name: Content Changes Table Comment

# **What it does**: When a PR is opened in docs-internal or docs, it adds the staging preview and live article links in a Content Directory Changes table in a comment
# **Why we have it**: To help Docs Content team members and contributors automatically have their staging/live article links added to the table
# **Who does it impact**: docs-internal/docs maintainers and contributors

on:
  workflow_dispatch:
  pull_request_target:
    types: [opened, synchronize, reopened]

jobs:
  PR-Preview-Links:
    name: Add staging/live links to PR
    runs-on: ubuntu-latest
    outputs:
      filterContentDir: ${{ steps.filter.outputs.filterContentDir }}
    steps:
      - name: Get files changed
        uses: dorny/paths-filter@eb75a1edc117d3756a18ef89958ee59f9500ba58
        id: filter
        with:
          # Base branch used to get changed files
          base: ${{ github.event.pull_request.base.ref }}

          # Enables setting an output in the format in `${FILTER_NAME}_files
          # with the names of the matching files formatted as JSON array
          list-files: json

          # Returns list of changed files matching each filter
          filters: |
            filterContentDir:
              - 'content/**/*'
  filterContentDir:
    needs: PR-Preview-Links
    if: ${{ needs.PR-Preview-Links.outputs.filterContentDir == 'true' }}
    runs-on: ubuntu-latest
    steps:
      - name: check out repo content
        uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f

      - name: Setup Node
        uses: actions/setup-node@38d90ce44d5275ad62cc48384b3d8a58c500bb5f
        with:
          node-version: 16.x
          cache: npm

      - name: Install dependencies
        run: npm ci

      - name: Get changes table
        uses: actions/github-script@2b34a689ec86a68d8ab9478298f91d5401337b7d
        id: changes
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          script: |
            const slugify = require('github-slugger').slug

            const HEROKU_APPNAME_MAX_LENGTH = 30

            const repoName = context.payload.repository.name
            const branchName = context.payload.pull_request.head.ref
            const prNumber = context.payload.number
            const stagingPrefix = getStagingPrefix(repoName, prNumber, branchName)

            const response = await github.repos.compareCommits({
              owner: context.repo.owner,
              repo: context.repo.repo,
              base: context.payload.pull_request.base.sha,
              head: context.payload.pull_request.head.sha
            })

            const files = response.data.files

            let markdownTable = '| **Source** | **Staging** | **Production** | **What Changed** |\n|:----------- |:----------- |:----------- |:----------- |\n'

            const pathPrefix = 'content/'
            const articleFiles = files.filter(({ filename }) => filename.startsWith(pathPrefix) && !filename.endsWith('/index.md'))
            for (const file of articleFiles) {
              const sourceUrl = file.blob_url
              const fileName = file.filename.slice(pathPrefix.length)
              const fileUrl = fileName.slice(0, fileName.lastIndexOf('.'))
              const stagingLink = `https://${stagingPrefix}.herokuapp.com/${fileUrl}`
              const productionLink = `https://docs.github.com/${fileUrl}`
              let markdownLine = ''

              if (file.status === 'modified') {
                markdownLine = `| [content/${fileName}](${sourceUrl}) | [Modified](${stagingLink}) | [Original](${productionLink}) | |\n`
              } else if (file.status === 'added') {
                markdownLine = `| New file: [content/${fileName}](${sourceUrl}) | [Modified](${stagingLink}) | | |\n`
              }
              markdownTable += markdownLine
            }

            function getStagingPrefix (prefix, prNumber, branch) {
              // Added a - in front of prNumber
              return `${prefix}-${prNumber}--${slugify(branch)}`
                .toLowerCase()
                .slice(0, HEROKU_APPNAME_MAX_LENGTH)
                .replace(/_/g, '-')
                .replace(/-+$/, '')
            }
            core.setOutput('changesTable', markdownTable)

      - name: Find content directory changes comment
        uses: peter-evans/find-comment@0da1f4fc1f20cd898368bd56089d391df418f52f
        id: findComment
        with:
          issue-number: ${{ github.event.pull_request.number }}
          comment-author: 'github-actions[bot]'
          body-includes: '<!-- MODIFIED_CONTENT_LINKING_COMMENT -->'

      - name: Update comment
        uses: peter-evans/create-or-update-comment@5221bf4aa615e5c6e95bb142f9673a9c791be2cd
        with:
          comment-id: ${{ steps.findComment.outputs.comment-id }}
          issue-number: ${{ github.event.pull_request.number }}
          body: |
            <!-- MODIFIED_CONTENT_LINKING_COMMENT -->
            ## Automatically generated comment ℹ️ 
            **This comment is automatically generated and will be overwritten every time changes are committed to this branch.**

            The table contains an overview of files in the `content` directory that have been changed in this pull request. It's provided to make it easy to review your changes on the staging site. Please note that changes to the `data` directory will not show up in this table.

            ---

            ### Content directory changes
            _You may find it useful to copy this table into the pull request summary. There you can edit it to share links to important articles or changes and to give a high-level overview of how the changes in your pull request support the overall goals of the pull request._
            ${{ steps.changes.outputs.changesTable }}
          edit-mode: replace