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import json, os, warnings

from PySide2 import QtCore
from PySide2.QtCore import QDir, QFileInfo, QStandardPaths, Qt, QUrl
from PySide2.QtGui import QIcon, QStandardItem, QStandardItemModel
from PySide2.QtWidgets import QMenu, QMessageBox, QTreeView

_url_role = Qt.UserRole + 1

# Default bookmarks as an array of arrays which is the form
# used to read from/write to a .json bookmarks file
_default_bookmarks = [
    ['Tool Bar'],
    ['http://qt.io', 'Qt', ':/qt-project.org/qmessagebox/images/qtlogo-64.png'],
    ['https://download.qt.io/snapshots/ci/pyside/', 'Downloads'],
    ['https://doc-snapshots.qt.io/qtforpython/', 'Documentation'],
    ['https://bugreports.qt.io/projects/PYSIDE/', 'Bug Reports'],
    ['https://www.python.org/', 'Python', None],
    ['https://wiki.qt.io/PySide2', 'Qt for Python', None],
    ['Other Bookmarks']
]

def _config_dir():
    return '{}/QtForPythonBrowser'.format(
        QStandardPaths.writableLocation(QStandardPaths.ConfigLocation))

_bookmark_file = 'bookmarks.json'

def _create_folder_item(title):
    result = QStandardItem(title)
    result.setFlags(Qt.ItemIsEnabled | Qt.ItemIsSelectable)
    return result

def _create_item(url, title, icon):
    result = QStandardItem(title)
    result.setFlags(Qt.ItemIsEnabled | Qt.ItemIsSelectable)
    result.setData(url, _url_role)
    if icon is not None:
        result.setIcon(icon)
    return result

# Create the model from an array of arrays
def _create_model(parent, serialized_bookmarks):
    result = QStandardItemModel(0, 1, parent)
    last_folder_item = None
    for entry in serialized_bookmarks:
        if len(entry) == 1:
            last_folder_item = _create_folder_item(entry[0])
            result.appendRow(last_folder_item)
        else:
            url = QUrl.fromUserInput(entry[0])
            title = entry[1]
            icon = QIcon(entry[2]) if len(entry) > 2 and entry[2] else None
            last_folder_item.appendRow(_create_item(url, title, icon))
    return result

# Serialize model into an array of arrays, writing out the icons
# into .png files under directory in the process
def _serialize_model(model, directory):
    result = []
    folder_count = model.rowCount()
    for f in range(0, folder_count):
        folder_item = model.item(f)
        result.append([folder_item.text()])
        item_count = folder_item.rowCount()
        for i in range(0, item_count):
            item = folder_item.child(i)
            entry = [item.data(_url_role).toString(), item.text()]
            icon = item.icon()
            if not icon.isNull():
                icon_sizes = icon.availableSizes()
                largest_size = icon_sizes[len(icon_sizes) - 1]
                icon_file_name = '{}/icon{:02}_{:02}_{}.png'.format(directory,
                               f, i, largest_size.width())
                icon.pixmap(largest_size).save(icon_file_name, 'PNG')
                entry.append(icon_file_name)
            result.append(entry)
    return result

# Bookmarks as a tree view to be used in a dock widget with
# functionality to persist and populate tool bars and menus.
class BookmarkWidget(QTreeView):
    """Provides a tree view to manage the bookmarks."""

    open_bookmark = QtCore.Signal(QUrl)
    open_bookmark_in_new_tab = QtCore.Signal(QUrl)
    changed = QtCore.Signal()

    def __init__(self):
        super(BookmarkWidget, self).__init__()
        self.setRootIsDecorated(False)
        self.setUniformRowHeights(True)
        self.setHeaderHidden(True)
        self._model = _create_model(self, self._read_bookmarks())
        self.setModel(self._model)
        self.expandAll()
        self.activated.connect(self._activated)
        self._model.rowsInserted.connect(self._changed)
        self._model.rowsRemoved.connect(self._changed)
        self._model.dataChanged.connect(self._changed)
        self._modified = False

    def _changed(self):
        self._modified = True
        self.changed.emit()

    def _activated(self, index):
        item = self._model.itemFromIndex(index)
        self.open_bookmark.emit(item.data(_url_role))

    def _action_activated(self, index):
        action = self.sender()
        self.open_bookmark.emit(action.data())

    def _tool_bar_item(self):
        return self._model.item(0, 0)

    def _other_item(self):
        return self._model.item(1, 0)

    def add_bookmark(self, url, title, icon):
        self._other_item().appendRow(_create_item(url, title, icon))

    def add_tool_bar_bookmark(self, url, title, icon):
        self._tool_bar_item().appendRow(_create_item(url, title, icon))

    # Synchronize the bookmarks under parent_item to a target_object
    # like QMenu/QToolBar, which has a list of actions. Update
    # the existing actions, append new ones if needed or hide
    # superfluous ones
    def _populate_actions(self, parent_item, target_object, first_action):
        existing_actions = target_object.actions()
        existing_action_count = len(existing_actions)
        a = first_action
        row_count = parent_item.rowCount()
        for r in range(0, row_count):
            item = parent_item.child(r)
            title = item.text()
            icon = item.icon()
            url = item.data(_url_role)
            if a < existing_action_count:
                action = existing_actions[a]
                if (title != action.toolTip()):
                    action.setText(BookmarkWidget.short_title(title))
                    action.setIcon(icon)
                    action.setToolTip(title)
                    action.setData(url)
                    action.setVisible(True)
            else:
                action = target_object.addAction(icon, BookmarkWidget.short_title(title))
                action.setToolTip(title)
                action.setData(url)
                action.triggered.connect(self._action_activated)
            a = a + 1
        while a < existing_action_count:
            existing_actions[a].setVisible(False)
            a = a + 1

    def populate_tool_bar(self, tool_bar):
        self._populate_actions(self._tool_bar_item(), tool_bar, 0)

    def populate_other(self, menu, first_action):
        self._populate_actions(self._other_item(), menu, first_action)

    def _current_item(self):
        index = self.currentIndex()
        if index.isValid():
            item = self._model.itemFromIndex(index)
            if item.parent(): # exclude top level items
                return item
        return None

    def context_menu_event(self, event):
        context_menu = QMenu()
        open_in_new_tab_action = context_menu.addAction("Open in New Tab")
        remove_action = context_menu.addAction("Remove...")
        current_item = self._current_item()
        open_in_new_tab_action.setEnabled(current_item is not None)
        remove_action.setEnabled(current_item is not None)
        chosen_action = context_menu.exec_(event.globalPos())
        if chosen_action == open_in_new_tab_action:
            self.open_bookmarkInNewTab.emit(current_item.data(_url_role))
        elif chosen_action == remove_action:
            self._remove_item(current_item)

    def _remove_item(self, item):
        button = QMessageBox.question(self, "Remove",
            "Would you like to remove \"{}\"?".format(item.text()),
            QMessageBox.Yes | QMessageBox.No)
        if button == QMessageBox.Yes:
            item.parent().removeRow(item.row())

    def write_bookmarks(self):
        if not self._modified:
            return
        dir_path = _config_dir()
        native_dir_path = QDir.toNativeSeparators(dir_path)
        dir = QFileInfo(dir_path)
        if not dir.isDir():
            print('Creating {}...'.format(native_dir_path))
            if not QDir(dir.absolutePath()).mkpath(dir.fileName()):
                warnings.warn('Cannot create {}.'.format(native_dir_path),
                              RuntimeWarning)
                return
        serialized_model = _serialize_model(self._model, dir_path)
        bookmark_file_name = os.path.join(native_dir_path, _bookmark_file)
        print('Writing {}...'.format(bookmark_file_name))
        with open(bookmark_file_name, 'w') as bookmark_file:
            json.dump(serialized_model, bookmark_file, indent = 4)

    def _read_bookmarks(self):
        bookmark_file_name = os.path.join(QDir.toNativeSeparators(_config_dir()),
                                        _bookmark_file)
        if os.path.exists(bookmark_file_name):
            print('Reading {}...'.format(bookmark_file_name))
            return json.load(open(bookmark_file_name))
        return _default_bookmarks

    # Return a short title for a bookmark action,
    # "Qt | Cross Platform.." -> "Qt"
    @staticmethod
    def short_title(t):
        i = t.find(' | ')
        if i == -1:
            i = t.find(' - ')
        return t[0:i] if i != -1 else t