"""HTTP REST API (FastAPI)."""

from __future__ import annotations

from typing import Any

import structlog
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel

from .config import Config
from .dispatch import CommandDispatcher
from .layouts import PREDEFINED_LAYOUTS
from .state import ControllerState

log = structlog.get_logger()


class LayoutSetReq(BaseModel):
    layout: str


def create_app(
    cfg: Config, state: ControllerState, dispatcher: CommandDispatcher
) -> FastAPI:
    app = FastAPI(
        title="cuda-grid-controller",
        version="0.1.0",
        description="Control plane для vf_cuda_grid FFmpeg filter",
    )

    @app.get("/health")
    async def health() -> dict[str, Any]:
        return {"status": "ok"}

    @app.get("/layouts")
    async def layouts() -> dict[str, Any]:
        return {"predefined": PREDEFINED_LAYOUTS}

    @app.get("/state")
    async def get_state() -> dict[str, Any]:
        out = {}
        for inst in cfg.instances:
            out[inst.name] = {
                "active_layout": await state.get_layout(inst.name),
                "zmq_endpoint": inst.zmq_endpoint,
            }
        return {"instances": out}

    @app.post("/layout/{instance}/set")
    async def set_layout(instance: str, req: LayoutSetReq) -> dict[str, Any]:
        inst = next((i for i in cfg.instances if i.name == instance), None)
        if inst is None:
            raise HTTPException(404, f"unknown instance '{instance}'")
        if req.layout not in PREDEFINED_LAYOUTS:
            raise HTTPException(
                400, f"unknown layout '{req.layout}'. Доступны: {PREDEFINED_LAYOUTS}"
            )
        await dispatcher.handle(instance, "layout.set", req.layout)
        return {"ok": True, "instance": instance, "layout": req.layout}

    return app