do not open same file twice

tabs.py

@@ -0,0 +1,58 @@
+import os
+from typing import Mapping
+
+from PyQt6.QtWidgets import *
+from PyQt6.QtCore import *
+from PyQt6.QtGui import *
+
+from bigtext import BigText
+from logFileModel import LogFileModel
+from settings import Settings
+
+class Tabs(QWidget):
+
+    tabs_by_index = {}
+    tabs_by_filename = {}
+
+    def __init__(self, settings: Settings):
+        super(Tabs, self).__init__()
+
+        self.settings = settings
+
+        self.tabs = QTabWidget()
+        self.tabs.setTabsClosable(True)
+        self.tabs.setMovable(True)
+        self.tabs.tabCloseRequested.connect(self._close_tab)
+
+        self.layout = QVBoxLayout(self)
+        self.layout.setContentsMargins(0, 0, 0, 0)
+
+        self.layout.addWidget(self.tabs)
+
+    def create_tab(self, file: str):
+        if not os.path.isfile(file):
+            message = QMessageBox(QMessageBox.Icon.Warning, "File not found",
+                                  "'%s' is not a file or cannot be opened" % (file))
+            message.exec()
+            return
+
+        model = LogFileModel(file)
+        big_text = BigText(model, self.settings)
+
+        if big_text.get_file() in self.tabs_by_filename:
+            for tab_index in range(0, self.tabs.count()):
+                widget : BigText = self.tabs.widget(tab_index)
+                if widget.get_file() == big_text.get_file():
+                    self.tabs.setCurrentIndex(tab_index)
+                    break
+        else:
+            tab_index = self.tabs.addTab(big_text, model.get_tab_name())
+            self.tabs_by_filename[big_text.get_file()] = big_text
+            self.tabs.setCurrentIndex(tab_index)
+
+    def _close_tab(self, tab_index: int):
+        big_text: BigText = self.tabs.widget(tab_index)
+        del self.tabs_by_filename[big_text.get_file()]
+        self.tabs.removeTab(tab_index)
+
+