class Dependabot::PullRequestCreator::CommitSigner

def commit_object
  time_str = Time.parse(T.must(author_details[:date])).strftime("%s %z")
  name = author_details[:name]
  email = author_details[:email]
  [
    "tree #{tree_sha}",
    "parent #{parent_sha}",
    "author #{name} <#{email}> #{time_str}",
    "committer #{name} <#{email}> #{time_str}",
    "",
    commit_message
  ].join("\n")
end

def initialize(
  author_details:,
  commit_message:,
  tree_sha:,
  parent_sha:,
  signature_key:
)
  @author_details = author_details
  @commit_message = commit_message
  @tree_sha = tree_sha
  @parent_sha = parent_sha
  @signature_key = signature_key
end

def signature
  begin
    require "gpgme"
  rescue LoadError
    raise LoadError,
          "Please add `gpgme` to your Gemfile or gemspec " \
          "enable commit signatures"
  end
  email = author_details[:email]
  dir = Dir.mktmpdir
  GPGME::Engine.home_dir = dir
  GPGME::Key.import(signature_key)
  crypto = GPGME::Crypto.new(armor: true)
  opts = { mode: GPGME::SIG_MODE_DETACH, signer: email }
  crypto.sign(commit_object, opts).to_s
rescue Errno::ENOTEMPTY
  FileUtils.remove_entry(T.must(dir), true)
  # This appears to be a Ruby bug which occurs very rarely
  raise if @retrying
  @retrying = T.let(true, T.nilable(T::Boolean))
  retry
ensure
  FileUtils.remove_entry(T.must(dir), true)
end