# frozen_string_literal: true

class GitRefsFinder
  include Gitlab::Utils::StrongMemoize

  def initialize(repository, params = {})
    @repository = repository
    @params = params
  end

  protected

  attr_reader :repository, :params

  def by_search(refs)
    return refs unless search

    matches = filter_refs(refs, search)
    return matches if regex_search?

    set_exact_match_as_first_result(matches, search)
  end

  def search
    @params[:search].to_s.presence
  end
  strong_memoize_attr :search

  def sort
    @params[:sort].to_s.presence || 'name'
  end

  def filter_refs(refs, term)
    regex_string = Regexp.quote(term.downcase)
    regex_string = unescape_regex_operators(regex_string) if regex_search?
    refs.select { |ref| /#{regex_string}/ === ref.name.downcase }
  end

  def set_exact_match_as_first_result(matches, term)
    exact_match_index = find_exact_match_index(matches, term)
    matches.insert(0, matches.delete_at(exact_match_index)) if exact_match_index
    matches
  end

  def find_exact_match_index(matches, term)
    matches.index { |ref| ref.name.casecmp(term) == 0 }
  end

  def regex_search?
    Regexp.union('^', '$', '*') === search
  end
  strong_memoize_attr :regex_search?, :regex_search

  def unescape_regex_operators(regex_string)
    regex_string.sub('\^', '^').gsub('\*', '.*?').sub('\$', '$')
  end
end