Fix inconsistent DateTime conversion (#65)

* Always return a Time object for DateTime cells

* Fix specs for DateTime parsing

Author: demimismo

lib/creek/styles/converter.rb

@@ -60,8 +60,10 @@ def self.call(value, type, style, options = {})
           value.to_i
         when :float, :percentage
           value.to_f
-        when :date, :time, :date_time
+        when :date
           convert_date(value, options)
+        when :time, :date_time
+          convert_datetime(value, options)
         when :bignum
           convert_bignum(value)
 
@@ -71,22 +73,17 @@ def self.call(value, type, style, options = {})
         end
       end
 
-      # the trickiest. note that  all these formats can vary on
-      # whether they actually contain a date, time, or datetime.
       def self.convert_date(value, options)
-        value                        = value.to_f
-        days_since_date_system_start = value.to_i
-        fraction_of_24               = value - days_since_date_system_start
+        date = base_date(options) + value.to_i
+        yyyy, mm, dd = date.strftime('%Y-%m-%d').split('-')
 
-        # http://stackoverflow.com/questions/10559767/how-to-convert-ms-excel-date-from-float-to-date-format-in-ruby
-        date = options.fetch(:base_date, Date.new(1899, 12, 30)) + days_since_date_system_start
+        ::Date.new(yyyy.to_i, mm.to_i, dd.to_i)
+      end
 
-        if fraction_of_24 > 0 # there is a time associated
-          seconds = (fraction_of_24 * 86400).round
-          return Time.utc(date.year, date.month, date.day) + seconds
-        else
-          return date
-        end
+      def self.convert_datetime(value, options)
+        date = base_date(options) + value.to_f.round(6)
+
+        round_datetime(date.strftime('%Y-%m-%d %H:%M:%S.%N'))
       end
 
       def self.convert_bignum(value)
@@ -96,6 +93,18 @@ def self.convert_bignum(value)
           value.to_f
         end
       end
+
+      private
+
+        def self.base_date(options)
+          options.fetch(:base_date, Date.new(1899, 12, 30))
+        end
+
+        def self.round_datetime(datetime_string)
+          /(?<yyyy>\d+)-(?<mm>\d+)-(?<dd>\d+) (?<hh>\d+):(?<mi>\d+):(?<ss>\d+.\d+)/ =~ datetime_string
+
+          ::Time.new(yyyy.to_i, mm.to_i, dd.to_i, hh.to_i, mi.to_i, ss.to_r).round(0)
+        end
     end
   end
 end

spec/fixtures/sample_dates.xlsx

@@ -3,13 +3,20 @@
 describe Creek::Styles::Converter do
 
   describe :call do
+
     def convert(value, type, style)
       Creek::Styles::Converter.call(value, type, style)
     end
 
+    describe :date do
+      it "works" do
+        expect(convert('41275', 'n', :date)).to eq(Date.new(2013,01,01))
+      end
+    end
+
     describe :date_time do
       it "works" do
-        expect(convert('41275', 'n', :date_time)).to eq(Date.new(2013,01,01))
+        expect(convert('41275', 'n', :date_time)).to eq(Time.new(2013,01,01))
       end
     end
   end

spec/fixtures/sheets/sample_dates.xlsx

@@ -26,6 +26,34 @@
   end
 end
 
+describe 'Creek parsing dates on a sample XLSX file' do
+  before(:all) do
+    @creek = Creek::Book.new 'spec/fixtures/sample_dates.xlsx'
+
+    @expected_datetime_rows = [
+      {'A3' => 'Date',              'B3' => Date.parse('2018-01-01')},
+      {'A4' => 'Datetime 00:00:00', 'B4' => Time.parse('2018-01-01 00:00:00')},
+      {'A5' => 'Datetime',          'B5' => Time.parse('2018-01-01 23:59:59')}]
+  end
+
+  after(:all) do
+    @creek.close
+  end
+
+  it 'parses dates successfully' do
+    rows = Array.new
+    row_count = 0
+    @creek.sheets[0].rows.each do |row|
+      rows << row
+      row_count += 1
+    end
+
+    (2..5).each do |number|
+      expect(rows[number]).to eq(@expected_datetime_rows[number-2])
+    end
+  end
+end
+
 describe 'Creek parsing a sample XLSX file' do
   before(:all) do
     @creek = Creek::Book.new 'spec/fixtures/sample.xlsx'
@@ -63,15 +91,9 @@
       row_count += 1
     end
 
-    expect(rows[0]).to eq(@expected_rows[0])
-    expect(rows[1]).to eq(@expected_rows[1])
-    expect(rows[2]).to eq(@expected_rows[2])
-    expect(rows[3]).to eq(@expected_rows[3])
-    expect(rows[4]).to eq(@expected_rows[4])
-    expect(rows[5]).to eq(@expected_rows[5])
-    expect(rows[6]).to eq(@expected_rows[6])
-    expect(rows[7]).to eq(@expected_rows[7])
-    expect(rows[8]).to eq(@expected_rows[8])
+    (0..8).each do |number|
+      expect(rows[number]).to eq(@expected_rows[number])
+    end
     expect(row_count).to eq(9)
   end