require 'aws-sdk'
require 'bjn_inventory/source_command'
require 'bjn_inventory/util/filter/json_aws'

module BjnInventory

    class SourceCommand

        class AwsElb < BjnInventory::SourceCommand

            def set_options(opt)
                # Amazon only allows 20 names in describe_tags, so this is one way of accomplishing that
                @page_size = opt[:page_size] || 20
                @regions = nil
                if opt[:region] and !opt[:region].empty?
                    @regions = opt[:region].respond_to?(:to_ary) ? opt[:region] : [ opt[:region] ]
                    region = @regions.first
                else
                    region = 'us-west-2'
                end

                @filters = BjnInventory::Util::Filter::JsonAws.new(filters: opt[:filters] || '[ ]', logger: logger)

                @client = opt[:client]
                @ec2_client = opt[:ec2_client]
                @profile = opt[:profile]
                ec2_client = @ec2_client || new_ec2_client(region)
                if @regions.nil? or @regions.empty?
                    logger.debug "Listing regions"
                    @regions = ec2_client.describe_regions().regions.map { |region| region.region_name }
                end
            end

            def new_ec2_client(region=nil)
                opts = {
                    region: (region || @regions.first)
                }
                opts.update({profile: @profile}) if @profile
                Aws::EC2::Client.new(opts)
            end

            def new_client(region=nil)
                opts = {
                    region: (region || @regions.first)
                }
                opts.update({profile: @profile}) if @profile
                Aws::ElasticLoadBalancing::Client.new(opts)
            end

            def retrieve_entries(override_client=nil)
                entries = @regions.map do |region|
                    client = override_client || @client || new_client(region)
                    _retrieve_entries([], client)
                end.flatten
            end

            def _retrieve_entries(current, client, marker=nil)
                logger.debug "Describing load balancers (page #{marker})"
                chunk_result = client.describe_load_balancers(marker: marker, page_size: @page_size)
                logger.debug "... described"
                marker = chunk_result.next_marker
                if chunk_result.load_balancer_descriptions.length > 0
                    chunk = Hash[chunk_result.load_balancer_descriptions.map { |lb| [lb.load_balancer_name, lb.to_h] }]
                    logger.debug "Describing load balancer tags"
                    # Amazon only allows 20 names to be submitted
                    chunk_tags = Hash[client.describe_tags(load_balancer_names: chunk.keys).tag_descriptions.map do |lbtags|
                                          [lbtags.load_balancer_name, { tags: lbtags.to_h[:tags] }]
                                      end]
                    logger.debug "... described"
                    chunk_list = chunk.map { |lbname, lb| lb.merge(chunk_tags[lbname]) }
                else
                    chunk_list = [ ]
                end
                chunk_list = @filters.select(chunk_list)
                if marker
                    return _retrieve_entries(current + chunk_list, client, marker)
                else
                    return current + chunk_list
                end
            end

        end

    end

end