from PySide6.QtWidgets import (
    QWidget,
    QLabel,
    QVBoxLayout,
    QHBoxLayout,
    QPushButton,
    QSizePolicy,
    QScrollArea,
    QStackedWidget,
    QApplication,
)
from PySide6.QtCore import Qt
from PySide6.QtGui import QFont
from PySide6.QtWidgets import QScroller
from screens.bluetooth import BluetoothScreen


class SettingsRow(QPushButton):
    def __init__(self, title: str, subtitle: str):
        super().__init__()
        self.setObjectName("SettingsRow")
        self.setCursor(Qt.PointingHandCursor)
        self.setCheckable(False)
        self.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Fixed)
        self.setMinimumHeight(70)

        row = QHBoxLayout(self)
        row.setContentsMargins(16, 10, 16, 10)
        row.setSpacing(12)

        text_col = QVBoxLayout()
        text_col.setContentsMargins(0, 0, 0, 0)
        text_col.setSpacing(2)

        lbl_title = QLabel(title)
        lbl_title.setObjectName("SettingsRowTitle")
        lbl_title.setFont(QFont("", 16, 600))

        lbl_sub = QLabel(subtitle)
        lbl_sub.setObjectName("SettingsRowSub")
        lbl_sub.setFont(QFont("", 12))
        lbl_sub.setWordWrap(False)

        text_col.addWidget(lbl_title)
        text_col.addWidget(lbl_sub)

        chevron = QLabel("›")
        chevron.setObjectName("SettingsChevron")
        chevron.setFont(QFont("", 20, 600))
        chevron.setAlignment(Qt.AlignRight | Qt.AlignVCenter)

        row.addLayout(text_col)
        row.addStretch(1)
        row.addWidget(chevron)


class SettingsScreen(QWidget):
    def __init__(self):
        super().__init__()
        root = QVBoxLayout(self)
        root.setContentsMargins(18, 16, 18, 16)
        root.setSpacing(12)

        self.stack = QStackedWidget()
        root.addWidget(self.stack, 1)

        self._list_screen = QWidget()
        list_layout = QVBoxLayout(self._list_screen)
        list_layout.setContentsMargins(0, 0, 0, 0)
        list_layout.setSpacing(12)

        list_title = QLabel("Настройки")
        list_title.setFont(QFont("", 24, 700))
        list_layout.addWidget(list_title)

        scroll = QScrollArea()
        scroll.setWidgetResizable(True)
        scroll.setFrameShape(QScrollArea.NoFrame)
        scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        scroll.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)

        # === TOUCH SCROLL (Raspberry safe) ===
        scroller = QScroller.scroller(scroll.viewport())
        scroller.grabGesture(
            scroll.viewport(),
            QScroller.LeftMouseButtonGesture
        )

        content = QWidget()
        content_layout = QVBoxLayout(content)
        content_layout.setContentsMargins(0, 0, 0, 0)
        content_layout.setSpacing(12)

        bt_row = self._add_section(
            content_layout,
            "Сеть",
            [
                ("Wi-Fi", "Доступные сети и подключение"),
                ("Bluetooth", "Сопряжение и устройства"),
            ],
            return_row_title="Bluetooth",
        )

        dev_row = self._add_section(
            content_layout,
            "Система",
            [
                ("Об устройстве", "Версия, память, серийный номер"),
                ("Параметры разработчика", "Отладка и логирование"),
            ],
            return_row_title="Параметры разработчика",
        )

        self._add_section(
            content_layout,
            "Дисплей и звук",
            [
                ("Экран", "Яркость, сон, тема"),
                ("Звук", "Громкость, эквалайзер"),
            ],
        )

        content_layout.addStretch(1)
        scroll.setWidget(content)
        list_layout.addWidget(scroll, 1)

        self._dev_screen = self._build_dev_screen()
        self._bt_screen = BluetoothScreen(self._show_list)
        self.stack.addWidget(self._list_screen)
        self.stack.addWidget(self._dev_screen)
        self.stack.addWidget(self._bt_screen)

        if dev_row is not None:
            dev_row.clicked.connect(self._show_dev)
        if bt_row is not None:
            bt_row.clicked.connect(self._show_bluetooth)

    def _build_dev_screen(self) -> QWidget:
        screen = QWidget()
        layout = QVBoxLayout(screen)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(12)

        hdr = QHBoxLayout()
        hdr.setContentsMargins(0, 0, 0, 0)
        hdr.setSpacing(12)

        back_btn = QPushButton("Назад")
        back_btn.setObjectName("SettingsBackBtn")
        back_btn.setMinimumSize(120, 44)
        back_btn.clicked.connect(self._show_list)

        title = QLabel("Параметры разработчика")
        title.setFont(QFont("", 22, 700))

        hdr.addWidget(back_btn)
        hdr.addWidget(title)
        hdr.addStretch(1)

        exit_btn = QPushButton("Переход к рабочему столу")
        exit_btn.setObjectName("DevExitBtn")
        exit_btn.setMinimumHeight(72)
        exit_btn.clicked.connect(self._exit_app)

        layout.addLayout(hdr)
        layout.addWidget(exit_btn)
        layout.addStretch(1)
        return screen

    def _add_section(
        self,
        root: QVBoxLayout,
        title: str,
        items: list[tuple[str, str]],
        return_row_title: str | None = None,
    ):
        section = QLabel(title)
        section.setObjectName("SettingsSection")
        section.setFont(QFont("", 14, 700))
        section.setContentsMargins(2, 8, 2, 0)
        root.addWidget(section)

        target_row = None
        for row_title, row_subtitle in items:
            row = SettingsRow(row_title, row_subtitle)
            root.addWidget(row)
            if return_row_title and row_title == return_row_title:
                target_row = row
        return target_row

    def _show_dev(self):
        self.stack.setCurrentWidget(self._dev_screen)

    def _show_list(self):
        self.stack.setCurrentWidget(self._list_screen)

    def _show_bluetooth(self):
        self.stack.setCurrentWidget(self._bt_screen)

    def _exit_app(self):
        app = QApplication.instance()
        if app is not None:
            app.quit()