From b046086d7f19a2e50320795891ebd7502d7af1ce Mon Sep 17 00:00:00 2001
From: Joseph Dayo <joseph.dayo@gmail.com>
Date: Tue, 19 Dec 2017 18:31:45 +0800
Subject: [PATCH] Add support for timezone offsets

---
 README.md                |  5 +++++
 lib/cron_parser.rb       | 20 ++++++++++++++------
 spec/cron_parser_spec.rb | 24 ++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index d40d529..847f3a4 100644
--- a/README.md
+++ b/README.md
@@ -14,5 +14,10 @@ next_time = cron_parser.next(Time.now)
 
 # Last occurrence
 most_recent_time = cron_parser.last(Time.now)
+
+# With Timezone
+
+cron_parser = CronParser.new('30 * * * * +08:00')
+
 ```
 
diff --git a/lib/cron_parser.rb b/lib/cron_parser.rb
index 41a8a5e..c556409 100644
--- a/lib/cron_parser.rb
+++ b/lib/cron_parser.rb
@@ -7,9 +7,9 @@ class CronParser
   # internal "mutable" time representation
   class InternalTime
     attr_accessor :year, :month, :day, :hour, :min
-    attr_accessor :time_source
+    attr_accessor :time_source, :offset
 
-    def initialize(time,time_source = Time)
+    def initialize(time, time_source = Time)
       @year = time.year
       @month = time.month
       @day = time.day
@@ -20,7 +20,11 @@ def initialize(time,time_source = Time)
     end
 
     def to_time
-      time_source.local(@year, @month, @day, @hour, @min, 0)
+      if @offset
+        time_source.new(@year, @month, @day, @hour, @min, 0, @offset)
+      else
+        time_source.local(@year, @month, @day, @hour, @min, 0)
+      end
     end
 
     def inspect
@@ -50,10 +54,11 @@ def inspect
      "fri" => "5",
      "sat" => "6"
   }
-
-  def initialize(source,time_source = Time)
+  attr_accessor :offset
+  def initialize(source,time_source = Time, offset = nil)
     @source = interpret_vixieisms(source)
     @time_source = time_source
+    @offset = offset
     validate_source
   end
 
@@ -80,6 +85,7 @@ def interpret_vixieisms(spec)
   # returns the next occurence after the given date
   def next(now = @time_source.now, num = 1)
     t = InternalTime.new(now, @time_source)
+    t.offset = time_specs[:offset]
 
     unless time_specs[:month][0].include?(t.month)
       nudge_month(t)
@@ -109,6 +115,7 @@ def next(now = @time_source.now, num = 1)
   # returns the last occurence before the given date
   def last(now = @time_source.now, num=1)
     t = InternalTime.new(now,@time_source)
+    t.offset = time_specs[:offset]
 
     unless time_specs[:month][0].include?(t.month)
       nudge_month(t, :last)
@@ -253,7 +260,8 @@ def time_specs
         :hour   => parse_element(tokens[1], 0..23), #hour
         :dom    => parse_element(tokens[2], 1..31), #DOM
         :month  => parse_element(tokens[3], 1..12), #mon
-        :dow    => parse_element(tokens[4], 0..6)  #DOW
+        :dow    => parse_element(tokens[4], 0..6),  #DOW
+        :offset => (tokens.length == 6) ? tokens[5] : nil,  #timezone offset
       }
     end
   end
diff --git a/spec/cron_parser_spec.rb b/spec/cron_parser_spec.rb
index 94f7ad0..164d6ce 100644
--- a/spec/cron_parser_spec.rb
+++ b/spec/cron_parser_spec.rb
@@ -8,6 +8,11 @@ def parse_date(str)
   Time.local(dt.year, dt.month, dt.day, dt.hour, dt.min, 0)
 end
 
+def parse_date_with_tz(str)
+  dt = DateTime.strptime(str, "%Y-%m-%d %H:%M %z")
+  Time.new(dt.year, dt.month, dt.day, dt.hour, dt.min, 0, dt.zone)
+end
+
 describe "CronParser#parse_element" do
   [
     ["*", 0..59, (0..59).to_a],
@@ -169,6 +174,25 @@ def parse_date(str)
   end
 end
 
+describe "With timezone" do
+  describe "#time_spec" do
+    it "returns the correct breakdown" do
+      parser = CronParser.new('0 17 * * * -08:00')
+      expect(parser.send(:time_specs)[:offset]).to eq("-08:00")
+    end
+  end
+
+  it "Should return in the specified timezone with the correct computed day" do
+    now = parse_date_with_tz('2017-12-14 17:15 -08:00')
+    expected_last = parse_date_with_tz('2017-12-14 17:00 -08:00')
+    expected_next = parse_date_with_tz('2017-12-15 17:00 -08:00')
+
+    parser = CronParser.new('0 17 * * * -08:00')
+    parser.next(now).should == expected_next
+    parser.last(now).should == expected_last
+  end
+end
+
 describe "CronParser#new" do
   it 'should not raise error when given a valid cronline' do
     expect { CronParser.new('30 * * * *') }.not_to raise_error