name: CI

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

jobs:
  format:
    name: Check Formatting
    runs-on: ubuntu-16.04
    steps:
      - uses: actions/checkout@v2

      - name: Set up Elixir
        uses: erlef/setup-elixir@v1
        with:
          otp-version: 22.2
          elixir-version: 1.10.4

      - name: Install dependencies
        run: mix deps.get

      - name: Run "mix format"
        run: mix format --check-formatted

  test:
    name: Build and test
    runs-on: ubuntu-16.04
    strategy:
      fail-fast: false
      matrix:
        pair:
          - erlang: 23.1
            elixir: 1.11.1
          - erlang: 22.2
            elixir: 1.11.1
          - erlang: 21.3
            elixir: 1.11.1
          - erlang: 22.2
            elixir: 1.10.4
          - erlang: 20.3.1
            elixir: 1.9.4
    env:
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    steps:
      - uses: actions/checkout@v2

      - name: Set up Elixir
        uses: erlef/setup-elixir@v1
        with:
          otp-version: ${{matrix.pair.erlang}}
          elixir-version: ${{matrix.pair.elixir}}

      - name: Install dependencies
        run: |
          mix local.hex --force
          mix local.rebar --force
          mix deps.get

      - name: Run tests
        run: MIX_ENV=test mix coveralls.github

      - name: Retrieve PLT Cache
        uses: actions/cache@v1
        id: plt-cache
        with:
          path: priv/plts
          key: ${{ runner.os }}-${{ matrix.pair.erlang }}-${{ matrix.pair.elixir }}-plts-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.lock')) }}

      - name: Create PLTs
        if: steps.plt-cache.outputs.cache-hit != 'true'
        run: |
          mkdir -p priv/plts
          mix dialyzer --plt

      - name: Run dialyzer
        run: mix dialyzer --no-check