# syntax=docker/dockerfile:1.4

# Find eligible builder and runner images on Docker Hub. We use Ubuntu/Debian
# instead of Alpine to avoid DNS resolution issues in production.
#
# https://hub.docker.com/r/hexpm/elixir/tags?name=ubuntu
# https://hub.docker.com/_/ubuntu/tags
#
# This file is based on these images:
#
#   - https://hub.docker.com/r/hexpm/elixir/tags - for the build image
#   - https://hub.docker.com/_/debian/tags?name=trixie-20251229-slim - for the release image
#   - https://pkgs.org/ - resource for finding needed packages
#   - Ex: docker.io/hexpm/elixir:1.20.2-erlang-29.0.3-debian-trixie-20260713-slim
#
ARG ELIXIR_VERSION=1.20.2
ARG OTP_VERSION=29.0.3
ARG DEBIAN_VERSION=trixie-20260713-slim

ARG BUILDER_IMAGE="docker.io/hexpm/elixir:${ELIXIR_VERSION}-erlang-${OTP_VERSION}-debian-${DEBIAN_VERSION}"
ARG RUNNER_IMAGE="docker.io/debian:${DEBIAN_VERSION}"

FROM ${BUILDER_IMAGE} AS builder
ENV MIX_OS_DEPS_COMPILE_PARTITION_COUNT=3
# Enable parallel compilation with 3 cores
ENV ELIXIR_ERL_OPTIONS="+JPperf true"
ENV ERL_AFLAGS="-kernel shell_history enabled"
# Disable TTY for cross-architecture builds
ENV TERM=dumb

# install build dependencies
RUN apt-get update \
    && DEBIAN_FRONTEND=noninteractive apt-get upgrade -y \
    && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends build-essential git curl libsnmp-dev \
    && rm -rf /var/lib/apt/lists/*

# prepare build dir
WORKDIR /app

# set build ENV
ENV MIX_ENV="prod"

# install hex + rebar (must use cache mounts so they persist into subsequent cache-mounted steps)
RUN --mount=type=cache,target=/root/.hex \
    --mount=type=cache,target=/root/.mix \
    mix local.hex --force \
    && mix local.rebar --force

# install mix dependencies
COPY mix.exs mix.lock ./
COPY vendor vendor
RUN --mount=type=cache,target=/root/.hex \
    --mount=type=cache,target=/root/.mix \
    mix deps.get --only $MIX_ENV
RUN mkdir config

# copy compile-time config files before we compile dependencies
# to ensure any relevant config change will trigger the dependencies
# to be re-compiled.
COPY config/config.exs config/${MIX_ENV}.exs config/
RUN --mount=type=cache,target=/root/.hex \
    --mount=type=cache,target=/root/.mix \
    mix deps.compile

RUN --mount=type=cache,target=/root/.mix \
    --mount=type=cache,target=/root/.npm \
    mix assets.setup

COPY priv priv

COPY c_src c_src

# Compile the C NIF before Elixir compilation
RUN cd c_src && make

COPY lib lib

# Compile the release
RUN --mount=type=cache,target=/root/.mix \
    mix compile

COPY assets assets

# compile assets
RUN --mount=type=cache,target=/root/.mix \
    mix assets.deploy

# Changes to config/runtime.exs don't require recompiling the code
COPY config/runtime.exs config/

COPY rel rel
RUN --mount=type=cache,target=/root/.mix \
    mix release

# start a new build stage so that the final image will only contain
# the compiled release and other runtime necessities
FROM ${RUNNER_IMAGE} AS final

RUN apt-get update \
    && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends libstdc++6 openssl libncurses6 locales ca-certificates iputils-ping snmp libsnmp40 libsctp1 \
    && rm -rf /var/lib/apt/lists/*

# Set the locale
RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen \
    && locale-gen

ENV LANG=en_US.UTF-8
ENV LANGUAGE=en_US:en
ENV LC_ALL=en_US.UTF-8

WORKDIR "/app"
RUN chown nobody /app

# set runner ENV
ENV MIX_ENV="prod"

# Only copy the final release from the build stage
COPY --from=builder --chown=nobody:root /app/_build/${MIX_ENV}/rel/towerops ./

USER nobody

# If using an environment that doesn't automatically reap zombie processes, it is
# advised to add an init process such as tini via `apt-get install`
# above and adding an entrypoint. See https://github.com/krallin/tini for details
# ENTRYPOINT ["/tini", "--"]

# Health check for container orchestration
HEALTHCHECK --interval=30s --timeout=3s --start-period=40s --retries=3 \
    CMD ["/app/bin/towerops", "rpc", "1 + 1"]

CMD ["/app/bin/server"]