class ConfigServerAgent

# File lib/config_server_agent.rb, line 10
def initialize(
        config_server_api_key:  ENV['CONFIG_SERVER_API_KEY'],
        config_server_host:     ENV['CONFIG_SERVER_HOST'],
        user_agent:             "ConfigServerAgent/#{ConfigServerAgent::VERSION}",
        user_agent_comment:     nil
)
        @config_server_api_key  = config_server_api_key  or raise ArgumentError, 'Missing config_server_api_key parameter'
        @config_server_host     = config_server_host     or raise ArgumentError, 'Missing config_server_host parameter'

        @config     = nil
        @mutex      = Mutex.new
        @user_agent = user_agent
        @user_agent += " (#{user_agent_comment})" if user_agent_comment
end

# File lib/config_server_agent.rb, line 54
def clear
        @config = nil
end

# File lib/config_server_agent.rb, line 25
def get_config
        return @config if @config
        @mutex.synchronize do
                @config ||= get_request('config_pack', {'cb' => Random.rand})
        end
end

# File lib/config_server_agent.rb, line 32
def get_selected_config(area, item=nil, **options)

        if options[:ignore_cache]
                @config = nil
        end

        data = get_config.group_by { |x| x['area'] }

        raise Error, "Area is missing: #{area}" unless data.key? area

        if item
                data.fetch(area, []).find { |row_item| break row_item["value"] if row_item["name"] == item }
        else
                data.fetch(area, [])
        end
end

# File lib/config_server_agent.rb, line 58
def notify_missing(area, missing)
        post_request 'notify_missing', area: area, name: missing
end

# File lib/config_server_agent.rb, line 49
def set_config(values)
        raise Error, 'values not found' if values.empty?
        post_request('set_values', values)
end

# File lib/config_server_agent.rb, line 79
def dispatch_request(endpoint)
        url          = URI "#{@config_server_host}/api/#{endpoint}"
        http         = Net::HTTP.new url.host, url.port
        http.use_ssl = url.scheme == 'https'

        request = yield url
        request['user-agent']    = @user_agent
        request['content-type']  = 'application/json'
        request['accept']        = 'application/json'
        request['api-key']       = @config_server_api_key

        process_response http.request(request)
end

# File lib/config_server_agent.rb, line 72
def get_request(endpoint, data={})
        dispatch_request(endpoint) do |url|
                url.query = URI.encode_www_form data
                Net::HTTP::Get.new url
        end
end

# File lib/config_server_agent.rb, line 64
def post_request(endpoint, data={})
        dispatch_request(endpoint) do |url|
                request = Net::HTTP::Post.new url
                request.body = data.to_json
                request
        end
end

# File lib/config_server_agent.rb, line 93
def process_response(response)
        unless response['content-type'].start_with? 'application/json'
                raise Error, "Unexpected content-type from server: #{response['content-type']}"
        end

        data = JSON.parse response.read_body

        raise Error, "Config Server error: #{data['error']}" unless response.is_a? Net::HTTPSuccess
        data

rescue JSON::ParserError
        raise Error, "Invalid JSON received from #{@config_server_host}"
end