Data client simplification / removal (#5507)

* Removed unused code from the data client module

* Move remaining code out of the data-client and remove it

app/src/main/java/fr/free/nrw/commons/utils/DateUtil.java

@@ -0,0 +1,53 @@
+package fr.free.nrw.commons.utils;
+
+import static android.text.format.DateFormat.getBestDateTimePattern;
+
+import androidx.annotation.NonNull;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+import java.util.TimeZone;
+
+public final class DateUtil {
+    private static Map<String, SimpleDateFormat> DATE_FORMATS = new HashMap<>();
+
+    // TODO: Switch to DateTimeFormatter when minSdk = 26.
+
+    public static synchronized String iso8601DateFormat(Date date) {
+        return getCachedDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.ROOT, true).format(date);
+    }
+
+    public static synchronized Date iso8601DateParse(String date) throws ParseException {
+        return getCachedDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.ROOT, true).parse(date);
+    }
+
+    public static String getMonthOnlyDateString(@NonNull Date date) {
+        return getDateStringWithSkeletonPattern(date, "MMMM d");
+    }
+
+    public static String getExtraShortDateString(@NonNull Date date) {
+        return getDateStringWithSkeletonPattern(date, "MMM d");
+    }
+
+    public static synchronized String getDateStringWithSkeletonPattern(@NonNull Date date, @NonNull String pattern) {
+        return getCachedDateFormat(getBestDateTimePattern(Locale.getDefault(), pattern), Locale.getDefault(), false).format(date);
+    }
+
+    private static SimpleDateFormat getCachedDateFormat(String pattern, Locale locale, boolean utc) {
+        if (!DATE_FORMATS.containsKey(pattern)) {
+            SimpleDateFormat df = new SimpleDateFormat(pattern, locale);
+            if (utc) {
+                df.setTimeZone(TimeZone.getTimeZone("UTC"));
+            }
+            DATE_FORMATS.put(pattern, df);
+        }
+        return DATE_FORMATS.get(pattern);
+    }
+
+    private DateUtil() {
+    }
+}

app/src/main/java/fr/free/nrw/commons/utils/StringUtil.java

@@ -0,0 +1,38 @@
+package fr.free.nrw.commons.utils;
+
+import android.os.Build;
+import android.text.Html;
+import android.text.Spanned;
+import android.text.SpannedString;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+public final class StringUtil {
+
+    /**
+     * @param source String that may contain HTML tags.
+     * @return returned Spanned string that may contain spans parsed from the HTML source.
+     */
+    @NonNull public static Spanned fromHtml(@Nullable String source) {
+        if (source == null) {
+            return new SpannedString("");
+        }
+        if (!source.contains("<") && !source.contains("&")) {
+            // If the string doesn't contain any hints of HTML entities, then skip the expensive
+            // processing that fromHtml() performs.
+            return new SpannedString(source);
+        }
+        source = source.replaceAll("&#8206;", "\u200E")
+                .replaceAll("&#8207;", "\u200F")
+                .replaceAll("&amp;", "&");
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            return Html.fromHtml(source, Html.FROM_HTML_MODE_LEGACY);
+        } else {
+            //noinspection deprecation
+            return Html.fromHtml(source);
+        }
+    }
+
+    private StringUtil() {
+    }
+}