"""
Metrics Exporter — Prometheus metrics для worker
"""

import asyncio
from typing import Optional
from aiohttp import web
from prometheus_client import Counter, Histogram, Gauge, generate_latest


class MetricsExporter:
    def __init__(self, port: int = 9090):
        self.port = port
        self.app: Optional[web.Application] = None
        self.runner: Optional[web.AppRunner] = None
        
        # Metrics
        self.jobs_processed = Counter(
            "worker_jobs_processed_total",
            "Total jobs processed",
            ["type", "status"]
        )
        self.job_duration = Histogram(
            "worker_job_duration_seconds",
            "Job execution duration",
            ["type"],
            buckets=[0.1, 0.5, 1.0, 5.0, 10.0, 30.0, 60.0]
        )
        self.gpu_utilization = Gauge(
            "worker_gpu_utilization",
            "GPU utilization percentage",
            ["node_id"]
        )
        self.vram_usage = Gauge(
            "worker_vram_usage_bytes",
            "VRAM usage in bytes",
            ["node_id"]
        )
        self.errors_total = Counter(
            "worker_errors_total",
            "Total errors",
            ["type", "error_type"]
        )
        
    async def start(self):
        """Запуск metrics server"""
        self.app = web.Application()
        self.app.router.add_get("/metrics", self.metrics_handler)
        
        self.runner = web.AppRunner(self.app)
        await self.runner.setup()
        
        site = web.TCPSite(self.runner, "0.0.0.0", self.port)
        await site.start()
        
        print(f"✅ Metrics server запущено на порту {self.port}")
        
    async def stop(self):
        """Зупинка metrics server"""
        if self.runner:
            await self.runner.cleanup()
            print("✅ Metrics server зупинено")
            
    async def metrics_handler(self, request):
        """HTTP handler для /metrics"""
        return web.Response(
            text=generate_latest(),
            content_type="text/plain"
        )