From f921a96e8506ca5d376a83f06b45ffd8df737fa7 Mon Sep 17 00:00:00 2001
From: Geoff Buesing <gbuesing@gmail.com>
Date: Sat, 22 Mar 2008 01:59:09 +0000
Subject: [PATCH] Adding rake tasks time:zones:all, time:zones:us and
 time:zones:local for finding time zone names for config.time_zone option

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@9074 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
---
 railties/CHANGELOG           |  2 ++
 railties/lib/tasks/misc.rake | 43 ++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/railties/CHANGELOG b/railties/CHANGELOG
index fc6bf18eba..a22efda9be 100644
--- a/railties/CHANGELOG
+++ b/railties/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Adding rake tasks time:zones:all, time:zones:us and time:zones:local for finding time zone names for config.time_zone option [Geoff Buesing]
+
 * Added support for installing plugins hosted at git repositories #11294 [danger]
 
 * Fixed that script/generate would not look for plugin generators in plugin_paths #11000 [glv]
diff --git a/railties/lib/tasks/misc.rake b/railties/lib/tasks/misc.rake
index e44ab2cf17..fcd860ae16 100644
--- a/railties/lib/tasks/misc.rake
+++ b/railties/lib/tasks/misc.rake
@@ -8,3 +8,46 @@ desc 'Generate a crytographically secure secret key. This is typically used to g
 task :secret do
   puts Rails::SecretKeyGenerator.new(ENV['ID']).generate_secret
 end
+
+namespace :time do
+  namespace :zones do
+    desc 'Displays names of all time zones recognized by the Rails TimeZone class, grouped by offset. Results can be filtered with optional OFFSET parameter, e.g., OFFSET=-6'
+    task :all => :environment do
+      build_time_zone_list(:all)
+    end
+    
+    desc 'Displays names of US time zones recognized by the Rails TimeZone class, grouped by offset. Results can be filtered with optional OFFSET parameter, e.g., OFFSET=-6'
+    task :us => :environment do
+      build_time_zone_list(:us_zones)
+    end
+    
+    desc 'Displays names of time zones recognized by the Rails TimeZone class with the same offset as the system local time'
+    task :local => :environment do
+      build_time_zone_list(:all, Time.now.beginning_of_year.utc_offset)
+    end
+    
+    # to find UTC -06:00 zones, OFFSET can be set to either -6, -6:00 or 21600
+    def build_time_zone_list(method, offset = ENV['OFFSET'])
+      if offset
+        offset = if offset.to_s.match(/(\+|-)?(\d+):(\d+)/)
+          sign = $1 == '-' ? -1 : 1
+          hours, minutes = $2.to_f, $3.to_f
+          ((hours * 3600) + (minutes.to_f * 60)) * sign
+        elsif offset.to_f.abs <= 13
+          offset.to_f * 3600
+        else
+          offset.to_f
+        end
+      end
+      previous_offset = nil
+      TimeZone.__send__(method).each do |zone|
+        if offset.nil? || offset == zone.utc_offset
+          puts "\n* UTC #{zone.formatted_offset} *" unless zone.utc_offset == previous_offset
+          puts zone.name
+          previous_offset = zone.utc_offset
+        end
+      end
+      puts "\n"
+    end
+  end
+end
\ No newline at end of file