name: Deploy

# Define when the workflow should run
on:
  # Allow manual triggering of the workflow from the Actions tab
  workflow_dispatch:

  # Allow inputs to be passed when manually triggering the workflow from the Actions tab
    inputs:
      DOCKERFILE_PATH:
        type: string
        description: 'Absolute path to the Dockerfile.'
        required: true
        default: 'dockerfiles/debian_mini'

      IMAGE_SIZE:
        type: string
        description: 'Image size, 950M max.'
        required: true
        default: '600M'

      LOGIN_UGID:
          type: string
          description: 'UID:GID of the starting process.'
          required: true
          default: "1000:1000"

      DEPLOY_TO_GITHUB_PAGES:
        type: boolean
        description: 'Deploy to Github pages.'
        required: true
        default: true

      GITHUB_RELEASE:
        type: boolean
        description: 'Upload GitHub release.'
        required: true
        default: false

      GITHUB_RELEASE_TAG:
        type: string
        description: 'Tag for the github release.'
        required: true
        default: "ext2_image"

jobs:

  build:
    runs-on: ubuntu-latest # Image to run the worker on.

    env:
      TAG: "ext2-webvm-base-image" # Tag of docker image.
      IMAGE_SIZE: '${{ github.event.inputs.IMAGE_SIZE }}'
      DEPLOY_DIR: /webvm_deploy/ # Path to directory where we host the final image from.

    permissions: # Permissions to grant the GITHUB_TOKEN.
      contents: write  # Required permission to make a github release.
      actions: 'write' # Required for the Dockerfile path guard clause.

    steps:
      # Checks-out our repository under $GITHUB_WORKSPACE, so our job can access it
      - uses: actions/checkout@v3
      # Guard clause that cancels the workflow in case of an invalid DOCKERFILE_PATH. 
      # The main reason for choosing this workaround for aborting the workflow is the fact that it does not display the workflow as successful, which can set false expectations.
      - name: DOCKERFILE_PATH guard clause
        shell: bash 
        run: |
          if [ ! -f ${{ github.event.inputs.DOCKERFILE_PATH }} ]; then
              echo "::error title=Invalid Dockerfile path::No file found at ${{ github.event.inputs.DOCKERFILE_PATH }}"
              gh run cancel ${{ github.run_id }}
              gh run watch ${{ github.run_id }}
          fi
        env:
          GH_TOKEN: ${{ github.token }} # As required by the GitHub-CLI

      # Setting the IMAGE_NAME variable in GITHUB_ENV to <Dockerfile name>_<date>_<run_id>.ext2.
      - name: Generate the image_name.
        id: image_name_gen
        run: |
          echo "IMAGE_NAME=$(basename ${{ github.event.inputs.DOCKERFILE_PATH }})_$(date +%Y%m%d)_${{ github.run_id }}.ext2" >> $GITHUB_ENV

      # We extract the uid and gid from the uid:gid input.
      - run: |
          echo "LOGIN_UID=$(echo ${{ github.event.inputs.LOGIN_UGID }} | cut -d ':' -f1)" >> $GITHUB_ENV
          echo "LOGIN_GID=$(echo ${{ github.event.inputs.LOGIN_UGID }} | cut -d ':' -f2)" >> $GITHUB_ENV

      # Create directory to host the image from.
      - run: sudo mkdir -p $DEPLOY_DIR

      # Build the i386 Dockerfile image.
      - run: docker build . --tag $TAG --file ${{ github.event.inputs.DOCKERFILE_PATH }} --platform=i386
      
      # Run the docker image so that we can export the container.
      # Run the Docker container with the Google Public DNS nameservers: 8.8.8.8, 8.8.4.4
      - run: docker run --dns 8.8.8.8 --dns 8.8.4.4 -d $TAG

      # We create and mount the base ext2 image to extract the Docker container's filesystem its contents into.
      - name: Create ext2 image.
        run: |
         # Preallocate space for the ext2 image
         sudo fallocate -l $IMAGE_SIZE ${IMAGE_NAME}
         # Format to ext2 linux kernel revision 0
         sudo mkfs.ext2 -r 0 ${IMAGE_NAME}
         # Mount the ext2 image to modify it
         sudo mount -o loop -t ext2 ${IMAGE_NAME} /mnt/

      # We opt for 'docker cp --archive' over 'docker save' since our focus is solely on the end product rather than individual layers and metadata.
      # However, it's important to note that despite being specified in the documentation, the '--archive' flag does not currently preserve uid/gid information when copying files from the container to the host machine.
      # Another compelling reason to use 'docker cp' is that it preserves resolv.conf.
      - name: Export and unpack container filesystem contents into mounted ext2 image.
        run: | 
          sudo docker cp -a $(sudo docker ps -aq):/ /mnt/
          sudo umount /mnt/
      # Result is an ext2 image for webvm.

      # Move required files for gh-pages deployment to the deployment directory $DEPLOY_DIR.
      - run: sudo mv assets examples xterm favicon.ico index.html login.html network.js scrollbar.css serviceWorker.js tower.ico $DEPLOY_DIR
      
      # The .txt suffix enabled HTTP compression for free
      - name: Generate image split chunks and .meta file
        run: |
          sudo split ${{ env.IMAGE_NAME }} ${{ env.DEPLOY_DIR }}/${{ env.IMAGE_NAME }}.c -a 6 -b 128k -x --additional-suffix=.txt
          sudo bash -c "stat -c%s ${{ env.IMAGE_NAME }} > ${{ env.DEPLOY_DIR }}/${{ env.IMAGE_NAME }}.meta"
      # This step updates the default index.html file by performing the following actions:
      #   1. Replaces all occurrences of UID and GID with their respective input parameters.
      #   2. Replaces all occurrences of IMAGE_URL with the URL to the image.
      #   3. Replaces all occurrences of DEVICE_TYPE to bytes.
      - name: Adjust index.html
        run: |
          sudo sed -i 's#UID#"${{ env.LOGIN_UID }}"#g' ${{ env.DEPLOY_DIR }}index.html
          sudo sed -i 's#GID#"${{ env.LOGIN_GID }}"#g' ${{ env.DEPLOY_DIR }}index.html
          sudo sed -i 's#IMAGE_URL#"${{ env.IMAGE_NAME }}"#g' ${{ env.DEPLOY_DIR }}index.html
          sudo sed -i 's#DEVICE_TYPE#"split"#g' ${{ env.DEPLOY_DIR }}index.html

      # We generate index.list files for our httpfs to function properly.
      - name: make index.list
        shell: bash
        run: |
          find $DEPLOY_DIR -type d | while read -r dir;
          do
            index_list="$dir/index.list";
            sudo rm -f "$index_list";
            sudo ls "$dir" | sudo tee "$index_list" > /dev/null;
            sudo chmod +rw "$index_list";     
            sudo echo "created $index_list"; 
          done

      # Create a gh-pages artifact in order to deploy to gh-pages.
      - name: Upload GitHub Pages artifact
        uses: actions/upload-pages-artifact@v1.0.7
        with:
          # Path of the directory containing the static assets for our gh pages deployment.
          path: ${{ env.DEPLOY_DIR }} # optional, default is _site/

      - name: github release # To upload our final ext2 image as a github release.
        if: ${{ github.event.inputs.GITHUB_RELEASE == 'true' }}
        uses: softprops/action-gh-release@v0.1.15
        with:
          target_commitish: ${{ github.sha }} # Last commit on the GITHUB_REF branch or tag
          tag_name: ${{ github.event.inputs.GITHUB_RELEASE_TAG }} # Tag of the release.
          fail_on_unmatched_files: 'true' # Fail in case of no matches with the file(s) glob(s).
          files: | # Assets to upload as release.
            ${{ env.IMAGE_NAME }}

  deploy_to_github_pages: # Job that deploys the github-pages artifact to github-pages.
    if: ${{ github.event.inputs.DEPLOY_TO_GITHUB_PAGES == 'true' }}
    needs: build
    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}

    # Grant GITHUB_TOKEN the permissions required to make a Pages deployment
    permissions:
      pages: write      # to deploy to Pages
      id-token: write   # to verify the deployment originates from an appropriate source

    runs-on: ubuntu-latest
    steps:
      # Deployment to github pages
      - name: Deploy GitHub Pages site
        id: deployment
        uses: actions/deploy-pages@v2.0.0