"""Theme persistence and Fluent Widgets integration.

与 DLPilot/SerialMate 的 theme.py 同源(三件套: setTheme + QPalette/QSS
+ DWM 标题栏), 仅改应用名。"""

import ctypes
import os

from PySide6.QtCore import QObject, QSettings, Qt
from PySide6.QtGui import QColor, QPalette
from qfluentwidgets import Theme, setTheme, setThemeColor

# Fluent widgets restyle themselves on setTheme(); QMainWindow, the native
# QTabWidget/QStatusBar and the Windows title bar keep the OS palette unless
# the palette, an app stylesheet and the DWM title bar attributes follow suit
# (same approach as DLPilot app_fluent.py).
_SURFACES = {
    False: {"window": "#f4f6f8", "base": "#ffffff", "text": "#1f2328",
            "dim": "#57606a", "border": "#d8dee4", "selected_text": "#ffffff"},
    True: {"window": "#202020", "base": "#2b2b2b", "text": "#f5f5f5",
           "dim": "#9a9a9a", "border": "#3a3a3a", "selected_text": "#1f2328"},
}


class ThemeManager(QObject):
    """Keep the appearance choice persistent and synchronized with Qt."""

    MODES = {"system", "light", "dark", "dark1", "dark2"}
    _THEMES = {
        "system": Theme.AUTO,
        "light": Theme.LIGHT,
        "dark": Theme.DARK,
        "dark1": Theme.DARK,
        "dark2": Theme.DARK,
    }
    _ACCENTS = {
        "light": "#0f6cbd",
        "dark": "#f2c94c",
        "dark1": "#5aa9e6",
        "dark2": "#35c6c8",
    }

    def __init__(self, app):
        super().__init__(app)
        self.app = app
        self.window = None
        self.settings = QSettings("LT8619C-Tools", "I2C-Lab")
        mode = self.settings.value("appearance/theme", "system")
        self.mode = mode if mode in self.MODES else "system"
        self.apply()
        app.styleHints().colorSchemeChanged.connect(self.apply)

    def set_window(self, window):
        """Register the main window so the native title bar follows the theme."""
        self.window = window
        self._apply_titlebar()

    def set_mode(self, mode):
        if mode not in self.MODES:
            raise ValueError(f"Unknown theme: {mode}")
        self.mode = mode
        self.settings.setValue("appearance/theme", mode)
        self.apply()

    def is_dark(self):
        if self.mode in {"dark", "dark1", "dark2"}:
            return True
        return self.mode == "system" and self.app.styleHints().colorScheme() == Qt.ColorScheme.Dark

    def apply(self, *_):
        is_dark = self.is_dark()
        setTheme(self._THEMES[self.mode])
        setThemeColor(self._ACCENTS.get(self.mode, self._ACCENTS["light"]))
        self._apply_palette(is_dark)
        self._apply_titlebar()

    def _apply_palette(self, is_dark):
        """Give native Qt surfaces the same colors as the Fluent widgets."""
        surface = _SURFACES[is_dark]
        accent = QColor(self._ACCENTS.get(self.mode, self._ACCENTS["light"]))
        palette = QPalette()
        for role, color in (
            (QPalette.Window, surface["window"]),
            (QPalette.Base, surface["base"]),
            (QPalette.AlternateBase, surface["base"]),
            (QPalette.Text, surface["text"]),
            (QPalette.WindowText, surface["text"]),
            (QPalette.Button, surface["base"]),
            (QPalette.ButtonText, surface["text"]),
            (QPalette.PlaceholderText, surface["dim"]),
            (QPalette.Highlight, accent),
            (QPalette.HighlightedText, surface["selected_text"]),
            (QPalette.ToolTipBase, surface["base"]),
            (QPalette.ToolTipText, surface["text"]),
        ):
            palette.setColor(role, QColor(color))
        self.app.setPalette(palette)
        self.app.setStyleSheet(f"""
            QMainWindow, QWidget#root {{ background-color: {surface['window']}; color: {surface['text']}; }}
            QTabWidget::pane {{ background: {surface['base']}; border: 1px solid {surface['border']}; border-radius: 6px; }}
            QTabBar {{ qproperty-drawBase: 0; }}
            QTabBar::tab {{ background: transparent; color: {surface['dim']}; padding: 6px 16px;
                            border: 1px solid transparent; border-top-left-radius: 6px;
                            border-top-right-radius: 6px; }}
            QTabBar::tab:selected {{ background: {surface['base']}; color: {surface['text']};
                                     border: 1px solid {surface['border']}; }}
            QTabBar::tab:hover:!selected {{ background: {surface['base']}; }}
            QSplitter::handle {{ background: {surface['window']}; }}
            QStatusBar {{ background: {surface['window']}; color: {surface['dim']};
                          border-top: 1px solid {surface['border']}; }}
            QToolTip {{ background-color: {surface['base']}; color: {surface['text']};
                        border: 1px solid {surface['border']}; }}
        """)

    def _apply_titlebar(self):
        """Ask DWM for a title bar in the current surface color (Win10/11)."""
        if self.window is None or os.name != "nt" or not hasattr(ctypes, "windll"):
            return
        try:
            hwnd = int(self.window.winId())
            dwm = ctypes.windll.dwmapi
            dark = ctypes.c_int(1 if self.is_dark() else 0)
            dwm.DwmSetWindowAttribute(hwnd, 20, ctypes.byref(dark), ctypes.sizeof(dark))
            surface = _SURFACES[self.is_dark()]
            dwm.DwmSetWindowAttribute(hwnd, 35, ctypes.byref(self._colorref(QColor(surface["window"]))), 4)
            dwm.DwmSetWindowAttribute(hwnd, 36, ctypes.byref(self._colorref(QColor(surface["text"]))), 4)
        except Exception:
            pass

    @staticmethod
    def _colorref(color):
        return ctypes.c_int(color.red() | (color.green() << 8) | (color.blue() << 16))