===== Stage 1: Build the Python Backend =====

FROM python:3.10-slim as python-builder
Set the working directory for the backend code

WORKDIR /app
Install system dependencies

RUN apt-get update && apt-get install -y --no-install-recommends build-essential
Copy ONLY the requirements file first to leverage Docker's layer caching

COPY backend/requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
Now copy the entire backend application code
The source is 'backend/' and the destination is the current WORKDIR ('/app')

COPY backend/ .
===== Stage 2: Final Production Image =====

FROM nginx:stable-alpine
Remove default Nginx config and copy our custom one

RUN rm /etc/nginx/conf.d/default.conf
COPY nginx.conf /etc/nginx/nginx.conf
Copy the installed Python environment from the builder stage

COPY --from=python-builder /usr/local/lib/python3.10/site-packages /usr/local/lib/python3.10/site-packages
COPY --from=python-builder /usr/local/bin /usr/local/bin
Copy the Python application code from the builder stage

COPY --from=python-builder /app /app
WORKDIR /app
Copy the static frontend files into the Nginx public directory
This is the key change to match your structure

COPY frontend/. /usr/share/nginx/html
Expose the port Nginx will listen on

EXPOSE 80
The command to start both Gunicorn (for Python) and Nginx (for serving files)
Gunicorn will find 'main.py' inside the '/app' WORKDIR

CMD ["sh", "-c", "gunicorn --worker-class eventlet -w 1 --bind 0.0.0.0:5000 main:app & nginx -g 'daemon off;'"]