From b5d9ce60bf3aafc0f4275a1eff69e36a1c18a6f2 Mon Sep 17 00:00:00 2001
From: zonble <zonble@gmail.com>
Date: Mon, 14 Feb 2022 01:38:26 +0800
Subject: [PATCH] Prevents the override model to remember symbols with scode -8
 or lower.

---
 Source/Engine/Gramambular/Node.h | 11 +++++++++++
 Source/KeyHandler.mm             | 12 +++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/Source/Engine/Gramambular/Node.h b/Source/Engine/Gramambular/Node.h
index 6e2bf45e..a877d27c 100644
--- a/Source/Engine/Gramambular/Node.h
+++ b/Source/Engine/Gramambular/Node.h
@@ -51,6 +51,7 @@ namespace Formosa {
             
             const string& key() const;
             double score() const;
+            double scoreForCandidate(string &candidate) const;
             const KeyValuePair currentKeyValue() const;
             double highestUnigramScore() const;
             
@@ -198,6 +199,16 @@ namespace Formosa {
             return m_score;
         }
 
+        inline double Node::scoreForCandidate(string &candidate) const
+        {
+            for (auto unigram : m_unigrams) {
+                if (unigram.keyValue.value == candidate) {
+                    return unigram.score;
+                }
+            }
+            return 0.0;
+        }
+
         inline double Node::highestUnigramScore() const {
             if (m_unigrams.empty()) {
                 return 0.0;
diff --git a/Source/KeyHandler.mm b/Source/KeyHandler.mm
index 1a00430f..8209ebc5 100644
--- a/Source/KeyHandler.mm
+++ b/Source/KeyHandler.mm
@@ -202,7 +202,17 @@ static NSString *const kGraphVizOutputfile = @"/tmp/McBopomofo-visualization.dot
         // If the length of the readings and the characters do not match,
         // it often means it is a special symbol and it should not be stored
         // in the user override model.
-        if (selectedNode.spanningLength == [value count]) {
+        BOOL addToOverrideModel = YES;
+        if (selectedNode.spanningLength != [value count]) {
+            addToOverrideModel = NO;
+        }
+        if (addToOverrideModel) {
+            double score = selectedNode.node->scoreForCandidate(stringValue);
+            if (score <= -8) {
+                addToOverrideModel = NO;
+            }
+        }
+        if (addToOverrideModel) {
             _userOverrideModel->observe(_walkedNodes, cursorIndex, stringValue, [[NSDate date] timeIntervalSince1970]);
         }
     }