action.yml

---
# https://help.github.com/en/articles/metadata-syntax-for-github-actions
name: 'Git ref matrix action'
description: "GitHub Action to create a stringified build matrix for branches and tags."
author: 'cytopia'
branding:
  icon: 'code'
  color: 'red'

inputs:
  repository_default_branch:
    description: 'The default branch of this repository to fetch latest tags from. Default: master'
    required: false
    default: 'master'
  branches:
    description: 'Comma separated list of branches to create build matrix for. Default: none'
    required: false
    default: ''
  tags:
    description: 'Comma separated list of tags to create build matrix for. Default: none'
    required: false
    default: ''
  num_latest_tags:
    description: 'Number of latest tags to add to build matrix. Default: 0'
    required: false
    default: 0
  disable_refs:
    description: 'A string flag (0 or 1 or false or true) to disable refs alltogether and return an empty matrix and has_refs=false.'
    required: false
    default: 'false'

outputs:
  matrix:
    description: "(string) Stringified JSON build matrix for defined git refs. (list of strings)"
    value: ${{ steps.set-matrix.outputs.matrix }}
  has_refs:
    description: "(string) String flag ('true' or 'false') that tells if we have matrix (list not empty) refs or not (list empty)."
    value: ${{ steps.set-matrix.outputs.has_refs }}

runs:
  using: "composite"
  steps:

    - name: "[SETUP] Checkout repository's default branch"
      uses: actions/checkout@v3
      with:
        ref: ${{ inputs.repository_default_branch }}
        fetch-depth: 0
        path: .git-ref-matrix-action
      if: ${{ (!inputs.disable_refs || inputs.disable_refs == 0 || inputs.disable_refs == '0' || inputs.disable_refs == 'false') && inputs.num_latest_tags > 0 }}

    - name: "[SETUP] Build and Export Matrix"
      id: set-matrix
      shell: bash
      run: |
        if [ "${{ inputs.disable_refs }}" = "1" ] || [ "${{ inputs.disable_refs }}" = "true" ]; then
          ###
          ### Output matrix
          ###
          echo "matrix=[]"      >> $GITHUB_OUTPUT
          echo "has_refs=false" >> $GITHUB_OUTPUT
          echo "matrix=[]"
          echo "has_refs=false"
        else
          ###
          ### Convert comma separated branches and tags to newline separated
          ###
          BRANCHES="$( echo "${{ inputs.branches }}" | sed 's/,/\n/g' )"
          TAGS="$( echo "${{ inputs.tags }}" | sed 's/,/\n/g' )"

          echo "BRANCHES:"
          echo "-------------------------"
          echo "${BRANCHES}"
          echo

          echo "TAGS:"
          echo "-------------------------"
          echo "${TAGS}"
          echo

          ###
          ### Get x number of latest tags of this repository (newline separated)
          ###
          if [ "${{ inputs.num_latest_tags }}" != "0" ]; then
            LATEST_TAGS="$( cd .git-ref-matrix-action && git tag --sort=creatordate | tail -${{ inputs.num_latest_tags }} )"
            rm -r .git-ref-matrix-action
          else
            LATEST_TAGS=''
          fi

          echo "LATEST_TAGS:"
          echo "-------------------------"
          echo "${LATEST_TAGS}"
          echo

          ###
          ### All newline separated refs (and make unique in case of duplicated tags)
          ###
          REFS="$( printf "%s\n%s\n%s\n" "${BRANCHES}" "${TAGS}" "${LATEST_TAGS}" | grep -Ev '^$' || true | sort -u )"

          echo "REFS:"
          echo "-------------------------"
          echo "${REFS}"
          echo

          ###
          ### Create element double-quoted and comma separated string (has leading comma)
          ###
          JSON=''
          while IFS= read -r line; do
            if [ -n "${line}" ]; then
              JSON="${JSON},$( printf '"%s"' "${line}" )"
            fi
          done <<< "${REFS}"

          ###
          ### Remove leading comma and encapsulate in square brackets
          ###
          JSON="$( printf '[%s]' "${JSON#,}" )"

          ###
          ### Set final output for 'matrix'
          ###
          echo "matrix=${JSON}" >> $GITHUB_OUTPUT

          ###
          ### Set 'has_refs'
          ###
          if [ "${JSON}" = "[]" ]; then
            HAS_REFS="false"
          else
            HAS_REFS="true"
          fi
          echo "has_refs=${HAS_REFS}" >> $GITHUB_OUTPUT

          ###
          ### Output matrix
          ###
          echo "matrix=${JSON}"
          echo "has_refs=${HAS_REFS}"
        fi