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

ROOT="$(cd "$(dirname "$0")/.." && pwd)"
BASE_REF="${BASE_REF:-}"

usage() {
  cat <<'EOF'
Usage:
  bash scripts/new-branch.sh <branch-name>

Creates a new development branch from the latest origin/main.

Environment:
  BASE_REF     Base ref to create from. Defaults to origin/main when available.
EOF
}

if [[ "${1:-}" == "-h" || "${1:-}" == "--help" || $# -ne 1 ]]; then
  usage
  [[ $# -eq 1 ]] && exit 0 || exit 1
fi

branch="$1"

if [[ -n "$(git -C "${ROOT}" status --porcelain=v1 --untracked-files=all)" ]]; then
  echo "New branch check failed: current worktree is not clean." >&2
  git -C "${ROOT}" status --short --untracked-files=all >&2
  exit 1
fi

if git -C "${ROOT}" remote get-url origin >/dev/null 2>&1; then
  git -C "${ROOT}" fetch origin --prune
fi

if [[ -z "${BASE_REF}" ]]; then
  for candidate in origin/main origin/master main master; do
    if git -C "${ROOT}" rev-parse --verify --quiet "${candidate}" >/dev/null; then
      BASE_REF="${candidate}"
      break
    fi
  done
fi

git -C "${ROOT}" rev-parse --verify --quiet "${BASE_REF}" >/dev/null || {
  echo "New branch check failed: base ref not found: ${BASE_REF}" >&2
  exit 1
}

git -C "${ROOT}" switch -c "${branch}" "${BASE_REF}"
echo "Created ${branch} from ${BASE_REF}."