module Rails::Command

def application_root # :nodoc:
  Pathname.new(File.expand_path("../..", APP_PATH)) if defined?(APP_PATH)
end

def command_type # :doc:
  @command_type ||= "command"
end

def environment # :nodoc:
  ENV["RAILS_ENV"].presence || ENV["RACK_ENV"].presence || "development"
end

def file_lookup_paths # :doc:
  @file_lookup_paths ||= [ "{#{lookup_paths.join(',')}}", "**", "*_command.rb" ]
end

def find_by_namespace(namespace, command_name = nil) # :nodoc:
  lookups = [ namespace ]
  lookups << "#{namespace}:#{command_name}" if command_name
  lookups.concat lookups.map { |lookup| "rails:#{lookup}" }
  lookup(lookups)
  namespaces = subclasses.index_by(&:namespace)
  namespaces[(lookups & namespaces.keys).first]
end

def hidden_commands # :nodoc:
  @hidden_commands ||= []
end

def invoke(full_namespace, args = [], **config)
  args = ["--help"] if rails_new_with_no_path?(args)
  full_namespace = full_namespace.to_s
  namespace, command_name = split_namespace(full_namespace)
  command = find_by_namespace(namespace, command_name)
  with_argv(args) do
    if command && command.all_commands[command_name]
      command.perform(command_name, args, config)
    else
      invoke_rake(full_namespace, args, config)
    end
  end
rescue UnrecognizedCommandError => error
  if error.name == full_namespace && command && command_name == full_namespace
    command.perform("help", [], config)
  else
    puts error.detailed_message
  end
  exit(1)
end

def invoke_rake(task, args, config)
  args = ["--describe", task] if HELP_MAPPINGS.include?(args[0])
  find_by_namespace("rake").perform(task, args, config)
end

def lookup_paths # :doc:
  @lookup_paths ||= %w( rails/commands commands )
end

def printing_commands # :nodoc:
  lookup!
  (subclasses - hidden_commands).flat_map(&:printing_commands)
end

def rails_new_with_no_path?(args)
  args == ["new"]
end

def root
  if defined?(ENGINE_ROOT)
    Pathname.new(ENGINE_ROOT)
  else
    application_root
  end
end

def split_namespace(namespace)
  case namespace
  when /^(.+):(\w+)$/
    [$1, $2]
  when ""
    ["help", "help"]
  when HELP_MAPPINGS, "help"
    ["help", "help_extended"]
  when VERSION_MAPPINGS
    ["version", "version"]
  else
    [namespace, namespace]
  end
end

def with_argv(argv)
  original_argv = ARGV.dup
  ARGV.replace(argv)
  yield
ensure
  ARGV.replace(original_argv)
end