import os
import sys

from PySide6.QtCore import Qt
from PySide6.QtGui import QColor, QFont, QFontInfo, QIcon, QPalette
from PySide6.QtWidgets import (
    QApplication,
    QGridLayout,
    QHBoxLayout,
    QLabel,
    QMainWindow,
    QPushButton,
    QWidget,
)

from .autoslicer import Autoslicer, AutoslicerParams
from .controller import ScanSlicerControllerMixin
from .ui_builders import ScanSlicerUiBuilderMixin


# _unwrap_qvariant: function definition for ScanSlicer behavior.
def _unwrap_qvariant(value):
    unwrapped = value
    for _ in range(4):
        if hasattr(unwrapped, "variant"):
            try:
                candidate = unwrapped.variant()
            except Exception:
                candidate = unwrapped
            if candidate is not unwrapped:
                unwrapped = candidate
                continue

        if hasattr(unwrapped, "value"):
            try:
                candidate = unwrapped.value()
            except TypeError:
                candidate = unwrapped.value
            except Exception:
                candidate = unwrapped
            if candidate is not unwrapped:
                unwrapped = candidate
                continue
        break
    return unwrapped


# _read_portal_dark_preference: function definition for ScanSlicer behavior.
def _read_portal_dark_preference():
    try:
        from PySide6.QtDBus import QDBusConnection, QDBusInterface, QDBusMessage
    except Exception:
        return None

    bus = QDBusConnection.sessionBus()
    if not bus.isConnected():
        return None

    iface = QDBusInterface(
        "org.freedesktop.portal.Desktop",
        "/org/freedesktop/portal/desktop",
        "org.freedesktop.portal.Settings",
        bus,
    )
    if not iface.isValid():
        return None

    for method in ("ReadOne", "Read"):
        reply = iface.call(method, "org.freedesktop.appearance", "color-scheme")
        if reply.type() == QDBusMessage.MessageType.ErrorMessage:
            continue

        args = reply.arguments()
        if not args:
            continue

        raw_value = _unwrap_qvariant(args[0])
        if isinstance(raw_value, dict) and "color-scheme" in raw_value:
            raw_value = _unwrap_qvariant(raw_value["color-scheme"])
        if isinstance(raw_value, (list, tuple)) and raw_value:
            raw_value = _unwrap_qvariant(raw_value[0])

        try:
            color_scheme = int(raw_value)
        except Exception:
            continue

        # XDG portal color-scheme values:
        # 0 = no preference, 1 = prefer dark, 2 = prefer light
        if color_scheme == 1:
            return True
        if color_scheme == 2:
            return False
    return None


# apply_dark_theme_if_requested: function definition for ScanSlicer behavior.
def apply_dark_theme_if_requested(app):
    theme_value = os.environ.get("GTK_THEME", "").lower()
    dark_theme_requested = "dark" in theme_value
    if not dark_theme_requested:
        portal_pref = _read_portal_dark_preference()
        if portal_pref is not None:
            dark_theme_requested = portal_pref

    if not dark_theme_requested:
        try:
            dark_theme_requested = app.styleHints().colorScheme() == Qt.ColorScheme.Dark
        except Exception:
            dark_theme_requested = False

    if not dark_theme_requested:
        return

    # Some container/desktop combinations do not propagate GTK dark theme
    # correctly to Qt widgets; enforce a dark palette when dark mode is requested.
    app.setStyle("Fusion")
    palette = QPalette()
    palette.setColor(QPalette.Window, QColor(53, 53, 53))
    palette.setColor(QPalette.WindowText, QColor(255, 255, 255))
    palette.setColor(QPalette.Base, QColor(35, 35, 35))
    palette.setColor(QPalette.AlternateBase, QColor(53, 53, 53))
    palette.setColor(QPalette.ToolTipBase, QColor(35, 35, 35))
    palette.setColor(QPalette.ToolTipText, QColor(255, 255, 255))
    palette.setColor(QPalette.Text, QColor(255, 255, 255))
    palette.setColor(QPalette.Button, QColor(53, 53, 53))
    palette.setColor(QPalette.ButtonText, QColor(255, 255, 255))
    palette.setColor(QPalette.BrightText, QColor(255, 0, 0))
    palette.setColor(QPalette.Highlight, QColor(42, 130, 218))
    palette.setColor(QPalette.HighlightedText, QColor(255, 255, 255))
    app.setPalette(palette)


# apply_global_text_size_offset: function definition for ScanSlicer behavior.
def apply_global_text_size_offset(app, pixel_offset=2):
    font = app.font()
    info = QFontInfo(font)
    pixel_size = info.pixelSize()

    if pixel_size > 0:
        font.setPixelSize(pixel_size + pixel_offset)
    else:
        point_size = info.pointSizeF()
        if point_size <= 0:
            point_size = 10.0
        font.setPointSizeF(point_size + (pixel_offset * 0.75))

    app.setFont(font)


# resolve_app_icon: function definition for ScanSlicer behavior.
def resolve_app_icon():
    icon = QIcon.fromTheme("scanslicer")
    if not icon.isNull():
        return icon

    appdir = os.environ.get("APPDIR", "").strip()
    if not appdir:
        return QIcon()

    candidates = (
        os.path.join(appdir, "usr", "share", "icons", "scanslicer.png"),
        os.path.join(appdir, "usr", "share", "icons", "scanslicer.svg"),
        os.path.join(appdir, "usr", "share", "pixmaps", "scanslicer.png"),
        os.path.join(appdir, "usr", "share", "pixmaps", "scanslicer.svg"),
        os.path.join(appdir, ".DirIcon"),
    )
    for candidate_path in candidates:
        if not os.path.exists(candidate_path):
            continue
        candidate_icon = QIcon(candidate_path)
        if not candidate_icon.isNull():
            return candidate_icon

    return QIcon()