from PySide6.QtWidgets import QApplication, QLineEdit, QComboBox
from PySide6.QtCore import QObject, Signal
import logging

class FocusTracker(QObject):
    """焦点跟踪器，用于跟踪当前焦点所在的输入框"""
    
    # 定义单例
    _instance = None
    
    # 信号：当焦点变化时触发
    focus_changed = Signal(object)
    
    @classmethod
    def get_instance(cls):
        """获取单例实例"""
        if cls._instance is None:
            cls._instance = FocusTracker()
        return cls._instance
    
    def __init__(self):
        """初始化焦点跟踪器"""
        if FocusTracker._instance is not None:
            raise Exception("FocusTracker是单例类，请使用get_instance()方法获取实例")
        
        super().__init__()
        self._current_focus = None
        self._initialized = False
        
    def initialize(self):
        """初始化焦点跟踪"""
        if self._initialized:
            return
            
        # 连接应用程序的焦点变化信号
        app = QApplication.instance()
        if app:
            app.focusChanged.connect(self._on_focus_changed)
            self._initialized = True
            logging.info("焦点跟踪器已初始化")
        else:
            logging.error("无法获取QApplication实例，焦点跟踪器初始化失败")
    
    def _on_focus_changed(self, old, now):
        """焦点变化处理"""
        # 关注QLineEdit和QComboBox控件
        if isinstance(now, (QLineEdit, QComboBox)):
            self._current_focus = now
            self.focus_changed.emit(now)
            widget_type = "输入框" if isinstance(now, QLineEdit) else "下拉框"
            logging.debug(f"焦点变化到{widget_type}: {now.objectName()}")
    
    def get_current_focus(self):
        """获取当前焦点所在的控件"""
        return self._current_focus
    
    def set_text_and_trigger_enter(self, text):
        """设置当前焦点控件的文本并触发回车事件"""
        if not self._current_focus:
            logging.warning("当前没有焦点控件，无法设置文本和触发回车事件")
            return False
            
        # 创建回车键事件
        from PySide6.QtGui import QKeyEvent
        from PySide6.QtCore import Qt, QEvent
        key_event = QKeyEvent(QEvent.KeyPress, Qt.Key_Return, Qt.NoModifier)
        
        # 根据控件类型处理
        if isinstance(self._current_focus, QLineEdit):
            # 设置文本
            self._current_focus.setText(text)
            
            # 发送事件到当前焦点控件
            QApplication.sendEvent(self._current_focus, key_event)
            
            logging.info(f"已将文本 '{text}' 设置到输入框并触发回车事件")
            return True
            
        elif isinstance(self._current_focus, QComboBox):
            # 对于ComboBox，先查找匹配的项
            combo_box = self._current_focus
            
            # 查找完全匹配的项
            index = combo_box.findText(text)
            if index >= 0:
                combo_box.setCurrentIndex(index)
                logging.info(f"已在下拉框中选择匹配项: '{text}'")
            else:
                # 如果没有完全匹配的项，设置为编辑文本（如果ComboBox是可编辑的）
                if combo_box.isEditable():
                    combo_box.setEditText(text)
                    logging.info(f"已将文本 '{text}' 设置到可编辑下拉框")
                else:
                    logging.warning(f"下拉框中没有匹配项 '{text}'，且下拉框不可编辑")
                    return False
            
            # 发送事件到当前焦点控件
            QApplication.sendEvent(combo_box, key_event)
            
            # 如果ComboBox有activated信号，手动触发
            try:
                if hasattr(combo_box, 'activated'):
                    combo_box.activated.emit(combo_box.currentIndex())
                    logging.debug("已触发下拉框的activated信号")
            except Exception as e:
                logging.error(f"触发下拉框activated信号失败: {e}")
            
            return True
        else:
            logging.warning(f"不支持的控件类型: {type(self._current_focus)}")
            return False