name: Deploy to HuggingFace Space

# Redeploys the HuggingFace Docker Space on every merge to main (a merged
# PR pushes to main). Mirrors the manual flow in deploy/huggingface/SETUP.md:
# HF's git endpoint rejects the >10 MiB .xiidm blobs that sit in branch
# *history*, so we push ONE squashed, history-free commit of the current
# tree (large binaries ride along via Git LFS).
#
# Required repo configuration (Settings → Secrets and variables → Actions):
#   - secret  HF_TOKEN     : a HuggingFace WRITE access token with access to the Space
#   - variable HF_SPACE    : the Space path, e.g. "your-user/co-study4grid-game"
#   - variable HF_USERNAME : (optional) the token owner's HF username — only
#                            needed when the Space lives under an ORG and so
#                            differs from the owner part of HF_SPACE.
#
# The job no-ops (does not fail) when HF_TOKEN / HF_SPACE are absent, so the
# workflow is inert until you opt in by setting them.

# Test-gated (D7): deploy runs ONLY after the "Tests" workflow completes
# successfully on main — a green build is the gate, not just a merge. A
# manual `workflow_dispatch` (optionally from an older commit) is the
# rollback path; see deploy/huggingface/SETUP.md → "Rolling back".
on:
  workflow_run:
    workflows: [ "Tests" ]
    types: [ completed ]
    branches: [ main ]
  workflow_dispatch: {}

# Never run two deploys at once; the latest merge wins.
concurrency:
  group: huggingface-space-deploy
  cancel-in-progress: true

permissions:
  contents: write   # push the per-deploy rollback tag back to origin

jobs:
  deploy:
    name: Push snapshot to HF Space
    runs-on: ubuntu-latest
    # workflow_run fires on completion regardless of result — only deploy a
    # SUCCESSFUL Tests run. workflow_dispatch always proceeds (rollback).
    if: >-
      github.event_name == 'workflow_dispatch' ||
      github.event.workflow_run.conclusion == 'success'
    steps:
      - name: Check the deploy is configured
        id: guard
        env:
          HF_TOKEN: ${{ secrets.HF_TOKEN }}
          HF_SPACE: ${{ vars.HF_SPACE }}
        run: |
          if [ -z "$HF_TOKEN" ] || [ -z "$HF_SPACE" ]; then
            echo "::notice::HF_TOKEN secret and/or HF_SPACE variable not set — skipping deploy."
            echo "configured=false" >> "$GITHUB_OUTPUT"
          else
            echo "configured=true" >> "$GITHUB_OUTPUT"
          fi

      # The tested commit: the head of the Tests run (workflow_run), or the
      # dispatched ref (workflow_dispatch / rollback).
      - name: Resolve the deployed commit
        if: steps.guard.outputs.configured == 'true'
        id: sha
        run: echo "sha=${{ github.event.workflow_run.head_sha || github.sha }}" >> "$GITHUB_OUTPUT"

      - name: Checkout the tested tree + LFS objects
        if: steps.guard.outputs.configured == 'true'
        uses: actions/checkout@v4
        with:
          ref: ${{ steps.sha.outputs.sha }}
          lfs: true
          fetch-depth: 1   # an orphan snapshot only needs the current tree

      - name: Configure git + LFS
        if: steps.guard.outputs.configured == 'true'
        run: |
          git lfs install --local
          git config user.name  "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"

      - name: Build a history-free snapshot
        if: steps.guard.outputs.configured == 'true'
        env:
          DEPLOY_SHA: ${{ steps.sha.outputs.sha }}
        run: |
          cp deploy/huggingface/README.md README.md   # HF needs the frontmatter at repo root
          git checkout --orphan hf-deploy
          git add -A
          # Drop inert local dev artifacts from the deployed snapshot.
          git rm -q --cached --ignore-unmatch \
            .claude/plan.md profiling_patch_results.json || true
          git commit -q -m "Deploy ${DEPLOY_SHA::7}"
          test "$(git rev-list --count HEAD)" -eq 1   # sanity: exactly one commit

      - name: Push to the HuggingFace Space
        if: steps.guard.outputs.configured == 'true'
        env:
          HF_TOKEN: ${{ secrets.HF_TOKEN }}
          HF_SPACE: ${{ vars.HF_SPACE }}
          HF_USERNAME: ${{ vars.HF_USERNAME }}
          DEPLOY_SHA: ${{ steps.sha.outputs.sha }}
        run: |
          user="${HF_USERNAME:-${HF_SPACE%%/*}}"
          # The token is a GitHub secret → masked in logs even inside the URL.
          git remote add space "https://${user}:${HF_TOKEN}@huggingface.co/spaces/${HF_SPACE}"
          git -c protocol.version=0 push -f space hf-deploy:main
          echo "::notice::Pushed snapshot of ${DEPLOY_SHA::7} to spaces/${HF_SPACE}; HF will rebuild."

      # Rollback pointer (D7): tag the exact commit deployed to the Space,
      # so a bad deploy can be reverted by re-dispatching this workflow from
      # a prior `space-deploy-*` tag. The Space push itself is force-pushed
      # and history-free, so this origin tag is the only durable record of
      # what shipped. Never fails the deploy.
      - name: Tag the deployed commit on origin
        if: steps.guard.outputs.configured == 'true'
        env:
          DEPLOY_SHA: ${{ steps.sha.outputs.sha }}
        run: |
          tag="space-deploy-$(date -u +%Y%m%d-%H%M%S)-${DEPLOY_SHA::7}"
          git tag -a "$tag" "$DEPLOY_SHA" -m "Deployed to HF Space" || { echo "::warning::tag create failed"; exit 0; }
          git push origin "refs/tags/$tag" || echo "::warning::tag push failed (non-fatal)"
          echo "::notice::Tagged deployed commit as $tag"