"""Main TelemetryClient — the public entry point for the SDK."""

from __future__ import annotations

import logging
from typing import Any

import httpx

from mosaicstack_telemetry._async import AsyncSubmitter
from mosaicstack_telemetry._sync import SyncSubmitter
from mosaicstack_telemetry.config import TelemetryConfig
from mosaicstack_telemetry.prediction_cache import PredictionCache
from mosaicstack_telemetry.queue import EventQueue
from mosaicstack_telemetry.types.events import TaskCompletionEvent
from mosaicstack_telemetry.types.predictions import (
    PredictionQuery,
    PredictionResponse,
)

logger = logging.getLogger("mosaicstack_telemetry")


class TelemetryClient:
    """Main client for Mosaic Stack Telemetry.

    Supports both sync and async usage patterns:

    **Sync (threading-based):**

        client = TelemetryClient(config)
        client.start()
        client.track(event)
        client.stop()

    **Async (asyncio-based):**

        client = TelemetryClient(config)
        await client.start_async()
        client.track(event)
        await client.stop_async()

    **Context managers:**

        with TelemetryClient(config) as client:
            client.track(event)

        async with TelemetryClient(config) as client:
            client.track(event)
    """

    def __init__(self, config: TelemetryConfig) -> None:
        errors = config.validate()
        if errors and config.enabled:
            logger.warning("Telemetry config validation errors: %s", "; ".join(errors))

        self._config = config
        self._queue = EventQueue(max_size=config.max_queue_size)
        self._prediction_cache = PredictionCache(ttl_seconds=config.prediction_cache_ttl_seconds)
        self._sync_submitter: SyncSubmitter | None = None
        self._async_submitter: AsyncSubmitter | None = None

    def start(self) -> None:
        """Start background submission using threading.Timer loop."""
        if not self._config.enabled:
            logger.info("Telemetry disabled, skipping start")
            return
        self._sync_submitter = SyncSubmitter(self._config, self._queue)
        self._sync_submitter.start()

    async def start_async(self) -> None:
        """Start with asyncio.Task for async contexts."""
        if not self._config.enabled:
            logger.info("Telemetry disabled, skipping async start")
            return
        self._async_submitter = AsyncSubmitter(self._config, self._queue)
        await self._async_submitter.start()

    def stop(self) -> None:
        """Stop background submission, flush remaining events synchronously."""
        if self._sync_submitter is not None:
            self._sync_submitter.stop()
            self._sync_submitter = None

    async def stop_async(self) -> None:
        """Async stop and flush."""
        if self._async_submitter is not None:
            await self._async_submitter.stop()
            self._async_submitter = None

    def track(self, event: TaskCompletionEvent) -> None:
        """Queue an event for submission. Always synchronous. Never blocks or throws.

        If telemetry is disabled, the event is silently dropped.
        """
        try:
            if not self._config.enabled:
                return
            self._queue.put(event)
            logger.debug("Event queued: %s", event.event_id)
        except Exception:
            logger.exception("Unexpected error in track()")

    def get_prediction(self, query: PredictionQuery) -> PredictionResponse | None:
        """Get a cached prediction. Returns None if not cached or expired."""
        return self._prediction_cache.get(query)

    def refresh_predictions_sync(self, queries: list[PredictionQuery]) -> None:
        """Fetch fresh predictions from server synchronously."""
        if not queries:
            return
        url = f"{self._config.server_url}/v1/predictions/batch"
        body = {"queries": [q.model_dump(mode="json") for q in queries]}

        try:
            with httpx.Client() as client:
                response = client.post(
                    url,
                    json=body,
                    headers={"User-Agent": self._config.user_agent},
                    timeout=self._config.request_timeout_seconds,
                )
                if response.status_code == 200:
                    data = response.json()
                    results = data.get("results", [])
                    for query, result_data in zip(queries, results):
                        pred = PredictionResponse.model_validate(result_data)
                        self._prediction_cache.put(query, pred)
                    logger.debug("Refreshed %d predictions", len(results))
                else:
                    logger.warning(
                        "Prediction refresh failed with status %d",
                        response.status_code,
                    )
        except Exception:
            logger.exception("Error refreshing predictions")

    async def refresh_predictions(self, queries: list[PredictionQuery]) -> None:
        """Fetch fresh predictions from server asynchronously."""
        if not queries:
            return
        url = f"{self._config.server_url}/v1/predictions/batch"
        body = {"queries": [q.model_dump(mode="json") for q in queries]}

        try:
            async with httpx.AsyncClient() as client:
                response = await client.post(
                    url,
                    json=body,
                    headers={"User-Agent": self._config.user_agent},
                    timeout=self._config.request_timeout_seconds,
                )
                if response.status_code == 200:
                    data = response.json()
                    results = data.get("results", [])
                    for query, result_data in zip(queries, results):
                        pred = PredictionResponse.model_validate(result_data)
                        self._prediction_cache.put(query, pred)
                    logger.debug("Refreshed %d predictions", len(results))
                else:
                    logger.warning(
                        "Prediction refresh failed with status %d",
                        response.status_code,
                    )
        except Exception:
            logger.exception("Error refreshing predictions")

    @property
    def queue_size(self) -> int:
        """Number of events currently in the queue."""
        return self._queue.size

    @property
    def is_running(self) -> bool:
        """Whether background submission is active."""
        if self._sync_submitter is not None:
            return self._sync_submitter.is_running
        if self._async_submitter is not None:
            return self._async_submitter.is_running
        return False

    # Sync context manager
    def __enter__(self) -> TelemetryClient:
        self.start()
        return self

    def __exit__(self, *exc: Any) -> None:
        self.stop()

    # Async context manager
    async def __aenter__(self) -> TelemetryClient:
        await self.start_async()
        return self

    async def __aexit__(self, *exc: Any) -> None:
        await self.stop_async()