name: rustc-pull

on:
  workflow_dispatch:
  schedule:
    # Run at 04:00 UTC every Monday and Thursday
    - cron: '0 4 * * 1,4'

jobs:
  pull:
    if: github.repository == 'rust-lang/rustc-dev-guide'
    runs-on: ubuntu-latest
    outputs:
      pr_url: ${{ steps.update-pr.outputs.pr_url }}
    permissions:
      contents: write
      pull-requests: write
    steps:
      - uses: actions/checkout@v4
        with:
          # We need the full history for josh to work
          fetch-depth: '0'
      - name: Install stable Rust toolchain
        run: rustup update stable
      - uses: Swatinem/rust-cache@v2
        with:
          workspaces: "josh-sync"
          # Cache the josh directory with checked out rustc
          cache-directories: "/home/runner/.cache/rustc-dev-guide-josh"
      - name: Install josh
        run: RUSTFLAGS="--cap-lints warn" cargo +stable install josh-proxy --git https://github.com/josh-project/josh --tag r24.10.04
      - name: Setup bot git name and email
        run: |
          git config --global user.name 'The rustc-dev-guide Cronjob Bot'
          git config --global user.email 'github-actions@github.com'
      - name: Perform rustc-pull
        id: rustc-pull
        # Turn off -e to disable early exit
        shell: bash {0}
        run: |
          cargo run --manifest-path josh-sync/Cargo.toml -- rustc-pull
          exitcode=$?

          # If no pull was performed, we want to mark this job as successful,
          # but we do not want to perform the follow-up steps.
          if [ $exitcode -eq 0 ]; then
            echo "pull_result=pull-finished" >> $GITHUB_OUTPUT
          elif [ $exitcode -eq 2 ]; then
            echo "pull_result=skipped" >> $GITHUB_OUTPUT
            exitcode=0
          fi

          exit ${exitcode}
      - name: Push changes to a branch
        if: ${{ steps.rustc-pull.outputs.pull_result == 'pull-finished' }}
        run: |
          # Update a sticky branch that is used only for rustc pulls
          BRANCH="rustc-pull"
          git switch -c $BRANCH
          git push -u origin $BRANCH --force
      - name: Create pull request
        id: update-pr
        if: ${{ steps.rustc-pull.outputs.pull_result == 'pull-finished' }}
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          # Check if an open pull request for an rustc pull update already exists
          # If it does, the previous push has just updated it
          # If not, we create it now
          RESULT=`gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | length' --json title`
          if [[ "$RESULT" -eq 0 ]]; then
            echo "Creating new pull request"
            PR_URL=`gh pr create -B master --title 'Rustc pull update' --body 'Latest update from rustc.'`
            echo "pr_url=$PR_URL" >> $GITHUB_OUTPUT
          else
            PR_URL=`gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | .[0].url' --json url,title`
            echo "Updating pull request ${PR_URL}"
            echo "pr_url=$PR_URL" >> $GITHUB_OUTPUT
          fi
  send-zulip-message:
    needs: [pull]
    if: ${{ !cancelled() }}
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Compute message
        id: create-message
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          if [ "${{ needs.pull.result }}" == "failure" ]; then
            WORKFLOW_URL="${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
            echo "message=Rustc pull sync failed. Check out the [workflow URL]($WORKFLOW_URL)." >> $GITHUB_OUTPUT
          else
            CREATED_AT=`gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | .[0].createdAt' --json createdAt,title`
            PR_URL=`gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | .[0].url' --json url,title`
            week_ago=$(date +%F -d '7 days ago')

            # If there is an open PR that is at least a week old, post a message about it
            if [[ -n $DATE_GH && $DATE_GH < $week_ago ]]; then
              echo "message=A PR with a Rustc pull has been opened for more a week. Check out the [PR](${PR_URL})." >> $GITHUB_OUTPUT
            fi
          fi
      - name: Send a Zulip message about updated PR
        if: ${{ steps.create-message.outputs.message != '' }}
        uses: zulip/github-actions-zulip/send-message@e4c8f27c732ba9bd98ac6be0583096dea82feea5
        with:
          api-key: ${{ secrets.ZULIP_API_TOKEN }}
          email: "rustc-dev-guide-gha-notif-bot@rust-lang.zulipchat.com"
          organization-url: "https://rust-lang.zulipchat.com"
          to: 196385
          type: "stream"
          topic: "Subtree sync automation"
          content: ${{ steps.create-message.outputs.message }}
