import sys
import keyboard
from PySide6.QtWidgets import QApplication
from PySide6.QtCore import QThread, Signal, QTimer, QObject

import state
from api import fetch_candidates
from ui import CandidateWindow

# --- 核心修复：信号桥接类 ---
class EventBridge(QObject):
    """负责将子线程的键盘事件安全转发到主线程"""
    request_refresh_sig = Signal()
    reset_ui_sig = Signal()

# --- 异步请求线程 ---
class FetchThread(QThread):
    result_ready = Signal(list)

    def __init__(self, text):
        super().__init__()
        self.text = text

    def run(self):
        # 执行耗时的网络请求
        res = fetch_candidates(self.text)
        self.result_ready.emit(res)

class IMEController:
    def __init__(self):
        self.app = QApplication(sys.argv)
        self.window = CandidateWindow()
        self.bridge = EventBridge()
        self.worker = None

        # 防抖定时器：必须在主线程初始化
        self.debounce_timer = QTimer()
        self.debounce_timer.setSingleShot(True)
        
        # 信号绑定：确保所有 UI/Timer 操作都在主线程执行
        self.bridge.request_refresh_sig.connect(self._handle_refresh_request)
        self.bridge.reset_ui_sig.connect(self.reset_ime)
        self.debounce_timer.timeout.connect(self._start_fetch)

    def on_key_event(self, event):
        """键盘钩子回调（运行在非主线程）"""
        if event.event_type == "up":
            return True

        name = event.name

        # 1. 输入字母
        if len(name) == 1 and name.isalpha():
            
            state.buffer += name
            self.bridge.request_refresh_sig.emit() # 安全转发
            return False

        # 2. 退格
        elif name == "backspace":
            if state.buffer:
                state.buffer = state.buffer[:-1]
                self.bridge.request_refresh_sig.emit()
                return False
            return True

        # 3. 选择候选词
        elif name == "space" or (name in "12345" and state.buffer):
            if state.candidates:
                idx = 0 if name == "space" else int(name) - 1
                if idx < len(state.candidates):
                    keyboard.write(state.candidates[idx])
                    self.bridge.reset_ui_sig.emit()
                    return False
            return True

        # 4. 确认/取消
        elif name in ["enter", "esc"]:
            if state.buffer:
                if name == "enter":
                    keyboard.write(state.buffer)
                self.bridge.reset_ui_sig.emit()
                return False
            return True
        
        return True


    def _handle_refresh_request(self):
        """主线程逻辑：控制定时器"""
        if not state.buffer:
            self.reset_ime()
            return
        # 只有在主线程调用的 start(150) 才不会报错
        self.debounce_timer.start(70)

    def _start_fetch(self):
        """主线程逻辑：启动异步拉取词条"""
        if self.worker and self.worker.isRunning():
            self.worker.terminate()
            self.worker.wait()
            
        self.worker = FetchThread(state.buffer)
        self.worker.result_ready.connect(self._on_data_received)
        self.worker.start()

    def _on_data_received(self, candidates):
        """主线程逻辑：更新UI内容"""
        state.candidates = candidates
        if candidates:
            self.window.update_candidates(candidates)
        else:
            self.window.hide()

    def reset_ime(self):
        """主线程逻辑：重置状态并隐藏UI"""
        state.buffer = ""
        state.candidates = []
        self.window.hide()
        if self.debounce_timer.isActive():
            self.debounce_timer.stop()

    def run(self):
        # 启动全局钩子
        keyboard.hook(self.on_key_event)
        # 进入 Qt 事件循环
        sys.exit(self.app.exec())

if __name__ == "__main__":
    # 注意：运行此脚本通常需要管理员/Root权限
    ime = IMEController()
    ime.run()