name: Nightly build & deploy

# Rebuilds the site (refreshing the Discord embed's "today" snapshot), uploads
# the built dist/ to the CMU AFS space over SFTP, then triggers CMU's publish
# CGI so the files go live.
on:
  # Midnight run. NOTE: cron here is UTC. 00:00 UTC is 8pm/7pm Eastern.
  # For midnight *Eastern*, use "0 5 * * *" (EST) or "0 4 * * *" (EDT).
  schedule:
    #- cron: "0 5 * * *"
    - cron: "*/10 * * * *"
  # Allow manual runs from the Gitea Actions UI.
  workflow_dispatch: {}
  # Also deploy on pushes to the main branch.
  push:
    branches:
      - main

jobs:
  build-and-deploy:
    # Pinned to the onsite CMU runner. Only a runner registered with the
    # "cmu-onsite" label can reach linux.andrew.cmu.edu, so this guarantees the
    # deploy runs from inside CMU's network. A cloud/public runner will never
    # pick up this job. The runner must be registered in Docker mode so this
    # label maps to a Node-capable Debian image (see README).
    runs-on: cmu-onsite

    env:
      # Absolute base URL where the site is served. Used to build the absolute
      # icon URL embedded for Discord. Set SITE_BASE_URL as a secret/variable,
      # e.g. https://www.andrew.cmu.edu/user/<username>
      SITE_BASE_URL: ${{ secrets.SITE_BASE_URL }}

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Set up Node
        uses: actions/setup-node@v4
        with:
          node-version: "20"
          cache: "npm"

      - name: Install dependencies
        run: npm ci

      - name: Build (injects today's Red-plan embed)
        env:
          # Discord fetches this absolute URL for the embed thumbnail.
          SITE_ICON_URL: "${{ secrets.SITE_BASE_URL }}/apple-touch-icon.png"
        run: npm run build

      - name: Install lftp
        # The node:20-bookworm container runs as root and has no `sudo`, so call
        # apt-get directly. openssh-client provides the `ssh` binary lftp uses
        # for its SFTP connect-program.
        run: |
          apt-get update
          apt-get install -y --no-install-recommends lftp openssh-client

      - name: Preflight — check SFTP host reachability
        env:
          SFTP_HOST: ${{ secrets.SFTP_HOST }}
          SFTP_PORT: ${{ secrets.SFTP_PORT }}
        run: |
          set -uo pipefail
          PORT="${SFTP_PORT:-22}"
          if [ -z "${SFTP_HOST}" ]; then
            echo "::error::SFTP_HOST secret is empty. Set it in Gitea → Settings → Actions → Secrets."
            exit 1
          fi
          echo "Testing TCP reachability of ${SFTP_HOST}:${PORT} ..."
          if ! timeout 15 bash -c "cat < /dev/null > /dev/tcp/${SFTP_HOST}/${PORT}" 2>/dev/null; then
            echo "::error::Cannot open a TCP connection to ${SFTP_HOST}:${PORT}. This is why lftp reports 'max-retries exceeded'."
            echo "Likely causes: wrong SFTP_HOST, wrong port, or the runner cannot reach CMU (needs VPN / on-campus network / firewall allowance)."
            exit 1
          fi
          echo "Host is reachable on ${PORT}. Showing the SSH banner:"
          # Non-fatal: just prints what the server advertises (SSH version, etc.)
          timeout 10 bash -c "exec 3<>/dev/tcp/${SFTP_HOST}/${PORT}; head -c 200 <&3" 2>/dev/null || true
          echo

      - name: Upload dist/ via SFTP
        env:
          SFTP_HOST: ${{ secrets.SFTP_HOST }}
          SFTP_PORT: ${{ secrets.SFTP_PORT }}
          SFTP_USERNAME: ${{ secrets.SFTP_USERNAME }}
          SFTP_PASSWORD: ${{ secrets.SFTP_PASSWORD }}
          SFTP_REMOTE_PATH: ${{ secrets.SFTP_REMOTE_PATH }}
        run: |
          set -euo pipefail
          PORT="${SFTP_PORT:-22}"

          # lftp drives SFTP by shelling out to the system `ssh`. We pass ssh
          # options explicitly so this works on a fresh runner against CMU:
          #   - StrictHostKeyChecking/UserKnownHostsFile: don't fail on an
          #     unknown host key (the runner has never seen CMU's key).
          #   - PubkeyAuthentication=no / PreferredAuthentications=password:
          #     force password auth so ssh doesn't stall trying keys/agent.
          #   - the KexAlgorithms/HostKeyAlgorithms "+..." lines re-enable
          #     algorithms some CMU hosts still use that modern OpenSSH disables
          #     by default (a common cause of a silent connection failure).
          #
          # To debug connection problems, temporarily add `debug 3;` before the
          # open line and `--verbose` to the mirror — both are omitted here to
          # keep the job log small (large logs slow the "Complete job" upload
          # back to the off-campus Gitea).
          lftp -c "
            set sftp:auto-confirm yes;
            set sftp:connect-program 'ssh -a -x \
              -o StrictHostKeyChecking=no \
              -o UserKnownHostsFile=/dev/null \
              -o PubkeyAuthentication=no \
              -o PreferredAuthentications=password \
              -o KexAlgorithms=+diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1 \
              -o HostKeyAlgorithms=+ssh-rsa,ssh-dss';
            set net:max-retries 2;
            set net:timeout 30;
            set net:reconnect-interval-base 5;
            open -u '${SFTP_USERNAME}','${SFTP_PASSWORD}' sftp://${SFTP_HOST}:${PORT};
            mkdir -f -p '${SFTP_REMOTE_PATH}';
            mirror -R --delete --only-newer ./dist/ '${SFTP_REMOTE_PATH}';
            bye
          "

      - name: Trigger CMU publish
        env:
          SFTP_USERNAME: ${{ secrets.SFTP_USERNAME }}
        run: |
          set -euo pipefail
          # FLAG=0 publishes; NAME is the AFS username (same as the SFTP user).
          # --fail makes curl exit non-zero on HTTP errors so the job fails
          # loudly if publishing is rejected.
          curl --fail --show-error --silent \
            "https://www.andrew.cmu.edu/cgi-bin/publish?FLAG=0&NAME=${SFTP_USERNAME}"
          echo "Publish request sent for ${SFTP_USERNAME}."