# frozen_string_literal: true

module Mozo
  module Counter
    # Redis-backed counter adapter. Replaces the DrbCounter (in-memory,
    # single-process, DRb-based) with a persistent, multi-process-safe,
    # battle-tested key-value store.
    #
    # Benefits over DrbCounter:
    #   - Persistent (survives restarts, no CouchDB reload dance)
    #   - Atomic INCR/DECR (no race conditions between Puma workers)
    #   - No separate process to manage (Redis is already needed for ActionCable)
    #   - Production-ready, widely deployed
    #
    # Usage:
    #   Mozo::Counter.connection = Mozo::Counter::Redis.new
    #   # or with custom config:
    #   Mozo::Counter.connection = Mozo::Counter::Redis.new(url: "redis://localhost:6379/2")
    #
    class Redis
      def initialize(url: nil)
        require 'redis'
        @redis = ::Redis.new(url: url || ENV.fetch('REDIS_URL', 'redis://localhost:6379/7'))
      end

      def get(key, options = {})
        value = @redis.get(key)
        quiet = options[:quiet]
        unless quiet
          Rails.logger.debug("[REDIS_COUNTER] GET #{key} = #{value.inspect}")
        end
        value&.to_i || 0
      rescue => e
        Rails.logger.error("[REDIS_COUNTER] GET #{key} failed: #{e.message}")
        0
      end

      def set(key, value)
        Rails.logger.debug("[REDIS_COUNTER] SET #{key} = #{value}")
        @redis.set(key, value)
      rescue => e
        Rails.logger.error("[REDIS_COUNTER] SET #{key} failed: #{e.message}")
        value
      end

      def incr(key, options = {})
        initial = options[:initial] || 1
        Rails.logger.debug("[REDIS_COUNTER] INCR #{key}")
        if @redis.exists?(key)
          @redis.incr(key)
        else
          @redis.set(key, initial)
          initial
        end
      rescue => e
        Rails.logger.error("[REDIS_COUNTER] INCR #{key} failed: #{e.message}")
        initial
      end

      def decr(key, options = {})
        initial = options[:initial] || 0
        Rails.logger.debug("[REDIS_COUNTER] DECR #{key}")
        if @redis.exists?(key)
          @redis.decr(key)
        else
          @redis.set(key, initial)
          initial
        end
      rescue => e
        Rails.logger.error("[REDIS_COUNTER] DECR #{key} failed: #{e.message}")
        initial
      end

      def flush
        Rails.logger.debug("[REDIS_COUNTER] FLUSHDB")
        @redis.flushdb
      end
    end
  end
end