# Validate -> sign -> self-verify -> commit the signature back to main.
#
# The index is served straight out of this repository over Gitea's anonymous
# raw endpoint, so "publishing" IS committing v1/index.json.sig to main. There
# is no separate static host and no deploy step.
#
#   https://git.unom.io/unom/punktfunk-plugin-index/raw/branch/main/v1/index.json
#   https://git.unom.io/unom/punktfunk-plugin-index/raw/branch/main/v1/index.json.sig
#
# This workflow holds INDEX_SIGNING_KEY, the private half of the key the host
# pins. It therefore only ever runs on `main` (post-merge) or by explicit
# dispatch -- never on a pull request. PR validation lives in validate.yml,
# which has no access to the key. That split is the point: a fork PR can change
# index.json all it likes, but nothing it does gets signed until a human merges.
name: publish
run-name: ${{ gitea.actor }} sign plugin index

on:
  push:
    branches: [main]
    # LOOP GUARD (primary -- this is the one relied on). This job's own output
    # is v1/index.json.sig, and it commits that file back to main, which would
    # retrigger the job. `paths-ignore` means "run unless EVERY changed path
    # matches", so the bot's signature-only commit is skipped, while a push
    # touching index.json (alone, or together with the signature) still runs.
    #
    # Do not add a `paths:` include list alongside this -- `paths` and
    # `paths-ignore` are mutually exclusive for a single event.
    paths-ignore:
      - "v1/index.json.sig"
  workflow_dispatch:

jobs:
  publish:
    runs-on: ubuntu-24.04
    timeout-minutes: 10
    steps:
      - uses: actions/checkout@v4
        with:
          ref: main
          # The token must be able to push to main. Gitea injects GITEA_TOKEN
          # automatically, which is sufficient for an unprotected branch. If
          # main is protected, set INDEX_BOT_TOKEN to a PAT permitted to push
          # through the protection; it takes precedence when present.
          token: ${{ secrets.INDEX_BOT_TOKEN || secrets.GITEA_TOKEN }}

      - uses: oven-sh/setup-bun@v2
        with:
          bun-version: latest

      # Full validation INCLUDING the live registry cross-check. If a pinned
      # hash no longer matches upstream, we must not sign it.
      - name: Validate index
        run: bun run validate

      - name: Sign index
        env:
          INDEX_SIGNING_KEY: ${{ secrets.INDEX_SIGNING_KEY }}
        run: |
          set -euo pipefail
          if [ -z "${INDEX_SIGNING_KEY:-}" ]; then
            echo "::error::INDEX_SIGNING_KEY secret is not set; refusing to publish an unsigned index"
            exit 1
          fi
          # The key reaches the tool via env only -- never a file in the
          # workspace, never an argument (which would show up in process lists).
          bun run sign

      # Self-check: re-verify what we just produced, with the same code path an
      # auditor would use. Catches a key/host mismatch BEFORE it ships, rather
      # than as every host in the field silently rejecting the catalog.
      - name: Verify signature
        run: bun run verify -- --pub "${{ vars.INDEX_PUBLIC_KEY || 'ed25519:qK18TE2qygIyObtMlHxUI/G1gKby8tPxuieAfnEKgYE=' }}"

      - name: Commit signature to main
        run: |
          set -euo pipefail

          # ed25519 is deterministic: the same key over the same bytes yields a
          # byte-identical signature. So a push that did not change index.json
          # (a README edit, a tooling change) re-signs to exactly what is
          # already committed and there is nothing to commit -- no churn, no
          # empty commits, and no loop even before the guards take effect.
          if [ -z "$(git status --porcelain -- v1/index.json.sig)" ]; then
            echo "signature unchanged -- nothing to commit"
            exit 0
          fi

          git config user.name "unom-bot"
          git config user.email "bot@unom.io"
          git add v1/index.json.sig

          # LOOP GUARD (secondary, belt-and-braces). Gitea's runner honours
          # skip-ci markers in the commit subject -- SKIP_WORKFLOW_STRINGS in
          # app.ini, which defaults to [skip ci],[ci skip],[no ci],
          # [skip actions],[actions skip]. The paths-ignore filter above is the
          # mechanism actually relied on, because it holds even where an
          # operator has narrowed SKIP_WORKFLOW_STRINGS. This marker is a
          # second line of defence and a signal to humans reading the log.
          git commit -m "chore(index): sign v1/index.json [skip ci]" \
                     -m "Signature over ${GITEA_SHA:-$GITHUB_SHA}. Generated by the publish workflow; do not edit by hand."

          git push origin HEAD:main

      - name: Summary
        run: |
          {
            echo "### Plugin index signed and published"
            echo
            echo "- plugins: $(bun -e 'console.log(JSON.parse(require("fs").readFileSync("v1/index.json","utf8")).plugins.length)')"
            echo "- advisories: $(bun -e 'console.log(JSON.parse(require("fs").readFileSync("v1/index.json","utf8")).security.length)')"
            echo
            echo "Served from:"
            echo '```'
            echo "https://git.unom.io/unom/punktfunk-plugin-index/raw/branch/main/v1/index.json"
            echo "https://git.unom.io/unom/punktfunk-plugin-index/raw/branch/main/v1/index.json.sig"
            echo '```'
          } >> "$GITEA_STEP_SUMMARY"