# One job, because the flake is the build.
#
# This used to be a kaniko pipeline whose only purpose was to publish the
# container image buck2's remote executor pulled; nothing about it ran the
# build. `nix flake check` runs fmt, clippy, the test suite and all three
# shared objects, and it pins what it runs with.
#
# The publish step is in the same job for the same reason: a second job would
# get a cold nix store and rebuild everything it was about to upload. The
# branch check is a shell `if` rather than a second job's `rules:` because
# there is nothing to gate but the last two commands.
stages: [check]

check:
  stage: check
  image: nixos/nix:latest
  # A cold run has to vendor ~800 crates and compile the workspace; the default
  # hour is not enough for that even with the builder doing the compiling.
  timeout: 3h
  variables:
    # The flake is fetched from the checkout, so the runner needs the git tree
    # rather than a shallow single commit.
    GIT_DEPTH: "0"
  before_script:
    # Compilation is offloaded to nixbuild.net; the runner evaluates, fetches
    # and uploads. max-jobs must not be zero: at zero the runner refuses to
    # build anything at all, which sends the fixed-output fetches (the rust
    # toolchain tarballs, every crate source) to nixbuild, where the build
    # sandbox has no network and they can only fail. Giving it nproc keeps
    # those fetches and crane's hundreds of trivial cargo-src/cargo-package
    # derivations local and parallel -- each one costs a serial ~1.5s ssh
    # round trip if dispatched -- while the expensive builds still go remote.
    #
    # nixbuild doubles as a substituter, which is what makes a warm pipeline
    # cheap: it already holds every vendor path from previous runs, and fetching
    # one measures ~0.55s against ~1.5s to dispatch it as a build. Its paths are
    # signed, but the key is per-account and only readable from the web UI, so
    # rather than carry it as a second secret we lean on the transport -- the
    # store is reached over SSH authenticated with our own key. cache.nixos.org
    # is verified by its own key either way; require-sigs only relaxes nixbuild.
    # The explicit priority matters: nix picks a substituter by priority rather
    # than by the order listed here, and an ssh-ng store defaults to 0 against
    # cache.nixos.org's 40, so without it nixbuild wins even for stock nixpkgs
    # paths and they crawl through one SSH connection instead of the CDN.
    #
    # Keep the builder's job count modest. nixbuild's sshd caps concurrent
    # sessions and refuses the excess, which nix surfaces as the thoroughly
    # misleading "Nix daemon disconnected unexpectedly (maybe it crashed?)".
    - |
      set -eu
      mkdir -p ~/.ssh
      # base64 because GitLab can only mask a single-line variable.
      printf '%s' "$NIXBUILD_SSH_KEY" | base64 -d > ~/.ssh/nixbuild
      chmod 600 ~/.ssh/nixbuild
      printf 'Host eu.nixbuild.net\n PubkeyAcceptedKeyTypes ssh-ed25519\n IdentityFile ~/.ssh/nixbuild\n IdentitiesOnly yes\n' > ~/.ssh/config
      printf 'eu.nixbuild.net ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPIQCZc54poJ8vqawd8TraNryQeJnvH1eLpIDgbiqymM\n' > ~/.ssh/known_hosts
      printf '%s\n' \
        'experimental-features = nix-command flakes' \
        'builders = ssh-ng://eu.nixbuild.net x86_64-linux - 16 1 big-parallel,benchmark' \
        'builders-use-substitutes = true' \
        'substituters = https://cache.nixos.org ssh-ng://eu.nixbuild.net?priority=50' \
        'require-sigs = false' \
        "max-jobs = $(nproc)" >> /etc/nix/nix.conf
  script:
    - nix flake check -L
    # The store paths are read-only symlink farms; the runner uploads plain
    # files, so dereference them into a tree it can zip.
    - nix build -L --no-link --print-out-paths .#libs .#android > /tmp/outs
    - mkdir -p artifacts && xargs -a /tmp/outs -I{} cp -rL {}/. artifacts/
    # Tarballs rooted at lib/ and include/, so a consumer's `flake = false`
    # input resolves to ${input}/lib/libjoltmoq.so with nothing in between.
    # One per target: the desktop objects carry a RUNPATH into the builder's
    # /nix/store and are only usable from nix, the Android ones link nothing
    # but the NDK sysroot and are what an APK actually packages.
    - |
      set -eu
      if [ "$CI_COMMIT_BRANCH" = "$CI_DEFAULT_BRANCH" ]; then
        tar czf x86_64-linux.tar.gz -C artifacts include lib/libvidya.so lib/libjolttui.so lib/libjoltmoq.so
        tar czf android-arm64-v8a.tar.gz -C artifacts include lib/arm64-v8a
        # Twice: once under the commit, which is what a consumer pins and what
        # never moves, and once under "latest", which is the URL a consumer's
        # `flake = false` input names so that `nix flake update` can find a new
        # build without anyone editing a digest. The lock file still pins the
        # bytes -- "latest" decides what an update *finds*, not what it builds.
        #
        # Uploading the same version and filename again does not replace the
        # old file, it adds a second one and downloads serve the newest, so the
        # "latest" package grows by one set of tarballs per pipeline. A project
        # cleanup policy is what keeps that bounded.
        api="$CI_API_V4_URL/projects/$CI_PROJECT_ID/packages/generic/jolt-native"
        nix shell nixpkgs#curl -c sh -eu -c '
          for v in "$2" latest; do
            for f in x86_64-linux.tar.gz android-arm64-v8a.tar.gz; do
              curl --fail-with-body --header "JOB-TOKEN: $CI_JOB_TOKEN" \
                --upload-file "$f" "$1/$v/$f"
            done
          done
        ' sh "$api" "$CI_COMMIT_SHA"
      fi
  artifacts:
    name: "jolt-native-$CI_COMMIT_SHORT_SHA"
    paths: [artifacts/]
    expire_in: 1 week
  rules:
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH