Merge pull request #51 from zendesk/craig/schedule-intersection

Add ability to intersect schedules

README.md

@@ -17,6 +17,7 @@ Time calculations using business hours.
   - Multiple schedule configurations.
 * Second-level precision on all calculations.
 * Accurate handling of Daylight Saving Time.
+* Schedule intersection.
 * Thread-safe.
 
 ## Anti-Features
@@ -50,7 +51,7 @@ Biz.configure do |config|
     sat: {'10:00' => '14:00'}
   }
 
-  config.holidays = [Date.new(2014, 1, 1), Date.new(2014, 12, 25)]
+  config.holidays = [Date.new(2016, 1, 1), Date.new(2016, 12, 25)]
 
   config.time_zone = 'America/Los_Angeles'
 end
@@ -120,6 +121,74 @@ Biz.periods
 #  #<Biz::TimeSegment start_time=2015-04-27 20:36:57 UTC end_time=2015-04-28 00:00:00 UTC>]
 ```
 
+## Schedule Intersection
+
+An intersection of two schedules can be found using `&`:
+
+```ruby
+schedule_1 = Biz::Schedule.new do |config|
+  config.hours = {
+    mon: {'09:00' => '17:00'},
+    tue: {'10:00' => '16:00'},
+    wed: {'09:00' => '17:00'},
+    thu: {'10:00' => '16:00'},
+    fri: {'09:00' => '17:00'},
+    sat: {'11:00' => '14:30'}
+  }
+
+  config.holidays = [Date.new(2016, 1, 1), Date.new(2016, 12, 25)]
+
+  config.time_zone = 'Etc/UTC'
+end
+
+schedule_2 = Biz::Schedule.new do |config|
+  config.hours = {
+    sun: {'10:00' => '12:00'},
+    mon: {'08:00' => '10:00'},
+    tue: {'11:00' => '15:00'},
+    wed: {'16:00' => '18:00'},
+    thu: {'11:00' => '12:00', '13:00' => '14:00'}
+  }
+
+  config.holidays = [
+    Date.new(2016, 1, 1),
+    Date.new(2016, 7, 4),
+    Date.new(2016, 11, 24)
+  ]
+
+  config.time_zone = 'America/Los_Angeles'
+end
+
+schedule_1 & schedule_2
+```
+
+The resulting schedule will be a combination of the two schedules: an
+intersection of the intervals, a union of the holidays, and the time zone of the
+first schedule.
+
+For the above example, the resulting schedule would be equivalent to one with
+the following configuration:
+
+```ruby
+Biz::Schedule.new do |config|
+  config.hours = {
+    mon: {'09:00' => '10:00'},
+    tue: {'11:00' => '15:00'},
+    wed: {'16:00' => '17:00'},
+    thu: {'11:00' => '12:00', '13:00' => '14:00'}
+  }
+
+  config.holidays = [
+    Date.new(2016, 1, 1),
+    Date.new(2016, 7, 4),
+    Date.new(2016, 11, 24),
+    Date.new(2016, 12, 25)
+  ]
+
+  config.time_zone = 'Etc/UTC'
+end
+```
+
 ## Core Extensions
 
 Optional extensions to core classes (`Date`, `Fixnum`, and `Time`) are available

lib/biz.rb

@@ -1,7 +1,6 @@
 require 'date'
 require 'delegate'
 require 'forwardable'
-require 'set'
 
 require 'clavius'
 require 'tzinfo'

lib/biz/configuration.rb

@@ -7,6 +7,8 @@ def initialize
       yield raw if block_given?
 
       Validation.perform(raw)
+
+      raw.freeze
     end
 
     def intervals
@@ -21,7 +23,12 @@ def intervals
 
     def holidays
       @holidays ||= begin
-        raw.holidays.map { |date| Holiday.new(date, time_zone) }.freeze
+        raw
+          .holidays
+          .uniq
+          .map { |date| Holiday.new(date, time_zone) }
+          .sort
+          .freeze
       end
     end
 
@@ -30,7 +37,7 @@ def time_zone
     end
 
     def weekdays
-      @weekdays ||= raw.hours.keys.to_set.freeze
+      @weekdays ||= raw.hours.keys.uniq.freeze
     end
 
     protected

lib/biz/interval.rb

@@ -1,18 +1,38 @@
 module Biz
   class Interval
 
+    extend Forwardable
+
     include Comparable
 
+    def self.to_hours(intervals)
+      intervals.each_with_object(
+        Hash.new do |hours, wday| hours.store(wday, {}) end
+      ) do |interval, hours|
+        hours[interval.wday_symbol].store(*interval.endpoints.map(&:timestamp))
+      end
+    end
+
     def initialize(start_time, end_time, time_zone)
       @start_time = start_time
       @end_time   = end_time
       @time_zone  = time_zone
     end
 
+    attr_reader :start_time,
+                :end_time,
+                :time_zone
+
+    delegate wday_symbol: :start_time
+
     def endpoints
       [start_time, end_time]
     end
 
+    def empty?
+      start_time >= end_time
+    end
+
     def contains?(time)
       (start_time...end_time).cover?(
         WeekTime.from_time(Time.new(time_zone).local(time))
@@ -27,18 +47,19 @@ def to_time_segment(week)
       )
     end
 
+    def &(other)
+      lower_bound = [self, other].map(&:start_time).max
+      upper_bound = [self, other].map(&:end_time).min
+
+      self.class.new(lower_bound, [lower_bound, upper_bound].max, time_zone)
+    end
+
     def <=>(other)
       return unless other.is_a?(self.class)
 
       [start_time, end_time, time_zone] <=>
         [other.start_time, other.end_time, other.time_zone]
     end
 
-    protected
-
-    attr_reader :start_time,
-                :end_time,
-                :time_zone
-
   end
 end

lib/biz/schedule.rb

@@ -46,6 +46,23 @@ def in_zone
       Time.new(time_zone)
     end
 
+    def &(other)
+      self.class.new do |config|
+        config.hours = Interval.to_hours(
+          intervals.flat_map { |interval|
+            other
+              .intervals
+              .map { |other_interval| interval & other_interval }
+              .reject(&:empty?)
+          }
+        )
+
+        config.holidays = [*holidays, *other.holidays].map(&:to_date)
+
+        config.time_zone = time_zone.name
+      end
+    end
+
     protected
 
     attr_reader :configuration

lib/biz/time_segment.rb

@@ -36,10 +36,10 @@ def contains?(time)
     end
 
     def &(other)
-      self.class.new(
-        lower_bound(other),
-        [lower_bound(other), upper_bound(other)].max
-      )
+      lower_bound = [self, other].map(&:start_time).max
+      upper_bound = [self, other].map(&:end_time).min
+
+      self.class.new(lower_bound, [lower_bound, upper_bound].max)
     end
 
     def <=>(other)
@@ -48,15 +48,5 @@ def <=>(other)
       [start_time, end_time] <=> [other.start_time, other.end_time]
     end
 
-    private
-
-    def lower_bound(other)
-      [self, other].map(&:start_time).max
-    end
-
-    def upper_bound(other)
-      [self, other].map(&:end_time).min
-    end
-
   end
 end

spec/configuration_spec.rb

@@ -39,7 +39,7 @@
   end
 
   describe '#intervals' do
-    context 'when left unconfigured' do
+    context 'when unconfigured' do
       subject(:configuration) {
         Biz::Configuration.new do |config|
           config.holidays  = holidays
@@ -126,35 +126,56 @@
   end
 
   describe '#holidays' do
-    context 'when left unconfigured' do
-      subject(:configuration) {
-        Biz::Configuration.new do |config|
-          config.hours     = hours
-          config.time_zone = time_zone
-        end
-      }
-
-      it 'returns the default set of holidays' do
-        expect(configuration.holidays).to eq []
-      end
-    end
+    let(:holidays) {
+      [Date.new(2006, 12, 25), Date.new(2006, 1, 1), Date.new(2006, 7, 4)]
+    }
 
     it 'returns the proper holidays' do
       expect(configuration.holidays).to eq [
         Biz::Holiday.new(
           Date.new(2006, 1, 1),
           TZInfo::Timezone.get('America/New_York')
         ),
+        Biz::Holiday.new(
+          Date.new(2006, 7, 4),
+          TZInfo::Timezone.get('America/New_York')
+        ),
         Biz::Holiday.new(
           Date.new(2006, 12, 25),
           TZInfo::Timezone.get('America/New_York')
         )
       ]
     end
+
+    context 'when unconfigured' do
+      subject(:configuration) {
+        Biz::Configuration.new do |config|
+          config.hours     = hours
+          config.time_zone = time_zone
+        end
+      }
+
+      it 'returns the default set of holidays' do
+        expect(configuration.holidays).to eq []
+      end
+    end
+
+    context 'when configured with duplicate holidays' do
+      let(:holidays) { Array.new(3) { Date.new(2006, 1, 1) } }
+
+      it 'removes the duplicate dates' do
+        expect(configuration.holidays).to eq [
+          Biz::Holiday.new(
+            Date.new(2006, 1, 1),
+            TZInfo::Timezone.get('America/New_York')
+          )
+        ]
+      end
+    end
   end
 
   describe '#time_zone' do
-    context 'when left unconfigured' do
+    context 'when unconfigured' do
       subject(:configuration) {
         Biz::Configuration.new do |config|
           config.hours    = hours
@@ -176,7 +197,7 @@
 
   describe '#weekdays' do
     it 'returns the active weekdays for the configured schedule' do
-      expect(configuration.weekdays).to eq Set.new(%i[mon tue wed thu fri sat])
+      expect(configuration.weekdays).to eq %i[mon tue wed thu fri sat]
     end
   end
 end