# Copyright 2019 PrivateStorage.io, LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

version: 2

aliases:
  - &PREPARE_VIRTUALENV
    run:
      name: "Prepare virtualenv"
      command: |
        virtualenv venv
        . venv/bin/activate
        pip install --upgrade certifi pip
        pip install ${PIP_REQUIREMENTS}

jobs:
  documentation:
    docker:
      - image: "circleci/python:3.7"

    environment:
      PIP_REQUIREMENTS: "-r docs/requirements.txt"

    steps:
      - "checkout"

      - <<: *PREPARE_VIRTUALENV

      - run:
          name: "Sphinx Documentation Build"
          command: |
            . venv/bin/activate
            sphinx-build docs/source docs/build

      - store_artifacts:
          path: "docs/build"
          destination: "docs"

  tests:
    docker:
      # Run in a highly Nix-capable environment.
      - image: "nixorg/nix:circleci"

    environment:
      # Specify a revision of NixOS/nixpkgs to run against.  This essentially
      # pins the majority of the software involved in the build.  This
      # revision is selected arbitrarily.  It's somewhat current as of the
      # time of this comment.  We can bump it to a newer version when that
      # makes sense.  Meanwhile, the platform won't shift around beneath us
      # unexpectedly.
      NIXPKGS_REV: "8bf142e001b6876b021c8ee90c2c7cec385fe8e9"

    steps:
      - run:
          # Get NIX_PATH set for the rest of the job so that the revision of
          # nixpkgs we selected will be used everywhere Nix pulls in software.
          # There is no way to set an environment variable containing the
          # value of another environment variable on CircleCI except to use
          # the `BASE_ENV` feature as we do here.
          name: "Setup NIX_PATH Environment Variable"
          command: |
            echo "export NIX_PATH=nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/$NIXPKGS_REV.tar.gz" >> $BASH_ENV

      - "checkout"

      - "run":
          # CircleCI won't let us interpolate NIXPKGS_REV into a cache key.
          # Only CircleCI's own environment variables or variables set via the
          # web interface in a "context" can be interpolated into cache keys.
          # However, we can interpolate the checksum of a file...  Since we
          # don't care about the exact revision, we just care that a new
          # revision gives us a new string, we can write the revision to a
          # file and then put the checksum of that file into the cache key.
          # This way, we don't have to maintain the nixpkgs revision in two
          # places and risk having them desynchronize.
          name: "Prepare For Cache Key"
          command: |
            echo "${NIXPKGS_REV}" > nixpkgs.rev

      - restore_cache:
          # Get all of Nix's state relating to the particular revision of
          # nixpkgs we're using.  It will always be the same.  CircleCI
          # artifacts and nixpkgs store objects are probably mostly hosted in
          # the same place (S3) so there's not a lot of difference for
          # anything that's pre-built.  For anything we end up building
          # ourselves, though, this saves us all of the build time (less the
          # download time).
          #
          # Read about caching dependencies: https://circleci.com/docs/2.0/caching/
          name: "Restore Nix Store Paths"
          keys:
            # Construct cache keys that allow sharing as long as nixpkgs
            # revision is unchanged.
            #
            # If nixpkgs changes then potentially a lot of cached packages for
            # the base system will be invalidated so we may as well drop them
            # and make a new cache with the new packages.
            - zkapauthorizer-nix-store-v4-{{ checksum "nixpkgs.rev" }}
            - zkapauthorizer-nix-store-v4-

      - run:
          name: "Run Test Suite"
          command: |
            # Building the package has, as a side effect, running the test
            # suite.  If the test suite fails, so does the build.
            #
            # Pass in a couple args here to control how the test suite is run
            # - configure Hypothesis so it can behave appropriately in a CI
            # environment (where resources are scarce, competetion with other
            # tenants is high, etc) and collect coverage information.
            #
            # Further, we want the "doc" output built as well because that's
            # where the coverage data ends up.
            #
            # Also limit the number of concurrent jobs because of resource
            # constraints on CircleCI. :/
            nix-build --cores 1 --max-jobs 1 --argstr hypothesisProfile ci --arg collectCoverage true --attr doc

      - run:
          name: "Cache codecov"
          command: |
            # Build codecov and any dependencies here, before we save the
            # cache, so that they make it in to the cache too.  Turns out
            # there is a python-cryptography dependency here that is expensive
            # to build that doesn't get built earlier.  This saves us a couple
            # minutes.
            nix-build --expr '(import <nixpkgs> { }).python.withPackages (ps: [ ps.codecov ])'

      - save_cache:
          name: "Cache Nix Store Paths"
          key: zkapauthorizer-nix-store-v4-{{ checksum "nixpkgs.rev" }}
          paths:
            - "/nix"

      - run:
          name: "Report Coverage"
          shell: "nix-shell -p 'python.withPackages (ps: [ ps.codecov ])'"
          command: |
            cp ./result-doc/share/doc/*/.coverage ./
            python -m coverage combine
            python -m coverage report
            codecov --file .coverage'

workflows:
  version: 2
  everything:
    jobs:
      - "documentation"
      - "tests"
