require 'net/http'
require 'json'
require 'digest/md5'

class RestApi
  include MproConfig
  include MproLogger

  def initialize(user)
    @user = user
    @args = []
  end

  def method_missing(method, *args)
    begin
      initialise_params
      convert_args_to_params(args.first)
      @params[:method] = method.to_s.gsub("_", ".")
      @params[:sig] = generate_sig
      escape_args
      response = send_request
      return response if response
    rescue Exception => exc
      MproLogger.mlog("#{@service_name} method call error: #{exc.message}")
      super
    end
  end

  private

    def initialise_params
      #should be overloaded
    end

    def convert_args_to_params(args)
      return unless args
      @args = []
      args.each do |k,v|
        @params[k] = case v
          when Array then v.join(',')
          else v.to_s
        end
        @args << k
      end
    end

    def escape_args
      @args.each do |k|
        @params[k] = CGI.escape(@params[k])
      end
    end

    def generate_sig
      @data = @params.
                sort{|a,b| a[0].to_s <=> b[0].to_s}.
                map{|arg| "#{arg[0]}=#{arg[1]}"}.
                join
      Digest::MD5.hexdigest(@sig.call)
    end

    def symbolize_keys(data)
      data = [data] if Hash === data
      return data unless Array === data
      response = []
      data.each do |item|
        response << case item
          when Array then
            symbolize_keys item
          when Hash then
            hash = {}
            item.each do |k,v|
              hash[k.to_sym] = Array === v ? symbolize_keys(v) : v
            end
            hash
          else item
        end
      end
      response.size == 1 ? response.first : response
    end

    def send_request
      query_string = @params.
                        map{|arg| "#{arg[0]}=#{arg[1]}"}.
                        join('&')
      http = Net::HTTP.new(@service_address, 80)
      path = "#{@service_path}?#{query_string}"
      resp, data = http.get(path)
      unless resp.code_type == Net::HTTPOK
        MproLogger.mlog("Bad response from #{@service_address}: #{resp.code}")
        return
      end

      attributes = JSON.parse(data)

      if Hash === attributes && attributes.has_key?("error")
        MproLogger.mlog("#{@service_name} request error: #{attributes['error'].inspect}")
        return
      end
      #puts attributes.inspect

      case attributes
        when Array then
          return symbolize_keys attributes
        when Hash then
          if attributes.has_key?("response")
            return symbolize_keys attributes["response"]
          else
            return symbolize_keys attributes
          end
        else return attributes
      end
    end
end