#!/usr/bin/env bash

set -euo pipefail

dry_run=false
force=false
prune=false

while [[ $# -gt 0 ]]; do
  case "$1" in
    -n|--dry-run)
      dry_run=true
      shift
      ;;
    -f|--force)
      force=true
      shift
      ;;
    -p|--prune)
      prune=true
      shift
      ;;
    *)
      echo "Unknown option: $1"
      echo "Usage: git delete-gone-branches [-n|--dry-run] [-f|--force] [-p|--prune]"
      exit 1
      ;;
  esac
done

if [ "$prune" = true ]; then
  git fetch --prune
fi

gone_branches=$(git for-each-ref --format \
  '%(if:equals=gone)%(upstream:track,nobracket)%(then)%(refname:short)%(end)' refs/heads/ | sed '/^$/d')

if [ -z "$gone_branches" ]; then
  echo "No branches with a gone remote found."
  exit 0
fi

if [ "$dry_run" = true ]; then
  echo "Would delete the following branches:"
  echo "$gone_branches"
  exit 0
fi

echo "The following branches will be deleted:"
echo "$gone_branches"

if [ "$force" = false ]; then
  read -r -p "Delete these branches? [y/N] " confirm
  if [[ ! "$confirm" =~ ^[yY]$ ]]; then
    echo "Aborted."
    exit 0
  fi
fi

echo "$gone_branches" | xargs git branch -D