# syntax=docker/dockerfile:1.6
# 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-20260316-slim - for the release image
#   - https://pkgs.org/ - resource for finding needed packages
#   - Ex: docker.io/hexpm/elixir:1.19.5-erlang-28.4.1-debian-trixie-20260316-slim
#
ARG ELIXIR_VERSION=1.19.5
ARG OTP_VERSION=28.4.1
ARG DEBIAN_VERSION=trixie-20260316-slim

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

# ---- wgrib2 build stage (cached independently) ----
FROM ${RUNNER_IMAGE} AS wgrib2-builder

ARG WGRIB2_VERSION=3.6.0
# g2c v2.1.0 is the first release where BUILD_G2C defaults ON, which
# is what wgrib2 v3.6.0 needs at link time (g2c_enc_jpeg2000 /
# g2c_dec_jpeg2000 come from the "new" file-based API). v1.9.0's
# same flag was OFF by default with a note about the API being
# experimental until 2.0.0.
ARG G2C_VERSION=2.1.0

# BuildKit cache mounts keep the .deb archive + apt-lists out of the
# image overlay and on the builder's cache storage, so image layers
# don't pay the disk cost and CI runners with tight /var budgets can
# still fetch ~100 MB of packages. The `rm -rf lists/*` below targets
# the cache-mount contents; BuildKit persists whatever remains for
# the next build.
RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
    --mount=type=cache,target=/var/lib/apt,sharing=locked \
    rm -f /etc/apt/apt.conf.d/docker-clean \
    && apt-get update \
    && apt-get install -y --no-install-recommends \
       build-essential gfortran cmake wget ca-certificates pkg-config \
       zlib1g-dev libaec-dev libpng-dev libopenjp2-7-dev

# NCEPLIBS-g2c: wgrib2 >= 3.x delegates GRIB2 decompression to this
# library via find_package whenever any of JASPER / OPENJPEG / PNG
# is enabled (wgrib2 CMakeLists:94). Build g2c with all the
# decoders we care about — PNG (MRMS PrecipRate / HRRR native),
# OpenJPEG (modern JPEG2000 replacement for the CVE-riddled Jasper),
# and AEC (CCSDS) — and disable Jasper so we don't need libjasper,
# which Debian dropped years ago.
WORKDIR /tmp/g2c
RUN wget -q --content-disposition "https://github.com/NOAA-EMC/NCEPLIBS-g2c/archive/refs/tags/v${G2C_VERSION}.tar.gz" \
      -O g2c.tar.gz \
  && tar xzf g2c.tar.gz \
  && cd NCEPLIBS-g2c-${G2C_VERSION} \
  && mkdir build && cd build \
  && cmake .. -DCMAKE_INSTALL_PREFIX=/usr/local \
              -DCMAKE_BUILD_TYPE=Release \
              -DUSE_PNG=ON \
              -DUSE_AEC=ON \
              -DUSE_OpenJPEG=ON \
              -DUSE_Jasper=OFF \
  && make -j$(nproc) \
  && make install

WORKDIR /tmp/wgrib2

# wgrib2 flags:
#   * USE_PNG / USE_OPENJPEG / USE_AEC each turn on the matching
#     encoder path inside wgrib2 and add the compression name to the
#     -config output. With g2c v2.1.0 underneath (which exports the
#     g2c_enc_* / g2c_dec_* new-API symbols) all three can be enabled
#     together — the earlier build failure was not about the flag
#     combination, it was g2c v1.9.0 shipping without BUILD_G2C.
RUN wget -q --content-disposition "https://github.com/NOAA-EMC/wgrib2/archive/refs/tags/v${WGRIB2_VERSION}.tar.gz" \
      -O wgrib2.tar.gz \
  && tar xzf wgrib2.tar.gz \
  && cd wgrib2-${WGRIB2_VERSION} \
  && mkdir build && cd build \
  && cmake .. -DCMAKE_INSTALL_PREFIX=/usr/local -DCMAKE_BUILD_TYPE=Release \
       -DUSE_PNG=ON -DUSE_OPENJPEG=ON -DUSE_AEC=ON \
  && make -j$(nproc) \
  && make install \
  && strip /usr/local/bin/wgrib2

# ---- Elixir build stage ----
FROM ${BUILDER_IMAGE} AS builder

# install build dependencies
RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
    --mount=type=cache,target=/var/lib/apt,sharing=locked \
    rm -f /etc/apt/apt.conf.d/docker-clean \
    && apt-get update \
    && apt-get install -y --no-install-recommends build-essential git

# prepare build dir
WORKDIR /app

# install hex + rebar
RUN mix local.hex --force \
  && mix local.rebar --force

# set build ENV
ENV MIX_ENV="prod"

# install mix dependencies (changes only when mix.exs/mix.lock change)
COPY mix.exs mix.lock ./
COPY vendor vendor
RUN mix deps.get --only $MIX_ENV

# copy compile-time config before compiling deps
RUN mkdir config
COPY config/config.exs config/${MIX_ENV}.exs config/
RUN mix deps.compile

# install esbuild + tailwind binaries (cached until mix.exs changes)
RUN mix assets.setup

# create priv dir so :code.priv_dir works at compile time
# (actual contents copied after compile to avoid cache busting)
RUN mkdir -p priv/models priv/static

# copy application code and compile
COPY lib lib
COPY algo.md algo.md
# agent-skills markdown is read at compile time by AgentSkillsController
# (sha256 digests are baked into the module attribute)
COPY priv/agent-skills priv/agent-skills
RUN mix compile

# copy assets and build (JS/CSS changes don't require recompilation)
COPY assets assets
RUN mix assets.deploy

# copy priv contents (migrations, ML model, static files)
# after compile so model retraining doesn't bust the compile cache
COPY priv priv

# runtime config doesn't require recompilation
COPY config/runtime.exs config/

COPY rel rel
RUN mix release

# ---- Final runtime stage ----
FROM ${RUNNER_IMAGE} AS final

# Build timestamp baked in by CI (--build-arg BUILD_TIMESTAMP=...).
# Only consumed in this final stage, so it never busts the earlier
# compile cache. Read at runtime by Microwaveprop.Application.build_timestamp/0.
ARG BUILD_TIMESTAMP=unknown

# Runtime deps. BuildKit cache mounts keep the .deb archives and apt
# lists out of the image layer, so the CI builder's tight /var disk
# cap doesn't trip during install. cdo is split into its own RUN
# layer because its dep tree (netCDF/HDF5/ecCodes/Fortran) is ~1 GB
# and we'd rather not have a single failed cdo install invalidate the
# base-runtime layer.
RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
    --mount=type=cache,target=/var/lib/apt,sharing=locked \
    rm -f /etc/apt/apt.conf.d/docker-clean \
    && apt-get update \
    && apt-get install -y --no-install-recommends \
       libstdc++6 openssl libncurses6 locales ca-certificates snmp \
       libgfortran5 libaec0 zlib1g libpng16-16t64 libopenjp2-7

RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
    --mount=type=cache,target=/var/lib/apt,sharing=locked \
    rm -f /etc/apt/apt.conf.d/docker-clean \
    && apt-get update \
    && apt-get install -y --no-install-recommends cdo

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
ENV MIX_ENV="prod"

WORKDIR "/app"
RUN chown nobody /app

COPY --from=wgrib2-builder /usr/local/bin/wgrib2 /usr/local/bin/wgrib2
# wgrib2 links dynamically against libg2c.so from the builder stage —
# carry it across and refresh the loader cache so /usr/local/lib is
# searched at exec time.
COPY --from=wgrib2-builder /usr/local/lib/libg2c.so* /usr/local/lib/
RUN ldconfig

COPY --from=builder --chown=nobody:root /app/_build/${MIX_ENV}/rel/microwaveprop ./

RUN echo "${BUILD_TIMESTAMP}" > /app/BUILD_TIMESTAMP \
  && chown nobody /app/BUILD_TIMESTAMP

USER nobody

CMD ["/app/bin/server"]
