name: Refresh registry-worker cache

# On every push that changes any registry content, regenerate the two
# in-repo indexes the registry-worker ingests:
#   plugins-index.json  — daemon-shaped flat plugins array (signed)
#   registry-index.json — dict-shaped dashboard payload (unsigned)
# then poke the worker's forced-refresh endpoint so it pulls both
# (3 subrequests total, regardless of registry size — fits Workers
# Free's 50-subrequest budget) and stores them.
#
# Without this, dashboard + daemon would have to wait for the next
# 02:00 UTC cron tick to see content changes (up to ~24h delay).
#
# === SECURITY MODEL ===
#
# REGISTRY_PRIVATE_KEY (Ed25519 PKCS#8) is the trust root for every
# `librefang plugin install <name>` worldwide. Threats and mitigations:
#
#   1. Compromised maintainer pushes a malicious plugins-index.json
#      directly to main. Mitigation: GitHub branch protection on `main`
#      requires PR review (admin-configured); .github/CODEOWNERS forces
#      sign-script and committed-artefact changes through the registry
#      owner.
#
#   2. Malicious PR adds a step that exfiltrates the secret. Mitigation:
#      .github/CODEOWNERS owns this file; can't be modified without
#      registry-owner approval. Action versions are SHA-pinned to block
#      action-supply-chain attacks (transitive `uses:` swap).
#
#   3. Sign step writes garbage. Mitigation: post-sign verify step
#      validates the signature against the corresponding pubkey before
#      committing — a malformed sign-script run is caught here, not
#      after publish.
#
#   4. Worker secret REGISTRY_REFRESH_TOKEN leaked. Mitigation: worker
#      no longer holds signing material (PR #4600), so a leaked token
#      lets an attacker trigger refreshes against existing committed
#      bytes — they can't substitute attacker-supplied bytes for the
#      worker to sign.

on:
  push:
    branches: [main]
    paths:
      - 'plugins/**'
      - 'agents/**'
      - 'skills/**'
      - 'hands/**'
      - 'channels/**'
      - 'providers/**'
      - 'workflows/**'
      - 'mcp/**'
      - 'scripts/build-plugins-index.mjs'
      - 'scripts/build-registry-index.mjs'
      - 'scripts/sign-plugins-index.mjs'
  workflow_dispatch:

permissions:
  contents: write         # push the regen to a side branch
  pull-requests: write    # open the regen PR for maintainer merge

jobs:
  refresh:
    runs-on: ubuntu-latest
    steps:
      # SHA-pinned to block action-supply-chain swaps. Update with care
      # (read the diff between current and target SHA upstream).
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2

      - uses: actions/setup-node@39370e3970a6d050c480ffad4ff0ed4d3fdee5af # v4.1.0
        with:
          node-version: '20'

      - name: Rebuild indexes
        run: |
          node scripts/build-plugins-index.mjs
          node scripts/build-registry-index.mjs

      # REGISTRY_PRIVATE_KEY is scoped to ONLY this step's env so prior
      # build steps and later trigger steps cannot read it. Keep this
      # narrow; do NOT lift the env to the job level.
      - name: Sign plugins-index.json
        env:
          REGISTRY_PRIVATE_KEY: ${{ secrets.REGISTRY_PRIVATE_KEY }}
        run: node scripts/sign-plugins-index.mjs

      # Defense in depth: verify the signature against the committed
      # pubkey before the .sig hits main. This catches an *accidental*
      # sign-script regression — a malformed signature, an env-leak that
      # produces zero bytes, an off-by-one in the JSON canonicalization.
      # It does NOT defend against an adversary, because an attacker
      # who can edit sign-plugins-index.mjs in a PR can edit this verify
      # step and the embedded pubkey in the same diff. The CODEOWNERS
      # gate on `/scripts/` and `/.github/workflows/` is what stops
      # adversarial edits, not this step.
      - name: Verify signature against committed pubkey
        env:
          REGISTRY_PUBLIC_KEY: joY8IYrUbbACfKRyp2CTcEbcEty8wcBwP1MTxU+vjaM=
        run: |
          node -e '
            const c = require("crypto"), fs = require("fs");
            const idx = fs.readFileSync("plugins-index.json");
            const sig = Buffer.from(
              fs.readFileSync("plugins-index.json.sig", "utf8").trim(),
              "base64",
            );
            const pub = Buffer.from(process.env.REGISTRY_PUBLIC_KEY, "base64");
            if (pub.length !== 32) {
              console.error("REGISTRY_PUBLIC_KEY is not a raw 32-byte Ed25519 pubkey");
              process.exit(1);
            }
            const spki = Buffer.concat([
              Buffer.from("302a300506032b6570032100", "hex"),
              pub,
            ]);
            const k = c.createPublicKey({ key: spki, format: "der", type: "spki" });
            if (!c.verify(null, idx, k, sig)) {
              console.error("plugins-index.json.sig does NOT verify against the committed pubkey");
              process.exit(1);
            }
            console.log("Signature verifies OK against committed pubkey.");
          '

      # Direct `git push` to `main` is rejected by branch protection
      # (GH006: "Changes must be made through a pull request"), which is
      # the intended security model documented at the top of this file
      # (mitigation #1). Open a PR with the regen instead so the same
      # human-review gate applies to bot-authored index updates. The PR
      # body links back to the triggering content commit so reviewers can
      # eyeball the regen against the source change.
      - name: Open PR with regenerated indexes if changed
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"
          git add plugins-index.json plugins-index.json.sig registry-index.json
          if git diff --cached --quiet; then
            echo "indexes already up-to-date"
            exit 0
          fi
          branch="automation/refresh-indexes-${GITHUB_SHA::8}"
          git switch -c "$branch"
          git commit -m "chore: regenerate registry indexes for ${GITHUB_SHA::8}"
          git push -u origin "$branch"
          gh pr create \
            --base main \
            --head "$branch" \
            --title "chore: regenerate registry indexes for ${GITHUB_SHA::8}" \
            --body "Auto-generated by \`.github/workflows/refresh-cache.yml\` after $GITHUB_SHA.

          Regenerates the two indexes the registry-worker ingests:
          - \`plugins-index.json\` + \`plugins-index.json.sig\` (signed)
          - \`registry-index.json\`

          The signature was verified against the committed pubkey in the
          generating run before this PR was opened (see the run linked
          on the commit).

          Branch protection on \`main\` blocks direct push (the documented
          security model — see the header of \`refresh-cache.yml\`), so
          this PR carries the regen for maintainer review and merge.
          Squash-merge is safe; \`[skip ci]\` is not needed since the
          regen run on the merge commit will be a no-op."

      - name: Trigger worker refresh
        env:
          REGISTRY_REFRESH_TOKEN: ${{ secrets.REGISTRY_REFRESH_TOKEN }}
        run: |
          if [ -z "$REGISTRY_REFRESH_TOKEN" ]; then
            echo "::error::REGISTRY_REFRESH_TOKEN secret is not set on this repo"
            exit 1
          fi
          response=$(curl -fsS -X POST \
            -H "Authorization: Bearer $REGISTRY_REFRESH_TOKEN" \
            -w "\nHTTP_CODE:%{http_code}" \
            https://stats.librefang.ai/api/registry/refresh)
          echo "$response"
          code=$(echo "$response" | grep -oE 'HTTP_CODE:[0-9]+' | cut -d: -f2)
          if [ "$code" != "200" ]; then
            echo "::error::worker returned $code"
            exit 1
          fi