"""
Qt navigation bar with breadcrumbs
Andrey Makarov, 2019
"""

import os
import platform
from pathlib import Path
from typing import Union

from PySide2 import QtCore, QtGui, QtWidgets
from PySide2.QtCore import Qt

from .layouts import LeftHBoxLayout
from .models_views import FilenameModel, MenuListView
from .stylesheet import style_root_toolbutton

if platform.system() == "Windows":
    from .platform.windows import get_path_label

TRANSP_ICON_SIZE = 40, 40  # px, size of generated semi-transparent icons
cwd_path = Path()  # working dir (.) https://stackoverflow.com/q/51330297


class BreadcrumbsAddressBar(QtWidgets.QFrame):
    "Windows Explorer-like address bar"
    listdir_error = QtCore.Signal(Path)  # failed to list a directory
    path_error = QtCore.Signal(Path)  # entered path does not exist
    path_selected = QtCore.Signal(Path)

    def __init__(self, parent=None):
        super().__init__(parent)
        self.os_type = platform.system()

        self.style_crumbs = StyleProxy(
            QtWidgets.QStyleFactory.create(
                QtWidgets.QApplication.instance().style().objectName()
            ),
            QtGui.QPixmap("iconfinder_icon-ios7-arrow-right_211607.png")
        )

        layout = QtWidgets.QHBoxLayout(self)

        self.file_ico_prov = QtWidgets.QFileIconProvider()
        self.fs_model = FilenameModel('dirs')

        pal = self.palette()
        pal.setColor(QtGui.QPalette.Background,
                     pal.color(QtGui.QPalette.Base))
        self.setPalette(pal)
        self.setAutoFillBackground(True)
        self.setFrameShape(self.StyledPanel)
        self.layout().setContentsMargins(4, 0, 0, 0)
        self.layout().setSpacing(0)

        self.path_icon = QtWidgets.QLabel(self)
        layout.addWidget(self.path_icon)

        # 点击后才会出现行编辑栏
        self.line_address = QtWidgets.QLineEdit(self)
        self.line_address.setFrame(False)
        # 先隐藏
        self.line_address.hide()
        self.line_address.keyPressEvent = self.line_address_keyPressEvent
        self.line_address.focusOutEvent = self.line_address_focusOutEvent
        self.line_address.contextMenuEvent = self.line_address_contextMenuEvent
        layout.addWidget(self.line_address)
        # Add QCompleter to address line
        # 地址栏文件夹列表提示
        # completer = self.init_completer(self.line_address, self.fs_model)
        # completer.activated.connect(self.set_path)

        # Container for `btn_crumbs_hidden`, `crumbs_panel`, `switch_space`
        # 文件夹名字,可点击
        self.crumbs_container = QtWidgets.QWidget(self)
        # self.crumbs_container.setStyleSheet("QWidget{border: 1px solid darkblue}")
        crumbs_cont_layout = QtWidgets.QHBoxLayout(self.crumbs_container)
        crumbs_cont_layout.setContentsMargins(0, 0, 0, 0)
        crumbs_cont_layout.setSpacing(0)
        layout.addWidget(self.crumbs_container)

        # Monitor breadcrumbs under cursor and switch popup menus
        self.mouse_pos_timer = QtCore.QTimer(self)
        self.mouse_pos_timer.timeout.connect(self.mouse_pos_timer_event)

        # Hidden breadcrumbs menu button
        # 历史目录按钮
        self.btn_root_crumb = QtWidgets.QToolButton(self)
        # self.btn_root_crumb.setStyleSheet("QToolButton{border: 1px solid darkorange}")
        self.btn_root_crumb.setAutoRaise(True)
        self.btn_root_crumb.setPopupMode(QtWidgets.QToolButton.InstantPopup)
        self.btn_root_crumb.setArrowType(Qt.RightArrow)
        self.btn_root_crumb.setStyleSheet(style_root_toolbutton)
        self.btn_root_crumb.setMinimumSize(self.btn_root_crumb.minimumSizeHint())
        self.btn_root_crumb.hide()
        crumbs_cont_layout.addWidget(self.btn_root_crumb)
        menu = QtWidgets.QMenu(self.btn_root_crumb)  # FIXME:
        menu.aboutToShow.connect(self._hidden_crumbs_menu_show)
        menu.aboutToHide.connect(self.mouse_pos_timer.stop)
        self.btn_root_crumb.setMenu(menu)
        self.init_rootmenu_places(menu)  # Desktop, Home, Downloads...
        self.update_rootmenu_devices()  # C:, D:...

        # Container for breadcrumbs
        self.crumbs_panel = QtWidgets.QWidget(self)
        crumbs_layout = LeftHBoxLayout(self.crumbs_panel)
        crumbs_layout.widget_state_changed.connect(self.crumb_hide_show)
        crumbs_layout.setContentsMargins(0, 0, 0, 0)
        crumbs_layout.setSpacing(0)
        crumbs_cont_layout.addWidget(self.crumbs_panel)

        # Clicking on empty space to the right puts the bar into edit mode
        self.switch_space = QtWidgets.QWidget(self)
        # s_policy = self.switch_space.sizePolicy()
        # s_policy.setHorizontalStretch(1)
        # self.switch_space.setSizePolicy(s_policy)
        self.switch_space.mouseReleaseEvent = self.switch_space_mouse_up
        # crumbs_cont_layout.addWidget(self.switch_space)
        crumbs_layout.set_space_widget(self.switch_space)

        self.btn_browse = QtWidgets.QToolButton(self)
        self.btn_browse.setAutoRaise(True)
        self.btn_browse.setText("...")
        self.btn_browse.setToolTip("Browse for folder")
        self.btn_browse.clicked.connect(self._browse_for_folder)
        layout.addWidget(self.btn_browse)

        self.setMaximumHeight(self.line_address.height())  # FIXME:

        self.ignore_resize = False
        self.path_ = None

    @staticmethod
    def init_completer(edit_widget, model):
        "Init QCompleter to work with filesystem"
        completer = QtWidgets.QCompleter(edit_widget)
        completer.setCaseSensitivity(Qt.CaseInsensitive)
        completer.setModel(model)
        # Optimize performance https://stackoverflow.com/a/33454284/1119602
        popup = completer.popup()
        popup.setUniformItemSizes(True)
        popup.setLayoutMode(QtWidgets.QListView.Batched)
        edit_widget.setCompleter(completer)
        edit_widget.textEdited.connect(model.setPathPrefix)
        return completer

    def get_icon(self, path: Union[str, Path]):
        "Path -> QIcon"
        fileinfo = QtCore.QFileInfo(str(path))
        dat = self.file_ico_prov.icon(fileinfo)
        if fileinfo.isHidden():
            pmap = QtGui.QPixmap(*TRANSP_ICON_SIZE)
            pmap.fill(Qt.transparent)
            painter = QtGui.QPainter(pmap)
            painter.setOpacity(0.5)
            dat.paint(painter, 0, 0, *TRANSP_ICON_SIZE)
            painter.end()
            dat = QtGui.QIcon(pmap)
        return dat

    def line_address_contextMenuEvent(self, event):
        self.line_address_context_menu_flag = True
        QtWidgets.QLineEdit.contextMenuEvent(self.line_address, event)

    def line_address_focusOutEvent(self, event):
        if getattr(self, 'line_address_context_menu_flag', False):
            self.line_address_context_menu_flag = False
            return  # do not cancel edit on context menu
        self._cancel_edit()

    def _hidden_crumbs_menu_show(self):
        "SLOT: fill menu with hidden breadcrumbs list"
        self.mouse_pos_timer.start(100)
        menu = self.sender()
        if hasattr(self, 'actions_hidden_crumbs'):
            for action in self.actions_hidden_crumbs:
                menu.removeAction(action)
        self.actions_hidden_crumbs = []

        first_action = menu.actions()[0]  # places section separator
        for i in self.crumbs_panel.layout().widgets('hidden'):
            action = QtWidgets.QAction(self.get_icon(i.path), i.text(), menu)
            action.path = i.path
            action.triggered.connect(self.set_path)
            menu.insertAction(first_action, action)
            self.actions_hidden_crumbs.append(action)
            first_action = action

    def init_rootmenu_places(self, menu):
        "Init common places actions in menu"
        menu.addSeparator()
        QSP = QtCore.QStandardPaths
        uname = os.environ.get('USER') or os.environ.get('USERNAME') or "Home"
        for name, path in (
                ("Desktop", QSP.writableLocation(QSP.DesktopLocation)),
                (uname, QSP.writableLocation(QSP.HomeLocation)),
                ("Documents", QSP.writableLocation(QSP.DocumentsLocation)),
                ("Downloads", QSP.writableLocation(QSP.DownloadLocation)),
                ):
            if self.os_type == "Windows":
                name = self.get_path_label(path)
            action = menu.addAction(self.get_icon(path), name)
            action.path = path
            action.triggered.connect(self.set_path)

    def get_path_label(self, drive_path):
        "Try to get path label using Shell32 on Windows"
        return get_path_label(drive_path.replace("/", "\\"))

    @staticmethod
    def list_network_locations():
        "List (name, path) locations in Network Shortcuts folder on Windows"
        HOME = QtCore.QStandardPaths.HomeLocation
        user_folder = QtCore.QStandardPaths.writableLocation(HOME)
        network_shortcuts = user_folder + "/AppData/Roaming/Microsoft/Windows/Network Shortcuts"
        for i in Path(network_shortcuts).iterdir():
            if not i.is_dir():
                continue
            link = Path(i) / "target.lnk"
            if not link.exists():
                continue
            path = QtCore.QFileInfo(str(link)).symLinkTarget()
            if path:  # `symLinkTarget` doesn't read e.g. FTP links
                yield i.name, path

    def update_rootmenu_devices(self):
        "Init or rebuild device actions in menu"
        menu = self.btn_root_crumb.menu()
        if hasattr(self, 'actions_devices'):
            for action in self.actions_devices:
                menu.removeAction(action)
        self.actions_devices = [menu.addSeparator()]
        for i in QtCore.QStorageInfo.mountedVolumes():  # QDir.drives():
            path, label = i.rootPath(), i.displayName()
            if label == path and self.os_type == "Windows":
                label = self.get_path_label(path)
            elif self.os_type == "Linux" and not path.startswith("/media"):
                # Add to list only volumes in /media
                continue
            caption = "%s (%s)" % (label, path.rstrip(r"\/"))
            action = menu.addAction(self.get_icon(path), caption)
            action.path = path
            action.triggered.connect(self.set_path)
            self.actions_devices.append(action)
        if self.os_type == "Windows":  # Network locations
            for label, path in self.list_network_locations():
                action = menu.addAction(self.get_icon(path), label)
                action.path = path
                action.triggered.connect(self.set_path)
                self.actions_devices.append(action)

    def _browse_for_folder(self):
        path = QtWidgets.QFileDialog.getExistingDirectory(
            self, "Choose folder", str(self.path()))
        if path:
            self.set_path(path)

    def line_address_keyPressEvent(self, event):
        "Actions to take after a key press in text address field"
        if event.key() == Qt.Key_Escape:
            self._cancel_edit()
        elif event.key() in (Qt.Key_Return, Qt.Key_Enter):
            if self.set_path(self.line_address.text()):
                self._show_address_field(False)
        else:
            QtWidgets.QLineEdit.keyPressEvent(self.line_address, event)

    def _clear_crumbs(self):
        layout = self.crumbs_panel.layout()
        while layout.count():
            widget = layout.takeAt(0).widget()
            if widget:
                # Unset style or `StyleProxy.drawPrimitive` is called once with
                # mysterious `QWidget` instead of `QToolButton` (Windows 7)
                widget.setStyle(None)
                widget.deleteLater()
    
    @staticmethod
    def path_title(path: Path):
        "Get folder name or drive name"
        # FIXME: C:\ has no name. Use rstrip on Windows only?
        return path.name or str(path).upper().rstrip(os.path.sep)

    def _insert_crumb(self, path):
        btn = QtWidgets.QToolButton(self.crumbs_panel)
        btn.setAutoRaise(True)
        btn.setPopupMode(btn.MenuButtonPopup)
        btn.mouseMoveEvent = self.crumb_mouse_move
        btn.setMouseTracking(True)
        if path.name:
            btn.setText(self.path_title(path))
        # 根目录是空字符串
        else:
            btn.setText('/')
        btn.path = path
        btn.clicked.connect(self.crumb_clicked)
        menu = MenuListView(btn)
        menu.setIcon(QtWidgets.QApplication.style().standardIcon(QtWidgets.QStyle.SP_ArrowRight))
        menu.aboutToShow.connect(self.crumb_menu_show)
        menu.setModel(self.fs_model)
        menu.clicked.connect(self.crumb_menuitem_clicked)
        menu.activated.connect(self.crumb_menuitem_clicked)
        menu.aboutToHide.connect(self.mouse_pos_timer.stop)
        btn.setMenu(menu)
        self.crumbs_panel.layout().insertWidget(0, btn)
        btn.setMinimumSize(btn.minimumSizeHint())  # fixed size breadcrumbs
        sp = btn.sizePolicy()
        sp.setVerticalPolicy(sp.Minimum)
        btn.setSizePolicy(sp)

    def crumb_mouse_move(self, event):
        ...
        # print('move!')

    def crumb_menuitem_clicked(self, index):
        "SLOT: breadcrumb menu item was clicked"
        self.set_path(index.data(Qt.EditRole))

    def crumb_clicked(self):
        "SLOT: breadcrumb was clicked"
        self.set_path(self.sender().path)

    def crumb_menu_show(self):
        "SLOT: fill subdirectory list on menu open"
        menu = self.sender()
        self.fs_model.setPathPrefix(str(menu.parent().path) + os.path.sep)
        menu.clear_selection()  # clear currentIndex after applying new model
        self.mouse_pos_timer.start(100)

    def set_path(self, path=None):
        """
        Set path displayed in this BreadcrumbsAddressBar
        Returns `False` if path does not exist or permission error.
        Can be used as a SLOT: `sender().path` is used if `path` is `None`)
        """
        path, emit_err = Path(path or self.sender().path), None
        try:
            if not os.path.exists(str(path)):
                emit_err = self.path_error
            elif not os.access(str(path), os.R_OK) or not os.access(str(path), os.X_OK):
                emit_err = self.listdir_error
        except PermissionError:
            emit_err = self.listdir_error
        # try:  # C: -> C:\, folder\..\folder -> folder
        #     path = path.resolve()
        # except PermissionError:
        #     emit_err = self.listdir_error
        # # 有可能是输入全路径的方式进入目录，当路径中某一个目录没有权限访问时，path.exists() 会出错
        # try:
        #     if not path.exists():
        #         emit_err = self.path_error
        # except PermissionError:
        #     emit_err = self.listdir_error
        # self._cancel_edit()  # exit edit mode
        if emit_err:  # permission error or path does not exist
            emit_err.emit(path)
            return False
        self._clear_crumbs()
        self.path_ = path
        self.line_address.setText(str(path))
        self._insert_crumb(path)
        for i in path.parents:
            if i == cwd_path:
                break
            self._insert_crumb(i)
        self.path_icon.setPixmap(self.get_icon(self.path_).pixmap(16, 16))
        self.path_selected.emit(self.path_)
        return True

    def _cancel_edit(self):
        "Set edit line text back to current path and switch to view mode"
        self.line_address.setText(str(self.path()))  # revert path
        self._show_address_field(False)  # switch back to breadcrumbs view

    def path(self):
        "Get path displayed in this BreadcrumbsAddressBar"
        return self.path_

    def switch_space_mouse_up(self, event):
        "EVENT: switch_space mouse clicked"
        if event.button() != Qt.LeftButton:  # left click only
            return
        self._show_address_field(True)

    def _show_address_field(self, b_show):
        "Show text address field"
        if b_show:
            self.crumbs_container.hide()
            self.line_address.show()
            self.line_address.setFocus()
            self.line_address.selectAll()
        else:
            self.line_address.hide()
            self.crumbs_container.show()

    def crumb_hide_show(self, widget, state:bool):
        "SLOT: a breadcrumb is hidden/removed or shown"
        layout = self.crumbs_panel.layout()
        arrow = Qt.LeftArrow if layout.count_hidden() > 0 else Qt.RightArrow
        self.btn_root_crumb.setArrowType(arrow)
        # if layout.count_hidden() > 0:
        #     ico = QtGui.QIcon("iconfinder_icon-ios7-arrow-left_211689.png")
        # else:
        #     ico = QtGui.QIcon("iconfinder_icon-ios7-arrow-right_211607.png")
        # self.btn_root_crumb.setIcon(ico)

    def minimumSizeHint(self):
        # print(self.layout().minimumSize().width())
        return QtCore.QSize(150, self.line_address.height())

    def mouse_pos_timer_event(self):
        "Monitor breadcrumbs under cursor and switch popup menus"
        pos = QtGui.QCursor.pos()
        app = QtCore.QCoreApplication.instance()
        w = app.widgetAt(pos)
        active_menu = app.activePopupWidget()
        if (w and isinstance(w, QtWidgets.QToolButton) and
            w is not active_menu.parent() and
            (w is self.btn_root_crumb or w.parent() is self.crumbs_panel)
        ):
            active_menu.close()
            w.showMenu()

class StyleProxy(QtWidgets.QProxyStyle):
    win_modern = ("windowsxp", "windowsvista")

    def __init__(self, style, arrow_pix):
        super().__init__(style)
        self.arrow_pix = arrow_pix
        self.stylename = self.baseStyle().objectName()

    def drawPrimitive(self, pe, opt, p: QtGui.QPainter, widget):
        # QToolButton elements:
        # 13: PE_PanelButtonCommand (Fusion) - Fusion button background, called from 15 and 24 calls
        # 15: PE_PanelButtonTool (Windows, Fusion) - left part background (XP/Vista styles do not draw it with `drawPrimitive`)
        # 19: PE_IndicatorArrowDown (Windows, Fusion) - right part down arrow (XP/Vista styles draw it in 24 call)
        # 24: PE_IndicatorButtonDropDown (Windows, XP, Vista, Fusion) - right part background (+arrow for XP/Vista)
        # 
        # Arrow is drawn along with PE_IndicatorButtonDropDown (XP/Vista)
        # https://github.com/qt/qtbase/blob/0c51a8756377c40180619046d07b35718fcf1784/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp#L1406
        # https://github.com/qt/qtbase/blob/0c51a8756377c40180619046d07b35718fcf1784/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp#L666
        # drawBackground paints with DrawThemeBackgroundEx WinApi function
        # https://docs.microsoft.com/en-us/windows/win32/api/uxtheme/nf-uxtheme-drawthemebackgroundex
        if (self.stylename in self.win_modern and
            pe == self.PE_IndicatorButtonDropDown
            ):
            pe = self.PE_IndicatorArrowDown  # see below
        if pe == self.PE_IndicatorArrowDown:
            opt_ = QtWidgets.QStyleOptionToolButton()
            widget.initStyleOption(opt_)
            rc = super().subControlRect(self.CC_ToolButton, opt_,
                                        self.SC_ToolButtonMenu, widget)
            if self.stylename in self.win_modern:
                # By default PE_IndicatorButtonDropDown draws arrow along
                # with right button art. Draw 2px clipped left part instead
                path = QtGui.QPainterPath()
                path.addRect(QtCore.QRectF(rc))
                p.setClipPath(path)
                super().drawPrimitive(self.PE_PanelButtonTool, opt, p, widget)
            # centered square
            rc.moveTop(int((rc.height() - rc.width()) / 2))
            rc.setHeight(rc.width())
            # p.setRenderHint(p.Antialiasing)
            p.drawPixmap(rc, self.arrow_pix, QtCore.QRect())
        else:
            super().drawPrimitive(pe, opt, p, widget)

    def subControlRect(self, cc, opt, sc, widget):
        rc = super().subControlRect(cc, opt, sc, widget)
        if (self.stylename in self.win_modern and
            sc == self.SC_ToolButtonMenu
            ):
            rc.adjust(-2, 0, 0, 0)  # cut 2 left pixels to create flat edge
        return rc