require 'yaml'
require_relative '../util/encryptor'

module Fluent
  module DataEntryPreferenceConfigurable
    @@supported_custom_confs = Hash.new{|h,k| h[k] = {}}

    def self.included(base)
      base.extend ClassMethods
      base.class_eval do
        config_param :custom_conf_path, :string, default: nil
        config_param :key, :string, default: nil
      end
    end

    def load_custom_conf(file_path = @custom_conf_path)
      custom_conf = if file_path and File.exists?(file_path)
                      YAML.load_file(file_path)
                    else
                      nil
                    end
      @@supported_custom_confs.each do |type, settings|
        settings.each do |key, option|
          apply_custom_conf(custom_conf, key, type, option) if custom_conf
          apply_custom_option(key, option)
        end
      end
    end

    def apply_custom_conf(conf, key, type, option)
      if conf[type.to_s] and value = conf[type.to_s][key.to_s]
        var_name = option[:var_name] || key
        instance_variable_set(:"@#{var_name}", value)
      end
    end

    def apply_custom_option(key, option)
      var_name = option[:var_name] || key
      original_value = instance_variable_get(:"@#{var_name}")
      value = original_value
      option.each do |option_name, option_value|
        value = Fluent::DataEntryPreferenceConfigurable.replace_value_with_option(
          key, value, option_name, option_value, key: @key)
      end
      if original_value != value
        instance_variable_set(:"@#{var_name}", value)
      end
    end

    module ClassMethods
      def custom_config_param(key, type, option = {})
        conf = class_variable_get(:@@supported_custom_confs)
        conf[type.to_sym][key.to_sym] = option
      end
    end

    def self.replace_value_with_option(param_name, param_value, option_name, option_value, opts = {})
      ret = param_value
      case option_name
      when :encrypted
        if option_value
          ret = Flydata::Util::Encryptor.decrypt(
            param_value, opts[:key], param_name)
        end
      end
      ret
    end
  end

  module MysqlBinlogFlydataInputPreference
    CUSTOM_CONFIG_PARAMS = {
      mysql_data_entry_preference: {
        database: {},
        tables: {},
        host: {},
        username: {},
        password: {encrypted: true},
      },
    }

    def self.included(base)
      base.class_eval do
        include DataEntryPreferenceConfigurable
        CUSTOM_CONFIG_PARAMS.each do |type, custom_conf|
          custom_conf.each do |key, option|
            custom_config_param key, type, option
          end
        end
      end
    end
  end
end