# Dockerfile for building and serving a Python FastAPI application using Poetry
# This Dockerfile uses a multi-stage build to keep the final image size small.
# It builds the application in a Python environment and serves it using Uvicorn.

# The User ID can be passed as a build argument to run the container as a non-root user.
ARG USER_ID=$(id -u)

# The Python version can be passed as a build argument.
# Default is set to Python 3.13.
ARG PYTHON_VERSION=3.13

# Builder stage
# This stage is used to install dependencies using Poetry and export them to a requirements.txt file.
FROM python:${PYTHON_VERSION}-slim as builder

# Set the User ID for non-root user
USER ${USER_ID}

# Install Poetry in the builder stage
RUN pip install --no-cache-dir poetry

# Set working directory
WORKDIR /app

# Copy the Poetry configuration files
COPY pyproject.toml poetry.lock ./

# Add the poetry plugin for exporting dependencies
RUN poetry self add poetry-plugin-export

# Force the requirements.txt to be generated without cache
ADD "https://www.random.org/cgi-bin/randbyte?nbytes=10&format=h" skipcache
# Export dependencies to requirements.txt
# This will create a requirements.txt file with the dependencies listed in pyproject.toml
RUN poetry export -f requirements.txt --output requirements.txt --without-hashes

# Final stage
# Use a fresh Python image to keep the final image small
FROM python:${PYTHON_VERSION}-slim

# Set the User ID for non-root user
USER ${USER_ID}

# Set working directory
WORKDIR /app

# Copy the requirements.txt generated in the builder stage and install dependencies
COPY --from=builder /app/requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy the project source code
COPY src/ src/

# Copy the Alembic configuration and migrations
COPY alembic.ini alembic.ini
COPY migrations/ migrations/

COPY .env .env

# Start fastapi application using uvicorn
EXPOSE 8000
ENV PYTHONPATH=/app/src
CMD ["uvicorn", "backend.main:app", "--host", "0.0.0.0", "--port", "8000", "--reload"]