require 'redis/reconnect_with_readonly/version'
require 'redis'
require 'redis/client'
require 'redis/errors'

class Redis
  class ReconnectWithReadonly
    @reconnect_attempts  = 3
    @initial_retry_wait = 0.5
    @max_retry_wait  = nil

    class << self
      attr_accessor :reconnect_attempts, :initial_retry_wait, :max_retry_wait
    end
  end
end

class Redis
  class Client
    def reconnect_with_readonly(&block)
      retries = 0
      begin
        yield block
      rescue CommandError => e
        if e.message =~ /READONLY/
          if retries < (max_retries = ReconnectWithReadonly.reconnect_attempts)
            wait = ReconnectWithReadonly.initial_retry_wait * retries
            wait = [wait, ReconnectWithReadonly.max_retry_wait].min if ReconnectWithReadonly.max_retry_wait
            logger.info {
              "Reconnect with readonly: #{e.message} " \
              "(retries: #{retries}/#{max_retries}) (wait: #{wait}sec)"
            } if logger
            sleep wait
            retries += 1
            retry
          else
            logger.info {
              "Reconnect with readonly: Give up " \
              "(retries: #{retries}/#{max_retries})"
            } if logger
          end
        else
          raise
        end
      end
    end

    def call_with_reconnect_with_readonly(command, &block)
      reconnect_with_readonly do
        call_without_reconnect_with_readonly(command, &block)
      end
    end

    def call_loop_with_reconnect_with_readonly(command, &block)
      reconnect_with_readonly do
        call_loop_without_reconnect_with_readonly(command, &block)
      end
    end

    def call_pipeline_with_reconnect_with_readonly(command, &block)
      reconnect_with_readonly do
        call_pipeline_without_reconnect_with_readonly(command, &block)
      end
    end

    alias :call_without_reconnect_with_readonly :call
    alias :call :call_with_reconnect_with_readonly
    alias :call_loop_without_reconnect_with_readonly :call_loop
    alias :call_loop :call_loop_with_reconnect_with_readonly
    alias :call_pipeline_without_reconnect_with_readonly :call_pipeline
    alias :call_pipeline :call_pipeline_with_reconnect_with_readonly
  end
end