require 'rmega/storage'
require 'rmega/request_error'
require 'rmega/crypto/crypto'
require 'rmega/utils'

module Rmega
  def self.login(email, password)
    Session.new(email, password).storage
  end

  class Session
    include Loggable

    attr_accessor :email, :request_id, :sid, :master_key

    def initialize(email, password)
      self.email = email
      self.request_id = random_request_id

      login(password)
    end

    def options
      Rmega.options
    end

    delegate :api_url, :api_request_timeout, to: :options

    def storage
      @storage ||= Storage.new(self)
    end

    def login(password)
      uh = Crypto.stringhash Crypto.prepare_key_pw(password), email
      resp = request a: 'us', user: email, uh: uh

      # Decrypt the master key
      encrypted_key = Crypto.prepare_key_pw password
      self.master_key = Crypto.decrypt_key encrypted_key, Utils.base64_to_a32(resp['k'])

      # Generate the session id
      self.sid = Crypto.decrypt_sid master_key, resp['csid'], resp['privk']
    end

    def random_request_id
      rand(1E7..1E9).to_i
    end

    def request(body)
      self.request_id += 1
      url = "#{api_url}?id=#{request_id}"
      url << "&sid=#{sid}" if sid
      logger.info "POST #{url}"
      logger.info "#{body.inspect}"
      response = HTTPClient.new.post url, [body].to_json, timeout: api_request_timeout
      logger.debug "#{response.code}\n#{response.body}"
      resp = JSON.parse(response.body).first
      raise RequestError.new(resp) if RequestError.error_code?(resp)
      resp
    end
  end
end