name: Checkout

inputs:
    fetch-depth:
        default: 1
        required: false
        type: number
    path:
        required: false
        type: string
    repository:
        default: ${{ github.repository }}
        required: false
        type: string
    ref:
        required: false
        type: string
    alternate_repository:
        required: false
        type: string
    alternate_ref:
        required: false
        type: string
    token:
        default: ${{ github.token }}
        required: false
        type: string

outputs:
    ref_exists:
        description: 'Specifies whether the ref exists or not'
        value: ${{ steps.repo.outputs.ref-exists }}

runs:
    using: composite

    steps:
        - id: repo
          shell: bash
          env:
              GH_TOKEN: ${{ inputs.token }}
          run: |
              if git ls-remote --heads --quiet --exit-code https://${{ inputs.token }}@github.com/${{ inputs.repository }}.git ${{ inputs.ref }}
              then
                echo "::notice::Checkout: ${{ inputs.repository }} using ${{ inputs.ref }}"
                echo "ref-exists=true" >> $GITHUB_OUTPUT
              else
                echo "::notice::Checkout: ${{ inputs.repository }} does not have ref ${{ inputs.ref }} (fallback to ${{ inputs.alternate_ref }})"
                echo "ref-exists=false" >> $GITHUB_OUTPUT
              fi

        - if: steps.repo.outputs.ref-exists == 'true'
          uses: actions/checkout@a12a3943b4bdde767164f792f33f40b04645d846
          with:
              fetch-depth: ${{ inputs.fetch-depth }}
              path: ${{ inputs.path }}
              repository: ${{ inputs.repository }}
              ref: ${{ inputs.ref }}
              token: ${{ inputs.token }}

        - if: steps.repo.outputs.ref-exists == 'false'
          uses: actions/checkout@a12a3943b4bdde767164f792f33f40b04645d846
          with:
              fetch-depth: ${{ inputs.fetch-depth }}
              path: ${{ inputs.path }}
              repository: ${{ inputs.alternate_repository }}
              ref: ${{ inputs.alternate_ref }}
              token: ${{ inputs.token }}