# frozen_string_literal: true

require 'net/http'
require 'logger'
require 'benchmark'
require 'rainbow'
require 'rack'

module HttpLog
  LOG_PREFIX = '[httplog] '.freeze
  class BodyParsingError < StandardError; end

  class << self
    attr_writer :configuration

    def configuration
      @configuration ||= Configuration.new
    end
    alias config configuration
    alias options configuration # TODO: remove with 1.0.0

    def reset!
      @configuration = nil
    end

    def configure
      yield(configuration)
    end

    def call(options = {})
      if config.json_log
        log_json(options)
      elsif config.compact_log
        log_compact(options[:method], options[:url], options[:response_code], options[:benchmark])
      else
        HttpLog.log_request(options[:method], options[:url])
        HttpLog.log_headers(options[:request_headers])
        HttpLog.log_data(options[:request_body])
        HttpLog.log_status(options[:response_code])
        HttpLog.log_benchmark(options[:benchmark])
        HttpLog.log_headers(options[:response_headers])
        HttpLog.log_body(options[:response_body], options[:encoding], options[:content_type])
      end
    end

    def url_approved?(url)
      return false if config.url_blacklist_pattern && url.to_s.match(config.url_blacklist_pattern)

      !config.url_whitelist_pattern || url.to_s.match(config.url_whitelist_pattern)
    end

    def log(msg)
      return unless config.enabled

      config.logger.log(config.severity, colorize(prefix + msg))
    end

    def log_connection(host, port = nil)
      return if config.json_log || config.compact_log || !config.log_connect

      log("Connecting: #{[host, port].compact.join(':')}")
    end

    def log_request(method, uri)
      return unless config.log_request

      log("Sending: #{method.to_s.upcase} #{uri}")
    end

    def log_headers(headers = {})
      return unless config.log_headers

      headers.each do |key, value|
        log("Header: #{key}: #{value}")
      end
    end

    def log_status(status)
      return unless config.log_status

      status = Rack::Utils.status_code(status) unless status == /\d{3}/
      log("Status: #{status}")
    end

    def log_benchmark(seconds)
      return unless config.log_benchmark

      log("Benchmark: #{seconds.to_f.round(6)} seconds")
    end

    def log_body(body, encoding = nil, content_type = nil)
      return unless config.log_response

      data = parse_body(body, encoding, content_type)

      if config.prefix_response_lines
        log('Response:')
        log_data_lines(data)
      else
        log("Response:\n#{data}")
      end
    rescue BodyParsingError => e
      log("Response: #{e.message}")
    end

    def parse_body(body, encoding, content_type)
      unless text_based?(content_type)
        raise BodyParsingError, "(not showing binary data)"
      end

      if body.is_a?(Net::ReadAdapter)
        # open-uri wraps the response in a Net::ReadAdapter that defers reading
        # the content, so the reponse body is not available here.
        raise BodyParsingError, '(not available yet)'
      end

      if encoding =~ /gzip/ && body && !body.empty?
        begin
          sio = StringIO.new(body.to_s)
          gz = Zlib::GzipReader.new(sio)
          body = gz.read
        rescue Zlib::GzipFile::Error => e
          log("(gzip decompression failed)")
        end
      end

      utf_encoded(body.to_s, content_type)
    end

    def log_data(data)
      return unless config.log_data
      data = utf_encoded(data.to_s.dup)

      if config.prefix_data_lines
        log('Data:')
        log_data_lines(data)
      else
        log("Data: #{data}")
      end
    end

    def log_compact(method, uri, status, seconds)
      return unless config.compact_log
      status = Rack::Utils.status_code(status) unless status == /\d{3}/
      log("#{method.to_s.upcase} #{uri} completed with status code #{status} in #{seconds} seconds")
    end

    def log_json(data = {})
      return unless config.json_log

      data[:response_code] = transform_response_code(data[:response_code]) if data[:response_code].is_a?(Symbol)

      parsed_body = begin
        parse_body(data[:response_body], data[:encoding], data[:content_type])
      rescue BodyParsingError => e
        e.message
      end

      if config.compact_log
        log({
          method: data[:method].to_s.upcase,
          url: data[:url],
          response_code: data[:response_code].to_i,
          benchmark: data[:benchmark]
        }.to_json)
      else
        log({
          method: data[:method].to_s.upcase,
          url: data[:url],
          request_body: data[:request_body],
          request_headers: data[:request_headers].to_h,
          response_code: data[:response_code].to_i,
          response_body: parsed_body,
          response_headers: data[:response_headers].to_h,
          benchmark: data[:benchmark]
        }.to_json)
      end
    end

    def transform_response_code(response_code_name)
      Rack::Utils::HTTP_STATUS_CODES.detect{ |k, v| v.to_s.downcase == response_code_name.to_s.downcase }.first
    end

    def colorize(msg)
      return msg unless config.color
      if config.color.is_a?(Hash)
        msg = Rainbow(msg).color(config.color[:color]) if config.color[:color]
        msg = Rainbow(msg).bg(config.color[:background]) if config.color[:background]
      else
        msg = Rainbow(msg).color(config.color)
      end
      msg
    rescue
      warn "HTTPLOG CONFIGURATION ERROR: #{config.color} is not a valid color"
      msg
    end

    private

    def utf_encoded(data, content_type = nil)
      charset = content_type.to_s.scan(/; charset=(\S+)/).flatten.first || 'UTF-8'
      begin
        data.force_encoding(charset)
      rescue StandardError
        data.force_encoding('UTF-8')
      end
      data.encode('UTF-8', invalid: :replace, undef: :replace)
    end

    def text_based?(content_type)
      # This is a very naive way of determining if the content type is text-based; but
      # it will allow application/json and the like without having to resort to more
      # heavy-handed checks.
      content_type =~ /^text/ ||
        content_type =~ /^application/ && !['application/octet-stream', 'application/pdf'].include?(content_type)
    end

    def log_data_lines(data)
      data.each_line.with_index do |line, row|
        if config.prefix_line_numbers
          log("#{row + 1}: #{line.chomp}")
        else
          log(line.strip)
        end
      end
    end

    def prefix
      if config.prefix.respond_to?(:call)
        config.prefix.call
      else
        config.prefix.to_s
      end
    end
  end
end