# -*- coding: utf-8 -*-
# -----------------------------------------------------------------------------
# Copyright (c) 2016 Pepijn Kenter.
# Copyright (c) 2019- Spyder Project Contributors
#
# Components of objectbrowser originally distributed under
# the MIT (Expat) license. Licensed under the terms of the MIT License;
# see NOTICE.txt in the Spyder root directory for details
# -----------------------------------------------------------------------------

# Standard library imports
import logging

# Third-party imports
from qtpy.QtCore import Qt, Signal, Slot
from qtpy.QtWidgets import (QAbstractItemView, QAction, QActionGroup,
                            QHeaderView, QTableWidget, QTreeView, QTreeWidget)

# Local imports
from spyder.config.base import _

logger = logging.getLogger(__name__)


# Toggle mixin
class ToggleColumnMixIn(object):
    """
    Adds actions to a QTableView that can show/hide columns
    by right clicking on the header
    """
    def add_header_context_menu(self, checked=None, checkable=None,
                                enabled=None):
        """
        Adds the context menu from using header information

        checked can be a header_name -> boolean dictionary. If given, headers
        with the key name will get the checked value from the dictionary.
        The corresponding column will be hidden if checked is False.

        checkable can be a header_name -> boolean dictionary. If given, headers
        with the key name will get the checkable value from the dictionary.

        enabled can be a header_name -> boolean dictionary. If given, headers
        with the key name will get the enabled value from the dictionary.
        """
        checked = checked if checked is not None else {}
        checkable = checkable if checkable is not None else {}
        enabled = enabled if enabled is not None else {}

        horizontal_header = self._horizontal_header()
        horizontal_header.setContextMenuPolicy(Qt.ActionsContextMenu)

        self.toggle_column_actions_group = QActionGroup(self)
        self.toggle_column_actions_group.setExclusive(False)
        self.__toggle_functions = []  # for keeping references

        for col in range(horizontal_header.count()):
            column_label = self.model().headerData(col, Qt.Horizontal,
                                                   Qt.DisplayRole)
            logger.debug("Adding: col {}: {}".format(col, column_label))
            action = QAction(str(column_label),
                             self.toggle_column_actions_group,
                             checkable=checkable.get(column_label, True),
                             enabled=enabled.get(column_label, True),
                             toolTip=_("Shows or hides "
                                       "the {} column").format(column_label))
            func = self.__make_show_column_function(col)
            self.__toggle_functions.append(func)  # keep reference
            horizontal_header.addAction(action)
            is_checked = checked.get(
                column_label,
                not horizontal_header.isSectionHidden(col))
            horizontal_header.setSectionHidden(col, not is_checked)
            action.setChecked(is_checked)
            action.toggled.connect(func)

    def get_header_context_menu_actions(self):
        """Returns the actions of the context menu of the header."""
        return self._horizontal_header().actions()

    def _horizontal_header(self):
        """
        Returns the horizontal header (of type QHeaderView).

        Override this if the horizontalHeader() function does not exist.
        """
        return self.horizontalHeader()

    def __make_show_column_function(self, column_idx):
        """Creates a function that shows or hides a column."""
        show_column = lambda checked: self.setColumnHidden(column_idx,
                                                           not checked)
        return show_column

    def read_view_settings(self, key, settings=None, reset=False):
        """
        Reads the persistent program settings

        :param reset: If True, the program resets to its default settings
        :returns: True if the header state was restored, otherwise returns
                  False
        """
        logger.debug("Reading view settings for: {}".format(key))
        header_restored = False
        # TODO: Implement settings management
#        if not reset:
#            if settings is None:
#                settings = get_qsettings()
#            horizontal_header = self._horizontal_header()
#            header_data = settings.value(key)
#            if header_data:
#                header_restored = horizontal_header.restoreState(header_data)
#
#            # update actions
#            for col, action in enumerate(horizontal_header.actions()):
#                is_checked = not horizontal_header.isSectionHidden(col)
#                action.setChecked(is_checked)

        return header_restored

    def write_view_settings(self, key, settings=None):
        """Writes the view settings to the persistent store."""
        logger.debug("Writing view settings for: {}".format(key))
#       TODO: Settings management
#        if settings is None:
#            settings = get_qsettings()
#        settings.setValue(key, self._horizontal_header().saveState())


class ToggleColumnTableWidget(QTableWidget, ToggleColumnMixIn):
    """
    A QTableWidget where right clicking on the header allows the user
    to show/hide columns.
    """
    pass


class ToggleColumnTreeWidget(QTreeWidget, ToggleColumnMixIn):
    """
    A QTreeWidget where right clicking on the header allows the user to
    show/hide columns.
    """
    def _horizontal_header(self):
        """
        Returns the horizontal header (of type QHeaderView).

        Override this if the horizontalHeader() function does not exist.
        """
        return self.header()


class ToggleColumnTreeView(QTreeView, ToggleColumnMixIn):
    """
    A QTreeView where right clicking on the header allows the user to
    show/hide columns.
    """

    def __init__(self, readonly=False):
        QTreeView.__init__(self)
        self.readonly = readonly
        from spyder.plugins.variableexplorer.widgets.collectionsdelegate \
            import ToggleColumnDelegate
        self.setItemDelegate(ToggleColumnDelegate(self))
        self.setEditTriggers(QAbstractItemView.DoubleClicked)
        self.expanded.connect(self.resize_columns_to_contents)
        self.collapsed.connect(self.resize_columns_to_contents)

    @Slot()
    def resize_columns_to_contents(self):
        """Resize all the columns to its contents."""
        self._horizontal_header().resizeSections(QHeaderView.ResizeToContents)

    def _horizontal_header(self):
        """
        Returns the horizontal header (of type QHeaderView).

        Override this if the horizontalHeader() function does not exist.
        """
        return self.header()