"""API FastAPI del Runtime server.

- WebSocket: `/ws/realtime` — pub/sub de tag updates + alarm events
- REST: `/tags`, `/tags/{id}/history`, `/alarms`, `/health`, `/project`
"""

from __future__ import annotations

import asyncio
import logging
from contextlib import asynccontextmanager, suppress
from datetime import datetime
from typing import Any

from fastapi import FastAPI, HTTPException, WebSocket, WebSocketDisconnect

from vmssailor.runtime.server.runtime_app import RuntimeApp
from vmssailor.version import __version__

logger = logging.getLogger(__name__)


def create_app(runtime: RuntimeApp) -> FastAPI:
    """Construye la FastAPI app y monta endpoints."""

    @asynccontextmanager
    async def lifespan(_app: FastAPI):
        await runtime.start()
        try:
            yield
        finally:
            await runtime.stop()

    app = FastAPI(
        title="VMS-Sailor Runtime API",
        version=__version__,
        description="On-board Runtime API: tags, history, alarms, control.",
        lifespan=lifespan,
    )
    app.state.runtime = runtime

    # ----- Health ------------------------------------------------------

    @app.get("/health")
    def health() -> dict[str, Any]:
        return {
            "status": "ok",
            "vmssailor_version": __version__,
            "tag_store": runtime.tag_store.stats(),
            "historian": runtime.historian.stats(),
            "active_alarms": len(runtime.alarm_engine.active_alarms()),
            "project": {
                "id": runtime.project.id,
                "name": runtime.project.name,
                "vessel": runtime.project.vessel.name,
            },
        }

    # ----- Project ----------------------------------------------------

    @app.get("/project")
    def project() -> dict[str, Any]:
        p = runtime.project
        return {
            "id": p.id,
            "name": p.name,
            "customer": p.customer,
            "vessel": {
                "id": p.vessel.id,
                "name": p.vessel.name,
                "type": p.vessel.type.value,
                "loa_m": p.vessel.length_overall_m,
                "beam_m": p.vessel.beam_max_m,
                "draft_m": p.vessel.draft_m,
            },
            "systems_enabled": [s.value for s in p.systems_enabled],
            "stats": p.stats(),
        }

    # ----- Tags --------------------------------------------------------

    @app.get("/tags")
    def list_tags() -> list[dict[str, Any]]:
        out: list[dict[str, Any]] = []
        for tag_id, tag in runtime.tag_store.all_tags().items():
            tv = runtime.tag_store.get(tag_id)
            out.append(
                {
                    "id": tag_id,
                    "description": tag.description,
                    "unit_si": tag.unit_si.value,
                    "controllable": tag.controllable,
                    "value": tv.value if tv else None,
                    "quality": tv.quality.value if tv else None,
                    "timestamp": tv.timestamp.isoformat() if tv else None,
                    "range_normal_min": tag.range_normal_min,
                    "range_normal_max": tag.range_normal_max,
                }
            )
        return out

    @app.get("/tags/{tag_id}")
    def get_tag(tag_id: str) -> dict[str, Any]:
        tag = runtime.tag_store.get_tag(tag_id)
        tv = runtime.tag_store.get(tag_id)
        if tag is None or tv is None:
            raise HTTPException(status_code=404, detail=f"Tag '{tag_id}' no encontrado.")
        return {
            "id": tag_id,
            "description": tag.description,
            "unit_si": tag.unit_si.value,
            "value": tv.value,
            "quality": tv.quality.value,
            "timestamp": tv.timestamp.isoformat(),
            "alarms": [a.model_dump(mode="json") for a in tag.alarms],
        }

    @app.get("/tags/{tag_id}/history")
    def history(
        tag_id: str,
        since: str | None = None,
        until: str | None = None,
        limit: int = 1000,
    ) -> list[dict[str, Any]]:
        if tag_id not in runtime.tag_store:
            raise HTTPException(status_code=404, detail=f"Tag '{tag_id}' no encontrado.")
        since_dt = datetime.fromisoformat(since) if since else None
        until_dt = datetime.fromisoformat(until) if until else None
        return runtime.historian.query(tag_id, since=since_dt, until=until_dt, limit=limit)

    # ----- Alarms ------------------------------------------------------

    @app.get("/alarms")
    def alarms(state: str | None = None) -> list[dict[str, Any]]:
        active = runtime.alarm_engine.active_alarms()
        if state == "active":
            return [a.model_dump(mode="json") for a in active]
        all_events = runtime.alarm_events
        return [a.model_dump(mode="json") for a in all_events]

    @app.post("/alarms/{alarm_id}/ack")
    def ack_alarm(alarm_id: str, user: str = "anonymous") -> dict[str, Any]:
        acked = runtime.alarm_engine.ack(alarm_id, user=user)
        if acked is None:
            raise HTTPException(status_code=404, detail=f"Alarma '{alarm_id}' no activa.")
        return acked.model_dump(mode="json")

    # ----- WebSocket ---------------------------------------------------

    @app.websocket("/ws/realtime")
    async def ws_realtime(ws: WebSocket) -> None:
        await ws.accept()
        q = runtime.tag_store.subscribe(maxsize=512)
        # Push current snapshot first
        for tv in runtime.tag_store.all_values().values():
            await ws.send_json(tv.to_event_dict())
        try:
            while True:
                try:
                    tv = await asyncio.wait_for(q.get(), timeout=30.0)
                    await ws.send_json(tv.to_event_dict())
                except TimeoutError:
                    await ws.send_json({"type": "heartbeat"})
        except WebSocketDisconnect:
            pass
        finally:
            runtime.tag_store.unsubscribe(q)
            with suppress(Exception):
                await ws.close()

    return app