import logging
import os
import sys
from typing import Union

from celery.signals import worker_init
from flask_login import user_loaded_from_request, user_logged_in
from opentelemetry import metrics, trace
from opentelemetry.propagate import set_global_textmap
from opentelemetry.propagators.b3 import B3MultiFormat
from opentelemetry.propagators.composite import CompositePropagator
from opentelemetry.trace.propagation.tracecontext import TraceContextTextMapPropagator

from configs import dify_config
from extensions.otel.semconv import DifySpanAttributes, GenAIAttributes
from libs.helper import extract_tenant_id
from models import Account, EndUser

logger = logging.getLogger(__name__)


def setup_context_propagation() -> None:
    set_global_textmap(
        CompositePropagator(
            [
                TraceContextTextMapPropagator(),
                B3MultiFormat(),
            ]
        )
    )


def shutdown_tracer() -> None:
    flush_telemetry()


def flush_telemetry() -> None:
    """
    Best-effort flush for telemetry providers.

    This is mainly used by short-lived command processes (e.g. Kubernetes CronJob)
    so counters/histograms are exported before the process exits.
    """
    provider = trace.get_tracer_provider()
    if hasattr(provider, "force_flush"):
        try:
            provider.force_flush()
        except Exception:
            logger.exception("otel: failed to flush trace provider")

    metric_provider = metrics.get_meter_provider()
    if hasattr(metric_provider, "force_flush"):
        try:
            metric_provider.force_flush()
        except Exception:
            logger.exception("otel: failed to flush metric provider")


def is_celery_worker():
    return "celery" in sys.argv[0].lower()


@user_logged_in.connect
@user_loaded_from_request.connect
def on_user_loaded(_sender, user: Union["Account", "EndUser"]):
    if dify_config.ENABLE_OTEL:
        from opentelemetry.trace import get_current_span

        if user:
            try:
                current_span = get_current_span()
                tenant_id = extract_tenant_id(user)
                if not tenant_id:
                    return
                if current_span:
                    current_span.set_attribute(DifySpanAttributes.TENANT_ID, tenant_id)
                    current_span.set_attribute(GenAIAttributes.USER_ID, user.id)
            except Exception:
                logger.exception("Error setting tenant and user attributes")
                pass


@worker_init.connect(weak=False)
def init_celery_worker(*args, **kwargs):
    if dify_config.ENABLE_OTEL:
        from opentelemetry.instrumentation.celery import CeleryInstrumentor
        from opentelemetry.metrics import get_meter_provider
        from opentelemetry.trace import get_tracer_provider

        from extensions.otel.celery_sqlcommenter import setup_celery_sqlcommenter

        tracer_provider = get_tracer_provider()
        metric_provider = get_meter_provider()
        if dify_config.DEBUG:
            logger.info("Initializing OpenTelemetry for Celery worker")
        CeleryInstrumentor(tracer_provider=tracer_provider, meter_provider=metric_provider).instrument()
        setup_celery_sqlcommenter()


def is_instrument_flag_enabled() -> bool:
    """
    Check if external instrumentation is enabled via environment variable.

    Third-party non-invasive instrumentation agents set this flag to coordinate
    with Dify's manual OpenTelemetry instrumentation.
    """
    return os.getenv("ENABLE_OTEL_FOR_INSTRUMENT", "").strip().lower() == "true"