name: LANCommander Launcher Tests — PR Visual Diff Comment

on:
    workflow_call:
        inputs:
            pr_number:
                description: 'Pull request number to comment on'
                required: true
                type: string
            artifact_run_id:
                description: 'Workflow run ID that produced the launcher-visual-artifacts artifact'
                required: true
                type: string

permissions:
    contents: write       # push diff PNGs to the gh-visual-diffs branch
    pull-requests: write  # post / update the comment

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

            - name: Download visual artifacts
              uses: actions/download-artifact@v4
              with:
                  name: launcher-visual-artifacts
                  path: visual
                  run-id: ${{ inputs.artifact_run_id }}
                  github-token: ${{ secrets.GITHUB_TOKEN }}

            - name: Read regression manifest
              id: manifest
              run: |
                  if [ ! -f visual/regressions.json ]; then
                      echo "no manifest — assuming no visual run"
                      echo "count=0" >> "$GITHUB_OUTPUT"
                      exit 0
                  fi
                  count=$(jq '.regressed_count' visual/regressions.json)
                  echo "count=$count" >> "$GITHUB_OUTPUT"

            - name: Skip when no regressions
              if: steps.manifest.outputs.count == '0'
              run: echo "No visual regressions; nothing to comment."

            # Push diff/actual/baseline PNGs to an orphan branch so raw.githubusercontent.com
            # URLs render inline in the PR comment. One folder per (PR, run).
            - name: Push diffs to gh-visual-diffs branch
              if: steps.manifest.outputs.count != '0'
              env:
                  PR: ${{ inputs.pr_number }}
                  RUN: ${{ inputs.artifact_run_id }}
              run: |
                  set -euo pipefail
                  git config user.name  "github-actions[bot]"
                  git config user.email "41898282+github-actions[bot]@users.noreply.github.com"

                  # Worktree off an orphan branch so we never touch the source tree.
                  if git ls-remote --exit-code --heads origin gh-visual-diffs >/dev/null; then
                      git fetch origin gh-visual-diffs
                      git worktree add /tmp/visual gh-visual-diffs
                  else
                      git worktree add --detach /tmp/visual
                      cd /tmp/visual
                      git checkout --orphan gh-visual-diffs
                      git rm -rf . 2>/dev/null || true
                      cd -
                  fi

                  DEST="/tmp/visual/pr-${PR}/run-${RUN}"
                  mkdir -p "$DEST"
                  cp -r visual/diffs       "$DEST/" 2>/dev/null || true
                  cp -r visual/screenshots "$DEST/" 2>/dev/null || true
                  cp -r visual/baselines   "$DEST/" 2>/dev/null || true

                  cd /tmp/visual
                  git add -A
                  git -c user.name=github-actions -c user.email=github-actions@github.com \
                      commit -m "Visual diffs for PR #${PR} run ${RUN}"
                  git push origin gh-visual-diffs

            - name: Post / update PR comment
              if: steps.manifest.outputs.count != '0'
              env:
                  GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
                  PR: ${{ inputs.pr_number }}
                  RUN: ${{ inputs.artifact_run_id }}
                  REPO: ${{ github.repository }}
                  MARKER: '<!-- launcher-visual-diff-comment -->'
              run: |
                  set -euo pipefail
                  base="https://raw.githubusercontent.com/${REPO}/gh-visual-diffs/pr-${PR}/run-${RUN}"

                  body=$(mktemp)
                  {
                      echo "$MARKER"
                      echo "## :art: Launcher visual regressions"
                      echo
                      echo "$(jq '.regressed_count' visual/regressions.json) baseline(s) drifted in [run ${RUN}](https://github.com/${REPO}/actions/runs/${RUN})."
                      echo
                      jq -r '.regressions[] | .name' visual/regressions.json | while read -r name; do
                          echo "<details><summary><strong>${name}</strong></summary>"
                          echo
                          echo "| Baseline | Actual | Diff |"
                          echo "| --- | --- | --- |"
                          echo "| ![baseline](${base}/baselines/${name}.png) | ![actual](${base}/screenshots/${name}.png) | ![diff](${base}/diffs/${name}.diff.png) |"
                          echo
                          echo "</details>"
                          echo
                      done
                      echo "_If these changes are intentional, run the **Update Visual Baselines** workflow to refresh._"
                  } >> "$body"

                  # Find an existing comment with our marker; update it if present.
                  existing=$(gh api repos/${REPO}/issues/${PR}/comments --paginate \
                      --jq ".[] | select(.body | startswith(\"${MARKER}\")) | .id" | head -1)

                  if [ -n "$existing" ]; then
                      gh api -X PATCH "repos/${REPO}/issues/comments/${existing}" --field "body=@${body}"
                  else
                      gh api -X POST "repos/${REPO}/issues/${PR}/comments" --field "body=@${body}"
                  fi