module Hbc
  module QualifiedToken
    REPO_PREFIX = "homebrew-".freeze

    # per https://github.com/Homebrew/homebrew/blob/4c7bc9ec3bca729c898ee347b6135ba692ee0274/Library/Homebrew/cmd/tap.rb#L121
    USER_REGEX = /[a-z0-9_\-]+/

    # per https://github.com/Homebrew/homebrew/blob/4c7bc9ec3bca729c898ee347b6135ba692ee0274/Library/Homebrew/cmd/tap.rb#L121
    REPO_REGEX = /(?:#{REPO_PREFIX})?\w+/

    # per https://github.com/caskroom/homebrew-cask/blob/master/CONTRIBUTING.md#generating-a-token-for-the-cask
    TOKEN_REGEX = /[a-z0-9\-]+/

    TAP_REGEX = %r{#{USER_REGEX}[/\-]#{REPO_REGEX}}

    QUALIFIED_TOKEN_REGEX = %r{#{TAP_REGEX}/#{TOKEN_REGEX}}

    def self.parse(arg)
      return nil unless arg.is_a?(String) && arg.downcase =~ /^#{QUALIFIED_TOKEN_REGEX}$/
      path_elements = arg.downcase.split("/")
      if path_elements.count == 2
        # eg phinze-cask/google-chrome.
        # Not certain this form is needed, but it was supported in the past.
        token = path_elements[1]
        dash_elements = path_elements[0].split("-")
        repo = dash_elements.pop
        dash_elements.pop if dash_elements.count > 1 && dash_elements[-1] + "-" == REPO_PREFIX
        user = dash_elements.join("-")
      else
        # eg caskroom/cask/google-chrome
        # per https://github.com/Homebrew/brew/blob/master/docs/brew-tap.md
        user, repo, token = path_elements
      end
      repo.sub!(/^#{REPO_PREFIX}/, "")
      odebug "[user, repo, token] might be [#{user}, #{repo}, #{token}]"
      [user, repo, token]
    end
  end
end