Fix IDs (#1016)

* Allow any String IDs as long as they're sortable

* Allow any String IDs as long as they're sortable

app/src/main/java/com/keylesspalace/tusky/util/NotificationPullJobCreator.java

@@ -16,8 +16,6 @@
 package com.keylesspalace.tusky.util;
 
 import android.content.Context;
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
 import android.util.Log;
 
 import com.evernote.android.job.Job;
@@ -28,15 +26,18 @@ import com.keylesspalace.tusky.entity.Notification;
 import com.keylesspalace.tusky.network.MastodonApi;
 
 import java.io.IOException;
-import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
 import javax.inject.Inject;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import retrofit2.Response;
 
+import static com.keylesspalace.tusky.util.StringUtils.isLessThan;
+
 /**
  * Created by charlag on 31/10/17.
  */
@@ -111,28 +112,24 @@ public final class NotificationPullJobCreator implements JobCreator {
 
         private void onNotificationsReceived(AccountEntity account, List<Notification> notificationList) {
             Collections.reverse(notificationList);
-            BigInteger newId = new BigInteger(account.getLastNotificationId());
-            BigInteger newestId = BigInteger.ZERO;
+            String newId = account.getLastNotificationId();
+            String newestId = "";
             boolean isFirstOfBatch = true;
 
             for (Notification notification : notificationList) {
-                BigInteger currentId = new BigInteger(notification.getId());
-                if (isBiggerThan(currentId, newestId)) {
+                String currentId = notification.getId();
+                if (isLessThan(newestId, currentId)) {
                     newestId = currentId;
                 }
-
-                if (isBiggerThan(currentId, newId)) {
+                if (isLessThan(newId, currentId)) {
                     NotificationHelper.make(context, notification, account, isFirstOfBatch);
                     isFirstOfBatch = false;
                 }
             }
 
-            account.setLastNotificationId(newestId.toString());
+            account.setLastNotificationId(newestId);
             accountManager.saveAccount(account);
         }
 
-        private boolean isBiggerThan(BigInteger newId, BigInteger lastShownNotificationId) {
-            return lastShownNotificationId.compareTo(newId) < 0;
-        }
     }
 }

app/src/main/java/com/keylesspalace/tusky/util/StringUtils.java

@@ -1,17 +0,0 @@
-package com.keylesspalace.tusky.util;
-
-import java.util.Random;
-
-public class StringUtils {
-
-    public static String randomAlphanumericString(int count) {
-        char[] chars = new char[count];
-        Random random = new Random();
-        final String POSSIBLE_CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
-        for (int i = 0; i < count; i++) {
-            chars[i] = POSSIBLE_CHARS.charAt(random.nextInt(POSSIBLE_CHARS.length()));
-        }
-        return new String(chars);
-    }
-
-}

app/src/main/java/com/keylesspalace/tusky/util/StringUtils.kt

@@ -0,0 +1,72 @@
+@file:JvmName("StringUtils")
+
+package com.keylesspalace.tusky.util
+
+import java.util.Random
+
+
+private const val POSSIBLE_CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+fun randomAlphanumericString(count: Int): String {
+    val chars = CharArray(count)
+    val random = Random()
+    for (i in 0 until count) {
+        chars[i] = POSSIBLE_CHARS[random.nextInt(POSSIBLE_CHARS.length)]
+    }
+    return String(chars)
+}
+
+// We sort statuses by ID. Something we need to invent some ID for placeholder.
+// Not sure if inc()/dec() should be made `operator` or not
+
+/**
+ * "Increment" string so that during sorting it's bigger than [this].
+ */
+fun String.inc(): String {
+    // We assume that we will stay in the safe range for now
+    val builder = this.toCharArray()
+    builder.last().inc()
+    return String(builder)
+}
+
+
+/**
+ * "Decrement" string so that during sorting it's smaller than [this].
+ */
+fun String.dec(): String {
+    val builder = this.toCharArray()
+    var i = builder.lastIndex
+    while (i > 0) {
+        if (builder[i] > '0') {
+            builder[i] = builder[i].dec()
+            break
+        } else {
+            builder[i] = 'z'
+        }
+        i--
+    }
+    // All characters were '0'
+    if (i == 0 && this.isNotEmpty()) {
+        // Remove one character
+        return String(builder.copyOfRange(1, builder.size))
+    }
+
+    return String(builder)
+}
+
+/**
+ * A < B (strictly) by length and then by content.
+ * Examples:
+ * "abc" < "bcd"
+ * "ab"  < "abc"
+ * "cb"  < "abc"
+ * not: "ab" < "ab"
+ * not: "abc" > "cb"
+ */
+fun String.isLessThan(other: String): Boolean {
+    return when {
+        this.length < other.length -> true
+        this.length > other.length -> false
+        else -> this < other
+    }
+}