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

from __future__ import annotations

from typing import Any

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

from .config import Config
from .dispatch import CommandDispatcher
from .layouts import PREDEFINED_LAYOUTS
from .overlays import Overlay
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",
    )

    def _check_instance(name: str):
        inst = next((i for i in cfg.instances if i.name == name), None)
        if inst is None:
            raise HTTPException(404, f"unknown instance '{name}'")
        return inst

    @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:
            overlays = await state.get_overlays(inst.name)
            out[inst.name] = {
                "active_layout": await state.get_layout(inst.name),
                "zmq_endpoint": inst.zmq_endpoint,
                "overlays_count": len(overlays),
            }
        return {"instances": out}

    @app.post("/layout/{instance}/set")
    async def set_layout(instance: str, req: LayoutSetReq) -> dict[str, Any]:
        _check_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}

    # ─── Overlays ──────────────────────────────────────────────────

    @app.post("/overlay/{instance}/add")
    async def overlay_add(
        instance: str, overlay: Overlay = Body(...)
    ) -> dict[str, Any]:
        _check_instance(instance)
        await dispatcher.handle(
            instance, "overlay.add", overlay.model_dump_json()
        )
        return {"ok": True, "id": overlay.id, "type": overlay.type}

    @app.get("/overlay/{instance}")
    async def overlay_list(instance: str) -> dict[str, Any]:
        _check_instance(instance)
        overlays = await state.get_overlays(instance)
        return {
            "instance": instance,
            "count": len(overlays),
            "overlays": [o.model_dump() for o in overlays],
        }

    @app.delete("/overlay/{instance}/{overlay_id}")
    async def overlay_remove(instance: str, overlay_id: str) -> dict[str, Any]:
        _check_instance(instance)
        await dispatcher.handle(instance, "overlay.remove", overlay_id)
        return {"ok": True}

    @app.delete("/overlay/{instance}")
    async def overlay_clear(instance: str) -> dict[str, Any]:
        _check_instance(instance)
        await dispatcher.handle(instance, "overlay.clear", "")
        return {"ok": True}

    @app.patch("/overlay/{instance}/{overlay_id}")
    async def overlay_update(
        instance: str, overlay_id: str, overlay: Overlay = Body(...)
    ) -> dict[str, Any]:
        _check_instance(instance)
        # Фиксируем id из URL — игнорируем body's id если отличается
        overlay.id = overlay_id
        await state.update_overlay(instance, overlay)
        await dispatcher.handle(
            instance, "overlay.add", overlay.model_dump_json()
        )
        return {"ok": True, "id": overlay_id}

    return app