name: Visual Regression

# Desktop-unchanged gate for the mobile work: snapshots the touched top-level
# views at desktop widths and fails if a base layout class changed instead of a
# mobile-only override being added.
#
# Baselines are platform-specific (Linux runner fonts differ from a developer's
# OS), so they are generated here and committed, not produced locally. Seed or
# refresh them by running this workflow manually with "update_baselines: true"
# on the target branch (a feature branch, not a protected one); the compare job
# then gates every PR into main against those committed baselines.
on:
  pull_request:
    branches: [main]
  workflow_dispatch:
    inputs:
      update_baselines:
        description: Regenerate and commit the visual baselines on this branch
        type: boolean
        default: false

concurrency:
  group: visual-${{ github.ref }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  # Gate PRs into main against the committed baselines. Until baselines exist
  # (first adoption), the comparison is skipped with a warning rather than
  # failing every PR; once they are committed the gate compares for real.
  compare:
    name: Compare against baselines
    if: github.event_name == 'pull_request'
    runs-on: ubuntu-latest
    timeout-minutes: 15
    steps:
      - name: Checkout Code
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

      - name: Check for committed baselines
        id: baselines
        run: |
          if compgen -G "e2e/*-snapshots/*.png" > /dev/null; then
            echo "present=true" >> "$GITHUB_OUTPUT"
          else
            echo "present=false" >> "$GITHUB_OUTPUT"
            echo "::warning::No visual baselines committed yet. Run this workflow manually with update_baselines=true on this branch to seed them, then this job will gate for real."
          fi

      - name: Start app & install Playwright
        if: steps.baselines.outputs.present == 'true'
        uses: ./.github/actions/start-app

      - name: Compare visual snapshots
        if: steps.baselines.outputs.present == 'true'
        run: npx playwright test --project=visual

      - name: Upload diff report on failure
        if: failure()
        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
        with:
          name: visual-report
          path: |
            e2e/report/
            test-results/
            ci-logs/
          retention-days: 7

  # Manual: regenerate the baselines on the runner platform and commit them to
  # the branch the workflow was dispatched on. Refuses to run on main: seed on a
  # feature branch, then merge the baselines in through a PR.
  seed:
    name: Seed / refresh baselines
    if: github.event_name == 'workflow_dispatch' && inputs.update_baselines
    runs-on: ubuntu-latest
    timeout-minutes: 15
    permissions:
      contents: write
    steps:
      - name: Refuse to seed on main
        if: github.ref_name == 'main'
        run: |
          echo "::error::Do not seed baselines on main. Dispatch this workflow on a feature branch, then merge the baselines in via a PR."
          exit 1

      - name: Checkout Code
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

      - name: Start app & install Playwright
        uses: ./.github/actions/start-app

      - name: Regenerate baselines
        run: npx playwright test --project=visual --update-snapshots

      - name: Commit baselines
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
          # Baselines live under a path that is gitignored for local runs, so
          # force-add the ones this run produced.
          git add -f 'e2e/*-snapshots/'
          if git diff --cached --quiet; then
            echo "Baselines unchanged."
          else
            git commit -m "test(visual): refresh desktop visual-regression baselines"
            git push origin "HEAD:${{ github.ref_name }}"
          fi