module Doorkeeper::Rails::Helpers

def doorkeeper_authorize!(*scopes)
  @_doorkeeper_scopes = scopes || Doorkeeper.configuration.default_scopes
  if !valid_doorkeeper_token?
    doorkeeper_render_error
  end
end

def doorkeeper_error
  if doorkeeper_invalid_token_response?
    OAuth::InvalidTokenResponse.from_access_token(doorkeeper_token)
  else
    OAuth::ForbiddenTokenResponse.from_scopes(@_doorkeeper_scopes)
  end
end

def doorkeeper_forbidden_render_options
  nil
end

def doorkeeper_invalid_token_response?
  !doorkeeper_token || !doorkeeper_token.accessible?
end

def doorkeeper_render_error
  error = doorkeeper_error
  headers.merge! error.headers.reject { |k| "Content-Type" == k }
  doorkeeper_render_error_with(error)
end

def doorkeeper_render_error_with(error)
  options = doorkeeper_render_options || {}
  if options.blank?
    head error.status
  else
    options[:status] = error.status
    options[:layout] = false if options[:layout].nil?
    render options
  end
end

def doorkeeper_render_options
  if doorkeeper_invalid_token_response?
    doorkeeper_unauthorized_render_options
  else
    doorkeeper_forbidden_render_options
  end
end

def doorkeeper_token
  @_doorkeeper_token ||= OAuth::Token.authenticate(
    request,
    *Doorkeeper.configuration.access_token_methods
  )
end

def doorkeeper_unauthorized_render_options
  nil
end

def valid_doorkeeper_token?
  doorkeeper_token && doorkeeper_token.acceptable?(@_doorkeeper_scopes)
end