estimator.rb in estimator-0.0.3

- old
+ new
@@ -1,47 +1,55 @@
 require 'estimator/version'
 require 'yaml'
 
 module Estimator
-  class Estimate
-    attr_reader :values
-    attr_reader :last_estimate
-    attr_reader :file_path
+    class Estimate
+        LAST_ESTIMATE_EMPTY_STRING = 'last estimate is empty'
 
-    def initialize( file_name )
-      file_name  = 'estimator_db.yml' if file_path.nil?
-      @file_path = "#{Dir.pwd}/#{file_name}"
-    end
+        attr_reader :values
+        attr_reader :last_estimate
+        attr_reader :file_path
 
-    def load
-      save! unless File.exists?( @file_path )
-      yaml_file      = ( YAML.load_file( @file_path ) || {} )
-      @values        = ( yaml_file[:values] || {} )
-      @last_estimate = ( yaml_file[:last_estimate] || 'last estimate is empty' )
-    end
+        # TODO: handle file better
+        def initialize( file_path )
+            @file_path = file_path
+            @values = {}
+            @last_estimate = LAST_ESTIMATE_EMPTY_STRING
+        end
 
-    def save!
-      File.open( @file_path, 'w' ) do |f|
-        f.write( {
-          values: @values,
-          last_estimate: @last_estimate
-        }.to_yaml )
-      end
-    end
+        def load( file_path = @file_path )
+            # TODO: change to exception?
+            return nil unless File.exists?( file_path )
+            # TODO: check for exception
+            yaml_file      = YAML.load_file( file_path )
+            @values        = yaml_file.fetch( :values, {} )
+            @last_estimate = yaml_file.fetch( :last_estimate, LAST_ESTIMATE_EMPTY_STRING )
+        end
 
-    def add_value( value, time = nil )
-      time = Time.now if time.nil?
-      @values[value.to_i] = time
-    end
+        def save!
+            File.open( @file_path, 'w' ) do |f|
+                f.write( {
+                    values: @values,
+                    last_estimate: @last_estimate
+                }.to_yaml )
+            end
+        end
 
-    def estimate
-      return 'add more values before estimating' unless @values.count > 1
-      # y = ax+b
-      b = @values.keys.sort.last
-      y = @values.keys.sort.first
-      x = @values[y] - @values[b]
-      a = (y-b)/x
-      @last_estimate = @values[b] + (-b/a)
-    end
+        def add_value( value, time = nil )
+            time = Time.now if time.nil?
+            @values[value] = time
+        end
 
-  end
+        # TODO: Moving Averages
+        # http://en.wikipedia.org/wiki/Moving_average
+        def estimate
+            return 'add more values before estimating' unless @values.count > 1
+            # y = ax+b
+            b = @values.keys.sort.last
+            y = @values.keys.sort.first
+            x = @values[y] - @values[b]
+            a = (y-b)/x
+            @last_estimate = @values[b] + (-b/a)
+        end
+
+    end
 end