from __future__ import annotations

from fastapi import APIRouter, HTTPException, Request
from fastapi.responses import StreamingResponse
from pydantic import BaseModel
from starlette.concurrency import run_in_threadpool

import camera_params
import config

router = APIRouter(prefix="/api/camera", tags=["camera"])


class ParamValuesIn(BaseModel):
    exposure_auto: bool
    exposure_auto_target_brightness: int
    exposure_auto_min: float
    exposure_auto_max: float
    exposure_time: int
    gain: float


def _get_spec(request: Request, cam_id: str) -> config.CameraSpec:
    session = request.app.state.session
    specs = {c.id: c for c in config.camera_specs(session.camera_count)}
    spec = specs.get(cam_id)
    if spec is None:
        raise HTTPException(404, f"unknown camera id '{cam_id}' for camera_count={session.camera_count}")
    return spec


@router.get("/{cam_id}/params")
async def get_params(cam_id: str, request: Request):
    spec = _get_spec(request, cam_id)
    session = request.app.state.session
    values = session.camera_values.get(cam_id) or camera_params.load_defaults(spec)
    session.camera_values[cam_id] = values
    return values.as_dict()


@router.post("/{cam_id}/params")
async def set_params(cam_id: str, body: ParamValuesIn, request: Request):
    spec = _get_spec(request, cam_id)
    session = request.app.state.session
    values = camera_params.CameraParamValues(**body.model_dump())
    session.camera_values[cam_id] = values
    return {"ok": True}


@router.post("/{cam_id}/params/apply")
async def apply_params(cam_id: str, request: Request):
    spec = _get_spec(request, cam_id)
    session = request.app.state.session
    pm = request.app.state.pm
    if not pm.is_running("camera"):
        raise HTTPException(409, "camera is not running")
    values = session.camera_values.get(cam_id) or camera_params.load_defaults(spec)
    results = await run_in_threadpool(camera_params.apply_params, spec, values)
    ok = all(r["ok"] for r in results)
    return {"ok": ok, "results": results}


@router.post("/{cam_id}/params/save")
async def save_params(cam_id: str, request: Request):
    spec = _get_spec(request, cam_id)
    session = request.app.state.session
    values = session.camera_values.get(cam_id) or camera_params.load_defaults(spec)
    try:
        await run_in_threadpool(camera_params.save_params, spec, values)
    except Exception as e:
        raise HTTPException(500, f"save failed: {e}")
    return {"ok": True, "path": spec.base_params_path}


@router.get("/{cam_id}/stream.mjpg")
async def stream(cam_id: str, request: Request):
    _get_spec(request, cam_id)  # validate
    ros = request.app.state.ros
    return StreamingResponse(
        ros.mjpeg_generator(cam_id),
        media_type="multipart/x-mixed-replace; boundary=frame",
    )