Implement events/scenes/rules reloading

* Store change time when loading
* On reload, check if a file exists and whether it is newer
* Fail if the rules file cannot be loaded
* Reload the rules file if the events/scenes file has been reloaded
  (This is needed because rules might depend on new or updated
  events/scenes)

hued

@@ -150,6 +150,9 @@ class Hued
 
   def initialize(options = {})
     @options = options
+    @ctime = Hash.new(Time.now)
+
+    # Set up the logger
     @log = Logger.new($stdout)
     @log.progname = "hued"
     @log.level = options[:debug] ? Logger::DEBUG : Logger::INFO
@@ -204,37 +207,41 @@ class Hued
   end
 
   def load
-    @log.info "Loading events..."
-    @events = Huey::Event.import("events.yml")
-    @events.each do |event|
-      event.actions["on"] = true if event.actions["on"].nil?
-      @log.info "* Loaded event: #{event.name}"
-    end
-    @log.info "Loaded #{@events.count} event#{"s" unless @events.count == 1}"
-
-    @log.info "Loading scenes..."
-    @scenes = {}
-    YAML.load_file("scenes.yml").each do |name, entry|
-      @scenes[name] = entry.map do |ev_options|
-        # Keys should be symbols
-        options = ev_options.inject({}) { |opts, (k, v)| opts[k.to_sym] = v; opts }
-        event = Huey::Event.new(options)
-        event.actions["on"] = true if event.actions["on"].nil?
-        event
+    [:events, :scenes].each do |items|
+      if File.exist? "#{items}.yml"
+        @log.info "Loading #{items}..."
+        send("load_#{items}")
       end
-      Scenes[name] = @scenes[name]
-      @log.info "* Loaded scene: #{name}"
     end
-    @log.info "Loaded #{@scenes.count} scene#{"s" unless @scenes.count == 1}"
 
-    @log.info "Loading rules"
-    @rules = YAML.load_file("rules.yml").map do |name, entry|
-               Rule.new(name, @log, entry)
-             end
-    @rules.each do |rule|
-      @log.info "* Loaded rule: #{rule.name}"
+    # Treat rules separately, we cannot start without it
+    if File.exist? "rules.yml"
+      @log.info "Loading rules"
+      load_rules
+    else
+      @log.error "Cannot find required file: rules.yml, aborting!"
+      exit 1
+    end
+  end
+
+  def reload
+    @log.debug "Checking if events/scenes/rules need to be reloaded..."
+    @reload_rules = false
+    [:events, :scenes].each do |items|
+      if File.exist?("#{items}.yml") and
+         File.ctime("#{items}.yml") > @ctime[items]
+        @log.info "Reloading events..."
+        send("load_#{items}")
+        # Rules may depend on events/scenes, reload the rules too!
+        @reload_rules = true
+      end
+    end
+
+    if File.exist?("rules.yml") and
+       (@reload_rules or File.ctime("rules.yml") > @ctime[:rules])
+      @log.info "Reloading rules..."
+      send("load_rules")
     end
-    @log.info "Loaded #{@rules.count} rule#{"s" unless @rules.count == 1}"
   end
 
   def execute
@@ -277,6 +284,47 @@ class Hued
     @log.info "Shutting down..."
   end
 
+  #######
+  private
+
+    def load_events
+      @ctime[:events] = File.ctime("events.yml")
+      @events = Huey::Event.import("events.yml")
+      @events.each do |event|
+        event.actions["on"] = true if event.actions["on"].nil?
+        @log.info "* Loaded event: #{event.name}"
+      end
+      @log.info "Loaded #{@events.count} event#{"s" unless @events.count == 1}"
+    end
+
+    def load_scenes
+      @ctime[:scenes] = File.ctime "scenes.yml"
+      @scenes = {}
+      YAML.load_file("scenes.yml").each do |name, entry|
+        @scenes[name] = entry.map do |ev_options|
+          # Keys should be symbols
+          options = ev_options.inject({}) { |opts, (k, v)| opts[k.to_sym] = v; opts }
+          event = Huey::Event.new(options)
+          event.actions["on"] = true if event.actions["on"].nil?
+          event
+        end
+        Scenes[name] = @scenes[name]
+        @log.info "* Loaded scene: #{name}"
+      end
+      @log.info "Loaded #{@scenes.count} scene#{"s" unless @scenes.count == 1}"
+    end
+
+    def load_rules
+      @ctime[:rules] = File.ctime "rules.yml"
+      @rules = YAML.load_file("rules.yml").map do |name, entry|
+                 Rule.new(name, @log, entry)
+               end
+      @rules.each do |rule|
+        @log.info "* Loaded rule: #{rule.name}"
+      end
+      @log.info "Loaded #{@rules.count} rule#{"s" unless @rules.count == 1}"
+    end
+
 end # class Hued
 
 # Option parsing