1 files changed, 230 insertions, 0 deletions
diff --git a/java/com/android/incallui/rtt/protocol/RttChatMessage.java b/java/com/android/incallui/rtt/protocol/RttChatMessage.java
new file mode 100644
index 000000000..5680529ee
--- /dev/null
+++ b/java/com/android/incallui/rtt/protocol/RttChatMessage.java
@@ -0,0 +1,230 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.incallui.rtt.protocol;
+
+import android.support.annotation.NonNull;
+import com.android.dialer.common.Assert;
+import com.android.dialer.rtt.RttTranscript;
+import com.android.dialer.rtt.RttTranscriptMessage;
+import com.google.common.base.Splitter;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+/** Message class that holds one RTT chat content. */
+public final class RttChatMessage {
+
+  private static final Splitter SPLITTER = Splitter.on(Constants.BUBBLE_BREAKER);
+
+  public boolean isRemote;
+  private long timstamp;
+  private final StringBuilder content = new StringBuilder();
+  private boolean isFinished;
+
+  public boolean isFinished() {
+    return isFinished;
+  }
+
+  public void finish() {
+    isFinished = true;
+  }
+
+  public void unfinish() {
+    isFinished = false;
+  }
+
+  public void append(String text) {
+    for (int i = 0; i < text.length(); i++) {
+      char c = text.charAt(i);
+      if (c == '\b' && content.length() > 0 && content.charAt(content.length() - 1) != '\b') {
+        content.deleteCharAt(content.length() - 1);
+      } else {
+        content.append(c);
+      }
+    }
+  }
+
+  public String getContent() {
+    return content.toString();
+  }
+
+  /**
+   * Computes delta change of two string.
+   *
+   * <p>e.g. "hello world" -> "hello" : "\b\b\b\b\b\b"
+   *
+   * <p>"hello world" -> "hello mom!" : "\b\b\b\b\bmom!"
+   *
+   * <p>"hello world" -> "hello d" : "\b\b\b\b\bd"
+   *
+   * <p>"hello world" -> "hello new world" : "\b\b\b\b\bnew world"
+   */
+  public static String computeChangedString(String oldMessage, String newMesssage) {
+    StringBuilder modify = new StringBuilder();
+    int indexChangeStart = 0;
+    while (indexChangeStart < oldMessage.length()
+        && indexChangeStart < newMesssage.length()
+        && oldMessage.charAt(indexChangeStart) == newMesssage.charAt(indexChangeStart)) {
+      indexChangeStart++;
+    }
+    for (int i = indexChangeStart; i < oldMessage.length(); i++) {
+      modify.append('\b');
+    }
+    for (int i = indexChangeStart; i < newMesssage.length(); i++) {
+      modify.append(newMesssage.charAt(i));
+    }
+    return modify.toString();
+  }
+
+  public static RttTranscript getRttTranscriptWithNewRemoteMessage(
+      RttTranscript rttTranscript, @NonNull String text) {
+    List<RttChatMessage> messageList = fromTranscript(rttTranscript);
+    updateRemoteRttChatMessage(messageList, text);
+    return RttTranscript.newBuilder()
+        .setId(rttTranscript.getId())
+        .setNumber(rttTranscript.getNumber())
+        .setTimestamp(rttTranscript.getTimestamp())
+        .addAllMessages(toTranscriptMessageList(messageList))
+        .build();
+  }
+
+  /** Update list of {@code RttChatMessage} based on given remote text. */
+  public static void updateRemoteRttChatMessage(
+      List<RttChatMessage> messageList, @NonNull String text) {
+    Assert.isNotNull(messageList);
+    Iterator<String> splitText = SPLITTER.split(text).iterator();
+
+    while (splitText.hasNext()) {
+      String singleMessageContent = splitText.next();
+      RttChatMessage message;
+      int index = getLastIndexUnfinishedRemoteMessage(messageList);
+      if (index < 0) {
+        message = new RttChatMessage();
+        message.append(singleMessageContent);
+        message.isRemote = true;
+        if (splitText.hasNext()) {
+          message.finish();
+        }
+        if (message.content.length() != 0) {
+          messageList.add(message);
+        }
+      } else {
+        message = messageList.get(index);
+        message.append(singleMessageContent);
+        if (splitText.hasNext()) {
+          message.finish();
+        }
+        if (message.content.length() == 0) {
+          messageList.remove(index);
+        }
+      }
+      StringBuilder content = message.content;
+      // Delete previous messages.
+      while (content.length() > 0 && content.charAt(0) == '\b') {
+        messageList.remove(message);
+        content.delete(0, 1);
+        int previous = getLastIndexRemoteMessage(messageList);
+        // There are more backspaces than existing characters.
+        if (previous < 0) {
+          while (content.length() > 0 && content.charAt(0) == '\b') {
+            content.deleteCharAt(0);
+          }
+          // Add message if there are still characters after backspaces.
+          if (content.length() > 0) {
+            message = new RttChatMessage();
+            message.append(content.toString());
+            message.isRemote = true;
+            if (splitText.hasNext()) {
+              message.finish();
+            }
+            messageList.add(message);
+          }
+          break;
+        }
+        message = messageList.get(previous);
+        message.unfinish();
+        message.append(content.toString());
+        content = message.content;
+      }
+    }
+    if (text.endsWith(Constants.BUBBLE_BREAKER)) {
+      int lastIndexRemoteMessage = getLastIndexRemoteMessage(messageList);
+      messageList.get(lastIndexRemoteMessage).finish();
+    }
+  }
+
+  private static int getLastIndexUnfinishedRemoteMessage(List<RttChatMessage> messageList) {
+    int i = messageList.size() - 1;
+    while (i >= 0 && (!messageList.get(i).isRemote || messageList.get(i).isFinished)) {
+      i--;
+    }
+    return i;
+  }
+
+  public static int getLastIndexRemoteMessage(List<RttChatMessage> messageList) {
+    int i = messageList.size() - 1;
+    while (i >= 0 && !messageList.get(i).isRemote) {
+      i--;
+    }
+    return i;
+  }
+
+  public static int getLastIndexLocalMessage(List<RttChatMessage> messageList) {
+    int i = messageList.size() - 1;
+    while (i >= 0 && messageList.get(i).isRemote) {
+      i--;
+    }
+    return i;
+  }
+
+  public static List<RttTranscriptMessage> toTranscriptMessageList(
+      List<RttChatMessage> messageList) {
+    List<RttTranscriptMessage> transcriptMessageList = new ArrayList<>();
+    for (RttChatMessage message : messageList) {
+      transcriptMessageList.add(
+          RttTranscriptMessage.newBuilder()
+              .setContent(message.getContent())
+              .setTimestamp(message.timstamp)
+              .setIsRemote(message.isRemote)
+              .setIsFinished(message.isFinished)
+              .build());
+    }
+    return transcriptMessageList;
+  }
+
+  public static List<RttChatMessage> fromTranscript(RttTranscript rttTranscript) {
+    List<RttChatMessage> messageList = new ArrayList<>();
+    if (rttTranscript == null) {
+      return messageList;
+    }
+    for (RttTranscriptMessage message : rttTranscript.getMessagesList()) {
+      RttChatMessage chatMessage = new RttChatMessage();
+      chatMessage.append(message.getContent());
+      chatMessage.timstamp = message.getTimestamp();
+      chatMessage.isRemote = message.getIsRemote();
+      if (message.getIsFinished()) {
+        chatMessage.finish();
+      }
+      messageList.add(chatMessage);
+    }
+    return messageList;
+  }
+
+  public RttChatMessage() {
+    timstamp = System.currentTimeMillis();
+  }
+}