name: 'doxygen-generation'
description: 'Generate doxygen documentation and push to gh-pages branch'
inputs:
  ref:
    description: 'Reference (e.g. branch or tag) to the commit for generating doxygen'
    required: false
    default: 'main'
  add_release:
    description: 'Add ref to releases listed in the index page.'
    required: false
    default: "false"
  generate_command:
    description: 'Command to generate doxygen bundle.'
    required: false
    default: |
        doxygen docs/doxygen/config.doxyfile 2>&1 | tee doxyoutput.txt
        if [ "$(wc -c < doxyoutput.txt | bc)" = "0" ]; then exit 0; else exit 1; fi
  output_dir:
    description: 'Relative output directory of generate_command.'
    required: false
    default: docs/doxygen/output/html
  doxygen_link:
    description: 'Download link for doxygen tar.gz (default version 1.9.6).'
    required: false
    default: "https://sourceforge.net/projects/doxygen/files/rel-1.9.6/doxygen-1.9.6.linux.bin.tar.gz"
  doxygen_dependencies:
    description: 'Space-separated dependencies for doxygen.'
    required: false
    default: libclang-11-dev libclang-cpp11 graphviz

runs:
  using: "composite"
  steps:
    - name: Checkout the repo for generating doxygen
      uses: actions/checkout@v2
      with:
        path: doxygen_source
        ref: ${{ inputs.ref }}

    - name: Install Doxygen
      shell: bash
      run: |
        wget -O doxygen.tgz "${{ inputs.doxygen_link }}" 
        if [ $? -ne 0 ]; then exit 1; fi
        sudo tar --strip-components=1 -xzf doxygen.tgz -C /usr/local
        sudo apt-get install -y ${{ inputs.doxygen_dependencies }}

    - name: Generate doxygen
      working-directory: ./doxygen_source
      shell: bash
      run: ${{ inputs.generate_command }}

    - name: Checkout the repo for storing doxygen
      uses: actions/checkout@v2
      with:
        path: doxygen_store

    - name: Switch to gh-pages branch
      working-directory: ./doxygen_store
      shell: bash
      run: |
        # Check if the gh-pages branch exists. If not, create it.
        branch_exist=$(git ls-remote --heads origin gh-pages)
        if [ -z ${branch_exist} ]; then
          git config --global user.name ${{ github.actor }}
          git config --global user.email ${{ github.actor }}@users.noreply.github.com
          git checkout --orphan gh-pages
          git reset --hard
          git commit --allow-empty -m "Created gh-pages branch"
          git push origin gh-pages
        fi
        # Switch to gh-pages branch
        git fetch
        git checkout gh-pages

    - name: Replace previous doxygen documentation
      shell: bash
      run: |
        rm -rf doxygen_store/${{ inputs.ref }}
        mv doxygen_source/${{ inputs.output_dir }} doxygen_store/${{ inputs.ref }}

    - name: Update template files
      working-directory: ./doxygen_store/
      shell: bash
      run: |
        cp -r $GITHUB_ACTION_PATH/template/* .

    - name: Ensure fields of doc_config.json exist
      working-directory: ./doxygen_store/
      shell: bash
      run: |
        sudo apt-get install -y jq
        if [ ! -d "_data" ]; then
          mkdir _data
          echo "{}" > _data/doc_config.json
        fi
        doc_title=$(echo '${{ github.repository }}' | awk -F '/' '{print $2}')
        jq '.name//="'$doc_title'"' _data/doc_config.json |
        jq '.releases//=[]' |
        jq '.branches//=["main"]' > tmp.json
        mv tmp.json _data/doc_config.json

    - name: Add to release list and update latest
      if: inputs.add_release != 'false'
      working-directory: ./doxygen_store/
      shell: bash
      run: |
        jq '.releases|=if index("${{ inputs.ref }}") then . else ["${{ inputs.ref }}"]+. end' _data/doc_config.json > tmp.json
        mv tmp.json _data/doc_config.json
        rm -f latest
        ln -s "${{ inputs.ref }}" latest

    - name: Commit new doxygen
      working-directory: ./doxygen_store
      shell: bash
      run: |
        git config --global user.name ${{ github.actor }}
        git config --global user.email ${{ github.actor }}@users.noreply.github.com
        commit_id=$(git rev-parse ${{ inputs.ref }})
        git add .
        # Only commit if doxygen is changed.
        changed=$(git diff-index HEAD)
        if [ -n "$changed" ]; then
          git commit -m "Doxygen for ${commit_id}"
          git push origin gh-pages
        fi