import time
import threading
from contextlib import contextmanager
from functools import wraps
from prometheus_client import Counter, Histogram, Summary, start_http_server, Gauge
from flask import current_app, g, request, Flask


class EveAIMetrics:
    """
    Central class for Prometheus metrics infrastructure.
    This class initializes the Prometheus HTTP server and provides
    shared functionality for metrics across components.

    Component-specific metrics should be defined in their respective modules.
    """

    def __init__(self, app: Flask = None):
        self.app = app
        self._metrics_server_started = False
        if app is not None:
            self.init_app(app)

    def init_app(self, app: Flask):
        """Initialize metrics with Flask app and start Prometheus server"""
        self.app = app
        self._start_metrics_server()

    def _start_metrics_server(self):
        """Start the Prometheus metrics HTTP server if not already running"""
        if not self._metrics_server_started:
            try:
                metrics_port = self.app.config.get('PROMETHEUS_PORT', 8000)
                start_http_server(metrics_port)
                self.app.logger.info(f"Prometheus metrics server started on port {metrics_port}")
                self._metrics_server_started = True
            except Exception as e:
                self.app.logger.error(f"Failed to start metrics server: {e}")

    @staticmethod
    def get_standard_buckets():
        """
        Return the standard duration buckets for histogram metrics.
        Components should use these for consistency across the system.
        """
        return [0.1, 0.5, 1, 2.5, 5, 10, 15, 30, 60, 120, 240, 360, float('inf')]

    @staticmethod
    def sanitize_label_values(labels_dict):
        """
        Convert all label values to strings as required by Prometheus.

        Args:
            labels_dict: Dictionary of label name to label value

        Returns:
            Dictionary with all values converted to strings
        """
        return {k: str(v) if v is not None else "" for k, v in labels_dict.items()}