From 7cccdd2006ff8245e78c2ef567109be4389acb5e Mon Sep 17 00:00:00 2001
From: bohung <bohung@rulingcom.com>
Date: Thu, 21 Jul 2022 23:31:58 +0800
Subject: [PATCH] Accelerate recurring events calculating.

---
 app/models/event.rb | 111 +++++++++++++++++++++-----------------------
 1 file changed, 54 insertions(+), 57 deletions(-)

diff --git a/app/models/event.rb b/app/models/event.rb
index 80e8dad..10756a2 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -17,6 +17,7 @@ class Event
   field :recurring, type: Boolean,default: false
   field :frequency
   field :period
+  field :recurring_end_date, type: DateTime
   field :create_user_id
   field :update_user_id
   field :module_key
@@ -147,69 +148,65 @@ class Event
     (date2.year-date1.year)*12+(date2.month-date1.month)
   end
   def self.recurring_event(start_date,end_date)
-    @recurring_events = self.where(:recurring => true)
+    @recurring_events = self.where(:recurring => true).any_of({:recurring_end_date=>nil}, {:recurring_end_date.gte=>start_date.utc})
     @recurring = []
     @recurring_events.each do |re|
-      edit_url = Rails.application.routes.url_helpers.edit_admin_calendar_path(:locale=>I18n.locale, :id=>re.id)
-      delete_url = Rails.application.routes.url_helpers.admin_calendar_path(:locale=>I18n.locale, :id=>re.id)
-      data = {:id => re.id.to_s, :title=>re.title, :note=>re.note || "", :allDay => re.all_day, :recurring => re.recurring, :calendar => re.calendar_type.id.to_s, :color => (re.calendar_type.color rescue nil), :edit_url => edit_url, :delete_url => delete_url, :url_linked => re.url_to_fronted}
-      case re.period
-      when 'Daily'
-        days = (end_date.to_date-re.start.to_date).to_i
+      has_recurring_end_date = re.recurring_end_date.present?
+      data = re.as_json
+      period_str = nil
+      is_month = false
+      is_year = false
+      days = 1
+      interval = nil
+      if re.period == 'Daily'
+        period_str = 'day'
+        interval = 1.day
+      elsif re.period == 'Weekly'
+        period_str = 'week'
+        days = 7
+        interval = 1.week
+      elsif re.period == 'Monthly'
+        period_str = 'month'
+        is_month = true
+        days = 30
+      elsif re.period == 'Yearly'
+        period_str = 'year'
+        is_year = true
+        days = 365
+      end
+      if period_str
+        org_start = re.start
+        @start_date = re.start
+        @end_date = re.end
         freq = re.frequency.to_i
-        start_key = (start_date.to_date-re.start.to_date).to_i
-        start_key = 1 if start_key<0
-        (start_key..days).each do |i|
-          if i%freq==0
-            @start_date = re.start + i
-            @end_date = re.end + i
-            @recurring << data.merge({:start => @start_date, :end => @end_date})
-          end
+        interval = freq.send(period_str)
+        if is_month
+          add_interval = ((start_date.year * 12 + start_date.month) - (@start_date.year * 12 + @start_date.month) - 1)
+        elsif is_year
+          add_interval = (start_date.year - @start_date.year - 1)
+        else
+          add_interval = (((start_date - @start_date - 1.day).to_i / 1.day) / days)
         end
-      when "Weekly"
-          @start_date = re.start
-          @end_date = re.end
-          @i = TimeDifference.between(re.start.to_date,end_date.to_date).in_weeks.to_i
-          (1..@i).each do |i|
-            @start_date += (7*re.frequency.to_i)
-            @end_date += (7*re.frequency.to_i)
-            @recurring << data.merge({:start => @start_date, :end => @end_date})
-          end
-      when "Monthly"
-        if !(start_date..end_date).cover?(re.start) && start_date.to_datetime>re.start
-          sd = re.start
-          ed = re.end
-          end_datetime = end_date.to_datetime
-          start_datetime = start_date.to_datetime
-          months = self.get_diff_month(sd,start_datetime)..self.get_diff_month(sd,end_datetime)
-          months.each do |diff_month|
-            if (diff_month%re.frequency.to_i)==0 
-              sd_tp = sd + diff_month.month
-              ed_tp = ed + diff_month.month
-              if sd_tp>start_date
-                @recurring << data.merge({:start => sd_tp, :end => ed_tp})
-              end
-            end
-          end
+        if add_interval < 0
+          add_interval = add_interval % freq
         end
-      when "Yearly"
-        if !(start_date..end_date).cover?(re.start)
-          sd = re.start
-          ed = re.end
-          start_datetime = start_date.to_datetime
-          end_datetime = end_date.to_datetime
-          if start_datetime>sd && start_datetime.year != sd.year
-            ((start_datetime.year-sd.year)..(end_datetime.year-sd.year)).each do |year_diff|
-              if (year_diff%re.frequency.to_i)==0
-                sd_tp = sd + year_diff.year
-                ed_tp = ed + year_diff.year
-                if (start_date..end_date)&(sd_tp..ed_tp)
-                  @recurring << data.merge({:start => sd_tp, :end => ed_tp})
-                end
-              end
-            end
-          end
+        rest = add_interval % freq
+        if rest != 0
+          add_interval += (freq - rest)
         end
+        add_interval = add_interval.send(period_str)
+        @start_date += add_interval
+        @end_date += add_interval
+        new_end_date = has_recurring_end_date ? [re.recurring_end_date,end_date].min : end_date
+        while @start_date <= new_end_date do
+          if @start_date >= start_date && @start_date != org_start
+            @recurring << data.merge({:start => @start_date.to_json.gsub('"',''), :end => @end_date.to_json.gsub('"','')})
+          end
+          @start_date += interval
+          @end_date += interval
+        end
+      else
+        next
       end
    end