comment-compare-url.yaml

name: Comment GitHub diff URL
on:
  pull_request:
    branches:
      - main
    types:
      - opened

jobs:
  comment:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    timeout-minutes: 3
    if: github.actor == 'renovate[bot]'
    steps:
      - name: Comment
        uses: actions/github-script@v6
        with:
          script: |
            const pullNumber = "${{ github.event.pull_request.number }}"

            const pr = await github.rest.pulls.get({
                pull_number: pullNumber,
                owner: context.repo.owner,
                repo: context.repo.repo,
            })
            console.log(pr.data.body)

            const re = /\| .+ \| digest \| `.+` -> `.+` \|\n/
            const results = re.exec(pr.data.body)
            if (results === null) {
              console.log("The description comment does not contain \`digest\`. So skip.")
              return
            }

            /*
            Input:
              | neovim/nvim-lspconfig | digest | `62856b2` -> `95b7a69` |

            Output
              repository: neovim/nvim-lspconfig
              baseSha: 62856b2
              targetSha: 95b7a69
            */
            const matched = results[0]
            const s = matched.replaceAll(" ", "").replaceAll("`", "").replace("->", "|").split("|")
            const repository = s[1]
            const baseSha = s[3]
            const targetSha = s[4]

            const url = `https://github.com/${repository}/compare/${baseSha}...${targetSha}`
            const body = `[diff](${url})`

            await github.rest.issues.createComment({
                issue_number: pullNumber,
                owner: context.repo.owner,
                repo: context.repo.repo,
                body: body
            })