require 'moneta'
require 'rack/cache/key'
require 'rack/cache/meta_store'
require 'rack/cache/entity_store'

module Rack
  module Cache
    # @api public
    Moneta = {}

    # @api private
    module MonetaResolver
      include Rack::Utils

      def resolve(uri)
        cache = Rack::Cache::Moneta[uri.to_s.sub(%r{^moneta://}, '')] ||=
          begin
            options = parse_query(uri.query).map do |key, value|
              [key.to_sym,
               case value
               when 'true'
                 true
               when 'false'
                 false
               else
                 value
               end]
            end
            ::Moneta.new(uri.host.to_sym, options.to_h)
          end
        new(cache)
      end
    end

    class MetaStore
      # @api public
      class Moneta < MetaStore
        extend MonetaResolver

        def initialize(cache)
          @cache = cache
        end

        def read(key)
          @cache[key] || []
        end

        def write(key, entries)
          @cache[key] = entries
        end

        def purge(key)
          @cache.delete(key)
          nil
        end
      end

      # @api public
      MONETA = Moneta
    end

    class EntityStore
      # @api public
      class Moneta < EntityStore
        extend MonetaResolver

        def initialize(cache)
          @cache = cache
        end

        def open(key)
          data = read(key)
          data && [data]
        end

        def exist?(key)
          @cache.key?(key)
        end

        def read(key)
          @cache[key]
        end

        def write(body, ttl = 0)
          buf = StringIO.new
          key, size = slurp(body) { |part| buf.write(part) }
          @cache.store(key, buf.string, ttl == 0 ? {} : { expires: ttl })
          [key, size]
        end

        def purge(key)
          @cache.delete(key)
          nil
        end
      end

      # @api public
      MONETA = Moneta
    end
  end
end
