From d67fe0e7583f1be18b35b33b7658e4427f1e3ded Mon Sep 17 00:00:00 2001
From: Amith Yamasani <yamasani@google.com>
Date: Tue, 28 Jul 2009 16:33:36 -0700
Subject: [PATCH] Improve auto-add heuristics.

Also add auto-switch back to alphabet mode on pressing enter key.
---
 .../inputmethod/latin/KeyboardSwitcher.java   | 10 +++---
 .../android/inputmethod/latin/LatinIME.java   | 32 ++++++++++++-------
 2 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/src/com/android/inputmethod/latin/KeyboardSwitcher.java b/src/com/android/inputmethod/latin/KeyboardSwitcher.java
index a5aebfbfe..16dd7b9a7 100644
--- a/src/com/android/inputmethod/latin/KeyboardSwitcher.java
+++ b/src/com/android/inputmethod/latin/KeyboardSwitcher.java
@@ -245,14 +245,16 @@ public class KeyboardSwitcher {
      * Returns true if the keyboard needs to switch back 
      */
     boolean onKey(int key) {
-        // Switch back to alpha mode if user types one or more non-space characters followed by
-        // a space.
+        // Switch back to alpha mode if user types one or more non-space/enter characters
+        // followed by a space/enter
         switch (mSymbolsModeState) {
             case SYMBOLS_MODE_STATE_BEGIN:
-                if (key != ' ' && key > 0) mSymbolsModeState = SYMBOLS_MODE_STATE_SYMBOL;
+                if (key != LatinIME.KEYCODE_SPACE && key != LatinIME.KEYCODE_ENTER && key > 0) {
+                    mSymbolsModeState = SYMBOLS_MODE_STATE_SYMBOL;
+                }
                 break;
             case SYMBOLS_MODE_STATE_SYMBOL:
-                if (key == ' ') return true;
+                if (key == LatinIME.KEYCODE_ENTER || key == LatinIME.KEYCODE_SPACE) return true;
                 break;
         }
         return false;
diff --git a/src/com/android/inputmethod/latin/LatinIME.java b/src/com/android/inputmethod/latin/LatinIME.java
index 3dfdc5f1f..5480c6780 100644
--- a/src/com/android/inputmethod/latin/LatinIME.java
+++ b/src/com/android/inputmethod/latin/LatinIME.java
@@ -76,10 +76,17 @@ public class LatinIME extends InputMethodService
     // How many continuous deletes at which to start deleting at a higher speed.
     private static final int DELETE_ACCELERATE_AT = 20;
     // Key events coming any faster than this are long-presses.
-    private static final int QUICK_PRESS = 200; 
+    private static final int QUICK_PRESS = 200;
+    // Weight added to a user picking a new word from the suggestion strip
+    static final int FREQUENCY_FOR_PICKED = 3;
+    // Weight added to a user typing a new word that doesn't get corrected (or is reverted)
+    static final int FREQUENCY_FOR_TYPED = 1;
+    // A word that is frequently typed and get's promoted to the user dictionary, uses this
+    // frequency.
+    static final int FREQUENCY_FOR_AUTO_ADD = 250;
     
-    private static final int KEYCODE_ENTER = 10;
-    private static final int KEYCODE_SPACE = ' ';
+    static final int KEYCODE_ENTER = '\n';
+    static final int KEYCODE_SPACE = ' ';
 
     // Contextual menu positions
     private static final int POS_SETTINGS = 0;
@@ -481,7 +488,7 @@ public class LatinIME extends InputMethodService
                 }
                 mCommittedLength = mComposing.length();
                 TextEntryState.acceptedTyped(mComposing);
-                mAutoDictionary.addWord(mComposing.toString(), 1);
+                mAutoDictionary.addWord(mComposing.toString(), FREQUENCY_FOR_TYPED);
             }
             updateSuggestions();
         }
@@ -845,7 +852,7 @@ public class LatinIME extends InputMethodService
         }
         // Add the word to the auto dictionary if it's not a known word
         if (mAutoDictionary.isValidWord(suggestion) || !mSuggest.isValidWord(suggestion)) {
-            mAutoDictionary.addWord(suggestion.toString(), 1);
+            mAutoDictionary.addWord(suggestion.toString(), FREQUENCY_FOR_PICKED);
         }
         mPredicting = false;
         mCommittedLength = suggestion.length();
@@ -1141,8 +1148,10 @@ public class LatinIME extends InputMethodService
     }
 
     class AutoDictionary extends ExpandableDictionary {
-        private static final int VALIDITY_THRESHOLD = 3;
-        private static final int PROMOTION_THRESHOLD = 6;
+        // If the user touches a typed word 2 times or more, it will become valid.
+        private static final int VALIDITY_THRESHOLD = 2 * FREQUENCY_FOR_PICKED;
+        // If the user touches a typed word 5 times or more, it will be added to the user dict.
+        private static final int PROMOTION_THRESHOLD = 5 * FREQUENCY_FOR_PICKED;
 
         public AutoDictionary(Context context) {
             super(context);
@@ -1155,10 +1164,11 @@ public class LatinIME extends InputMethodService
         }
 
         @Override
-        public void addWord(String word, int frequency) {
-            super.addWord(word, 1);
-            if (getWordFrequency(word) > PROMOTION_THRESHOLD) {
-                LatinIME.this.promoteToUserDictionary(word, frequency);
+        public void addWord(String word, int addFrequency) {
+            super.addWord(word, addFrequency);
+            final int freq = getWordFrequency(word);
+            if (freq > PROMOTION_THRESHOLD) {
+                LatinIME.this.promoteToUserDictionary(word, FREQUENCY_FOR_AUTO_ADD);
             }
         }
     }