require 'net/https'
require 'cgi/util'
require 'multi_json'
# helpers
require 'domoscio_rails/version'
require 'domoscio_rails/json'
require 'domoscio_rails/errors'
require 'domoscio_rails/authorization_token'
# resources
require 'domoscio_rails/http_calls'
require 'domoscio_rails/resource'
require 'domoscio_rails/data/content.rb'
require 'domoscio_rails/data/event.rb'
require 'domoscio_rails/data/instance.rb'
require 'domoscio_rails/data/learning_session.rb'
require 'domoscio_rails/data/student.rb'
require 'domoscio_rails/knowledge/knowledge_edge.rb'
require 'domoscio_rails/knowledge/knowledge_graph.rb'
require 'domoscio_rails/knowledge/knowledge_node_content.rb'
require 'domoscio_rails/knowledge/knowledge_node_student.rb'
require 'domoscio_rails/knowledge/knowledge_node.rb'
require 'domoscio_rails/objective/objective_knowledge_node_student.rb'
require 'domoscio_rails/objective/objective_knowledge_node.rb'
require 'domoscio_rails/objective/objective_student.rb'
require 'domoscio_rails/objective/objective.rb'
require 'domoscio_rails/tag/tag_edge.rb'
require 'domoscio_rails/tag/tag_set.rb'
require 'domoscio_rails/tag/tag.rb'
require 'domoscio_rails/tag/tagging.rb'
require 'domoscio_rails/utils/gameplay_util.rb'
require 'domoscio_rails/utils/recommendation_util.rb'
require 'domoscio_rails/utils/review_util.rb'

module DomoscioRails
  class Configuration
    attr_accessor :root_url, :client_id, :client_passphrase, :temp_dir, :version

    # Refers to AdaptiveEngine Version
    def version
      @version || 2
    end

    def root_url
      @root_url || ""
    end
  end

  class << self
    attr_accessor :configuration
  end

  def self.configure
    self.configuration ||= Configuration.new
    yield configuration
  end

  def self.api_uri(url='')
    URI(configuration.root_url + url)
  end

  #
  # - +method+: HTTP method; lowercase symbol, e.g. :get, :post etc.
  # - +url+: the part after Configuration#root_url
  # - +params+: hash; entity data for creation, update etc.; will dump it by JSON and assign to Net::HTTPRequest#body
  # - +filters+: hash; pagination params etc.; will encode it by URI and assign to URI#query
  # - +headers+: hash; request_headers by default
  # - +before_request_proc+: optional proc; will call it passing the Net::HTTPRequest instance just before Net::HTTPRequest#request
  #
  # Raises DomoscioRails::ResponseError if response code != 200.
  #
  def self.request(method, url, params={}, filters={}, headers = request_headers, before_request_proc = nil)
    return false if @disabled
    # sets a default page size to 2k
    params.merge!({'per_page': 2000}) unless params[:per_page]
    uri = api_uri(url)
    uri.query = URI.encode_www_form(filters) unless filters.empty?
    res = DomoscioRails.send_request(uri, method, params, headers, before_request_proc)
    return res if res.kind_of? DomoscioRails::ProcessingError
    begin
      raise_http_failure(uri, res, params)
      data = DomoscioRails::JSON.load(res.body.nil? ? '' : res.body)
      DomoscioRails::AuthorizationToken::Manager.storage.store({access_token: res['Accesstoken'], refresh_token: res['Refreshtoken']})
    rescue MultiJson::LoadError => exception
      data = ProcessingError.new(uri, 500, exception, res.body, params)
    rescue ResponseError => exception
      data = exception
    end

    if res['Total'] && !filters[:page]
      pagetotal = (res['Total'].to_i / res['Per-Page'].to_f).ceil
      for j in 2..pagetotal
        res = DomoscioRails.send_request(uri, method, params.merge({page: j}), headers, before_request_proc)
        return res if res.kind_of? DomoscioRails::ProcessingError
        begin
          raise_http_failure(uri, res, params)
          body = DomoscioRails::JSON.load(res.body.nil? ? '' : res.body)
          data += body
          data.flatten!
        rescue MultiJson::LoadError => exception
          return ProcessingError.new(uri, 500, exception, res.body, params)
        rescue ResponseError => exception
          return exception
        end
      end
    end
    data
  end

  def self.send_request(uri, method, params, headers, before_request_proc)
    begin
      res = Net::HTTP.start(uri.host, uri.port, use_ssl: uri.scheme == 'https') do |http|
        req = Net::HTTP::const_get(method.capitalize).new(uri.request_uri, headers)
        req.body = DomoscioRails::JSON.dump(params)
        before_request_proc.call(req) if before_request_proc
        http.request req
      end
    rescue Timeout::Error, Errno::EINVAL, Errno::ECONNREFUSED, Errno::ECONNRESET, EOFError, Net::HTTPBadResponse, Net::HTTPHeaderSyntaxError, Net::ProtocolError => exception
      ProcessingError.new(uri, 500, exception, res)
    end
  end

  private

  def self.raise_http_failure(uri, res, params)
    unless res.kind_of? Net::HTTPSuccess
      if res.blank?
        raise ResponseError.new(uri, 500, {error: {status: 500, message: 'AdaptiveEngine not available'}}, {}, params)
      else
        body = DomoscioRails::JSON.load((res.body.nil? ? '' : res.body), :symbolize_keys => true)
        raise ResponseError.new(uri, res.code.to_i, body, res.body, params)
      end
    end
  end

  def self.user_agent
    @uname ||= get_uname
    {
      bindings_version: DomoscioRails::VERSION,
      lang: 'ruby',
      lang_version: "#{RUBY_VERSION} p#{RUBY_PATCHLEVEL} (#{RUBY_RELEASE_DATE})",
      platform: RUBY_PLATFORM,
      uname: @uname
    }
  end

  def self.get_uname
    `uname -a 2>/dev/null`.strip if RUBY_PLATFORM =~ /linux|darwin/i
  rescue Errno::ENOMEM
    'uname lookup failed'
  end

  def self.request_headers
    auth_token = DomoscioRails::AuthorizationToken::Manager.get_token
    if !auth_token.is_a? String
      headers = {
        'user_agent' => "#{DomoscioRails.user_agent}",
        'AccessToken' => "#{auth_token[:access_token]}",
        'RefreshToken' => "#{auth_token[:refresh_token]}",
        'Content-Type' => 'application/json'
      }
    else
      headers = {
        'user_agent' => "#{DomoscioRails.user_agent}",
        'Authorization' => "Token token=#{DomoscioRails.configuration.client_passphrase}",
        'Content-Type' => 'application/json'
      }
    end
    headers
  end
end