Titlecasing time zone summary

Additional fix:
1. Fixed the SpannableUtil.getResourcesText to actually
preserve Spannable (TtsSpan in this use case)  during formatting.

Bug: 185453652
Test: make RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.datetime.timezone
Change-Id: Iae5e1d4261ec0a34222ae1d042c7f3f027f2e512

src/com/android/settings/datetime/timezone/SpannableUtil.java

@@ -18,14 +18,72 @@ package com.android.settings.datetime.timezone;
 
 import android.annotation.StringRes;
 import android.content.res.Resources;
+import android.icu.text.CaseMap;
+import android.icu.text.Edits;
 import android.text.Spannable;
 import android.text.SpannableStringBuilder;
+import android.util.Log;
 
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Formattable;
+import java.util.FormattableFlags;
 import java.util.Formatter;
+import java.util.List;
 import java.util.Locale;
 
 
 public class SpannableUtil {
+    private static final String TAG = "SpannableUtil";
+
+    private static class SpannableFormattable implements Formattable {
+
+        private final Spannable mSpannable;
+
+        private SpannableFormattable(Spannable spannable) {
+            this.mSpannable = spannable;
+        }
+
+        @Override
+        public void formatTo(Formatter formatter, int flags, int width, int precision) {
+            CharSequence s = handlePrecision(mSpannable, precision);
+            s = handleWidth(s, width, (flags & FormattableFlags.LEFT_JUSTIFY) != 0);
+            try {
+                formatter.out().append(s);
+            } catch (IOException e) {
+                // The error should never occur because formatter.out() returns
+                // SpannableStringBuilder which doesn't throw IOException.
+                Log.e(TAG, "error in SpannableFormattable", e);
+            }
+        }
+
+        private static CharSequence handlePrecision(CharSequence s, int precision) {
+            if (precision != -1 && precision < s.length()) {
+                return s.subSequence(0, precision);
+            }
+            return s;
+        }
+
+        private static CharSequence handleWidth(CharSequence s, int width, boolean isLeftJustify) {
+            if (width == -1) {
+                return s;
+            }
+            int diff = width - s.length();
+            if (diff <= 0) {
+                return s;
+            }
+            SpannableStringBuilder sb = new SpannableStringBuilder();
+            if (!isLeftJustify) {
+                sb.append(" ".repeat(diff));
+            }
+            sb.append(s);
+            if (isLeftJustify) {
+                sb.append(" ".repeat(diff));
+            }
+            return sb;
+        }
+    }
 
     /**
      * {@class Resources} has no method to format string resource with {@class Spannable} a
@@ -35,7 +93,56 @@ public class SpannableUtil {
             Object... args) {
         final Locale locale = res.getConfiguration().getLocales().get(0);
         final SpannableStringBuilder builder = new SpannableStringBuilder();
+        // Formatter converts CharSequence to String by calling toString() if an arg isn't
+        // Formattable. Wrap Spannable by SpannableFormattable to preserve Spannable objects.
+        for (int i = 0; i < args.length; i++) {
+            if (args[i] instanceof Spannable) {
+                args[i] = new SpannableFormattable((Spannable) args[i]);
+            }
+        }
         new Formatter(builder, locale).format(res.getString(resId), args);
         return builder;
     }
+
+    private static final CaseMap.Title TITLE_CASE_MAP =
+            CaseMap.toTitle().sentences().noLowercase();
+
+    /**
+     * Titlecasing {@link CharSequence} and {@link Spannable} by using {@link CaseMap.Title}.
+     */
+    public static CharSequence titleCaseSentences(Locale locale, CharSequence src) {
+        if (src instanceof Spannable) {
+            return applyCaseMapToSpannable(locale, TITLE_CASE_MAP, (Spannable) src);
+        } else {
+            return TITLE_CASE_MAP.apply(locale, null, src);
+        }
+    }
+
+    private static Spannable applyCaseMapToSpannable(Locale locale, CaseMap.Title caseMap,
+            Spannable src) {
+        Edits edits = new Edits();
+        SpannableStringBuilder dest = new SpannableStringBuilder();
+        caseMap.apply(locale, null, src, dest, edits);
+        if (!edits.hasChanges()) {
+            return src;
+        }
+        Edits.Iterator iterator = edits.getCoarseChangesIterator();
+        List<int[]> changes = new ArrayList<>();
+        while (iterator.next()) {
+            int[] change = new int[] {
+                iterator.sourceIndex(),       // 0
+                iterator.oldLength(),         // 1
+                iterator.destinationIndex(),  // 2
+                iterator.newLength(),         // 3
+            };
+            changes.add(change);
+        }
+        // Replacement starts from the end to avoid shifting the source index during replacement
+        Collections.reverse(changes);
+        SpannableStringBuilder result = new SpannableStringBuilder(src);
+        for (int[] c : changes) {
+            result.replace(c[0], c[0] + c[1], dest, c[2], c[2] + c[3]);
+        }
+        return result;
+    }
 }