display charts correctly even when invalid min/max values are present

app/models/channel.rb

@@ -90,6 +90,44 @@ class Channel < ActiveRecord::Base
   cattr_reader :per_page
   @@per_page = 15
 
+  # access a last value by string: channel_1417_field_1
+  def self.value_from_string(channel_string, user)
+    # remove % from the string and create the array
+    channel_array = channel_string.gsub('%', '').split('_')
+    # exit if the string doesn't have 4 parts
+    return nil if channel_array.length != 4
+
+    # get the channel
+    channel = Channel.find(channel_array[1])
+    # exit if the channel is not public or not owned by the user
+    return nil if !(channel.public_flag? || channel.user_id == user.try(:id))
+    # get the field id
+    field_id = channel_array[3].to_i
+
+    # get the feed
+    begin
+      # add a timeout since this query may be really long if there is a lot of data,
+      # but the last instance of the field is very far back
+      Timeout.timeout(5, Timeout::Error) do
+        # look for a feed where the value isn't null
+        @feed = Feed.where(:channel_id => channel.id)
+          .where("field? is not null", field_id)
+          .select("entry_id, field#{field_id}")
+          .order('entry_id desc')
+          .first
+      end
+    rescue Timeout::Error
+    rescue
+    end
+
+    # no feed found
+    return nil if @feed.blank?
+
+    # return the feed value
+    return @feed["field#{field_id}"]
+  end
+
+
   # search for public channels within a certain distance from the origin
   # requires latitude, longitude, and distance to be present as options keys
   # distance is in kilometers

app/views/apps/index.html.erb

@@ -96,13 +96,19 @@
         <div class="helplink">(<a href="/docs/react"><%= t(:help_options) %></a>)</div>
       </h3>
       <%= t(:help_apps_react) %>
-      <br><br>
 
       <h3>
         <%= t(:talkback) %>
         <div class="helplink">(<a href="/docs/talkback"><%= t(:help_options) %></a>)</div>
       </h3>
       <%= t(:help_apps_talkback) %>
+      <br><br>
+
+      <h3>
+        <%= t(:timecontrol) %>
+        <div class="helplink">(<a href="/docs/timecontrol"><%= t(:help_options) %></a>)</div>
+      </h3>
+      <%= t(:help_apps_timecontrol) %>
 
     </div>
   </div>

app/views/charts/show.html.erb

@@ -44,7 +44,7 @@
                // add location if possible
                if (this.location) { p.name = this.location; }
                // if a numerical value exists add it
-               if (!isNaN(parseInt(v))<% if params[:max] %> && p.y <= <%= params[:max]%><% end %><% if params[:min] %> && p.y >= <%= params[:min]%><% end %>) { chartData.push(p); }
+               if (!isNaN(parseInt(v))<% if params[:max].present? && Feed.numeric?(params[:max]) %> && p.y <= <%= params[:max] %><% end %><% if params[:min].present? && Feed.numeric?(params[:max]) %> && p.y >= <%= params[:min] %><% end %>) { chartData.push(p); }
             });
 
             // specify the chart options
@@ -97,7 +97,7 @@
                               shift = true ;
                             }
                             // if a numerical value exists and it is a new date, add it
-                            if (!isNaN(parseInt(v)) && (p.x != last_date)<% if params[:max] %> && p.y <= <%= params[:max]%><% end %><% if params[:min] %> && p.y >= <%= params[:min]%><% end %>) {
+                            if (!isNaN(parseInt(v)) && (p.x != last_date)<% if params[:max].present? && Feed.numeric?(params[:max]) %> && p.y <= <%= params[:max] %><% end %><% if params[:min].present? && Feed.numeric?(params[:min]) %> && p.y >= <%= params[:min] %><% end %>) {
                               dynamicChart.series[0].addPoint(p, true, shift);
                             }
                             else {