# frozen_string_literal: true

require 'time'
require 'json'
require_relative '../elastic_common_schema'

module Twiglet
  class Logger
    include ElasticCommonSchema

    def initialize(conf:, scoped_properties: {})
      @service = conf[:service]
      @now = conf[:now] || -> { Time.now.utc }
      @output = conf[:output] || $stdout

      raise 'configuration must have a service name' \
        unless @service.is_a?(String) && !@service.strip.empty?

      @scoped_properties = scoped_properties
    end

    def debug(message)
      log(level: 'debug', message: message)
    end

    def info(message)
      log(level: 'info', message: message)
    end

    def warning(message)
      log(level: 'warning', message: message)
    end

    def error(message, error = nil)
      if error
        message = message.merge({
                                  error_name: error.message,
                                  backtrace: error.backtrace
                                })
      end

      log(level: 'error', message: message)
    end

    def critical(message)
      log(level: 'critical', message: message)
    end

    def with(scoped_properties)
      Logger.new(conf: { service: @service,
                         now: @now,
                         output: @output },
                 scoped_properties: scoped_properties)
    end

    private

    def log(level:, message:)
      raise 'Message must be a Hash' unless message.is_a?(Hash)

      message = message.transform_keys(&:to_sym)
      message.key?(:message) || raise('Log object must have a \'message\' property')

      message[:message].strip.empty? && raise('The \'message\' property of log object must not be empty')

      total_message = {
        service: {
          name: @service
        },
        "@timestamp": @now.call.iso8601(3),
        log: {
          level: level
        }
      }
      total_message = total_message.merge(@scoped_properties)
                                   .merge!(message)
                                   .then { |log_entry| to_nested(log_entry) }

      @output.puts total_message.to_json
    end
  end
end