ARG BASE_IMAGE=nixos/nix:latest

# Nix builder
FROM nixos/nix:latest AS builder-source

RUN mkdir -p ~/.config/nix && \
    echo "experimental-features = nix-command flakes" >> ~/.config/nix/nix.conf

# Copy our source and setup our working dir.
COPY nix/ci-env.nix /tmp/build/nix/ci-env.nix
COPY nix/packages.nix /tmp/build/nix/packages.nix
COPY nix/utils.nix /tmp/build/nix/utils.nix
COPY flake.nix /tmp/build/
COPY flake.lock /tmp/build/
WORKDIR /tmp/build

FROM builder-source AS builder

# Build our Nix CI environment (all build tools in a single store path)
RUN nix \
    --option filter-syscalls false \
    build

# Copy the Nix store closure into a directory. The Nix store closure is the
# entire set of Nix store values that we need for our build.
RUN mkdir /tmp/nix-store-closure && \
    cp -R $(nix-store -qR result/) /tmp/nix-store-closure

# Final image
FROM ${BASE_IMAGE}

# bash is not located at /bin/bash in nixos/nix, so we need to create a symlink to it.
RUN if [ -d /nix ]; then \
        ln -s /root/.nix-profile/bin/bash /bin/bash; \
    fi

# Use Bash as the default shell for RUN commands, using the options
# `set -o errexit -o pipefail`, and as the entrypoint.
SHELL ["/bin/bash", "-e", "-o", "pipefail", "-c"]
ENTRYPOINT ["/bin/bash"]

# Copy /nix/store and the env symlink tree
COPY --from=builder /tmp/nix-store-closure /nix/store
COPY --from=builder /tmp/build/result /nix/ci-env

ENV PATH="/nix/ci-env/bin:$PATH"

RUN <<EOF
ccache --version
clang-format --version
cmake --version
conan --version
g++ --version
gcc --version
gcovr --version
git --version
make --version
mold --version
ninja --version
perl --version
pkg-config --version
pre-commit --version
python3 --version
run-clang-tidy --help
vim --version
EOF