# Multi-stage build for optimized production image
FROM rust:1.83 as builder

WORKDIR /app

# Copy manifests for dependency caching
COPY Cargo.toml Cargo.lock* ./

# Copy source code
COPY src ./src

# Build for release
RUN cargo build --release

# Runtime stage
FROM debian:bookworm-slim

# Install CA certificates and curl for HTTPS requests and health checks
RUN apt-get update && \
    apt-get install -y ca-certificates curl && \
    rm -rf /var/lib/apt/lists/*

# Create app user
RUN useradd -r -s /bin/false appuser

# Copy the binary from builder stage
COPY --from=builder /app/target/release/emailer-microservice /usr/local/bin/emailer-microservice

# Set ownership
RUN chown appuser:appuser /usr/local/bin/emailer-microservice

# Switch to non-root user
USER appuser

# Environment defaults
ENV HOST=0.0.0.0
ENV PORT=4000
ENV RUST_LOG=info

# Expose port
EXPOSE 4000

# Health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
    CMD curl -f http://localhost:4000/health || exit 1

# Run the binary
CMD ["emailer-microservice"]