name: 'Cache APT Packages'
description: 'Install APT based packages and cache them for future runs.'
author: awalsh128
branding:
  icon: 'hard-drive'  
  color: 'green'

inputs:
  packages:
    description: 'Space delimited list of packages to install.'
    required: true
    default: ''
  version:
    description: 'Version will create a new cache and install packages.'
    required: false
    default: ''

outputs:
  cache-hit:
    description: 'A boolean value to indicate a cache was found for the packages requested.'
    # This compound expression is needed because lhs can be empty.
    # Need to output true and false instead of true and nothing.
    value: ${{ steps.load-cache.outputs.cache-hit || false }}

runs:
  using: "composite"
  steps:
    - name: Validate Packages
      run: ${{ github.action_path }}/validate_pkgs.sh ${{ inputs.packages }}
      shell: bash

    - name: Create Cache Key
      run: |
        normalized_list=$(${{ inputs.packages }} | sed 's/[\s,]+/ /g' | sort)
        value=$(echo $normalized_list @ ${{ inputs.version }})
        echo "CACHE_KEY=$(echo value | md5sum | /bin/cut -f1 -d' ')" >> $GITHUB_ENV
      shell: bash

    - name: Load Package Cache
      id: load-cache
      uses: actions/cache@v2
      with:
        path: ~/cache-apt-pkgs
        key: cache-apt-pkgs_${{ env.CACHE_KEY }}

    - name: Load Packages      
      run: |
        if [ ${{ steps.load-cache.outputs.cache-hit }} ]; then
          ${{ github.action_path }}/restore_pkgs.sh ~/cache-apt-pkgs /
        else
          ${{ github.action_path }}/install_and_cache_pkgs.sh ~/cache-apt-pkgs ${{ inputs.packages }}
        fi
      shell: bash