#!/usr/bin/env bash
set -euo pipefail

# Sync selected skills from upstream (github.com/obra/superpowers)
# Usage: ./scripts/sync-upstream.sh [--dry-run]

REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
cd "$REPO_ROOT"

DRY_RUN=${DRY_RUN:-false}
if [[ "${1:-}" == "--dry-run" ]]; then
  DRY_RUN=true
fi

SKILLS=(
  systematic-debugging
  test-driven-development
  verification-before-completion
  writing-plans
  requesting-code-review
  receiving-code-review
  finishing-a-development-branch
)

echo "Fetching upstream..."
git fetch upstream --depth=1

UPSTREAM_REF="upstream/main"
CURRENT_REF="HEAD"

CHANGED=false
for skill in "${SKILLS[@]}"; do
  echo ""
  echo "=== Checking skills/$skill ==="

  # Get list of files that differ
  diff_files=$(git diff --name-only "$CURRENT_REF" "$UPSTREAM_REF" -- "skills/$skill" 2>/dev/null || true)

  if [[ -z "$diff_files" ]]; then
    echo "  Up to date"
    continue
  fi

  echo "  Changes detected:"
  echo "$diff_files" | sed 's/^/    /'

  if [[ "$DRY_RUN" == true ]]; then
    echo "  (dry-run, skipping copy)"
    CHANGED=true
    continue
  fi

  # Checkout the entire skill directory from upstream
  git checkout "$UPSTREAM_REF" -- "skills/$skill"
  echo "  Merged from upstream"
  CHANGED=true
done

if [[ "$CHANGED" == false ]]; then
  echo ""
  echo "All skills up to date. Nothing to do."
  exit 0
fi

if [[ "$DRY_RUN" == true ]]; then
  echo ""
  echo "Dry run complete. Run without --dry-run to apply changes."
  exit 0
fi

# Stage everything in skills/
git add -A skills/

if git diff --cached --quiet; then
  echo ""
  echo "No changes to commit after merge."
  exit 0
fi

echo ""
echo "Changes staged. Commit with:"
echo "  git commit -m 'Sync skills from obra/superpowers upstream (v$(git describe --tags "$UPSTREAM_REF" 2>/dev/null || echo "$(git rev-parse --short "$UPSTREAM_REF")"))'"