import logging

from prometheus_client import Counter, Histogram, start_http_server

NAMESPACE = "skyembed"

logger = logging.getLogger(__name__)


class PromMetrics:
    _instance = None

    def __new__(cls):
        if cls._instance is None:
            cls._instance = super().__new__(cls)
            cls._instance._initialized = False
        return cls._instance

    def __init__(self):
        if self._initialized:
            return

        self.embedding_performed = Counter(
            name="embedding_performed",
            namespace=NAMESPACE,
            documentation="Number of embeddings performed",
            labelnames=["status"],
        )

        self.embedding_duration = Histogram(
            name="embedding_duration_seconds",
            namespace=NAMESPACE,
            buckets=(
                0.001,
                0.005,
                0.01,
                0.025,
                0.05,
                0.1,
                0.25,
                0.5,
                1.0,
                2.5,
                5.0,
                10.0,
            ),
            labelnames=["status"],
            documentation="Time taken to create an embedding",
        )

        self.events_handled = Counter(
            name="events_handled",
            namespace=NAMESPACE,
            documentation="Number of events handled",
            labelnames=["kind", "status"],
        )

        self.upserts = Counter(
            name="upserts",
            namespace=NAMESPACE,
            documentation="Number of database upserts",
            labelnames=["kind", "status"],
        )

        self.upsert_duration = Histogram(
            name="upsert_duration_seconds",
            namespace=NAMESPACE,
            buckets=(
                0.001,
                0.005,
                0.01,
                0.025,
                0.05,
                0.1,
                0.25,
                0.5,
                1.0,
                2.5,
                5.0,
                10.0,
            ),
            labelnames=["kind", "status"],
            documentation="Time taken to perform an upsert",
        )

        self._initialized = True

    def start_http(self, port: int, addr: str = "0.0.0.0"):
        logger.info(f"Starting Prometheus client on {addr}:{port}")
        start_http_server(port=port, addr=addr)
        logger.info(f"Prometheus client running on {addr}:{port}")


prom_metrics = PromMetrics()