Add scaled time calculation.

Fixed #39.

app/models/game.rb

@@ -1,5 +1,9 @@
+require 'simple'
+
 class Game < ActiveRecord::Base
-  TIME_SCALE_FACTOR = 1 / 0.2
+  include SimpleExtensions
+
+  TIME_SCALE_FACTOR = [1 / 0.8, 1 / 0.2]
 
   acts_as_limited
   has_many :market_prices
@@ -56,15 +60,22 @@ def current_price market
     market.current_price @game
   end
 
-  def time_since time
-    TIME_SCALE_FACTOR * speed * (Time.now - time)
-  end
-
   def in_progress?
     not ended
   end
 
+  def time_since_update
+    time_since updated_at
+  end
+
   def to_s
     "#{states.count} confirmed players, #{started ? "started #{started}" : "not started"}"
   end
+
+  private
+
+  def time_since time
+    range_map(speed, 0, 100, TIME_SCALE_FACTOR[0],
+        TIME_SCALE_FACTOR[1]) * (Time.now - time)
+  end
 end

db/schema.rb

@@ -47,7 +47,7 @@
     t.integer  "x",                                   :null => false
     t.integer  "y",                                   :null => false
     t.integer  "elevation",         :default => 0,    :null => false
-    t.string   "type",                                :null => false
+    t.string   "block_type",                          :null => false
     t.float    "wind_speed",        :default => 0.0,  :null => false
     t.integer  "water_flow",        :default => 0,    :null => false
     t.integer  "sunfall",           :default => 5125, :null => false

lib/simple.rb

@@ -0,0 +1,6 @@
+module SimpleExtensions
+  def range_map(value, istart, istop, ostart, ostop)
+    ostart + (ostop - ostart) * (
+        Float((value - istart)) / Float((istop - istart)))
+  end
+end

spec/models/game_spec.rb

@@ -73,21 +73,26 @@
       (@game.current_price @market).should eq(@market.current_price @game)
     end
 
-    context "should know how much game-relative time has passed" do
+    context "that has been updated" do
       before do
         @game.updated_at = Time.now - 60
         @now = Time.now
+        Time.stubs(:now).returns(@now)
       end
 
-      it "with a real-time speed" do
+      it "should scale time passed based on game speed" do
         @game.speed = 0
-        assert_equal @game.time_since(@now), @now - @game.updated_at
+        real_time = @game.time_since_update
+        @game.speed = 1
+        fast_time = @game.time_since_update
+        real_time.should be > (@now - @game.updated_at)
+        fast_time.should be > (@now - @game.updated_at)
+        real_time.should be < fast_time
       end
 
-      it "with maxiumum speed" do
+      it "should know how much time has passed with maxiumum speed" do
         @game.speed = 1
-        assert_equal @game.time_since(@now),
-            Game::TIME_SCALE_FACTOR * (@now - @game.updated_at)
+        @game.time_since_update.should be > (@now - @game.updated_at)
       end
     end
   end