require 'yajl'

module Aws
  module RiKanjoo
    class Ec2
      attr_reader :region, :instance_type, :ri_util

      def initialize(region, instance_type, ri_util)
        @region             = region
        @instance_type      = instance_type
        @ri_util            = ri_util
        @os                 = 'linux'
        @current_price_url  = 'http://a0.awsstatic.com/pricing/1/ec2'
        @previous_price_url = 'http://a0.awsstatic.com/pricing/1/ec2/previous-generation'
      end

      def om_price_from_contents(contents)
        region = convert_region(@region)

        # parse
        json = parse_contents(contents)

        # select 'region' and 'instance_type'
        json['config']['regions'].each do |r|
          # r = {"region"=>"us-east", "instanceTypes"=>[{"type"=>"generalCurrentGen", ...
          next unless r['region'] == region
          r['instanceTypes'].each do |type|
            # type = {"type"=>"generalCurrentGen", "sizes"=>[{"size"=>"m3.medium", "vCPU"=>"1" ...
            type['sizes'].each do |i|
              next unless i['size'] == @instance_type

              return { hr_price: i['valueColumns'][0]['prices']['USD'] }
            end
          end
        end

        abort("[ec2][#{region}][#{@instance_type}] Not found om-price?")
      end

      def ri_price_from_contents(contents)
        region = clean_region(@region)

        # parse
        json = parse_contents(contents)

        ri_info = nil

        json['config']['regions'].each do |r|
          next unless r['region'] == region

          r['instanceTypes'].each do |type|
            type['sizes'].each do |i|
              next unless i['size'] == @instance_type

              ri_info = ri_info ||= {}
              i['valueColumns'].each do |y|
                case y['name']
                when 'yrTerm1'
                  ri_info[@ri_util] = { upfront: y['prices']['USD'] }
                when 'yrTerm1Hourly'
                  ri_info[@ri_util].store(:hr_price, y['prices']['USD'])
                end
              end
            end
          end
        end

        abort("[ec2][#{region}][#{@instance_type}] Not found ri-price?") unless ri_info

        return ri_info
      end

      def price_url
        return (self.previous_generation_type) ? @previous_price_url : @current_price_url
      end

      def om_price_file
        return "#{@os}-od.min.js"
      end

      def ri_price_file
        return (self.previous_generation_type) ? "#{@ri_util}_#{@os}.min.js" : "#{@os}-ri-#{@ri_util}.min.js"
      end

      def previous_generation_type
        case @instance_type
        when /^(c1|m2|cc2\.8xlarge|cr1\.8xlarge|hi1\.4xlarge|cg1\.4xlarge)/ then true
        when /^m1/ then (@instance_type == 'm1.small') ? false : true
        else false
        end
      end

      def parse_contents(data)
        data = data.gsub("/*\n * This file is intended for use only on aws.amazon.com. We do not guarantee its availability or accuracy.\n *\n * Copyright 2014 Amazon.com, Inc. or its affiliates. All rights reserved.\n */\ncallback({",'{').gsub("\);", '').gsub(/([a-zA-Z]+):/, '"\1":')
        return Yajl::Parser.parse(data)
      end

      def convert_region(region)
        # not same om region
        case region
        when 'us-east-1'      then 'us-east'
        when 'us-west-1'      then 'us-west'
        when 'us-west-2'      then 'us-west-2'
        when 'eu-west-1'      then 'eu-ireland'
        when 'ap-southeast-1' then 'apac-sin'
        when 'ap-northeast-1' then 'apac-tokyo'
        when 'ap-southeast-2' then 'apac-syd'
        when 'sa-east-1'      then 'sa-east-1'
        end
      end

      def clean_region(region)
        return region.gsub(/^us-east-1$/, 'us-east')
      end
    end
  end
end