local Cache(name, settings) = {
  name: name,
  image: "meltwater/drone-cache",
  pull: true,
  settings: {
    backend: "filesystem",
    cache_key: "{{ .Repo.Name }}",
    archive_format: "gzip",
    mount: [
      "/nix/store"
    ]
  } + settings,
  volumes: [
    {
      name: "cache",
      path: "/tmp/cache"
    }
  ]
};

local Pipeline(channel) = {
  kind: "pipeline",
  type: "docker",
  name: channel,
  // This is ignored by the drone-cli YAML translator, so unfortunately, it has
  // to be copy-pasted into relevant steps.
  environment: {
    NIXPKGS_ALLOW_UNFREE: 1,
    NUR_REPO: "xeals",
    CACHIX_CACHE: "xeals",
    CACHIX_SIGNING_KEY: { from_secret: "cachix_key" },
  },
  volumes: [
    {
      name: "cache",
      temp: {}
    }
  ],
  steps: [
    Cache("restore-nix-store", {
      restore: true
    }),
    {
      name: "build",
      image: "nixos/nix",
      commands: [
        "nix-channel --add https://nixos.org/channels/" + channel + " nixos",
        "nix-channel --update",
        "nix-build ci.nix -A buildOutputs",
        "nix eval -f default.nix 'lib'",
        "nix eval -f default.nix 'modules'",
        "nix eval -f default.nix 'overlays'"
      ],
      environment: {
        NIXPKGS_ALLOW_UNFREE: 1
      }
    },
    {
      name: "deploy",
      image: "nixpkgs/cachix",
      commands: [
        'nix-build ci.nix -A cacheOutputs | cachix push "${CACHIX_CACHE}"'//,
        // 'if [[ "cron" != "${DRONE_BUILD_EVENT}" && -z "${DRONE_PULL_REQUEST}" && "master" = "${DRONE_BRANCH}" ]]; then
        //   curl -XPOST "https://nur-update.herokuapp.com/update?repo=${NUR_REPO}"; fi'
      ],
      environment: {
        NIXPKGS_ALLOW_UNFREE: 1,
        NUR_REPO: "xeals",
        CACHIX_CACHE: "xeals",
        CACHIX_SIGNING_KEY: { from_secret: "cachix_key" },
      },
    },
    Cache("save-nix-store", {
      rebuild: true
    }) + {
      when: { status: [ "success", "failure" ] }
    },
  ]
};

[
  Pipeline("nixpkgs-unstable"),
  Pipeline("nixos-unstable"),
  Pipeline("nixos-20.03"),
]