
                    for client in stats['top_clients']:
                        ws.cell(row=row, column=1, value=client['name']).border = border
                        ws.cell(row=row, column=2, value=client['lessons_count']).border = border
                        ws.cell(row=row, column=3, value=round(client['total_revenue'], 2)).border = border
                        ws.cell(row=row, column=4, value=client['average_grade']).border = border
                        row += 1
            
            # Настройка ширины столбцов
            ws.column_dimensions['A'].width = 30
            ws.column_dimensions['B'].width = 20
            ws.column_dimensions['C'].width = 20
            ws.column_dimensions['D'].width = 20
            
            # Сохраняем в буфер
            buffer = io.BytesIO()
            wb.save(buffer)
            buffer.seek(0)
            return buffer
            
        except ImportError:
            logger.error("openpyxl not installed. Install it with: pip install openpyxl")
            raise Exception("Excel export requires openpyxl library. Install it with: pip install openpyxl")
        except Exception as e:
            logger.error(f"Error generating Excel: {e}", exc_info=True)
            raise