module Rmega
  class APIResponse
    attr_reader :body, :code

    # Check out the error codes list at https://mega.co.nz/#doc (section 11)
    ERRORS = {
      -1  => 'An internal error has occurred. Please submit a bug report, detailing the exact circumstances in which this error occurred.',
      -2  => 'You have passed invalid arguments to this command.',
      -3  => 'A temporary congestion or server malfunction prevented your request from being processed. No data was altered. Retry. Retries must be spaced with exponential backoff.',
      -4  => 'You have exceeded your command weight per time quota. Please wait a few seconds, then try again (this should never happen in sane real-life applications).',
      -5  => 'The upload failed. Please restart it from scratch.',
      -6  => 'Too many concurrent IP addresses are accessing this upload target URL.',
      -7  => 'The upload file packet is out of range or not starting and ending on a chunk boundary.',
      -8  => 'The upload target URL you are trying to access has expired. Please request a fresh one.',
      -9  => 'Object (typically, node or user) not found',
      -10 => 'Circular linkage attempted',
      -11 => 'Access violation (e.g., trying to write to a read-only share)',
      -12 => 'Trying to create an object that already exists',
      -13 => 'Trying to access an incomplete resource',
      -14 => 'A decryption operation failed (never returned by the API)',
      -15 => 'Invalid or expired user session, please relogin',
      -16 => 'User blocked',
      -17 => 'Request over quota',
      -18 => 'Resource temporarily not available, please try again later',
      -19 => 'Too many connections on this resource',
      -20 => 'Write failed',
      -21 => 'Read failed',
      -22 => 'Invalid application key; request not processed',
    }.freeze

    def initialize(http_response)
      @code = http_response.code.to_i
      @body = http_response.body ? http_response.body : ""
    end

    def error?
      unknown_error? or known_error? or temporary_error?
    end

    def ok?
      !error?
    end

    def as_error
      if unknown_error?
        return TemporaryServerError.new
      elsif temporary_error?
        return TemporaryServerError.new(error_message)
      else
        return ServerError.new(error_message)
      end
    end

    def as_json
      @as_body ||= JSON.parse(body).first
    end

    private

    def as_error_code
      @error_code ||= body.scan(/\A\[{0,1}(\-\d+)\]{0,1}\z/).flatten.first.to_i
    end

    def error_message
      ERRORS[as_error_code]
    end

    def temporary_error?
      known_error? and [-3, -6, -18, -19].include?(as_error_code)
    end

    def unknown_error?
      code == 500 or body.empty?
    end

    def known_error?
      as_error_code < 0
    end
  end
end