action.yml

name: Deploy PR Preview
author: Ross Williams
description: >
  Deploy a pull request preview to GitHub Pages, similar to Vercel and
  Netlify.

branding:
  icon: git-pull-request
  color: yellow

inputs:
  # Main parameters
  preview-branch:
    description: Branch on which the previews will be deployed.
    required: false
    default: gh-pages
  umbrella-dir:
    description: Name of the directory containing all previews.
    required: false
    default: pr-preview
  source-dir:
    description: >
      Directory containing files to deploy.

      Required when deploying a preview; will raise a warning if specified
      when removing a preview.
    required: false
    default: ""
  action:
    description: >
      Determines what this action will do when it is executed. Supported
      values: `deploy`, `remove`.

      If set to `deploy`, will attempt to deploy the preview and overwrite
      any existing preview in that location.

      If set to `remove`, will attempt to remove the preview in that
      location.
    required: true

  # Parameters for simulating a pull request
  pr-number:
    description: >
      The number of the PR to comment on when updating the preview
      deployment. If the initiating event is `pull_request` or
      `pull_request_target`, defaults to the number of the initiating PR.
      Required otherwise.
    required: false
    default: ${{ github.event.number }}

outputs:
  deployment-url:
    description: The URL at which the preview has been deployed
    value: ${{ steps.url.outputs.url }}

runs:
  using: composite
  steps:
    - name: Store environment variables and validate inputs
      env:
        action: ${{ inputs.action }}
        umbrella: ${{ inputs.umbrella-dir }}
        source_dir: ${{ inputs.source-dir }}
        pr: ${{ inputs.pr-number }}
        actionref: ${{ github.action_ref }}
        actionrepo: ${{ github.action_repository }}
      run: |
        if [ -z "$action" ]; then
          echo "::error::Action input is required (deploy/remove)" >&2
          exit 1
        fi

        if [ "$action" != "deploy" ] && [ "$action" != "remove" ]; then
          echo "::error::Unknown action $action" >&2
          exit 1
        fi

        if [ "$action" = "deploy" ] && [ -z "$source_dir" ]; then
          echo "::error::Source dir must be defined when deploying" >&2
          exit 1
        fi

        if [ "$action" = "remove" ] && [ -n "$source_dir" ]; then
          echo "::warning::Source dir should not be defined when removing" >&2
        fi

        if [ -z "$pr" ]; then
          echo "::error::PR number required for non-pull_request event" >&2
          exit 1
        fi

        echo "action=$action" >> "$GITHUB_ENV"

        echo "targetdir=$umbrella/pr-$pr" >> "$GITHUB_ENV"
        echo "pr=$pr" >> "$GITHUB_ENV"

        org=$(echo "$GITHUB_REPOSITORY" | cut -d "/" -f 1 | tr '[:upper:]' '[:lower:]' )
        thirdleveldomain=$(echo "$GITHUB_REPOSITORY" | cut -d "/" -f 2 | cut -d "." -f 1 | tr '[:upper:]' '[:lower:]' )

        echo "debug_org=$org" >> $GITHUB_ENV
        echo "debug_thirdleveldomain=$thirdleveldomain" >> $GITHUB_ENV

        if [ "$org" == "$thirdleveldomain" ]; then
          pagesurl="${org}.github.io"
        else
          pagesurl=$(echo "$GITHUB_REPOSITORY" | sed 's/\//.github.io\//')
        fi

        echo "pagesurl=$pagesurl" >> $GITHUB_ENV

        echo "emptydir=$(mktemp -d)" >> "$GITHUB_ENV"
        echo "datetime=$(date '+%Y-%m-%d %H:%M %Z')" >> "$GITHUB_ENV"

        echo "actionref=$actionref" >> "$GITHUB_ENV"
        echo "actionrepo=$actionrepo" >> "$GITHUB_ENV"
      shell: bash

    - name: Determine action version
      run: |
        version=$(
          "${{ github.action_path }}/lib/find-current-git-tag.sh" \
          -p $actionrepo -f $actionref
        )
        echo "action_version=$version" >> "$GITHUB_ENV"
      shell: bash

    - name: Deploy preview directory
      if: env.action == 'deploy'
      uses: JamesIves/github-pages-deploy-action@v4
      with:
        branch: ${{ inputs.preview-branch }}
        folder: ${{ inputs.source-dir }}
        target-folder: ${{ env.targetdir }}
        commit-message: Deploy preview for PR ${{ env.pr }} 🛫
        force: false

    - name: Expose deployment URL
      id: url
      run: echo "::set-output name=url::https://${{ env.pagesurl }}/${{ env.targetdir }}/"
      shell: bash

    - name: Leave a comment after deployment
      if: env.action == 'deploy' && env.deployment_status == 'success'
      uses: marocchino/sticky-pull-request-comment@v2
      with:
        header: pr-preview
        number: ${{ env.pr }}
        message: "\
          [PR Preview Action]\
          (${{ github.server_url }}/${{ env.actionrepo }})
          ${{ env.action_version }}

          :---:

          🛫 Deployed preview to
          https://${{ env.pagesurl }}/${{ env.targetdir }}/

          on branch [`${{ inputs.preview-branch }}`](\
          ${{ github.server_url }}/${{ github.repository }}\
          /tree/${{ inputs.preview-branch }})
          at ${{ env.datetime }}
          "

    - name: Remove preview directory
      if: env.action == 'remove'
      uses: JamesIves/github-pages-deploy-action@v4
      with:
        branch: ${{ inputs.preview-branch }}
        folder: ${{ env.emptydir }}
        target-folder: ${{ env.targetdir }}
        commit-message: Remove preview for PR ${{ env.pr }} 🛬
        force: false

    - name: Leave a comment after removal
      if: env.action == 'remove' && env.deployment_status == 'success'
      uses: marocchino/sticky-pull-request-comment@v2
      with:
        header: pr-preview
        number: ${{ env.pr }}
        message: "\
          [PR Preview Action]\
          (${{ github.server_url }}/${{ env.actionrepo }})
          ${{ env.action_version }}

          :---:

          🛬 Preview removed because the pull request was closed.

          ${{ env.datetime }}
          "