# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:

# Copyright 2014-2021 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
#
# This file is part of qutebrowser.
#
# qutebrowser is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# qutebrowser is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with qutebrowser.  If not, see <https://www.gnu.org/licenses/>.

"""The ListView to display downloads in."""

import functools
from typing import Callable, MutableSequence, Tuple, Union

from PyQt5.QtCore import pyqtSlot, QSize, Qt
from PyQt5.QtWidgets import QListView, QSizePolicy, QMenu, QStyleFactory

from qutebrowser.browser import downloads
from qutebrowser.config import stylesheet
from qutebrowser.utils import qtutils, utils


_ActionListType = MutableSequence[
    Union[
        Tuple[None, None],  # separator
        Tuple[str, Callable[[], None]],
    ]
]


class DownloadView(QListView):

    """QListView which shows currently running downloads as a bar.

    Attributes:
        _menu: The QMenu which is currently displayed.
    """

    STYLESHEET = """
        QListView {
            background-color: {{ conf.colors.downloads.bar.bg }};
            font: {{ conf.fonts.downloads }};
        }

        QListView::item {
            padding-right: 2px;
        }
    """

    def __init__(self, model, parent=None):
        super().__init__(parent)
        if not utils.is_mac:
            self.setStyle(QStyleFactory.create('Fusion'))
        stylesheet.set_register(self)
        self.setResizeMode(QListView.Adjust)
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setSizePolicy(QSizePolicy.MinimumExpanding, QSizePolicy.Fixed)
        self.setFocusPolicy(Qt.NoFocus)
        self.setFlow(QListView.LeftToRight)
        self.setSpacing(1)
        self._menu = None
        model.rowsInserted.connect(self._update_geometry)
        model.rowsRemoved.connect(self._update_geometry)
        model.dataChanged.connect(self._update_geometry)
        self.setModel(model)
        self.setWrapping(True)
        self.setContextMenuPolicy(Qt.CustomContextMenu)
        self.customContextMenuRequested.connect(self.show_context_menu)
        self.clicked.connect(self.on_clicked)

    def __repr__(self):
        model = self.model()
        if model is None:
            count = 'None'  # type: ignore[unreachable]
        else:
            count = model.rowCount()
        return utils.get_repr(self, count=count)

    def _model(self) -> downloads.DownloadModel:
        """Get the current download model.

        Ensures the model is not None.
        """
        model = self.model()
        assert isinstance(model, downloads.DownloadModel), model
        return model

    @pyqtSlot()
    def _update_geometry(self):
        """Wrapper to call updateGeometry.

        For some reason, this is needed so that PyQt disconnects the signals and handles
        arguments correctly. Probably a WORKAROUND for an unknown PyQt bug.
        """
        self.updateGeometry()

    @pyqtSlot(bool)
    def on_fullscreen_requested(self, on):
        """Hide/show the downloadview when entering/leaving fullscreen."""
        if on:
            self.hide()
        else:
            self.show()

    @pyqtSlot('QModelIndex')
    def on_clicked(self, index):
        """Handle clicking of an item.

        Args:
            index: The QModelIndex of the clicked item.
        """
        if not index.isValid():
            return
        item = self._model().data(index, downloads.ModelRole.item)
        if item.done and item.successful:
            item.open_file()
            item.remove()

    def _get_menu_actions(
            self,
            item: downloads.AbstractDownloadItem
    ) -> _ActionListType:
        """Get the available context menu actions for a given DownloadItem.

        Args:
            item: The DownloadItem to get the actions for, or None.
        """
        model = self._model()
        actions: _ActionListType = []
        if item is None:
            pass
        elif item.done:
            if item.successful:
                actions.append(("Open", item.open_file))
                actions.append(("Open directory", functools.partial(
                    item.open_file, open_dir=True, cmdline=None)))
            else:
                actions.append(("Retry", item.try_retry))
            actions.append(("Remove", item.remove))
        else:
            actions.append(("Cancel", item.cancel))

        if item is not None:
            actions.append(("Copy URL", functools.partial(
                utils.set_clipboard, item.url().toDisplayString())))
        if model.can_clear():
            actions.append((None, None))
            actions.append(("Remove all finished", model.download_clear))
        return actions

    @pyqtSlot('QPoint')
    def show_context_menu(self, point):
        """Show the context menu."""
        index = self.indexAt(point)
        if index.isValid():
            item = self._model().data(index, downloads.ModelRole.item)
        else:
            item = None
        self._menu = QMenu(self)
        actions = self._get_menu_actions(item)
        for (name, handler) in actions:
            if name is None and handler is None:
                self._menu.addSeparator()
            else:
                assert name is not None
                assert handler is not None
                action = self._menu.addAction(name)
                action.triggered.connect(handler)
        if actions:
            self._menu.popup(self.viewport().mapToGlobal(point))

    def minimumSizeHint(self):
        """Override minimumSizeHint so the size is correct in a layout."""
        return self.sizeHint()

    def sizeHint(self):
        """Return sizeHint based on the view contents."""
        idx = self._model().last_index()
        bottom = self.visualRect(idx).bottom()
        if bottom != -1:
            margins = self.contentsMargins()
            height = (bottom + margins.top() + margins.bottom() +
                      2 * self.spacing())
            size = QSize(0, height)
        else:
            size = QSize(0, 0)
        qtutils.ensure_valid(size)
        return size