"""
Server Metrics Graphs Module for Pterodactyl Discord Bot

This module provides graphing capabilities for server CPU and memory usage.
Generates line graphs as PNG images for embedding in Discord messages.
"""

import matplotlib
matplotlib.use('Agg')  # Use non-interactive backend for server environments
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
from collections import deque
from datetime import datetime, timedelta
from typing import Dict, Tuple, Optional
import io
import logging
import math

# Get the logger from the main bot module
logger = logging.getLogger('pterodisbot')

class ServerMetricsGraphs:
    """
    Manages CPU and memory usage graphs for individual servers.
    
    Features:
    - Stores last 6 data points (1 minute of history at 10-second intervals)
    - Generates PNG images of line graphs for Discord embedding
    - Automatic data rotation (FIFO queue with max 6 points)
    - Separate tracking for CPU percentage and memory MB usage
    - Dynamic CPU scaling in 100% increments for multi-vCPU servers
    - Clean graph styling optimized for Discord dark theme
    """
    
    def __init__(self, server_id: str, server_name: str):
        """
        Initialize metrics tracking for a server.
        
        Args:
            server_id: Pterodactyl server identifier
            server_name: Human-readable server name
        """
        self.server_id = server_id
        self.server_name = server_name
        
        # Use deque with maxlen=6 for automatic FIFO rotation
        # Each entry is a tuple: (timestamp, cpu_percent, memory_mb)
        self.data_points = deque(maxlen=6)
        
        # Track if we have enough data for meaningful graphs (at least 2 points)
        self.has_sufficient_data = False
        
        logger.debug(f"Initialized metrics tracking for server {server_name} ({server_id})")
    
    def add_data_point(self, cpu_percent: float, memory_mb: float, timestamp: Optional[datetime] = None):
        """
        Add a new data point to the metrics history.
        
        Args:
            cpu_percent: Current CPU usage percentage
            memory_mb: Current memory usage in megabytes
            timestamp: Optional timestamp, defaults to current time
        """
        if timestamp is None:
            timestamp = datetime.now()
        
        # Add new data point (automatically rotates old data due to maxlen=6)
        self.data_points.append((timestamp, cpu_percent, memory_mb))
        
        # Update sufficient data flag
        self.has_sufficient_data = len(self.data_points) >= 2
        
        logger.debug(f"Added metrics data point for {self.server_name}: CPU={cpu_percent}%, Memory={memory_mb}MB")
    
    def _calculate_cpu_scale_limit(self, max_cpu_value: float) -> int:
        """
        Calculate appropriate CPU scale limit in 100% increments.
        
        Args:
            max_cpu_value: Maximum CPU value in the dataset
            
        Returns:
            Scale limit rounded up to nearest 100% increment
        """
        if max_cpu_value <= 100:
            return 100
        
        # Round up to nearest 100% increment
        # e.g., 150% -> 200%, 250% -> 300%, 350% -> 400%
        return math.ceil(max_cpu_value / 100) * 100
    
    def generate_cpu_graph(self) -> Optional[io.BytesIO]:
        """
        Generate a CPU usage line graph as a PNG image.
        
        Returns:
            BytesIO object containing PNG image data, or None if insufficient data
        """
        if not self.has_sufficient_data:
            logger.debug(f"Insufficient data for CPU graph generation: {self.server_name}")
            return None
        
        try:
            # Extract timestamps and CPU data
            timestamps = [point[0] for point in self.data_points]
            cpu_values = [point[1] for point in self.data_points]
            
            # Calculate dynamic CPU scale limit
            max_cpu = max(cpu_values)
            cpu_scale_limit = self._calculate_cpu_scale_limit(max_cpu)
            
            # Create figure with dark theme styling
            plt.style.use('dark_background')
            fig, ax = plt.subplots(figsize=(8, 4), dpi=100)
            fig.patch.set_facecolor('#2f3136')  # Discord dark theme background
            ax.set_facecolor('#36393f')  # Slightly lighter for graph area
            
            # Plot CPU line with gradient fill
            line = ax.plot(timestamps, cpu_values, color='#7289da', linewidth=2.5, marker='o', markersize=4)
            ax.fill_between(timestamps, cpu_values, alpha=0.3, color='#7289da')
            
            # Customize axes with dynamic scaling
            ax.set_ylabel('CPU Usage (%)', color='#ffffff', fontsize=10)
            ax.set_ylim(0, cpu_scale_limit)
            
            # Add horizontal grid lines at 100% increments for better readability
            for i in range(100, cpu_scale_limit + 1, 100):
                ax.axhline(y=i, color='#ffffff', alpha=0.2, linestyle='--', linewidth=0.8)
            
            # Format time axis
            ax.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M:%S'))
            ax.xaxis.set_major_locator(mdates.SecondLocator(interval=20))
            plt.setp(ax.xaxis.get_majorticklabels(), rotation=45, ha='right', color='#ffffff', fontsize=8)
            
            # Style the graph
            ax.tick_params(colors='#ffffff', labelsize=8)
            ax.grid(True, alpha=0.3, color='#ffffff')
            ax.spines['bottom'].set_color('#ffffff')
            ax.spines['left'].set_color('#ffffff')
            ax.spines['top'].set_visible(False)
            ax.spines['right'].set_visible(False)
            
            # Add title with scale info for multi-vCPU servers
            title = f'{self.server_name} - CPU Usage'
            if cpu_scale_limit > 100:
                estimated_vcpus = cpu_scale_limit // 100
                title += f' (~{estimated_vcpus} vCPU cores)'
            ax.set_title(title, color='#ffffff', fontsize=12, pad=20)
            
            # Tight layout to prevent label cutoff
            plt.tight_layout()
            
            # Save to BytesIO
            img_buffer = io.BytesIO()
            plt.savefig(img_buffer, format='png', facecolor='#2f3136', edgecolor='none', 
                       bbox_inches='tight', dpi=100)
            img_buffer.seek(0)
            
            # Clean up matplotlib resources
            plt.close(fig)
            
            logger.debug(f"Generated CPU graph for {self.server_name} (scale: 0-{cpu_scale_limit}%)")
            return img_buffer
            
        except Exception as e:
            logger.error(f"Failed to generate CPU graph for {self.server_name}: {str(e)}")
            plt.close('all')  # Clean up any remaining figures
            return None
    
    def generate_memory_graph(self) -> Optional[io.BytesIO]:
        """
        Generate a memory usage line graph as a PNG image.
        
        Returns:
            BytesIO object containing PNG image data, or None if insufficient data
        """
        if not self.has_sufficient_data:
            logger.debug(f"Insufficient data for memory graph generation: {self.server_name}")
            return None
        
        try:
            # Extract timestamps and memory data
            timestamps = [point[0] for point in self.data_points]
            memory_values = [point[2] for point in self.data_points]
            
            # Create figure with dark theme styling
            plt.style.use('dark_background')
            fig, ax = plt.subplots(figsize=(8, 4), dpi=100)
            fig.patch.set_facecolor('#2f3136')  # Discord dark theme background
            ax.set_facecolor('#36393f')  # Slightly lighter for graph area
            
            # Plot memory line with gradient fill
            line = ax.plot(timestamps, memory_values, color='#43b581', linewidth=2.5, marker='o', markersize=4)
            ax.fill_between(timestamps, memory_values, alpha=0.3, color='#43b581')
            
            # Customize axes
            ax.set_ylabel('Memory Usage (MB)', color='#ffffff', fontsize=10)
            ax.set_ylim(0, max(memory_values) * 1.1)  # Dynamic scaling with 10% padding
            
            # Format time axis
            ax.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M:%S'))
            ax.xaxis.set_major_locator(mdates.SecondLocator(interval=20))
            plt.setp(ax.xaxis.get_majorticklabels(), rotation=45, ha='right', color='#ffffff', fontsize=8)
            
            # Style the graph
            ax.tick_params(colors='#ffffff', labelsize=8)
            ax.grid(True, alpha=0.3, color='#ffffff')
            ax.spines['bottom'].set_color('#ffffff')
            ax.spines['left'].set_color('#ffffff')
            ax.spines['top'].set_visible(False)
            ax.spines['right'].set_visible(False)
            
            # Add title
            ax.set_title(f'{self.server_name} - Memory Usage', color='#ffffff', fontsize=12, pad=20)
            
            # Tight layout to prevent label cutoff
            plt.tight_layout()
            
            # Save to BytesIO
            img_buffer = io.BytesIO()
            plt.savefig(img_buffer, format='png', facecolor='#2f3136', edgecolor='none', 
                       bbox_inches='tight', dpi=100)
            img_buffer.seek(0)
            
            # Clean up matplotlib resources
            plt.close(fig)
            
            logger.debug(f"Generated memory graph for {self.server_name}")
            return img_buffer
            
        except Exception as e:
            logger.error(f"Failed to generate memory graph for {self.server_name}: {str(e)}")
            plt.close('all')  # Clean up any remaining figures
            return None

    def generate_combined_graph(self) -> Optional[io.BytesIO]:
        """
        Generate a combined CPU and memory usage graph as a PNG image.
        
        Returns:
            BytesIO object containing PNG image data, or None if insufficient data
        """
        if not self.has_sufficient_data:
            logger.debug(f"Insufficient data for combined graph generation: {self.server_name}")
            return None
        
        try:
            # Extract data
            timestamps = [point[0] for point in self.data_points]
            cpu_values = [point[1] for point in self.data_points]
            memory_values = [point[2] for point in self.data_points]
            
            # Calculate dynamic CPU scale limit
            max_cpu = max(cpu_values)
            cpu_scale_limit = self._calculate_cpu_scale_limit(max_cpu)
            
            # Create figure with two subplots
            plt.style.use('dark_background')
            fig, (ax1, ax2) = plt.subplots(2, 1, figsize=(8, 6), dpi=100, sharex=True)
            fig.patch.set_facecolor('#2f3136')
            
            # CPU subplot
            ax1.set_facecolor('#36393f')
            ax1.plot(timestamps, cpu_values, color='#7289da', linewidth=2.5, marker='o', markersize=4)
            ax1.fill_between(timestamps, cpu_values, alpha=0.3, color='#7289da')
            ax1.set_ylabel('CPU Usage (%)', color='#ffffff', fontsize=10)
            ax1.set_ylim(0, cpu_scale_limit)
            ax1.tick_params(colors='#ffffff', labelsize=8)
            ax1.grid(True, alpha=0.3, color='#ffffff')
            
            # Add horizontal grid lines at 100% increments for CPU subplot
            for i in range(100, cpu_scale_limit + 1, 100):
                ax1.axhline(y=i, color='#ffffff', alpha=0.2, linestyle='--', linewidth=0.8)
            
            # Title with vCPU info if applicable
            title = f'{self.server_name} - Resource Usage'
            if cpu_scale_limit > 100:
                estimated_vcpus = cpu_scale_limit // 100
                title += f' (~{estimated_vcpus} vCPU cores)'
            ax1.set_title(title, color='#ffffff', fontsize=12)
            
            # Memory subplot
            ax2.set_facecolor('#36393f')
            ax2.plot(timestamps, memory_values, color='#43b581', linewidth=2.5, marker='o', markersize=4)
            ax2.fill_between(timestamps, memory_values, alpha=0.3, color='#43b581')
            ax2.set_ylabel('Memory (MB)', color='#ffffff', fontsize=10)
            ax2.set_ylim(0, max(memory_values) * 1.1)
            ax2.tick_params(colors='#ffffff', labelsize=8)
            ax2.grid(True, alpha=0.3, color='#ffffff')
            
            # Format time axis (only on bottom subplot)
            ax2.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M:%S'))
            ax2.xaxis.set_major_locator(mdates.SecondLocator(interval=20))
            plt.setp(ax2.xaxis.get_majorticklabels(), rotation=45, ha='right', color='#ffffff', fontsize=8)
            
            # Style both subplots
            for ax in [ax1, ax2]:
                ax.spines['bottom'].set_color('#ffffff')
                ax.spines['left'].set_color('#ffffff')
                ax.spines['top'].set_visible(False)
                ax.spines['right'].set_visible(False)
            
            plt.tight_layout()
            
            # Save to BytesIO
            img_buffer = io.BytesIO()
            plt.savefig(img_buffer, format='png', facecolor='#2f3136', edgecolor='none', 
                    bbox_inches='tight', dpi=100)
            img_buffer.seek(0)
            
            plt.close(fig)
            
            logger.debug(f"Generated combined graph for {self.server_name} (CPU scale: 0-{cpu_scale_limit}%)")
            return img_buffer
            
        except Exception as e:
            logger.error(f"Failed to generate combined graph for {self.server_name}: {str(e)}")
            plt.close('all')
            return None
    
    def get_data_summary(self) -> Dict[str, any]:
        """
        Get summary statistics for the current data points.
        
        Returns:
            Dictionary containing data point count, latest values, and trends
        """
        if not self.data_points:
            return {
                'point_count': 0,
                'has_data': False,
                'latest_cpu': 0,
                'latest_memory': 0
            }
        
        # Get latest values
        latest_point = self.data_points[-1]
        latest_cpu = latest_point[1]
        latest_memory = latest_point[2]
        
        # Calculate CPU scale info
        max_cpu = max(point[1] for point in self.data_points)
        cpu_scale_limit = self._calculate_cpu_scale_limit(max_cpu)
        estimated_vcpus = cpu_scale_limit // 100
        
        # Calculate trends if we have multiple points
        cpu_trend = 'stable'
        memory_trend = 'stable'
        
        if len(self.data_points) >= 2:
            first_point = self.data_points[0]
            cpu_change = latest_cpu - first_point[1]
            memory_change = latest_memory - first_point[2]
            
            # Determine trends (>5% change considered significant)
            if abs(cpu_change) > 5:
                cpu_trend = 'increasing' if cpu_change > 0 else 'decreasing'
            
            if abs(memory_change) > 50:  # 50MB change threshold
                memory_trend = 'increasing' if memory_change > 0 else 'decreasing'
        
        return {
            'point_count': len(self.data_points),
            'has_data': self.has_sufficient_data,
            'latest_cpu': latest_cpu,
            'latest_memory': latest_memory,
            'cpu_trend': cpu_trend,
            'memory_trend': memory_trend,
            'cpu_scale_limit': cpu_scale_limit,
            'estimated_vcpus': estimated_vcpus,
            'time_span_minutes': len(self.data_points) * 10 / 60  # Convert to minutes
        }


class ServerMetricsManager:
    """
    Global manager for all server metrics graphs.
    
    Handles:
    - Creation and cleanup of ServerMetricsGraphs instances
    - Bulk operations across all tracked servers
    - Memory management for graph storage
    """
    
    def __init__(self):
        """Initialize the metrics manager."""
        self.server_graphs: Dict[str, ServerMetricsGraphs] = {}
        logger.info("Initialized ServerMetricsManager")
    
    def get_or_create_server_graphs(self, server_id: str, server_name: str) -> ServerMetricsGraphs:
        """
        Get existing ServerMetricsGraphs instance or create a new one.
        
        Args:
            server_id: Pterodactyl server identifier
            server_name: Human-readable server name
            
        Returns:
            ServerMetricsGraphs instance for the specified server
        """
        if server_id not in self.server_graphs:
            self.server_graphs[server_id] = ServerMetricsGraphs(server_id, server_name)
            logger.debug(f"Created new metrics graphs for server {server_name}")
        
        return self.server_graphs[server_id]
    
    def add_server_data(self, server_id: str, server_name: str, cpu_percent: float, memory_mb: float):
        """
        Add data point to a server's metrics tracking.
        
        Args:
            server_id: Pterodactyl server identifier
            server_name: Human-readable server name
            cpu_percent: Current CPU usage percentage
            memory_mb: Current memory usage in megabytes
        """
        graphs = self.get_or_create_server_graphs(server_id, server_name)
        graphs.add_data_point(cpu_percent, memory_mb)
    
    def remove_server(self, server_id: str):
        """
        Remove a server from metrics tracking.
        
        Args:
            server_id: Pterodactyl server identifier to remove
        """
        if server_id in self.server_graphs:
            del self.server_graphs[server_id]
            logger.debug(f"Removed metrics tracking for server {server_id}")
    
    def get_server_graphs(self, server_id: str) -> Optional[ServerMetricsGraphs]:
        """
        Get ServerMetricsGraphs instance for a specific server.
        
        Args:
            server_id: Pterodactyl server identifier
            
        Returns:
            ServerMetricsGraphs instance or None if not found
        """
        return self.server_graphs.get(server_id)
    
    def cleanup_old_servers(self, active_server_ids: list):
        """
        Remove tracking for servers that no longer exist.
        
        Args:
            active_server_ids: List of currently active server IDs
        """
        servers_to_remove = []
        for server_id in self.server_graphs:
            if server_id not in active_server_ids:
                servers_to_remove.append(server_id)
        
        for server_id in servers_to_remove:
            self.remove_server(server_id)
        
        if servers_to_remove:
            logger.info(f"Cleaned up metrics for {len(servers_to_remove)} inactive servers")
    
    def get_summary(self) -> Dict[str, any]:
        """
        Get summary of all tracked servers.
        
        Returns:
            Dictionary with tracking statistics
        """
        return {
            'total_servers': len(self.server_graphs),
            'servers_with_data': sum(1 for graphs in self.server_graphs.values() if graphs.has_sufficient_data),
            'total_data_points': sum(len(graphs.data_points) for graphs in self.server_graphs.values())
        }