Add config.link_karma_threshold.

README.md

@@ -18,7 +18,8 @@ gem "lita-karma"
 
 ### Optional attributes
 
-* `cooldown` (Integer, nil) - Controls how long a user must wait after modifying a term before they can modify it again. The value should be an integer number of seconds. Set it to `nil` to disable rate limiting. Default: `300` (5 minutes.
+* `cooldown` (Integer, nil) - Controls how long a user must wait after modifying a term before they can modify it again. The value should be an integer number of seconds. Set it to `nil` to disable rate limiting. Default: `300` (5 minutes).
+* `link_karma_threshold` (Integer, nil) - Controls how many points a term must have before it can be linked to other terms or before terms can be linked to it. Treated as an absolute value, so it applies to both positive and negative karma. Set it to `nil` to allow all terms to be linked regardless of karma. Default: `10`.
 * `term_pattern` (Regexp) - Determines what Lita will recognize as a valid term for tracking karma. Default: `/[\[\]\p{Word}\._|\{\}]{2,}/`.
 * `term_normalizer` (Proc) - A custom callable that determines how each term will be normalized before being stored in Redis. The proc should take one argument, the term as matched via regular expression, and return one value, the normalized version of the term.
 

lib/lita/handlers/karma.rb

@@ -5,6 +5,7 @@ module Handlers
     # Tracks karma points for arbitrary terms.
     class Karma < Handler
       config :cooldown, types: [Integer, nil], default: 300
+      config :link_karma_threshold, types: [Integer, nil], default: 10
       config :term_pattern, type: Regexp, default: /[\[\]\p{Word}\._|\{\}]{2,}/
       config :term_normalizer do
         validate do |value|
@@ -68,6 +69,18 @@ def link(response)
         response.matches.each do |match|
           term1, term2 = normalize_term(match[0]), normalize_term(match[1])
 
+          if config.link_karma_threshold
+            threshold = config.link_karma_threshold.abs
+
+            _total_score, term2_score, _links = scores_for(term2)
+            _total_score, term1_score, _links = scores_for(term1)
+
+            if term1_score.abs < threshold || term2_score.abs < threshold
+              response.reply "Terms must have less than -#{threshold} or more than #{threshold} karma to be linked or linked to."
+              return
+            end
+          end
+
           if redis.sadd("links:#{term1}", term2)
             redis.sadd("linked_to:#{term2}", term1)
             response.reply "#{term2} has been linked to #{term1}."
@@ -293,15 +306,7 @@ def scores_for(term)
       end
 
       def set_cooldown(term, user_id)
-        cooldown = Lita.config.handlers.karma.cooldown
-
-        if cooldown
-          redis.setex(
-            "cooldown:#{user_id}:#{term}",
-            cooldown.to_i,
-            1
-          )
-        end
+        redis.setex("cooldown:#{user_id}:#{term}", config.cooldown.to_i, 1) if config.cooldown
       end
     end
 

spec/lita/handlers/karma_spec.rb

@@ -5,6 +5,7 @@
 
   before do
     registry.config.handlers.karma.cooldown = nil
+    registry.config.handlers.karma.link_karma_threshold = nil
     described_class.routes.clear
     subject.define_routes(payload)
   end
@@ -180,6 +181,45 @@
         /foo: 3 \(1\), linked to: ba[rz]: 1, ba[rz]: 1/
       )
     end
+
+    context "when link_karma_threshold is set" do
+      before do
+        registry.config.handlers.karma.link_karma_threshold = 1
+      end
+
+      it "doesn't allow a term to be linked if both are below the threshold" do
+        send_command("foo += bar")
+        expect(replies.last).to include("must have less than")
+      end
+
+      it "doesn't allow a term to be linked if it's below the threshold" do
+        send_command("foo++")
+        send_command("foo += bar")
+        expect(replies.last).to include("must have less than")
+      end
+
+      it "doesn't allow a term to be linked to another term below the threshold" do
+        send_command("bar++")
+        send_command("foo += bar")
+        expect(replies.last).to include("must have less than")
+      end
+
+      it "allows links if both terms meet the threshold" do
+        send_command("foo++ bar++")
+        send_command("foo += bar")
+        expect(replies.last).to include("has been linked")
+        send_command("bar += foo")
+        expect(replies.last).to include("has been linked")
+      end
+
+      it "uses the absolute value for terms with negative karma" do
+        send_command("foo-- bar--")
+        send_command("foo += bar")
+        expect(replies.last).to include("has been linked")
+        send_command("bar += foo")
+        expect(replies.last).to include("has been linked")
+      end
+    end
   end
 
   describe "#unlink" do