From c991f997b96b9c4782ad1997d7f2be2350ca0a9a Mon Sep 17 00:00:00 2001
From: Iain Beeston <iainbeeston@users.noreply.github.com>
Date: Sat, 12 Jan 2019 15:54:07 +0000
Subject: [PATCH] Added support for parsing VEVENT from iCal format

---
 CHANGELOG.md                        |  1 +
 lib/ice_cube/parsers/ical_parser.rb | 58 +++++++++++++++++++++--------
 spec/examples/from_ical_spec.rb     | 42 +++++++++++++++++++++
 3 files changed, 85 insertions(+), 16 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c0022b92..3a2ec2e9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Added
+- Added support for parsing VEVENT from iCal format (#465)
 - Indonesian translations. ([#505](https://github.com/seejohnrun/ice_cube/pull/505)) by [@achmiral](https://github.com/achmiral)
 
 ### Changed
diff --git a/lib/ice_cube/parsers/ical_parser.rb b/lib/ice_cube/parsers/ical_parser.rb
index 429bd84c..78a62389 100644
--- a/lib/ice_cube/parsers/ical_parser.rb
+++ b/lib/ice_cube/parsers/ical_parser.rb
@@ -2,30 +2,56 @@ module IceCube
   class IcalParser
     def self.schedule_from_ical(ical_string, options = {})
       data = {}
+      current_state = :parsing_calendar
       ical_string.each_line do |line|
         (property, value) = line.split(":")
         (property, _tzid) = property.split(";")
-        case property
-        when "DTSTART"
-          data[:start_time] = TimeUtil.deserialize_time(value)
-        when "DTEND"
-          data[:end_time] = TimeUtil.deserialize_time(value)
-        when "RDATE"
-          data[:rtimes] ||= []
-          data[:rtimes] += value.split(",").map { |v| TimeUtil.deserialize_time(v) }
-        when "EXDATE"
-          data[:extimes] ||= []
-          data[:extimes] += value.split(",").map { |v| TimeUtil.deserialize_time(v) }
-        when "DURATION"
-          data[:duration] # FIXME
-        when "RRULE"
-          data[:rrules] ||= []
-          data[:rrules] += [rule_from_ical(value)]
+
+        if current_state == :parsing_calendar
+          current_state = parse_calendar(data, property, value)
+        elsif current_state == :parsing_event
+          current_state = parse_event(data, property, value)
         end
       end
       Schedule.from_hash data
     end
 
+    def self.parse_calendar(data, property, value)
+      case property
+      when "DTSTART"
+        data[:start_time] = TimeUtil.deserialize_time(value)
+      when "DTEND"
+        data[:end_time] = TimeUtil.deserialize_time(value)
+      when "RDATE"
+        data[:rtimes] ||= []
+        data[:rtimes] += value.split(",").map { |v| TimeUtil.deserialize_time(v) }
+      when "EXDATE"
+        data[:extimes] ||= []
+        data[:extimes] += value.split(",").map { |v| TimeUtil.deserialize_time(v) }
+      when "DURATION"
+        data[:duration] # FIXME
+      when "RRULE"
+        data[:rrules] ||= []
+        data[:rrules] += [rule_from_ical(value)]
+      when "BEGIN"
+        return :parsing_event if value.chomp == "VEVENT"
+      end
+
+      :parsing_calendar
+    end
+
+    def self.parse_event(data, property, value)
+      case property
+      when "DTSTART"
+        data[:rtimes] ||= []
+        data[:rtimes] += value.split(",").map { |v| TimeUtil.deserialize_time(v) }
+      when "END"
+        return :parsing_calendar if value.chomp == "VEVENT"
+      end
+
+      :parsing_event
+    end
+
     def self.rule_from_ical(ical)
       raise ArgumentError, "empty ical rule" if ical.nil?
 
diff --git a/spec/examples/from_ical_spec.rb b/spec/examples/from_ical_spec.rb
index 2ab66c3c..9477afbd 100644
--- a/spec/examples/from_ical_spec.rb
+++ b/spec/examples/from_ical_spec.rb
@@ -115,6 +115,17 @@ module IceCube
   RRULE:FREQ=WEEKLY;INTERVAL=2;WKST=SU;BYDAY=FR
     ICAL
 
+    ical_string_with_events = <<-ICAL.gsub(/^\s*/, "")
+  BEGIN:VEVENT
+  DTSTART;VALUE=DATE:20120406
+  DTEND;VALUE=DATE:20120407
+  END:VEVENT
+  BEGIN:VEVENT
+  DTSTART;VALUE=DATE:20120409
+  DTEND;VALUE=DATE:20120410
+  END:VEVENT
+    ICAL
+
     def sorted_ical(ical)
       ical.split("\n").sort.map { |field|
         k, v = field.split(":")
@@ -378,6 +389,30 @@ def sorted_ical(ical)
       end
     end
 
+    describe "one-off dates" do
+      it "handles a specific day as a recurrence time" do
+        start_time = Time.now
+
+        schedule = IceCube::Schedule.new(start_time)
+        schedule.add_recurrence_time(start_time)
+
+        ical = schedule.to_ical
+        expect(sorted_ical(IceCube::Schedule.from_ical(ical).to_ical)).to eq(sorted_ical(ical))
+      end
+
+      it "converts events to recurrence times" do
+        start_time = Time.utc(2019, 1, 16)
+
+        schedule = IceCube::Schedule.new(start_time)
+        schedule.add_recurrence_time(start_time)
+
+        event_ical = "DTSTART:20190116T000000Z\nBEGIN:VEVENT\nDTSTART:20190116T000000Z\nDTEND:20190117T000000Z\nEND:VEVENT"
+
+        ical = schedule.to_ical
+        expect(sorted_ical(IceCube::Schedule.from_ical(event_ical).to_ical)).to eq(sorted_ical(ical))
+      end
+    end
+
     describe "multiple rules" do
       it "handles multiple recurrence rules" do
         schedule = IceCube::Schedule.from_ical ical_string_with_multiple_rules
@@ -385,6 +420,13 @@ def sorted_ical(ical)
       end
     end
 
+    describe "events" do
+      it "converts each event into it's own recurrence time" do
+        schedule = IceCube::Schedule.from_ical ical_string_with_events
+        expect(schedule.recurrence_times.count).to eq(2)
+      end
+    end
+
     describe "invalid ical data" do
       shared_examples_for("an invalid ical string") do
         it do