# coding:utf-8
import sys

from PySide2.QtCore import Qt, QEvent
from PySide2.QtGui import QIcon
from PySide2.QtWidgets import QLabel, QHBoxLayout, QWidget

from ..utils import startSystemMove
from .title_bar_buttons import (CloseButton, MaximizeButton, MinimizeButton,
                                SvgTitleBarButton, TitleBarButton)


class TitleBarBase(QWidget):
    """ Title bar base class """

    def __init__(self, parent):
        super().__init__(parent)
        self.minBtn = MinimizeButton(parent=self)
        self.closeBtn = CloseButton(parent=self)
        self.maxBtn = MaximizeButton(parent=self)

        self._isDoubleClickEnabled = True

        self.resize(200, 32)
        self.setFixedHeight(32)

        # connect signal to slot
        self.minBtn.clicked.connect(self.window().showMinimized)
        self.maxBtn.clicked.connect(self.__toggleMaxState)
        self.closeBtn.clicked.connect(self.window().close)

        self.window().installEventFilter(self)

    def eventFilter(self, obj, e):
        if obj is self.window():
            if e.type() == QEvent.WindowStateChange:
                self.maxBtn.setMaxState(self.window().isMaximized())
                return False

        return super().eventFilter(obj, e)

    def mouseDoubleClickEvent(self, event):
        """ Toggles the maximization state of the window """
        if event.button() != Qt.LeftButton or not self._isDoubleClickEnabled:
            return

        self.__toggleMaxState()

    def mouseMoveEvent(self, e):
        if sys.platform != "win32" or not self.canDrag(e.pos()):
            return

        startSystemMove(self.window(), e.globalPos())

    def mousePressEvent(self, e):
        if sys.platform == "win32" or not self.canDrag(e.pos()):
            return

        startSystemMove(self.window(), e.globalPos())

    def __toggleMaxState(self):
        """ Toggles the maximization state of the window and change icon """
        if self.window().isMaximized():
            self.window().showNormal()
        else:
            self.window().showMaximized()
            
        if sys.platform == "win32":
            from ..utils.win32_utils import releaseMouseLeftButton
            releaseMouseLeftButton(self.window().winId())

    def _isDragRegion(self, pos):
        """ Check whether the position belongs to the area where dragging is allowed """
        width = 0
        for button in self.findChildren(TitleBarButton):
            if button.isVisible():
                width += button.width()

        return 0 < pos.x() < self.width() - width

    def _hasButtonPressed(self):
        """ whether any button is pressed """
        return any(btn.isPressed() for btn in self.findChildren(TitleBarButton))

    def canDrag(self, pos):
        """ whether the position is draggable """
        return self._isDragRegion(pos) and not self._hasButtonPressed()

    def setDoubleClickEnabled(self, isEnabled):
        """ whether to switch window maximization status when double clicked
        Parameters
        ----------
        isEnabled: bool
            whether to enable double click
        """
        self._isDoubleClickEnabled = isEnabled


class TitleBar(TitleBarBase):
    """ Title bar """

    def __init__(self, parent):
        super().__init__(parent)
        self.hBoxLayout = QHBoxLayout(self)

        # add buttons to layout
        self.hBoxLayout.setSpacing(0)
        self.hBoxLayout.setContentsMargins(0, 0, 0, 0)
        self.hBoxLayout.setAlignment(Qt.AlignVCenter | Qt.AlignLeft)
        self.hBoxLayout.addStretch(1)
        self.hBoxLayout.addWidget(self.minBtn, 0, Qt.AlignRight)
        self.hBoxLayout.addWidget(self.maxBtn, 0, Qt.AlignRight)
        self.hBoxLayout.addWidget(self.closeBtn, 0, Qt.AlignRight)


class StandardTitleBar(TitleBar):
    """ Title bar with icon and title """

    def __init__(self, parent):
        super().__init__(parent)
        # add window icon
        self.iconLabel = QLabel(self)
        self.iconLabel.setFixedSize(20, 20)
        self.hBoxLayout.insertSpacing(0, 10)
        self.hBoxLayout.insertWidget(1, self.iconLabel, 0, Qt.AlignLeft)
        self.window().windowIconChanged.connect(self.setIcon)

        # add title label
        self.titleLabel = QLabel(self)
        self.hBoxLayout.insertWidget(2, self.titleLabel, 0, Qt.AlignLeft)
        self.titleLabel.setStyleSheet("""
            QLabel{
                background: transparent;
                font: 13px 'Segoe UI', 'Microsoft YaHei', 'PingFang SC';
                padding: 0 4px
            }
        """)
        self.window().windowTitleChanged.connect(self.setTitle)

    def setTitle(self, title):
        """ set the title of title bar
        Parameters
        ----------
        title: str
            the title of title bar
        """
        self.titleLabel.setText(title)
        self.titleLabel.adjustSize()

    def setIcon(self, icon):
        """ set the icon of title bar
        Parameters
        ----------
        icon: QIcon | QPixmap | str
            the icon of title bar
        """
        self.iconLabel.setPixmap(QIcon(icon).pixmap(20, 20))