lib/dry/effects/providers/random.rb in dry-effects-0.1.2 vs lib/dry/effects/providers/random.rb in dry-effects-0.1.3

@@ -4,10 +4,81 @@
 
 module Dry
   module Effects
     module Providers
       class Random < Provider[:random]
-        public :rand
+        DEFAULT = -> _ { ::Random::DEFAULT.rand }
+
+        DEFAULT_RANGE = 0.0...1.0
+
+        def rand(range_or_limit = nil)
+          range_or_limit ||= DEFAULT_RANGE
+
+          if range_or_limit.is_a?(::Range)
+            low = range_or_limit.begin
+            high = range_or_limit.end
+            exclude_end = range_or_limit.exclude_end?
+          elsif range_or_limit >= 1
+            low = 0
+            high = range_or_limit.floor
+            exclude_end = true
+          else
+            low = 0.0
+            high = range_or_limit.to_f
+            exclude_end = true
+          end
+
+          if low.is_a?(::Integer)
+            next_integer(low, high, exclude_end)
+          else
+            next_float(low, high)
+          end
+        end
+
+        def call(options = Undefined)
+          @prev = nil
+          @generator = build_generator(options)
+          yield
+        end
+
+        def next_integer(low, high, exclude_end)
+          @prev = @generator.(@prev) % 1
+
+          value = low + (@prev * (high - low)).round
+
+          if value.eql?(high) && exclude_end
+            low
+          else
+            value
+          end
+        end
+
+        def next_float(low, high)
+          @prev = @generator.(@prev) % 1
+
+          low + (@prev * (high - low))
+        end
+
+        def build_generator(options)
+          case options
+          when Undefined
+            DEFAULT
+          when ::Hash
+            if options.key?(:seed)
+              random = ::Random.new(options[:seed])
+            else
+              random = ::Random::DEFAULT
+            end
+
+            -> _ { random.rand }
+          else
+            generator = options
+
+            lambda do |prev|
+              prev.nil? ? generator.() : generator.(prev)
+            end
+          end
+        end
       end
     end
   end
 end