1 files changed, 71 insertions, 0 deletions
diff --git a/python/edu/course-creator/src/org/jetbrains/plugins/coursecreator/StudyDocumentListener.java b/python/edu/course-creator/src/org/jetbrains/plugins/coursecreator/StudyDocumentListener.java
new file mode 100644
index 000000000000..d803e0e8fd97
--- /dev/null
+++ b/python/edu/course-creator/src/org/jetbrains/plugins/coursecreator/StudyDocumentListener.java
@@ -0,0 +1,71 @@
+package org.jetbrains.plugins.coursecreator;
+
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.LogicalPosition;
+import com.intellij.openapi.editor.event.DocumentAdapter;
+import com.intellij.openapi.editor.event.DocumentEvent;
+import com.intellij.openapi.editor.impl.event.DocumentEventImpl;
+import org.jetbrains.plugins.coursecreator.format.TaskFile;
+import org.jetbrains.plugins.coursecreator.format.TaskWindow;
+
+/**
+ * author: liana
+ * data: 7/16/14.
+ * Listens changes in study files and updates
+ * coordinates of all the windows in current task file
+ */
+public abstract class StudyDocumentListener extends DocumentAdapter {
+  private final TaskFile myTaskFile;
+  private int oldLine;
+  private int oldLineStartOffset;
+  private TaskWindow myTaskWindow;
+
+  public StudyDocumentListener(TaskFile taskFile) {
+    myTaskFile = taskFile;
+  }
+
+
+  //remembering old end before document change because of problems
+  // with fragments containing "\n"
+  @Override
+  public void beforeDocumentChange(DocumentEvent e) {
+    int offset = e.getOffset();
+    int oldEnd = offset + e.getOldLength();
+    Document document = e.getDocument();
+    oldLine = document.getLineNumber(oldEnd);
+    oldLineStartOffset = document.getLineStartOffset(oldLine);
+    int line = document.getLineNumber(offset);
+    int offsetInLine = offset - document.getLineStartOffset(line);
+    LogicalPosition pos = new LogicalPosition(line, offsetInLine);
+    myTaskWindow = myTaskFile.getTaskWindow(document, pos);
+
+  }
+
+  @Override
+  public void documentChanged(DocumentEvent e) {
+    if (e instanceof DocumentEventImpl) {
+      if (!needModify()) {
+        return;
+      }
+      DocumentEventImpl event = (DocumentEventImpl)e;
+      Document document = e.getDocument();
+      int offset = e.getOffset();
+      int change = event.getNewLength() - event.getOldLength();
+      if (myTaskWindow != null) {
+        updateTaskWindowLength(e.getNewFragment(), myTaskWindow, change);
+      }
+      int newEnd = offset + event.getNewLength();
+      int newLine = document.getLineNumber(newEnd);
+      int lineChange = newLine - oldLine;
+      myTaskFile.incrementLines(oldLine + 1, lineChange);
+      int newEndOffsetInLine = offset + e.getNewLength() - document.getLineStartOffset(newLine);
+      int oldEndOffsetInLine = offset + e.getOldLength() - oldLineStartOffset;
+      myTaskFile.updateLine(lineChange, oldLine, newEndOffsetInLine, oldEndOffsetInLine);
+    }
+  }
+
+  protected abstract void updateTaskWindowLength(CharSequence fragment, TaskWindow taskWindow, int change);
+
+  protected  abstract boolean needModify();
+}
+