import json
import logging
from typing import Dict, List, Optional, Any

class ChartGenerator:
    """Generate Chart.js configurations for data visualization"""
    
    def __init__(self):
        self.chart_colors = [
            '#007bff', '#28a745', '#ffc107', '#dc3545', '#6f42c1',
            '#fd7e14', '#20c997', '#6c757d', '#343a40', '#007bff'
        ]
    
    def create_chart_config(self, metrics: List[Dict], section_title: str) -> Optional[Dict]:
        """Create Chart.js configuration based on metrics data"""
        
        if not metrics:
            return None
        
        # Analyze metrics to determine best chart type
        chart_type = self._determine_chart_type(metrics)
        
        if chart_type == 'line':
            return self._create_line_chart(metrics, section_title)
        elif chart_type == 'bar':
            return self._create_bar_chart(metrics, section_title)
        elif chart_type == 'pie':
            return self._create_pie_chart(metrics, section_title)
        elif chart_type == 'doughnut':
            return self._create_doughnut_chart(metrics, section_title)
        else:
            return self._create_default_chart(metrics, section_title)
    
    def _determine_chart_type(self, metrics: List[Dict]) -> str:
        """Determine the most appropriate chart type for the data"""
        
        # Analyze metric types
        has_percentages = any('%' in str(metric.get('metric', '')) for metric in metrics)
        has_time_series = any('year' in str(metric.get('context', '')).lower() for metric in metrics)
        has_categories = len(metrics) <= 6  # Good for pie/doughnut charts
        
        if has_time_series and len(metrics) > 2:
            return 'line'
        elif has_percentages and has_categories:
            return 'doughnut'
        elif len(metrics) <= 5:
            return 'bar'
        else:
            return 'line'
    
    def _create_line_chart(self, metrics: List[Dict], title: str) -> Dict:
        """Create line chart configuration"""
        
        labels = []
        data_points = []
        
        for i, metric in enumerate(metrics[:10]):  # Limit to 10 points
            labels.append(f"Point {i+1}")
            data_points.append(self._extract_numeric_value(metric.get('metric', '0')))
        
        return {
            'type': 'line',
            'data': {
                'labels': labels,
                'datasets': [{
                    'label': f'{title} Trend',
                    'data': data_points,
                    'borderColor': self.chart_colors[0],
                    'backgroundColor': self.chart_colors[0] + '20',
                    'tension': 0.4,
                    'fill': True
                }]
            },
            'options': {
                'responsive': True,
                'plugins': {
                    'title': {
                        'display': True,
                        'text': f'{title} - Data Analysis'
                    },
                    'legend': {
                        'position': 'top'
                    }
                },
                'scales': {
                    'y': {
                        'beginAtZero': True,
                        'title': {
                            'display': True,
                            'text': 'Value'
                        }
                    }
                }
            }
        }
    
    def _create_bar_chart(self, metrics: List[Dict], title: str) -> Dict:
        """Create bar chart configuration"""
        
        labels = []
        data_points = []
        
        for metric in metrics[:8]:  # Limit to 8 bars for readability
            context = metric.get('context', '')
            # Extract meaningful label from context
            label = self._extract_label_from_context(context) or f"Metric {len(labels)+1}"
            labels.append(label)
            data_points.append(self._extract_numeric_value(metric.get('metric', '0')))
        
        return {
            'type': 'bar',
            'data': {
                'labels': labels,
                'datasets': [{
                    'label': title,
                    'data': data_points,
                    'backgroundColor': self.chart_colors[:len(data_points)],
                    'borderColor': self.chart_colors[:len(data_points)],
                    'borderWidth': 1
                }]
            },
            'options': {
                'responsive': True,
                'plugins': {
                    'title': {
                        'display': True,
                        'text': f'{title} - Comparative Analysis'
                    },
                    'legend': {
                        'display': False
                    }
                },
                'scales': {
                    'y': {
                        'beginAtZero': True,
                        'title': {
                            'display': True,
                            'text': 'Value'
                        }
                    },
                    'x': {
                        'title': {
                            'display': True,
                            'text': 'Categories'
                        }
                    }
                }
            }
        }
    
    def _create_pie_chart(self, metrics: List[Dict], title: str) -> Dict:
        """Create pie chart configuration"""
        
        labels = []
        data_points = []
        
        for metric in metrics[:6]:  # Limit to 6 slices for readability
            context = metric.get('context', '')
            label = self._extract_label_from_context(context) or f"Category {len(labels)+1}"
            labels.append(label)
            data_points.append(self._extract_numeric_value(metric.get('metric', '0')))
        
        return {
            'type': 'pie',
            'data': {
                'labels': labels,
                'datasets': [{
                    'data': data_points,
                    'backgroundColor': self.chart_colors[:len(data_points)],
                    'borderColor': '#ffffff',
                    'borderWidth': 2
                }]
            },
            'options': {
                'responsive': True,
                'plugins': {
                    'title': {
                        'display': True,
                        'text': f'{title} - Distribution Analysis'
                    },
                    'legend': {
                        'position': 'right'
                    }
                }
            }
        }
    
    def _create_doughnut_chart(self, metrics: List[Dict], title: str) -> Dict:
        """Create doughnut chart configuration"""
        
        config = self._create_pie_chart(metrics, title)
        config['type'] = 'doughnut'
        config['options']['plugins']['title']['text'] = f'{title} - Key Metrics Overview'
        
        return config
    
    def _create_default_chart(self, metrics: List[Dict], title: str) -> Dict:
        """Create default chart when type cannot be determined"""
        return self._create_bar_chart(metrics, title)
    
    def _extract_numeric_value(self, metric_str: str) -> float:
        """Extract numeric value from metric string"""
        import re
        
        if not metric_str:
            return 0.0
        
        # Remove common non-numeric characters
        cleaned = re.sub(r'[^0-9.,\-+]', '', str(metric_str))
        
        # Handle percentages
        if '%' in str(metric_str):
            cleaned = cleaned.replace('%', '')
        
        # Handle currency
        if '$' in str(metric_str):
            cleaned = cleaned.replace('$', '')
            # Handle billions, millions, etc.
            if 'billion' in str(metric_str).lower():
                try:
                    return float(cleaned.replace(',', '')) * 1000000000
                except:
                    return 0.0
            elif 'million' in str(metric_str).lower():
                try:
                    return float(cleaned.replace(',', '')) * 1000000
                except:
                    return 0.0
        
        # Try to convert to float
        try:
            return float(cleaned.replace(',', ''))
        except:
            return 0.0
    
    def _extract_label_from_context(self, context: str) -> Optional[str]:
        """Extract meaningful label from context"""
        if not context:
            return None
        
        # Simple extraction of first few words
        words = context.split()[:3]
        return ' '.join(words) if words else None
    
    def create_multi_series_chart(self, data_series: List[Dict], title: str) -> Dict:
        """Create chart with multiple data series"""
        
        datasets = []
        labels = []
        
        for i, series in enumerate(data_series):
            series_data = series.get('data', [])
            datasets.append({
                'label': series.get('name', f'Series {i+1}'),
                'data': [self._extract_numeric_value(str(val)) for val in series_data],
                'borderColor': self.chart_colors[i % len(self.chart_colors)],
                'backgroundColor': self.chart_colors[i % len(self.chart_colors)] + '20',
                'tension': 0.4
            })
            
            if not labels and series.get('labels'):
                labels = series.get('labels', [])
        
        if not labels:
            labels = [f"Point {i+1}" for i in range(max(len(ds['data']) for ds in datasets) if datasets else 0)]
        
        return {
            'type': 'line',
            'data': {
                'labels': labels,
                'datasets': datasets
            },
            'options': {
                'responsive': True,
                'plugins': {
                    'title': {
                        'display': True,
                        'text': f'{title} - Multi-Series Analysis'
                    },
                    'legend': {
                        'position': 'top'
                    }
                },
                'scales': {
                    'y': {
                        'beginAtZero': True,
                        'title': {
                            'display': True,
                            'text': 'Value'
                        }
                    }
                }
            }
        }
    
    def generate_chart_html(self, chart_config: Dict, chart_id: str) -> str:
        """Generate HTML for embedding chart"""
        
        return f"""
        <div class="chart-container" style="position: relative; height: 400px; margin: 20px 0;">
            <canvas id="{chart_id}"></canvas>
        </div>
        <script>
            const chartConfig_{chart_id} = {json.dumps(chart_config)};
            const ctx_{chart_id} = document.getElementById('{chart_id}').getContext('2d');
            new Chart(ctx_{chart_id}, chartConfig_{chart_id});
        </script>
        """