FROM debian:oldstable-slim

# Linux build environment for ImGui repository (Make-based Linux build)
RUN set -eux; \
    apt-get update; \
    # Install essential build tools and dependencies
    apt-get install -y --no-install-recommends \
        build-essential \
        gcc-multilib \
        g++-multilib \
        libglfw3-dev \
        libsdl2-dev \
        libfreetype6-dev \
        libvulkan-dev \
        pkg-config \
        make \
        ca-certificates; \
    rm -rf /var/lib/apt/lists/*

# Copy source into the image
WORKDIR /imgui
COPY . /imgui

# Build Linux example_null from source
RUN set -eux; \
    cd examples/example_null; \
    make clean; \
    WITH_EXTRA_WARNINGS=1 make

# Create a predictable entry path for smoke tests: /imgui/example_null -> built executable
RUN set -eux; \
    EXE=$(find /imgui -type f -name example_null -executable -print -quit 2>/dev/null || true); \
    if [ -n "$EXE" ]; then \
      ln -sf "$EXE" /imgui/example_null; \
    fi

# Default to an interactive shell for inspection
CMD ["/bin/bash"]