"""Windows Node MVP 的注册、管理与长连接端点。"""

from __future__ import annotations

import asyncio
from uuid import UUID

from fastapi import Depends, HTTPException, WebSocket, WebSocketDisconnect, status

from core.compute_nodes import (
    ComputeNodeError,
    authenticate_node,
    create_enrollment,
    enroll_node,
    list_nodes,
    mark_node_offline,
    set_node_disabled,
    update_node_runtime,
)
from web.schemas import (
    ComputeEnrollmentCreateRequest,
    ComputeNodeDisableRequest,
    ComputeNodeEnrollRequest,
)


class NodeConnectionManager:
    def __init__(self) -> None:
        self._connections: dict[UUID, WebSocket] = {}
        self._lock = asyncio.Lock()

    async def activate(self, node_id: UUID, websocket: WebSocket) -> None:
        async with self._lock:
            old = self._connections.get(node_id)
            self._connections[node_id] = websocket
        if old is not None and old is not websocket:
            await old.close(code=4001, reason="replaced by a newer connection")

    async def remove(self, node_id: UUID, websocket: WebSocket) -> bool:
        async with self._lock:
            if self._connections.get(node_id) is websocket:
                self._connections.pop(node_id, None)
                return True
        return False

    async def close(self, node_id: UUID) -> None:
        async with self._lock:
            websocket = self._connections.pop(node_id, None)
        if websocket is not None:
            await websocket.close(code=4003, reason="node disabled")


node_connections = NodeConnectionManager()


def _bearer(authorization: str | None) -> str:
    scheme, _, token = (authorization or "").partition(" ")
    if scheme.lower() != "bearer" or not token:
        raise ComputeNodeError("missing node bearer token")
    return token


def register_compute_node_routes(app, *, require_admin) -> None:
    @app.post(
        "/v1/compute/nodes/enroll",
        tags=["compute-nodes"],
        status_code=status.HTTP_201_CREATED,
    )
    def node_enroll(body: ComputeNodeEnrollRequest):
        try:
            return enroll_node(**body.model_dump())
        except ComputeNodeError as exc:
            raise HTTPException(400, str(exc)) from exc

    @app.websocket("/v1/compute/nodes/connect")
    async def node_connect(websocket: WebSocket):
        try:
            node_id = UUID(websocket.headers.get("x-node-id", ""))
            token = _bearer(websocket.headers.get("authorization"))
            identity = await asyncio.to_thread(authenticate_node, node_id, token)
        except (ValueError, ComputeNodeError):
            await websocket.close(code=1008, reason="invalid node credentials")
            return
        await websocket.accept()
        await node_connections.activate(node_id, websocket)
        try:
            await websocket.send_json({"type": "connected", "heartbeat_seconds": 15})
            while True:
                message = await websocket.receive_json()
                message_type = message.get("type")
                payload = message.get("payload") or {}
                if message_type not in {"hello", "heartbeat"} or not isinstance(
                    payload, dict
                ):
                    await websocket.send_json(
                        {"type": "error", "code": "unsupported_message"}
                    )
                    continue
                if payload.get("install_id") and payload["install_id"] != str(
                    identity["install_id"]
                ):
                    await websocket.close(code=1008, reason="install identity mismatch")
                    return
                await asyncio.to_thread(
                    update_node_runtime,
                    node_id,
                    status="online",
                    runtime=payload,
                )
                await websocket.send_json(
                    {"type": "ack", "message_id": message.get("message_id")}
                )
        except (ComputeNodeError, WebSocketDisconnect, RuntimeError, ValueError):
            pass
        finally:
            if await node_connections.remove(node_id, websocket):
                await asyncio.to_thread(mark_node_offline, node_id)

    @app.post("/v1/admin/compute-node-enrollments", tags=["admin"])
    def admin_create_compute_enrollment(
        body: ComputeEnrollmentCreateRequest,
        user_id: UUID = Depends(require_admin),  # noqa: B008
    ):
        try:
            return create_enrollment(user_id, **body.model_dump())
        except ComputeNodeError as exc:
            raise HTTPException(400, str(exc)) from exc

    @app.get("/v1/admin/compute-nodes", tags=["admin"])
    def admin_compute_nodes(user_id: UUID = Depends(require_admin)):  # noqa: B008
        return {"results": list_nodes()}

    @app.patch("/v1/admin/compute-nodes/{node_id}", tags=["admin"])
    async def admin_disable_compute_node(
        node_id: UUID,
        body: ComputeNodeDisableRequest,
        user_id: UUID = Depends(require_admin),  # noqa: B008
    ):
        if not await asyncio.to_thread(set_node_disabled, node_id, body.disabled):
            raise HTTPException(404, "compute node not found")
        if body.disabled:
            await node_connections.close(node_id)
        return {
            "node_id": str(node_id),
            "status": "disabled" if body.disabled else "offline",
        }