create-docs-pr.yml

#                    Commits                                        0 Open PRs                                                                     1 Open PR                                                                       2 Open PRs                         
#  ------------------------------------------- ---------------------------------------------------- ------------------------------------------------------------------------------------------------------- --------------------------------------------------------- 
#   Neither ahead or behind                     Nothing                                              Dismiss PRs                                                                                             Dismiss PRs                                              
#   `documentation-gitbook` is behind           Open A PR from `main` into `documentation-gitbook`   Determine the directionality, if wrong dismiss and open a PR from `main` into `documentation-gitbook`   Dismiss the PR from `documentation-gitbook` into `main`  
#   `documentation-gitbook` is behind           Open A PR from `documentation-gitbook` into `main`   Determine the directionality, if wrong dismiss and open a PR from `documentation-gitbook` into `main`   Dismiss the PR from `main` into `documentation-gitbook`  
#   `documentation-gitbook` is ahead & behind   Open 2 PRs                                           Determine the directionality of the missing one and open that                                           Nothing                                                  

name: create-docs-pr

on:
  workflow_dispatch:
  schedule:
    - cron: '1 10 * * 1-5'

jobs:
  create-pr:
    runs-on: ubuntu-latest
    env:
      DOCS_BRANCH: documentation-gitbook
      PR_LABELS: 'documentation,high priority'
      PR_ASSIGNEES: 'emprzy,jcblemai,pearsonca,saraloo,TimothyWillard'
      PR_TITLE: 'Sync GitBook'
      OWNER: 'HopkinsIDD'
      REPO: 'flepiMoP'
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          lfs: true
          fetch-depth: 0
      - name: Determine Commits Ahead/Behind
        run: |
          git fetch --all
          DOCS_AHEAD_MAIN=$( eval "git rev-list --count origin/main..origin/$DOCS_BRANCH -- documentation/" )
          DOCS_BEHIND_MAIN=$( eval "git rev-list --count origin/$DOCS_BRANCH..origin/main -- documentation/" )
          echo "DOCS_AHEAD_MAIN=$DOCS_AHEAD_MAIN" >> $GITHUB_ENV
          echo "DOCS_BEHIND_MAIN=$DOCS_BEHIND_MAIN" >> $GITHUB_ENV
      - name: Create PR If Needed
        uses: actions/github-script@v7
        id: create-pr
        with:
          result-encoding: string
          retries: 5
          script: |
            const { DOCS_AHEAD_MAIN, DOCS_BEHIND_MAIN, DOCS_BRANCH, PR_LABELS, PR_ASSIGNEES, PR_TITLE, OWNER, REPO } = process.env
            const prLabels = PR_LABELS.split(",")
            const prAssignees = PR_ASSIGNEES.split(",")
            const cc = prAssignees.map(x => "@" + x).join(", ")
            const docsAheadMain = parseInt(DOCS_AHEAD_MAIN, 10)
            const docsBehindMain = parseInt(DOCS_BEHIND_MAIN, 10)
            if (isNaN(docsAheadMain) || isNaN(docsBehindMain)) {
              throw new Error(`Cannot convert either "${DOCS_AHEAD_MAIN}" or "${DOCS_BEHIND_MAIN}" to integers.`)
            }
            const initialResults = await github.rest.search.issuesAndPullRequests({ 
              q: `owner:${OWNER} repo:${REPO} is:open is:pr in:title '${PR_TITLE}'`
            })
            const count = initialResults.data.total_count
            if (count > 2) {
              throw new Error(`There are ${count} open PRs containing '${PR_TITLE}', but this action can only handle 0, 1, or 2 open PRs.`)
            }
            console.log(`${DOCS_BRANCH} is ${docsAheadMain} ahead, ${docsBehindMain} behind main. The open PR count is ${count}.`)
            async function dismissAllPRs() {
              initialResults.data.items.forEach((item) => {
                github.rest.pulls.update({
                  owner: OWNER,
                  repo: REPO,
                  pull_number: item.number,
                  state: "closed"
                })
              })
            }
            async function createPR({ from, to, body }) {
              let prBody = `cc: ${cc}.`
              if (body !== null) {
                prBody = `${body} ${prBody}`
              }
              const today = (new Date()).toLocaleDateString()
              const pr = await github.rest.pulls.create({
                owner: OWNER,
                repo: REPO,
                head: from,
                base: to,
                title: `${today} ${PR_TITLE} From ${from} Into ${to}`,
                body: prBody
              })
              github.rest.issues.addLabels({
                owner: OWNER,
                repo: REPO,
                issue_number: pr.data.number,
                labels: prLabels
              })
              github.rest.issues.addAssignees({
                owner: OWNER,
                repo: REPO,
                issue_number: pr.data.number,
                assignees: prAssignees
              })
              return pr.data.number
            }
            async function handleSingleDirection({ from, to }) {
              if (count === 0) {
                // There isn't the 1 expected PR, open it
                createPR({
                  from: from,
                  to: to,
                  body: null
                })
              } else if (count === 1) {
                // There is a PR open, determine direction
                let title = initialResults.data.items[0].title
                if (!title.includes(`${PR_TITLE} From ${from} Into ${to}`)) {
                  // Wrong direction, close & recreate
                  dismissAllPRs()
                  createPR({
                    from: from,
                    to: to,
                    body: null
                  }) 
                }
              } else {
                // There are two PRs open, close the wrong direction
                initialResults.data.items.forEach((item) => {
                  if (!title.includes(`${PR_TITLE} From ${from} Into ${to}`)) {
                    github.rest.pulls.update({
                      owner: OWNER,
                      repo: REPO,
                      pull_number: item.number,
                      state: "closed"
                    })
                  }
                })
              }
            }
            if (docsAheadMain > 0 && docsBehindMain > 0) {
              // Need PRs both ways
              if (count === 0) {
                // There are 0 PRs open, open both of them
                const docsIntoMainPrNumber = await createPR({
                  from: DOCS_BRANCH,
                  to: "main",
                  body: null
                })
                createPR({
                  from: "main",
                  to: DOCS_BRANCH,
                  body: `Please merge GH-${docsIntoMainPrNumber} first.`
                })
              } else if (count === 1) {
                // There is already a PR open in one direction, open the other direction
                let title = initialResults.data.items[0].title 
                let number = initialResults.data.items[0].number
                if (title.includes(`${PR_TITLE} From ${DOCS_BRANCH} Into main`)) {
                  // From docs into main already exists, create main into docs
                  createPR({
                    from: "main",
                    to: DOCS_BRANCH,
                    body: `Please merge GH-${number} first.`
                  })
                } else {
                  // From main into docs already exists, create docs into main
                  const docsIntoMainPrNumber = await createPR({
                    from: DOCS_BRANCH,
                    to: "main",
                    body: null
                  })
                  github.rest.issues.createComment({
                    owner: OWNER,
                    repo: REPO,
                    issue_number: number,
                    body: `Please merge GH-${docsIntoMainPrNumber} first.`
                  })
                }
              }
            } else if (docsAheadMain > 0) {
              // Need a PR from docs to main
              handleSingleDirection({
                from: DOCS_BRANCH,
                to: "main"
              })
            } else if (docsBehindMain > 0) {
              // Need a PR from main to docs
              handleSingleDirection({
                from: "main",
                to: DOCS_BRANCH
              })
            } else if (count > 0) {
              // Ahead/behind commits is 0 but there are stale PRs to close
              dismissAllPRs()
            }