"""Station config router: read/update the singleton station branding config."""

import os
import uuid

from fastapi import APIRouter, Depends, HTTPException, UploadFile, status

from app.auth import get_current_admin_user
from app.database import get_session
from app.models import StationConfig
from app.schemas import StationConfigResponse, StationConfigUpdate
from app.user_models import User
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

router = APIRouter()

UPLOAD_DIR = os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "uploads")
MAX_FILE_SIZE = 5 * 1024 * 1024  # 5 MB


@router.get("", response_model=StationConfigResponse)
async def get_station_config(session: AsyncSession = Depends(get_session)):
    """Return the singleton station config. Public endpoint."""
    result = await session.execute(
        select(StationConfig).where(StationConfig.key == "default")
    )
    config = result.scalar_one_or_none()
    if config is None:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Station config not found. Run seed to initialize.",
        )
    return config


@router.put("", response_model=StationConfigResponse)
async def update_station_config(
    payload: StationConfigUpdate,
    session: AsyncSession = Depends(get_session),
    current_user: User = Depends(get_current_admin_user),
):
    """Partial update of station config. Admin only."""
    result = await session.execute(
        select(StationConfig).where(StationConfig.key == "default")
    )
    config = result.scalar_one_or_none()
    if config is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Station config not found")

    for key, value in payload.model_dump(exclude_unset=True).items():
        setattr(config, key, value)

    await session.commit()
    await session.refresh(config)
    return config


@router.post("/upload")
async def upload_image(
    file: UploadFile,
    current_user: User = Depends(get_current_admin_user),
):
    """Upload an image file for station branding. Admin only.

    Saves the file to the uploads/ directory with a UUID filename.
    Returns the relative URL path.
    """
    # Validate MIME type
    if not file.content_type or not file.content_type.startswith("image/"):
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Only image files are allowed",
        )

    # Read and validate size
    content = await file.read()
    if len(content) > MAX_FILE_SIZE:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="File size exceeds 5 MB limit",
        )

    # Ensure upload directory exists
    os.makedirs(UPLOAD_DIR, exist_ok=True)

    # Generate unique filename preserving extension
    ext = os.path.splitext(file.filename or "upload")[1] if file.filename else ".bin"
    filename = f"{uuid.uuid4().hex}{ext}"
    filepath = os.path.join(UPLOAD_DIR, filename)

    with open(filepath, "wb") as f:
        f.write(content)

    return {"url": f"uploads/{filename}"}