From 840dbf0c3dab1342dce9cb8db2a53cef045f3c3c Mon Sep 17 00:00:00 2001
From: Tomasz Kuklis <tomasz.kuklis@gmail.com>
Date: Mon, 12 Dec 2011 12:56:45 +0100
Subject: [PATCH 01/11] support const loans

---
 lib/excel.rb         | 35 +++++++++++++++++++++++
 lib/monetico.rb      |  1 +
 lib/monetico/loan.rb | 38 +++++++++++++++++++------
 monetico.gemspec     |  3 ++
 spec/loan_spec.rb    | 66 ++++++++++++++++++++++++++++++++++++++++++++
 spec/spec_helper.rb  |  7 +++++
 6 files changed, 142 insertions(+), 8 deletions(-)
 create mode 100644 lib/excel.rb
 create mode 100644 spec/loan_spec.rb
 create mode 100644 spec/spec_helper.rb

diff --git a/lib/excel.rb b/lib/excel.rb
new file mode 100644
index 0000000..1bf6758
--- /dev/null
+++ b/lib/excel.rb
@@ -0,0 +1,35 @@
+module Excel
+  def pmt(rate, nper, pv, fv=0, type=0)
+    ((-pv * pvif(rate, nper) - fv ) / ((1.0 + rate * type) * fvifa(rate, nper)))
+  end
+
+  def ipmt(rate, per, nper, pv, fv=0, type=0)
+    p = pmt(rate, nper, pv, fv, 0);
+    ip = -(pv * pow1p(rate, per - 1) * rate + p * pow1pm1(rate, per - 1))
+    (type == 0) ? ip : ip / (1 + rate)
+  end
+
+  def ppmt(rate, per, nper, pv, fv=0, type=0)
+    p = pmt(rate, nper, pv, fv, type)
+    ip = ipmt(rate, per, nper, pv, fv, type)
+    p - ip
+  end
+  
+  protected
+  
+  def pow1pm1(x, y)
+    (x <= -1) ? ((1 + x) ** y) - 1 : Math.exp(y * Math.log(1.0 + x)) - 1
+  end
+
+  def pow1p(x, y)
+    (x.abs > 0.5) ? ((1 + x) ** y) : Math.exp(y * Math.log(1.0 + x))
+  end
+
+  def pvif(rate, nper)
+    pow1p(rate, nper)
+  end
+
+  def fvifa(rate, nper)
+    (rate == 0) ? nper : pow1pm1(rate, nper) / rate
+  end
+end
diff --git a/lib/monetico.rb b/lib/monetico.rb
index 04cbbc5..d3fa0f4 100644
--- a/lib/monetico.rb
+++ b/lib/monetico.rb
@@ -1,4 +1,5 @@
 require "bigdecimal"
+require 'excel'
 require "monetico/loan"
 require "monetico/version"
 
diff --git a/lib/monetico/loan.rb b/lib/monetico/loan.rb
index 8b26154..51190ef 100644
--- a/lib/monetico/loan.rb
+++ b/lib/monetico/loan.rb
@@ -1,5 +1,7 @@
 module Monetico
   class Loan
+    include Excel
+    
     CADENCE = {
       monthly: 12,
       weekly: 52,
@@ -28,30 +30,50 @@ def total_interests
     end
 
     def interests(idx)
-      (@amount - (idx - 1) * capital) * @interest_rate
+      if const?
+        interests_for_period(idx)
+      else
+        (@amount - (idx - 1) * capital) * @interest_rate
+      end
     end
 
     def payback(range) 
       from = range.begin
       to = range.end
-
+      
+      current_amount = 0.0
+      
       if const?
         par = (1 + @interest_rate) ** @no_installments
-
+                
         range.map do |n|
-          { no: n, interests: interests(n), amount: @amount * @interest_rate * par / (par - 1) }
+          current_amount += monthly_payment
+          { no: n, interests: interests(n), amount: monthly_payment, capital: capital_for_period(n), balance:  @amount + total_interests - current_amount}
         end
       else
         range.map do |n|
-          { no: n, interests: interests(n), amount: capital + interests(n) }
+          amount = capital + interests(n)
+          current_amount += amount
+          { no: n, interests: interests(n), amount: amount, capita: capital, balance: @amount + total_interests - current_amount}
         end
       end 
     end
-
+        
+    def monthly_payment
+      pmt(@interest_rate, @no_installments, @amount).abs  
+    end
+   
+    def interests_for_period(n)
+      ipmt(@interest_rate, n, @no_installments, @amount).abs
+    end
+    
+    def capital_for_period(n)
+      ppmt(@interest_rate, n, @no_installments, @amount).abs
+    end
+           
     def const?
       @kind == :const
     end
     private :const?
-
   end
-end
\ No newline at end of file
+end
diff --git a/monetico.gemspec b/monetico.gemspec
index 29c704c..3aba412 100644
--- a/monetico.gemspec
+++ b/monetico.gemspec
@@ -18,4 +18,7 @@ Gem::Specification.new do |gem|
   gem.name          = "monetico"
   gem.require_paths = ["lib"]
   gem.version       = Monetico::VERSION
+  
+  gem.add_development_dependency "rspec"
+  gem.add_development_dependency "rake"
 end
diff --git a/spec/loan_spec.rb b/spec/loan_spec.rb
new file mode 100644
index 0000000..32ebfec
--- /dev/null
+++ b/spec/loan_spec.rb
@@ -0,0 +1,66 @@
+require "spec_helper"
+
+describe Monetico::Loan do
+  describe "const loan" do
+    before :all do
+      @loan = Monetico::Loan.new(200000.0, 0.065, 360, :monthly, :const)
+    end
+    
+    it "capital returns amount/no_installments" do
+      @loan.monthly_payment.to_f.round_down(2).abs.should == 1264.13
+    end
+    
+    it "total_interests returns sum of interests" do
+      @loan.total_interests.to_f.round_down(2).should == 255088.98
+    end
+            
+    it "monthly_capital(1) returns capital for first payment" do
+      @loan.capital_for_period(1).to_f.round_down(2).abs.should == 180.80
+    end
+    
+    it "monthly_intersts(1) returns capital for first payment" do
+      @loan.interests_for_period(1).to_f.round_down(2).abs.should == 1083.33
+    end
+    
+    it "monthly_capital(117) returns capital for first payment" do
+      @loan.capital_for_period(117).to_f.round_down(2).abs.should == 338.34
+    end
+    
+    it "monthly_intersts(117) returns capital for first payment" do
+      @loan.interests_for_period(117).to_f.round_down(2).abs.should == 925.80
+    end
+  
+    it "payback(1..360) returns payback table and last item balance should be 0.0" do
+      table =  @loan.payback(1..360)
+    
+      table[359][:balance].to_f.round_down(2).should == 0.0
+    end  
+    
+  end
+
+  describe "desc loan" do
+    before :all do
+      @loan = Monetico::Loan.new(200000.0, 0.065, 360, :monthly, :desc)
+    end
+    
+    it "capital returns amount/no_installments" do
+      @loan.capital.to_f.round_down(2).abs.should == 555.56
+    end
+    
+    it "total_interests returns sum of interests" do
+      @loan.total_interests.to_f.round_down(2).should == 195541.67
+    end
+            
+    it "interests(1) returns intersts for 1 payment" do
+      @loan.interests(1).to_f.round_down(2).should ==  1083.33
+    end
+  
+    it "payback(1..360) returns payback table and last item balance should be 0.0" do
+      table =  @loan.payback(1..360)
+    
+      table[359][:balance].to_f.round_down(2).should == 0.0
+    end  
+    
+  end
+end
+
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
new file mode 100644
index 0000000..b69ba9c
--- /dev/null
+++ b/spec/spec_helper.rb
@@ -0,0 +1,7 @@
+require "bundler"
+Bundler.setup
+
+require "rspec"
+
+Dir[File.expand_path(File.dirname(__FILE__) + "/../lib/**/*.rb")].each { |f| require f }
+

From 275590413e284c3029d6160a19822943c30ed818 Mon Sep 17 00:00:00 2001
From: Tomasz Kuklis <tomasz.kuklis@gmail.com>
Date: Mon, 12 Dec 2011 13:44:42 +0100
Subject: [PATCH 02/11] fixed attribute name

---
 lib/monetico/loan.rb | 2 +-
 spec/loan_spec.rb    | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/monetico/loan.rb b/lib/monetico/loan.rb
index 51190ef..5185c65 100644
--- a/lib/monetico/loan.rb
+++ b/lib/monetico/loan.rb
@@ -54,7 +54,7 @@ def payback(range)
         range.map do |n|
           amount = capital + interests(n)
           current_amount += amount
-          { no: n, interests: interests(n), amount: amount, capita: capital, balance: @amount + total_interests - current_amount}
+          { no: n, interests: interests(n), amount: amount, capital: capital, balance: @amount + total_interests - current_amount}
         end
       end 
     end
diff --git a/spec/loan_spec.rb b/spec/loan_spec.rb
index 32ebfec..7111dce 100644
--- a/spec/loan_spec.rb
+++ b/spec/loan_spec.rb
@@ -59,8 +59,7 @@
       table =  @loan.payback(1..360)
     
       table[359][:balance].to_f.round_down(2).should == 0.0
-    end  
-    
+    end      
   end
 end
 

From 2d6fd5cb143534b377f7a3453769e34e4e59ade0 Mon Sep 17 00:00:00 2001
From: Aleksander Kwiatkowski <bobikx@poczta.fm>
Date: Fri, 10 Feb 2012 15:13:09 +0100
Subject: [PATCH 03/11] tests and bigdecimal compatibility

---
 .rvmrc                     |  6 ++--
 Gemfile                    |  9 ++++++
 Rakefile                   | 56 +++++++++++++++++++++++++++++++++++++-
 lib/monetico.rb            | 18 ++++--------
 lib/monetico/calculable.rb | 23 ++++++++++++++++
 spec/monetico_spec.rb      | 38 ++++++++++++++++++++++++++
 spec/spec_helper.rb        |  6 ++++
 7 files changed, 140 insertions(+), 16 deletions(-)
 create mode 100644 lib/monetico/calculable.rb
 create mode 100644 spec/monetico_spec.rb
 create mode 100644 spec/spec_helper.rb

diff --git a/.rvmrc b/.rvmrc
index ee3b09c..f357ddc 100644
--- a/.rvmrc
+++ b/.rvmrc
@@ -1,2 +1,4 @@
-rvm_gemset_create_on_use_flag=1
-rvm gemset use monetico 
+#rvm_gemset_create_on_use_flag=1
+#rvm gemset use monetico
+
+rvm use 1.9.3@monetico --create
diff --git a/Gemfile b/Gemfile
index 4a8b71e..1906b91 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,3 +2,12 @@ source 'http://rubygems.org'
 
 # Specify your gem's dependencies in monetico.gemspec
 gemspec
+
+group :development, :test do
+  gem "rdoc"
+  gem "shoulda"
+  gem "bundler", "~> 1.0.0"
+  gem "rspec"
+  gem "jeweler" #, "~> 1.6.4"
+  gem "simplecov", ">= 0"
+end
diff --git a/Rakefile b/Rakefile
index f57ae68..380d971 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,2 +1,56 @@
+# encoding: utf-8
+
 #!/usr/bin/env rake
-require "bundler/gem_tasks"
+#require "bundler/gem_tasks"
+
+require 'rubygems'
+require 'bundler'
+begin
+  Bundler.setup(:default, :development)
+rescue Bundler::BundlerError => e
+  $stderr.puts e.message
+  $stderr.puts "Run `bundle install` to install missing gems"
+  exit e.status_code
+end
+require 'rake'
+
+#require 'jeweler'
+#Jeweler::Tasks.new do |gem|
+#  # gem is a Gem::Specification... see http://docs.rubygems.org/read/chapter/20 for more options
+#  gem.name = "gem name"
+#  gem.homepage = "http://github.com/zaiste/monetico"
+#  gem.license = "licence"
+#  gem.summary = %Q{summary}
+#  gem.description = %Q{desc}
+#  gem.email = "..."
+#  gem.authors = ["..."]
+#  # dependencies defined in Gemfile
+#
+#  gem.files = FileList[
+#    "[A-Z]*", "{bin,generators,lib,test}/**/*"
+#  ]
+#end
+#Jeweler::RubygemsDotOrgTasks.new
+
+require 'rspec/core'
+require 'rspec/core/rake_task'
+RSpec::Core::RakeTask.new(:spec) do |spec|
+  spec.pattern = FileList['spec/**/*_spec.rb']
+end
+
+RSpec::Core::RakeTask.new(:rcov) do |spec|
+  spec.pattern = 'spec/**/*_spec.rb'
+  spec.rcov = true
+end
+
+task :default => :spec
+
+require 'rake/rdoctask'
+Rake::RDocTask.new do |rdoc|
+  version = File.exist?('VERSION') ? File.read('VERSION') : ""
+
+  rdoc.rdoc_dir = 'rdoc'
+  rdoc.title = "simple_metar_parser #{version}"
+  rdoc.rdoc_files.include('README*')
+  rdoc.rdoc_files.include('lib/**/*.rb')
+end
diff --git a/lib/monetico.rb b/lib/monetico.rb
index 04cbbc5..3adabae 100644
--- a/lib/monetico.rb
+++ b/lib/monetico.rb
@@ -1,23 +1,15 @@
 require "bigdecimal"
+require "monetico/calculable"
 require "monetico/loan"
 require "monetico/version"
 
 class Float
-  def big; BigDecimal(self.to_s); end
-
-  def round_to(x)
-    (self * 10**x).ceil.to_f / 10**x
-  end
+  include Monetico::Calculable
+end
 
-  def round_down(x)
-    if self >= 0 
-      (self * 10**x).floor.to_f / 10**x
-    else
-      -((-self * 10**x).floor.to_f / 10**x)
-    end
-  end
+class BigDecimal
+  include Monetico::Calculable
 end
 
 module Monetico
-  # Your code goes here...
 end
diff --git a/lib/monetico/calculable.rb b/lib/monetico/calculable.rb
new file mode 100644
index 0000000..d862259
--- /dev/null
+++ b/lib/monetico/calculable.rb
@@ -0,0 +1,23 @@
+module Monetico
+  module Calculable
+    DEF_PREC = 2
+
+    def big
+      BigDecimal(self.to_s);
+    end
+
+    def round_to(x = DEF_PREC)
+      (self * 10**x).ceil.to_f / 10**x
+    end
+
+    alias_method :round_up, :round_to
+
+    def round_down(x = DEF_PREC)
+      if self >= 0
+        (self * 10**x).floor.to_f / 10**x
+      else
+        -((-self * 10**x).floor.to_f / 10**x)
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/monetico_spec.rb b/spec/monetico_spec.rb
new file mode 100644
index 0000000..40554ea
--- /dev/null
+++ b/spec/monetico_spec.rb
@@ -0,0 +1,38 @@
+require 'spec_helper'
+require 'rspec'
+
+describe Monetico do
+  before :each  do
+  end
+
+  it "should round up/down BigDecimal" do
+    b = BigDecimal.new('1.0155')
+    b.round_down(2).should == 1.01
+    b.round_up(2).should == 1.02
+    b.round_to(2).should == 1.02
+    b.round_down.should == 1.01
+    b.round_up.should == 1.02
+
+    b.round_down(1).should == 1.0
+    b.round_up(1).should == 1.1
+
+    b.round_down(0).should == 1.0
+    b.round_up(0).should == 2.0
+  end
+
+  it "should round up/down Float" do
+    b = 1.0155
+    b.round_down(2).should == 1.01
+    b.round_up(2).should == 1.02
+    b.round_to(2).should == 1.02
+    b.round_down.should == 1.01
+    b.round_up.should == 1.02
+
+    b.round_down(1).should == 1.0
+    b.round_up(1).should == 1.1
+
+    b.round_down(0).should == 1.0
+    b.round_up(0).should == 2.0
+  end
+
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
new file mode 100644
index 0000000..b375372
--- /dev/null
+++ b/spec/spec_helper.rb
@@ -0,0 +1,6 @@
+require "bundler"
+Bundler.setup
+
+require "rspec"
+
+Dir[File.expand_path(File.dirname(__FILE__) + "/../lib/**/*.rb")].each { |f| require f }
\ No newline at end of file

From 69e2eba5d3cbfe541fd3ac9ec807bd6018479cc9 Mon Sep 17 00:00:00 2001
From: Aleksander Kwiatkowski <bobikx@poczta.fm>
Date: Wed, 15 Feb 2012 15:37:44 +0100
Subject: [PATCH 04/11] some changes

---
 lib/monetico.rb   |  5 +++++
 spec/loan_spec.rb | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 spec/loan_spec.rb

diff --git a/lib/monetico.rb b/lib/monetico.rb
index 3adabae..e6f2ad0 100644
--- a/lib/monetico.rb
+++ b/lib/monetico.rb
@@ -11,5 +11,10 @@ class BigDecimal
   include Monetico::Calculable
 end
 
+class Fixnum
+  # usable for #big
+  include Monetico::Calculable
+end
+
 module Monetico
 end
diff --git a/spec/loan_spec.rb b/spec/loan_spec.rb
new file mode 100644
index 0000000..f6730cc
--- /dev/null
+++ b/spec/loan_spec.rb
@@ -0,0 +1,37 @@
+require 'spec_helper'
+require 'rspec'
+
+describe Monetico::Loan do
+  before :each do
+  end
+
+  it "should calculate loan" do
+    amount = 1000.0
+    interest_rate = 0.2
+    number_of_installments = 3
+    cadence = :weekly
+    kind = :const
+    #kind = :desc
+
+    loan_calc = Monetico::Loan.new(amount, interest_rate, number_of_installments, cadence, kind)
+    puts loan_calc.to_yaml
+
+    loan_calc.payback(1..number_of_installments).each do |l|
+      #puts lo_nu.inspect
+      puts l[:amount].to_f
+      puts l[:interests].to_f
+      puts l[:capital].to_f
+      puts l[:balance].to_f
+      puts "*"
+      #payback_items.create(
+      #  number: lo_nu[:no],
+      #  pay_day: created_at + lo_nu[:no].send(period),
+      #  interests: lo_nu[:interests],
+      #  capital: lo_nu[:capital],
+      #  balance: lo_nu[:balance]
+      #)
+    end
+
+  end
+
+end

From 1e5df9203de2b9a9ff63a716e77ffd84975a570a Mon Sep 17 00:00:00 2001
From: Aleksander Kwiatkowski <bobikx@poczta.fm>
Date: Wed, 15 Feb 2012 15:43:09 +0100
Subject: [PATCH 05/11] merging Tomek's changes

---
 lib/monetico.rb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/monetico.rb b/lib/monetico.rb
index 3adabae..b86cedf 100644
--- a/lib/monetico.rb
+++ b/lib/monetico.rb
@@ -1,4 +1,5 @@
 require "bigdecimal"
+require "excel"
 require "monetico/calculable"
 require "monetico/loan"
 require "monetico/version"

From eca0d139280c7be833d0be0cd41ba5e19d6698a3 Mon Sep 17 00:00:00 2001
From: Aleksander Kwiatkowski <bobikx@poczta.fm>
Date: Thu, 16 Feb 2012 17:37:02 +0100
Subject: [PATCH 06/11] fixing and roonding (in progress)

---
 lib/monetico.rb             |  1 +
 lib/monetico/calculable.rb  |  2 +
 lib/monetico/loan.rb        | 30 ++++++++++++-
 lib/monetico/money_array.rb | 47 ++++++++++++++++++++
 spec/loan_spec.rb           | 86 +++++++++++++++++++++----------------
 spec/money_round_spec.rb    | 55 ++++++++++++++++++++++++
 6 files changed, 182 insertions(+), 39 deletions(-)
 create mode 100644 lib/monetico/money_array.rb
 create mode 100644 spec/money_round_spec.rb

diff --git a/lib/monetico.rb b/lib/monetico.rb
index 1d9b8fb..24e19c5 100644
--- a/lib/monetico.rb
+++ b/lib/monetico.rb
@@ -1,5 +1,6 @@
 require "bigdecimal"
 require "excel"
+require "monetico/money_array"
 require "monetico/calculable"
 require "monetico/loan"
 require "monetico/version"
diff --git a/lib/monetico/calculable.rb b/lib/monetico/calculable.rb
index d862259..2ae9eb2 100644
--- a/lib/monetico/calculable.rb
+++ b/lib/monetico/calculable.rb
@@ -6,6 +6,8 @@ def big
       BigDecimal(self.to_s);
     end
 
+    alias_method :to_big, :big
+
     def round_to(x = DEF_PREC)
       (self * 10**x).ceil.to_f / 10**x
     end
diff --git a/lib/monetico/loan.rb b/lib/monetico/loan.rb
index 5185c65..e16067f 100644
--- a/lib/monetico/loan.rb
+++ b/lib/monetico/loan.rb
@@ -46,18 +46,44 @@ def payback(range)
       if const?
         par = (1 + @interest_rate) ** @no_installments
                 
-        range.map do |n|
+        res = range.map do |n|
           current_amount += monthly_payment
           { no: n, interests: interests(n), amount: monthly_payment, capital: capital_for_period(n), balance:  @amount + total_interests - current_amount}
         end
+
+        res = round_calculation(res)
+        return res
       else
-        range.map do |n|
+        res = range.map do |n|
           amount = capital + interests(n)
           current_amount += amount
           { no: n, interests: interests(n), amount: amount, capital: capital, balance: @amount + total_interests - current_amount}
         end
+        
+        res = round_calculation(res)
+        return res
       end 
     end
+
+    # all payback items for all
+    def payback_all
+      payback(1..@no_installments)
+    end
+
+    def round_calculation(res)
+      [:interests, :amount, :capital, :balance].each do |k|
+        tmp = MoneyArray.factory( res.collect{|r| r[k]} )
+        tmp = tmp.money_round
+
+        puts tmp.to_yaml
+
+        res.each_with_index do |r,i|
+          r[k] = tmp[i]
+        end
+
+      end
+      return res
+    end
         
     def monthly_payment
       pmt(@interest_rate, @no_installments, @amount).abs  
diff --git a/lib/monetico/money_array.rb b/lib/monetico/money_array.rb
new file mode 100644
index 0000000..e221e9d
--- /dev/null
+++ b/lib/monetico/money_array.rb
@@ -0,0 +1,47 @@
+module Monetico
+  class MoneyArray < Array
+    def money_round
+      return self.class.money_round(self)
+    end
+
+    def array_sum
+      self.inject(nil) { |sum, x| sum ? sum+x : x }
+    end
+
+    def self.factory(_from)
+      obj = self.new
+      _from.each do |f|
+        obj << f
+      end
+      return obj
+    end
+
+    # round series of values to achieve proper sum
+    def self.money_round(a)
+      sum = a.array_sum
+      rest = 0.0
+      result = MoneyArray.new
+
+      a.each do |b|
+        rounded = ((b * 100).round / 100.0)
+        real = b
+
+        # compensation
+        if rest >= 1.0
+          rounded -= 1.0
+          rest -= 1.0
+        elsif rest <= -1.0
+          rounded -= -1.0
+          rest -= -1.0
+        end
+
+        result << rounded.to_big
+        rest += real - rounded
+      end
+
+      # puts "rest #{rest}"
+      return result
+
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/loan_spec.rb b/spec/loan_spec.rb
index 82889ec..09501df 100644
--- a/spec/loan_spec.rb
+++ b/spec/loan_spec.rb
@@ -1,42 +1,53 @@
 require "spec_helper"
 
 describe Monetico::Loan do
-  #describe "const loan" do
-  #  before :all do
-  #    @loan = Monetico::Loan.new(200000.0, 0.065, 360, :monthly, :const)
-  #  end
-  #
-  #  it "capital returns amount/no_installments" do
-  #    @loan.monthly_payment.to_f.round_down(2).abs.should == 1264.13
-  #  end
-  #
-  #  it "total_interests returns sum of interests" do
-  #    @loan.total_interests.to_f.round_down(2).should == 255088.98
-  #  end
-  #
-  #  it "monthly_capital(1) returns capital for first payment" do
-  #    @loan.capital_for_period(1).to_f.round_down(2).abs.should == 180.80
-  #  end
-  #
-  #  it "monthly_intersts(1) returns capital for first payment" do
-  #    @loan.interests_for_period(1).to_f.round_down(2).abs.should == 1083.33
-  #  end
-  #
-  #  it "monthly_capital(117) returns capital for first payment" do
-  #    @loan.capital_for_period(117).to_f.round_down(2).abs.should == 338.34
-  #  end
-  #
-  #  it "monthly_intersts(117) returns capital for first payment" do
-  #    @loan.interests_for_period(117).to_f.round_down(2).abs.should == 925.80
-  #  end
-  #
-  #  it "payback(1..360) returns payback table and last item balance should be 0.0" do
-  #    table = @loan.payback(1..360)
-  #
-  #    table[359][:balance].to_f.round_down(2).should == 0.0
-  #  end
-  #
-  #end
+  describe "const loan" do
+    before :all do
+      # tests were updated using
+      # http://www.money.pl/banki/kalkulatory/kredytowy/
+      @loan = Monetico::Loan.new(200000.0, 0.065, 360, :monthly, :const)
+    end
+
+    it "first monthly_payment" do
+      @loan.monthly_payment.to_f.round_down(2).abs.should == 1264.14
+      @loan.monthly_payment.to_f.round_down.abs.should == 1264.14
+    end
+
+    it "total_interests returns sum of interests" do
+      @loan.total_interests.to_f.round_down(2).should == 255088.98
+    end
+
+    it "monthly_capital(1) returns capital for first payment" do
+      @loan.capital_for_period(1).to_f.round_down(2).abs.should == 180.80
+    end
+
+    it "monthly_interests(1) returns capital for first payment" do
+      @loan.interests_for_period(1).to_f.round_down(2).abs.should == 1083.33
+    end
+
+    it "monthly_capital(117) returns capital for payment" do
+      @loan.capital_for_period(117).to_f.round_down(2).abs.should == 338.34
+    end
+
+    it "monthly_intersts(117) returns capital for payment" do
+      @loan.interests_for_period(117).to_f.round_down(2).abs.should == 925.80
+    end
+
+    it "monthly_capital(231) returns capital for payment" do
+      @loan.capital_for_period(231).to_f.round_down(2).abs.should == 626.33
+    end
+
+    it "monthly_intersts(231) returns capital for payment" do
+      @loan.interests_for_period(231).to_f.round_down(2).abs.should == 637.81
+    end
+
+    #it "payback(1..360) returns payback table and last item balance should be 0.0" do
+    #  table = @loan.payback(1..360)
+    #
+    #  table[359][:balance].to_f.round_down(2).should == 0.0
+    #end
+
+  end
 
   #describe "desc loan" do
   #  before :all do
@@ -67,7 +78,8 @@
     amount = 1000.0
     interest_rate = 0.2
     number_of_installments = 3
-    cadence = :weekly
+    #cadence = :weekly
+    cadence = :monthly
     kind = :const
     #kind = :desc
 
diff --git a/spec/money_round_spec.rb b/spec/money_round_spec.rb
new file mode 100644
index 0000000..f61c572
--- /dev/null
+++ b/spec/money_round_spec.rb
@@ -0,0 +1,55 @@
+require "spec_helper"
+
+describe Monetico::MoneyArray do
+  describe "round simple array" do
+    before :all do
+    end
+
+    it "should round simple array" do
+      ma = Monetico::MoneyArray.new
+      ma << 10.001
+      ma << 9.999
+      puts ma.class
+
+      ma.money_round.each do |m|
+        # precision check
+        rest = (m * 100.00) % 1
+        puts "#{m} - rest #{rest}"
+      end
+
+    end
+
+    it "should round simple loan results" do
+      #344.50566129375136
+      #16.666666666666668
+      #327.8389946270847
+      #689.0113225874981
+      #*
+      #344.50566129375136
+      #11.20268342288194
+      #333.3029778708694
+      #344.5056612937467
+      #*
+      #344.50566129375136
+      #5.647633791700789
+      #338.85802750205056
+
+      ma = Monetico::MoneyArray.new
+      # also testes using floats
+      ma << BigDecimal.new("327.8389946270847")
+      ma << BigDecimal.new("333.3029778708694")
+      ma << BigDecimal.new("338.85802750205056")
+
+      puts ma.array_sum
+
+      ma.money_round.each do |m|
+        # precision check
+        rest = (m * 100.00) % 1
+        puts "#{m} - rest #{rest}"
+      end
+
+    end
+
+  end
+end
+

From 173be9af54ec9f848e75e168157cd988d7e30e78 Mon Sep 17 00:00:00 2001
From: Aleksander Kwiatkowski <bobikx@poczta.fm>
Date: Fri, 17 Feb 2012 10:41:08 +0100
Subject: [PATCH 07/11] fixing and rounding (in progress)

---
 lib/monetico/loan.rb        | 26 +++++++++++++++++++++-----
 lib/monetico/money_array.rb | 10 +++++++++-
 spec/loan_spec.rb           | 28 ++++++++++++++--------------
 3 files changed, 44 insertions(+), 20 deletions(-)

diff --git a/lib/monetico/loan.rb b/lib/monetico/loan.rb
index e16067f..1478069 100644
--- a/lib/monetico/loan.rb
+++ b/lib/monetico/loan.rb
@@ -84,18 +84,34 @@ def round_calculation(res)
       end
       return res
     end
-        
-    def monthly_payment
+
+    # not rounded
+    def monthly_payment_float
       pmt(@interest_rate, @no_installments, @amount).abs  
     end
-   
-    def interests_for_period(n)
+
+    # rounded
+    def monthly_payment
+      MoneyArray.money_round_value(monthly_payment_float)
+    end
+
+    # not rounded
+    def interests_for_period_float(n)
       ipmt(@interest_rate, n, @no_installments, @amount).abs
     end
+
+    # rounded
+    def interests_for_period(n)
+      MoneyArray.money_round_value(interests_for_period_float(n))
+    end
     
-    def capital_for_period(n)
+    def capital_for_period_float(n)
       ppmt(@interest_rate, n, @no_installments, @amount).abs
     end
+
+    def capital_for_period(n)
+      MoneyArray.money_round_value(capital_for_period_float(n))
+    end
            
     def const?
       @kind == :const
diff --git a/lib/monetico/money_array.rb b/lib/monetico/money_array.rb
index e221e9d..8b10ea0 100644
--- a/lib/monetico/money_array.rb
+++ b/lib/monetico/money_array.rb
@@ -16,6 +16,14 @@ def self.factory(_from)
       return obj
     end
 
+    # round up currency value
+    def self.money_round_value(v)
+      return ((v * 100).round / 100.0).to_big
+      # TODO delete it
+      #return ((v * 100).floor / 100.0)
+      #return ((v * 100).ceil / 100.0)
+    end
+
     # round series of values to achieve proper sum
     def self.money_round(a)
       sum = a.array_sum
@@ -23,7 +31,7 @@ def self.money_round(a)
       result = MoneyArray.new
 
       a.each do |b|
-        rounded = ((b * 100).round / 100.0)
+        rounded = money_round_value(b)
         real = b
 
         # compensation
diff --git a/spec/loan_spec.rb b/spec/loan_spec.rb
index 09501df..25e7a6e 100644
--- a/spec/loan_spec.rb
+++ b/spec/loan_spec.rb
@@ -9,42 +9,42 @@
     end
 
     it "first monthly_payment" do
-      @loan.monthly_payment.to_f.round_down(2).abs.should == 1264.14
-      @loan.monthly_payment.to_f.round_down.abs.should == 1264.14
+      @loan.monthly_payment.to_f.should == 1264.14
+      @loan.monthly_payment.to_f.should == 1264.14
     end
 
     it "total_interests returns sum of interests" do
-      @loan.total_interests.to_f.round_down(2).should == 255088.98
+      @loan.total_interests.to_f.should == 255088.98
     end
 
     it "monthly_capital(1) returns capital for first payment" do
-      @loan.capital_for_period(1).to_f.round_down(2).abs.should == 180.80
+      @loan.capital_for_period(1).to_f.abs.should == 180.80
     end
 
     it "monthly_interests(1) returns capital for first payment" do
-      @loan.interests_for_period(1).to_f.round_down(2).abs.should == 1083.33
+      @loan.interests_for_period(1).to_f.abs.should == 1083.33
     end
 
     it "monthly_capital(117) returns capital for payment" do
-      @loan.capital_for_period(117).to_f.round_down(2).abs.should == 338.34
+      @loan.capital_for_period(117).to_f.abs.should == 338.34
     end
 
     it "monthly_intersts(117) returns capital for payment" do
-      @loan.interests_for_period(117).to_f.round_down(2).abs.should == 925.80
+      @loan.interests_for_period(117).to_f.abs.should == 925.80
     end
 
     it "monthly_capital(231) returns capital for payment" do
-      @loan.capital_for_period(231).to_f.round_down(2).abs.should == 626.33
+      @loan.capital_for_period(231).to_f.abs.should == 626.33
     end
 
     it "monthly_intersts(231) returns capital for payment" do
-      @loan.interests_for_period(231).to_f.round_down(2).abs.should == 637.81
+      @loan.interests_for_period(231).to_f.abs.should == 637.81
     end
 
     #it "payback(1..360) returns payback table and last item balance should be 0.0" do
     #  table = @loan.payback(1..360)
     #
-    #  table[359][:balance].to_f.round_down(2).should == 0.0
+    #  table[359][:balance].to_f.should == 0.0
     #end
 
   end
@@ -55,21 +55,21 @@
   #  end
   #
   #  it "capital returns amount/no_installments" do
-  #    @loan.capital.to_f.round_down(2).abs.should == 555.56
+  #    @loan.capital.to_f.abs.should == 555.56
   #  end
   #
   #  it "total_interests returns sum of interests" do
-  #    @loan.total_interests.to_f.round_down(2).should == 195541.67
+  #    @loan.total_interests.to_f.should == 195541.67
   #  end
   #
   #  it "interests(1) returns intersts for 1 payment" do
-  #    @loan.interests(1).to_f.round_down(2).should == 1083.33
+  #    @loan.interests(1).to_f.should == 1083.33
   #  end
   #
   #  it "payback(1..360) returns payback table and last item balance should be 0.0" do
   #    table = @loan.payback(1..360)
   #
-  #    table[359][:balance].to_f.round_down(2).should == 0.0
+  #    table[359][:balance].to_f.should == 0.0
   #  end
   #
   #end

From 4d74ed6201dd56b408d64e31abaed1313b45a2d9 Mon Sep 17 00:00:00 2001
From: Aleksander Kwiatkowski <bobikx@poczta.fm>
Date: Mon, 20 Feb 2012 13:14:05 +0100
Subject: [PATCH 08/11] fixing and rounding, optimization, added method amount
 for loan - amount of money to pay off, huge refactoring

---
 lib/monetico/loan.rb        | 252 +++++++++++++++++++++++++++---------
 lib/monetico/money_array.rb |   1 -
 spec/loan_spec.rb           | 128 ++++++++++--------
 3 files changed, 262 insertions(+), 119 deletions(-)

diff --git a/lib/monetico/loan.rb b/lib/monetico/loan.rb
index 1478069..6476414 100644
--- a/lib/monetico/loan.rb
+++ b/lib/monetico/loan.rb
@@ -1,83 +1,208 @@
 module Monetico
   class Loan
     include Excel
-    
+
     CADENCE = {
       monthly: 12,
       weekly: 52,
     }
 
-    def initialize(amount, interest_rate, no_installments, cadence=:monthly, kind=:desc)
+    # methods
+    # <ex. capital_real> - rounded
+    # <ex. capital_real_real> - float, used in internal calculations
+    # <ex. calculate_capital> - calculate for the first time, float
+
+    def initialize(amount, interest_rate, no_installments, cadence = :monthly, kind = :desc)
       @amount = amount.big
-      @interest_rate = interest_rate.big / CADENCE[cadence] 
+      @interest_rate = interest_rate.big / CADENCE[cadence]
       @no_installments = no_installments
       @kind = kind
     end
 
-    def capital 
+    private
+
+    # Capital - amount / number of installments
+    def capital
+      round capital_real
+    end
+
+    public :capital
+
+    def capital_real
+      @capital = calculate_capital if @capital.nil?
+      @capital
+    end
+
+    def calculate_capital
       @amount / @no_installments
     end
 
+    # Total amount of interests
     def total_interests
+      round total_interests_real
+    end
+
+    public :total_interests
+
+    def total_interests_real
+      @total_interests = calculate_total_interests if @total_interests.nil?
+      @total_interests
+    end
+
+    def calculate_total_interests
       if const?
         par = (1 + @interest_rate) ** @no_installments
-        payback_amount = @amount * @interest_rate * par / (par - 1) 
-
-        payback_amount * @no_installments - @amount 
+        payback_amount = @amount * @interest_rate * par / (par - 1)
+        payback_amount * @no_installments - @amount
       else
-        0.5.big * @interest_rate * @no_installments * (@amount + capital)
+        0.5.big * @interest_rate * @no_installments * (@amount + capital_real)
       end
     end
 
+    # Interests for period/installment
     def interests(idx)
+      round interests_real(idx)
+    end
+
+    public :interests
+
+    def interests_real(idx)
+      @interests = Array.new if @interests.nil?
+      @interests[idx] = calculate_interests(idx) if @interests[idx].nil?
+      @interests[idx]
+    end
+
+    # little refactoring
+    alias_method :interests_for_period, :interests
+
+    def calculate_interests(idx)
       if const?
-        interests_for_period(idx)
+        ipmt(@interest_rate, idx, @no_installments, @amount).abs
       else
-        (@amount - (idx - 1) * capital) * @interest_rate
+        (@amount - (idx - 1) * capital_real) * @interest_rate
       end
     end
 
-    def payback(range) 
-      from = range.begin
-      to = range.end
-      
+    # Monthly payment
+    def monthly_payment
+      round monthly_payment_real
+    end
+
+    public :monthly_payment
+
+    def monthly_payment_real
+      @monthly_payment = calculate_monthly_payment if @monthly_payment_float.nil?
+      @monthly_payment
+    end
+
+    def calculate_monthly_payment
+      pmt(@interest_rate, @no_installments, @amount).abs
+    end
+
+    # Capital for period
+    def capital_for_period(idx)
+      round capital_for_period_real(idx)
+    end
+
+    public :capital_for_period
+
+    def capital_for_period_real(idx)
+      # only for desc
+      return capital_real if not const?
+
+      # only for const
+      @capitals = Array.new if @capitals.nil?
+      @capitals[idx] = calculate_capital_for_period(idx) if @capitals[idx].nil?
+      @capitals[idx]
+    end
+
+    def calculate_capital_for_period(idx)
+      ppmt(@interest_rate, idx, @no_installments, @amount).abs
+    end
+
+    # Amount for period
+    def amounts(idx)
+      capital_for_period(idx) + interests(idx)
+    end
+
+    public :amounts
+
+    def const?
+      @kind == :const
+    end
+
+    public 'const?'
+
+    # round money value
+    def round(v)
+      MoneyArray.money_round_value(v)
+    end
+
+    # Loan debug
+    def to_s
+      s = "Loan\n"
+      table = payback_all
+      table.each_with_index do |t, i|
+        s += "#{t[:no]}: #{t[:amount].to_f};\t#{t[:balance].to_f};\t#{t[:capital].to_f};\t#{t[:interests].to_f}\n"
+      end
+      return s
+    end
+
+    public :to_s
+
+    # Paybacks items
+    # all payback items for all
+    def calculate_payback
+      from = 1
+      to = @no_installments
+      range = (from..to)
+
       current_amount = 0.0
-      
+
       if const?
         par = (1 + @interest_rate) ** @no_installments
-                
+
         res = range.map do |n|
-          current_amount += monthly_payment
-          { no: n, interests: interests(n), amount: monthly_payment, capital: capital_for_period(n), balance:  @amount + total_interests - current_amount}
+          current_amount += monthly_payment_real
+          { no: n, interests: interests(n), amount: monthly_payment_real, capital: capital_for_period(n), balance: @amount + total_interests_real - current_amount }
         end
-
-        res = round_calculation(res)
-        return res
       else
         res = range.map do |n|
-          amount = capital + interests(n)
+          amount = capital_real + interests(n)
           current_amount += amount
-          { no: n, interests: interests(n), amount: amount, capital: capital, balance: @amount + total_interests - current_amount}
+          { no: n, interests: interests(n), amount: amount, capital: capital_real, balance: @amount + total_interests_real - current_amount }
         end
-        
-        res = round_calculation(res)
-        return res
-      end 
+      end
+      @paybacks = res
+      @paybacks_round = round_paybacks(res)
+    end
+
+    def payback_real(range)
+      calculate_payback if @paybacks.nil?
+      @paybacks[range]
+    end
+
+    def payback(range)
+      calculate_payback if @paybacks.nil?
+      @paybacks_round[range]
     end
 
-    # all payback items for all
     def payback_all
-      payback(1..@no_installments)
+      calculate_payback if @paybacks.nil?
+      @paybacks_round
     end
 
-    def round_calculation(res)
+    public :payback_all
+
+    public :payback
+
+
+    def round_paybacks(res)
       [:interests, :amount, :capital, :balance].each do |k|
-        tmp = MoneyArray.factory( res.collect{|r| r[k]} )
+        tmp = MoneyArray.factory(res.collect { |r| r[k] })
         tmp = tmp.money_round
 
-        puts tmp.to_yaml
-
-        res.each_with_index do |r,i|
+        res.each_with_index do |r, i|
           r[k] = tmp[i]
         end
 
@@ -85,37 +210,36 @@ def round_calculation(res)
       return res
     end
 
-    # not rounded
-    def monthly_payment_float
-      pmt(@interest_rate, @no_installments, @amount).abs  
-    end
+    # temporary
+
+    #def capital_real
+    #  r(@amount / @no_installments)
+    #end
+
+    #def total_interests_real_float
+    #  if const?
+    #    par = (1 + @interest_rate) ** @no_installments
+    #    payback_amount = @amount * @interest_rate * par / (par - 1)
+    #    res = payback_amount * @no_installments - @amount
+    #  else
+    #    res = 0.5.big * @interest_rate * @no_installments * (@amount + capital_real)
+    #  end
+    #  res
+    #end
+
+    #def total_interests_real
+    #  r(total_interests_float)
+    #end
+
+    #def interests_real(idx)
+    #  if const?
+    #    res = interests_for_period(idx)
+    #  else
+    #    res = (@amount - (idx - 1) * capital_real) * @interest_rate
+    #  end
+    #  r(res)
+    #end
 
-    # rounded
-    def monthly_payment
-      MoneyArray.money_round_value(monthly_payment_float)
-    end
 
-    # not rounded
-    def interests_for_period_float(n)
-      ipmt(@interest_rate, n, @no_installments, @amount).abs
-    end
-
-    # rounded
-    def interests_for_period(n)
-      MoneyArray.money_round_value(interests_for_period_float(n))
-    end
-    
-    def capital_for_period_float(n)
-      ppmt(@interest_rate, n, @no_installments, @amount).abs
-    end
-
-    def capital_for_period(n)
-      MoneyArray.money_round_value(capital_for_period_float(n))
-    end
-           
-    def const?
-      @kind == :const
-    end
-    private :const?
   end
 end
diff --git a/lib/monetico/money_array.rb b/lib/monetico/money_array.rb
index 8b10ea0..44258df 100644
--- a/lib/monetico/money_array.rb
+++ b/lib/monetico/money_array.rb
@@ -47,7 +47,6 @@ def self.money_round(a)
         rest += real - rounded
       end
 
-      # puts "rest #{rest}"
       return result
 
     end
diff --git a/spec/loan_spec.rb b/spec/loan_spec.rb
index 25e7a6e..e0dae10 100644
--- a/spec/loan_spec.rb
+++ b/spec/loan_spec.rb
@@ -41,67 +41,87 @@
       @loan.interests_for_period(231).to_f.abs.should == 637.81
     end
 
-    #it "payback(1..360) returns payback table and last item balance should be 0.0" do
-    #  table = @loan.payback(1..360)
-    #
-    #  table[359][:balance].to_f.should == 0.0
-    #end
+    # TODO
+    it "payback_all returns payback table and last item balance should be 0.0" do
+      #table = @loan.payback(1..360) # 1 or 0 should be the first payback item?
+      table = @loan.payback_all
+
+      #table.size.should == 360
+
+      table[0][:capital].to_f.abs.should == 180.80
+      table[0][:interests].to_f.abs.should == 1083.33
+      #table[0][:amount].to_f.abs.should == 180.80
+      #table[0][:balance].to_f.abs.should == 180.80
+
+
+      #table.last[:capital].to_f.abs.should == 180.80
+      #table.last[:interests].to_f.abs.should == 1083.33
+      #table.last[:amount].to_f.abs.should == 180.80
+      table.last[:balance].to_f.should == 0.0
+    end
 
   end
 
-  #describe "desc loan" do
-  #  before :all do
-  #    @loan = Monetico::Loan.new(200000.0, 0.065, 360, :monthly, :desc)
-  #  end
-  #
-  #  it "capital returns amount/no_installments" do
-  #    @loan.capital.to_f.abs.should == 555.56
-  #  end
-  #
-  #  it "total_interests returns sum of interests" do
-  #    @loan.total_interests.to_f.should == 195541.67
-  #  end
-  #
-  #  it "interests(1) returns intersts for 1 payment" do
-  #    @loan.interests(1).to_f.should == 1083.33
-  #  end
+  describe "desc loan" do
+    before :all do
+      @loan = Monetico::Loan.new(200000.0, 0.065, 360, :monthly, :desc)
+    end
+
+    it "capital returns amount/no_installments" do
+      @loan.capital.to_f.abs.should == 555.56
+    end
+
+    it "total_interests returns sum of interests" do
+      @loan.total_interests.to_f.should == 195541.67
+    end
+
+    it "interests(1) returns intersts for 1 payment" do
+      @loan.interests(1).to_f.should == 1083.33
+    end
+
+    it "amount(1) returns amount for 1 payment" do
+      @loan.amounts(1).to_f.should == 1638.89
+    end
+
+    it "payback_all returns payback table and last item balance should be 0.0" do
+      table = @loan.payback_all
+      table[359][:balance].to_f.should == 0.0
+    end
+
+    it "can return debug string using to_s" do
+      @loan.to_s.should be_kind_of(String)
+    end
+
+  end
+
+  #it "should calculate loan" do
+  #  amount = 1000.0
+  #  interest_rate = 0.2
+  #  number_of_installments = 3
+  #  #cadence = :weekly
+  #  cadence = :monthly
+  #  kind = :const
+  #  #kind = :desc
   #
-  #  it "payback(1..360) returns payback table and last item balance should be 0.0" do
-  #    table = @loan.payback(1..360)
+  #  loan_calc = Monetico::Loan.new(amount, interest_rate, number_of_installments, cadence, kind)
+  #  puts loan_calc.to_yaml
   #
-  #    table[359][:balance].to_f.should == 0.0
+  #  loan_calc.payback(1..number_of_installments).each do |l|
+  #    #puts lo_nu.inspect
+  #    puts l[:amount].to_f
+  #    puts l[:interests].to_f
+  #    puts l[:capital].to_f
+  #    puts l[:balance].to_f
+  #    puts "*"
+  #    #payback_items.create(
+  #    #  number: lo_nu[:no],
+  #    #  pay_day: created_at + lo_nu[:no].send(period),
+  #    #  interests: lo_nu[:interests],
+  #    #  capital: lo_nu[:capital],
+  #    #  balance: lo_nu[:balance]
+  #    #)
   #  end
-  #
   #end
 
-  it "should calculate loan" do
-    amount = 1000.0
-    interest_rate = 0.2
-    number_of_installments = 3
-    #cadence = :weekly
-    cadence = :monthly
-    kind = :const
-    #kind = :desc
-
-    loan_calc = Monetico::Loan.new(amount, interest_rate, number_of_installments, cadence, kind)
-    puts loan_calc.to_yaml
-
-    loan_calc.payback(1..number_of_installments).each do |l|
-      #puts lo_nu.inspect
-      puts l[:amount].to_f
-      puts l[:interests].to_f
-      puts l[:capital].to_f
-      puts l[:balance].to_f
-      puts "*"
-      #payback_items.create(
-      #  number: lo_nu[:no],
-      #  pay_day: created_at + lo_nu[:no].send(period),
-      #  interests: lo_nu[:interests],
-      #  capital: lo_nu[:capital],
-      #  balance: lo_nu[:balance]
-      #)
-    end
-  end
-
 end
 

From 52dbf8ef2ebb9030a6b26de5e9370942e3896d87 Mon Sep 17 00:00:00 2001
From: Aleksander Kwiatkowski <bobikx@poczta.fm>
Date: Mon, 20 Feb 2012 14:05:23 +0100
Subject: [PATCH 09/11] cleaning

---
 .gitignore                  |  1 +
 lib/monetico/money_array.rb |  1 +
 monetico.gemspec            |  4 ++++
 spec/loan_spec.rb           |  8 ++++++++
 spec/money_round_spec.rb    | 11 ++++++-----
 5 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/.gitignore b/.gitignore
index d87d4be..12ff7e0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 .bundle
 .config
 .yardoc
+Gemfile
 Gemfile.lock
 InstalledFiles
 _yardoc
diff --git a/lib/monetico/money_array.rb b/lib/monetico/money_array.rb
index 44258df..878f504 100644
--- a/lib/monetico/money_array.rb
+++ b/lib/monetico/money_array.rb
@@ -1,5 +1,6 @@
 module Monetico
   class MoneyArray < Array
+    # round money values to proper precision, ...
     def money_round
       return self.class.money_round(self)
     end
diff --git a/monetico.gemspec b/monetico.gemspec
index 3aba412..86014d7 100644
--- a/monetico.gemspec
+++ b/monetico.gemspec
@@ -21,4 +21,8 @@ Gem::Specification.new do |gem|
   
   gem.add_development_dependency "rspec"
   gem.add_development_dependency "rake"
+
+  gem.add_development_dependency "rdoc"
+  gem.add_development_dependency "shoulda"
+  gem.add_development_dependency "simplecov"
 end
diff --git a/spec/loan_spec.rb b/spec/loan_spec.rb
index e0dae10..f05f937 100644
--- a/spec/loan_spec.rb
+++ b/spec/loan_spec.rb
@@ -83,6 +83,14 @@
       @loan.amounts(1).to_f.should == 1638.89
     end
 
+    it "interests(123) returns intersts for 1 payment" do
+      @loan.interests(123).to_f.should == 716.20
+    end
+
+    it "amount(123) returns amount for 1 payment" do
+      @loan.amounts(123).to_f.should == 1271.76
+    end
+
     it "payback_all returns payback table and last item balance should be 0.0" do
       table = @loan.payback_all
       table[359][:balance].to_f.should == 0.0
diff --git a/spec/money_round_spec.rb b/spec/money_round_spec.rb
index f61c572..0137fcf 100644
--- a/spec/money_round_spec.rb
+++ b/spec/money_round_spec.rb
@@ -9,12 +9,12 @@
       ma = Monetico::MoneyArray.new
       ma << 10.001
       ma << 9.999
-      puts ma.class
 
       ma.money_round.each do |m|
         # precision check
         rest = (m * 100.00) % 1
-        puts "#{m} - rest #{rest}"
+        #puts "#{m} - rest #{rest}"
+        rest.should == 0.0
       end
 
     end
@@ -40,14 +40,15 @@
       ma << BigDecimal.new("333.3029778708694")
       ma << BigDecimal.new("338.85802750205056")
 
-      puts ma.array_sum
-
       ma.money_round.each do |m|
         # precision check
         rest = (m * 100.00) % 1
-        puts "#{m} - rest #{rest}"
+        #puts "#{m} - rest #{rest}"
+        rest.should == 0.0
       end
 
+      # sum after rounding
+      ma.money_round.array_sum.should == 1000.0
     end
 
   end

From d05e153ee6a01ae7cea736d48ce784edc301c04c Mon Sep 17 00:00:00 2001
From: Aleksander Kwiatkowski <bobikx@poczta.fm>
Date: Mon, 20 Feb 2012 14:11:09 +0100
Subject: [PATCH 10/11] cleaning

---
 .rvmrc                   |  5 ++---
 Rakefile                 | 20 +-------------------
 lib/monetico/loan.rb     | 30 ------------------------------
 spec/loan_spec.rb        | 29 -----------------------------
 spec/money_round_spec.rb | 14 --------------
 5 files changed, 3 insertions(+), 95 deletions(-)

diff --git a/.rvmrc b/.rvmrc
index f357ddc..ca9e207 100644
--- a/.rvmrc
+++ b/.rvmrc
@@ -1,4 +1,3 @@
-#rvm_gemset_create_on_use_flag=1
-#rvm gemset use monetico
-
+rvm_gemset_create_on_use_flag=1
+rvm gemset use monetico
 rvm use 1.9.3@monetico --create
diff --git a/Rakefile b/Rakefile
index 380d971..0d17dde 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,7 +1,7 @@
 # encoding: utf-8
 
 #!/usr/bin/env rake
-#require "bundler/gem_tasks"
+require "bundler/gem_tasks"
 
 require 'rubygems'
 require 'bundler'
@@ -14,24 +14,6 @@ rescue Bundler::BundlerError => e
 end
 require 'rake'
 
-#require 'jeweler'
-#Jeweler::Tasks.new do |gem|
-#  # gem is a Gem::Specification... see http://docs.rubygems.org/read/chapter/20 for more options
-#  gem.name = "gem name"
-#  gem.homepage = "http://github.com/zaiste/monetico"
-#  gem.license = "licence"
-#  gem.summary = %Q{summary}
-#  gem.description = %Q{desc}
-#  gem.email = "..."
-#  gem.authors = ["..."]
-#  # dependencies defined in Gemfile
-#
-#  gem.files = FileList[
-#    "[A-Z]*", "{bin,generators,lib,test}/**/*"
-#  ]
-#end
-#Jeweler::RubygemsDotOrgTasks.new
-
 require 'rspec/core'
 require 'rspec/core/rake_task'
 RSpec::Core::RakeTask.new(:spec) do |spec|
diff --git a/lib/monetico/loan.rb b/lib/monetico/loan.rb
index 6476414..2c3778f 100644
--- a/lib/monetico/loan.rb
+++ b/lib/monetico/loan.rb
@@ -210,36 +210,6 @@ def round_paybacks(res)
       return res
     end
 
-    # temporary
-
-    #def capital_real
-    #  r(@amount / @no_installments)
-    #end
-
-    #def total_interests_real_float
-    #  if const?
-    #    par = (1 + @interest_rate) ** @no_installments
-    #    payback_amount = @amount * @interest_rate * par / (par - 1)
-    #    res = payback_amount * @no_installments - @amount
-    #  else
-    #    res = 0.5.big * @interest_rate * @no_installments * (@amount + capital_real)
-    #  end
-    #  res
-    #end
-
-    #def total_interests_real
-    #  r(total_interests_float)
-    #end
-
-    #def interests_real(idx)
-    #  if const?
-    #    res = interests_for_period(idx)
-    #  else
-    #    res = (@amount - (idx - 1) * capital_real) * @interest_rate
-    #  end
-    #  r(res)
-    #end
-
 
   end
 end
diff --git a/spec/loan_spec.rb b/spec/loan_spec.rb
index f05f937..13d0adf 100644
--- a/spec/loan_spec.rb
+++ b/spec/loan_spec.rb
@@ -102,34 +102,5 @@
 
   end
 
-  #it "should calculate loan" do
-  #  amount = 1000.0
-  #  interest_rate = 0.2
-  #  number_of_installments = 3
-  #  #cadence = :weekly
-  #  cadence = :monthly
-  #  kind = :const
-  #  #kind = :desc
-  #
-  #  loan_calc = Monetico::Loan.new(amount, interest_rate, number_of_installments, cadence, kind)
-  #  puts loan_calc.to_yaml
-  #
-  #  loan_calc.payback(1..number_of_installments).each do |l|
-  #    #puts lo_nu.inspect
-  #    puts l[:amount].to_f
-  #    puts l[:interests].to_f
-  #    puts l[:capital].to_f
-  #    puts l[:balance].to_f
-  #    puts "*"
-  #    #payback_items.create(
-  #    #  number: lo_nu[:no],
-  #    #  pay_day: created_at + lo_nu[:no].send(period),
-  #    #  interests: lo_nu[:interests],
-  #    #  capital: lo_nu[:capital],
-  #    #  balance: lo_nu[:balance]
-  #    #)
-  #  end
-  #end
-
 end
 
diff --git a/spec/money_round_spec.rb b/spec/money_round_spec.rb
index 0137fcf..902ebfa 100644
--- a/spec/money_round_spec.rb
+++ b/spec/money_round_spec.rb
@@ -20,20 +20,6 @@
     end
 
     it "should round simple loan results" do
-      #344.50566129375136
-      #16.666666666666668
-      #327.8389946270847
-      #689.0113225874981
-      #*
-      #344.50566129375136
-      #11.20268342288194
-      #333.3029778708694
-      #344.5056612937467
-      #*
-      #344.50566129375136
-      #5.647633791700789
-      #338.85802750205056
-
       ma = Monetico::MoneyArray.new
       # also testes using floats
       ma << BigDecimal.new("327.8389946270847")

From 4d600e9172aa2da60ea179b37175eecf26d52160 Mon Sep 17 00:00:00 2001
From: Aleksander Kwiatkowski <bobikx@poczta.fm>
Date: Mon, 20 Feb 2012 14:12:14 +0100
Subject: [PATCH 11/11] cleaning

---
 .gitignore | 1 -
 Gemfile    | 6 ------
 2 files changed, 7 deletions(-)

diff --git a/.gitignore b/.gitignore
index 12ff7e0..d87d4be 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,7 +3,6 @@
 .bundle
 .config
 .yardoc
-Gemfile
 Gemfile.lock
 InstalledFiles
 _yardoc
diff --git a/Gemfile b/Gemfile
index 1906b91..b6cc049 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,10 +4,4 @@ source 'http://rubygems.org'
 gemspec
 
 group :development, :test do
-  gem "rdoc"
-  gem "shoulda"
-  gem "bundler", "~> 1.0.0"
-  gem "rspec"
-  gem "jeweler" #, "~> 1.6.4"
-  gem "simplecov", ">= 0"
 end