name: Publish to npm

on:
  push:
    tags:
      - 'v[0-9]+.[0-9]+.[0-9]+'

permissions:
  contents: read
  id-token: write

jobs:
  publish:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Verify tag is on main
        run: |
          git merge-base --is-ancestor "$GITHUB_SHA" origin/main || {
            echo "Tag $GITHUB_REF_NAME ($GITHUB_SHA) is not on main; refusing to publish."
            exit 1
          }

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: 24
          registry-url: 'https://registry.npmjs.org'

      - name: Verify tag matches package.json version
        run: node -e "const {version}=require('./package.json'); const tag=process.env.GITHUB_REF_NAME.replace(/^v/,''); if(version!==tag){console.error(\`Tag \${tag} does not match package.json version \${version}\`); process.exit(1);}"

      - name: Upgrade npm
        run: npm install -g npm@11

      - name: Install dependencies
        run: npm ci

      - name: Verify
        run: npm run typecheck && npm test

      - name: Publish
        run: npm publish --provenance --access public