from PySide6.QtCore import Qt, QSettings, Signal
from PySide6.QtGui import QFont
from PySide6.QtWidgets import (
    QWidget,
    QLabel,
    QVBoxLayout,
    QHBoxLayout,
    QPushButton,
    QSlider,
    QButtonGroup,
    QScrollArea,
    QScroller,
)


class DisplayScreen(QWidget):
    theme_changed = Signal(str)

    def __init__(self):
        super().__init__()
        self._settings = QSettings("car_ui", "ui")

        root = QVBoxLayout(self)
        root.setContentsMargins(0, 0, 0, 0)
        root.setSpacing(12)

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

        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)

        content_layout.addWidget(self._build_brightness_card())
        content_layout.addWidget(self._build_sleep_card())
        content_layout.addWidget(self._build_theme_card())
        content_layout.addStretch(1)

        scroll.setWidget(content)
        root.addWidget(scroll, 1)

    def _build_brightness_card(self) -> QWidget:
        card, body = _card("Яркость")
        brightness = _read_int_setting(self._settings, "display/brightness", 70)
        auto_brightness = _read_bool_setting(
            self._settings,
            "display/auto_brightness",
            False,
        )

        row_toggle, toggle_btn = _toggle_row(
            "Автояркость",
            checked=auto_brightness,
        )
        row_slider, slider, value_label = _slider_row(
            "Яркость экрана",
            10,
            100,
            brightness,
            lambda v: f"{v}%",
        )
        slider.setEnabled(not auto_brightness)

        toggle_btn.toggled.connect(
            lambda v: self._settings.setValue("display/auto_brightness", v)
        )
        toggle_btn.toggled.connect(lambda v: slider.setEnabled(not v))
        slider.valueChanged.connect(
            lambda v: self._settings.setValue("display/brightness", v)
        )

        body.addWidget(row_toggle)
        body.addWidget(row_slider)
        return card

    def _build_sleep_card(self) -> QWidget:
        card, body = _card("Сон")
        sleep_minutes = _read_int_setting(
            self._settings,
            "display/sleep_minutes",
            10,
        )
        row, slider, value_label = _slider_row(
            "Отключать экран через",
            0,
            30,
            sleep_minutes,
            _format_sleep_minutes,
        )
        slider.valueChanged.connect(
            lambda v: self._settings.setValue("display/sleep_minutes", v)
        )
        body.addWidget(row)
        return card

    def _build_theme_card(self) -> QWidget:
        card, body = _card("Тема")
        row = QWidget()
        row.setObjectName("SoundToneRow")
        layout = QHBoxLayout(row)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(10)

        group = QButtonGroup(row)
        group.setExclusive(True)

        current_theme = self._settings.value("display/theme", "night")
        theme_map = {}
        for label, key in (("День", "day"), ("Ночь", "night")):
            btn = QPushButton(label)
            btn.setObjectName("SoundToneBtn")
            btn.setCheckable(True)
            btn.setMinimumHeight(40)
            btn.setFont(QFont("", 13, 600))
            if key == current_theme:
                btn.setChecked(True)
            group.addButton(btn)
            theme_map[btn] = key
            layout.addWidget(btn, 1)

        def _apply_theme(btn: QPushButton):
            theme_key = theme_map.get(btn, "night")
            self._settings.setValue("display/theme", theme_key)
            self.theme_changed.emit(theme_key)

        group.buttonClicked.connect(_apply_theme)

        body.addWidget(row)
        return card


def _card(title: str) -> tuple[QWidget, QVBoxLayout]:
    card = QWidget()
    card.setObjectName("SoundCard")
    layout = QVBoxLayout(card)
    layout.setContentsMargins(14, 12, 14, 12)
    layout.setSpacing(10)

    header = QLabel(title)
    header.setObjectName("SoundCardTitle")
    header.setFont(QFont("", 14, 700))

    layout.addWidget(header)
    return card, layout


def _toggle_row(label: str, checked: bool) -> tuple[QWidget, QPushButton]:
    row = QWidget()
    row.setObjectName("SoundToggleRow")
    layout = QHBoxLayout(row)
    layout.setContentsMargins(0, 0, 0, 0)
    layout.setSpacing(12)

    lbl = QLabel(label)
    lbl.setFont(QFont("", 13, 600))

    btn = QPushButton("Выкл")
    btn.setObjectName("SoundToggle")
    btn.setCheckable(True)
    btn.setChecked(checked)
    btn.setMinimumHeight(36)
    btn.setMinimumWidth(86)
    btn.setFont(QFont("", 12, 700))

    def _sync_text(is_checked: bool):
        btn.setText("Вкл" if is_checked else "Выкл")

    btn.toggled.connect(_sync_text)
    _sync_text(btn.isChecked())

    layout.addWidget(lbl)
    layout.addStretch(1)
    layout.addWidget(btn)
    return row, btn


def _slider_row(
    label: str,
    minimum: int,
    maximum: int,
    value: int,
    formatter,
) -> tuple[QWidget, QSlider, QLabel]:
    row = QWidget()
    row.setObjectName("SoundSliderRow")
    layout = QVBoxLayout(row)
    layout.setContentsMargins(0, 0, 0, 0)
    layout.setSpacing(6)

    header = QWidget()
    header_layout = QHBoxLayout(header)
    header_layout.setContentsMargins(0, 0, 0, 0)
    header_layout.setSpacing(8)

    lbl = QLabel(label)
    lbl.setFont(QFont("", 13, 600))
    val = QLabel(formatter(value))
    val.setObjectName("SoundValue")
    val.setFont(QFont("", 12, 600))
    val.setAlignment(Qt.AlignRight | Qt.AlignVCenter)

    header_layout.addWidget(lbl)
    header_layout.addStretch(1)
    header_layout.addWidget(val)

    slider = QSlider(Qt.Horizontal)
    slider.setObjectName("SoundSlider")
    slider.setRange(minimum, maximum)
    slider.setValue(value)
    slider.valueChanged.connect(lambda v: val.setText(formatter(v)))

    layout.addWidget(header)
    layout.addWidget(slider)
    return row, slider, val


def _format_sleep_minutes(value: int) -> str:
    if value <= 0:
        return "Никогда"
    return f"{value} мин"


def _read_int_setting(settings: QSettings, key: str, default: int) -> int:
    raw = settings.value(key, default)
    try:
        return int(raw)
    except (TypeError, ValueError):
        return default


def _read_bool_setting(settings: QSettings, key: str, default: bool) -> bool:
    raw = settings.value(key, default)
    if isinstance(raw, bool):
        return raw
    if isinstance(raw, (int, float)):
        return bool(raw)
    if isinstance(raw, str):
        return raw.strip().lower() in {"1", "true", "yes", "on"}
    return default