#  Copyright (c) 2015, Enthought, Inc.
#  All rights reserved.
#
#  This software is provided without warranty under the terms of the BSD
#  license included in enthought/LICENSE.txt and may be redistributed only
#  under the conditions described in the aforementioned license.  The license
#  is also available online at http://www.enthought.com/licenses/BSD.txt

from __future__ import absolute_import

from traits.api import (Bool, Dict, Either, Enum, Font, Instance, List,
                        Property, Str)

from traitsui.basic_editor_factory import BasicEditorFactory
from traitsui.editors.tabular_editor import TabularEditor
from traitsui.item import Item
from traitsui.tabular_adapter import TabularAdapter
from traitsui.toolkit import toolkit_object
from traitsui.ui_editor import UIEditor
from traitsui.view import View
import six


class DataFrameAdapter(TabularAdapter):
    """ Generic tabular adapter for data frames
    """

    #: The text to use for a generic entry.
    text = Property

    #: The alignment for each cell
    alignment = Property(Enum('left', 'center', 'right'))

    #: The text to use for a row index.
    index_text = Property

    #: The alignment to use for a row index.
    index_alignment = Property

    #: The font to use for each column
    font = Property

    #: The format to use for each column
    format = Property

    #: The format for each element, or a mapping column ID to format.
    _formats = Either(Str, Dict, default='%s')

    #: The font for each element, or a mapping column ID to font.
    _fonts = Either(Font, Dict, default='Courier 10')

    def _get_index_alignment(self):
        import numpy as np

        index = getattr(self.object, self.name).index
        if np.issubdtype(index.dtype, np.number):
            return 'right'
        else:
            return 'left'

    def _get_alignment(self):
        import numpy as np

        column = self.item[self.column_id]
        if np.issubdtype(column.dtype, np.number):
            return 'right'
        else:
            return 'left'

    def _get_font(self):
        if isinstance(self._fonts, toolkit_object('font_trait:TraitsFont')):
            return self._fonts
        else:
            return self._fonts.get(self.column_id, 'Courier 10')

    def _get_format(self):
        if isinstance(self._formats, six.string_types):
            return self._formats
        else:
            return self._formats.get(self.column_id, '%s')

    def _get_content(self):
        return self.item[self.column_id].iloc[0]

    def _get_text(self):
        format = self.get_format(self.object, self.name, self.row, self.column)
        return format % self.get_content(self.object, self.name, self.row,
                                         self.column)

    def _set_text(self, value):
        column = self.item[self.column_id]
        dtype = column.dtype
        value = dtype.type(value)
        column.iloc[0] = value

    def _get_index_text(self):
        return str(self.item.index[0])

    def _set_index_text(self, value):
        index = getattr(self.object, self.name).index
        dtype = index.dtype
        value = dtype.type(value)
        index.values[self.row] = value

    #---- Adapter methods that are not sensitive to item type ----------------

    def get_item(self, object, trait, row):
        """ Override the base implementation to work with DataFrames

        This returns a dataframe with one row, rather than a series, since
        using a dataframe preserves dtypes.

        """
        return getattr(object, trait).iloc[row:row + 1]

    def delete(self, object, trait, row):
        """ Override the base implementation to work with DataFrames

        Unavoidably does a copy of the data, setting the trait with the new
        value.
        """
        import pandas as pd

        df = getattr(object, trait)
        if 0 < row < len(df) - 1:
            new_df = pd.concat([df.iloc[:row,:], df.iloc[row + 1:,:]])
        elif row == 0:
            new_df = df.iloc[row + 1:,:]
        else:
            new_df = df.iloc[:row,:]
        setattr(object, trait, new_df)

    def insert(self, object, trait, row, value):
        """ Override the base implementation to work with DataFrames

        Unavoidably does a copy of the data, setting the trait with the new
        value.
        """
        import pandas as pd

        df = getattr(object, trait)
        if 0 < row < len(df) - 1:
            new_df = pd.concat([df.iloc[:row,:], value, df.iloc[row:,:]])
        elif row == 0:
            new_df = pd.concat([value, df])
        else:
            new_df = pd.concat([df, value])
        setattr(object, trait, new_df)


class _DataFrameEditor(UIEditor):
    """ TraitsUI-based editor implementation for data frames """

    # Indicate that the editor is scrollable/resizable:
    scrollable = True

    # Should column titles be displayed:
    show_titles = Bool(True)

    # The tabular adapter being used for the editor view:
    adapter = Instance(DataFrameAdapter)

    #-- Private Methods ------------------------------------------------------

    def _target_name(self, name):
        if name:
            return 'object.object.' + name
        else:
            return ''

    def _data_frame_view(self):
        """ Return the view used by the editor.
        """

        return View(
            Item(
                self._target_name(self.name),
                id='tabular_editor',
                show_label=False,
                editor=TabularEditor(
                    show_titles=self.factory.show_titles,
                    editable=self.factory.editable,
                    adapter=self.adapter,
                    selected=self._target_name(self.factory.selected),
                    selected_row=self._target_name(self.factory.selected_row),
                    selectable=self.factory.selectable,
                    multi_select=self.factory.multi_select,
                    activated=self._target_name(self.factory.activated),
                    activated_row=self._target_name(self.factory.activated_row),  # noqa
                    clicked=self._target_name(self.factory.clicked),
                    dclicked=self._target_name(self.factory.dclicked),
                    right_clicked=self._target_name(self.factory.right_clicked),  # noqa
                    right_dclicked=self._target_name(self.factory.right_dclicked),  # noqa
                    column_clicked=self._target_name(self.factory.column_clicked),  # noqa
                    column_right_clicked=self._target_name(self.factory.column_right_clicked),  # noqa
                    operations=self.factory.operations,
                    update=self._target_name(self.factory.update),
                    refresh=self._target_name(self.factory.refresh),
                )
            ),
            id='data_frame_editor',
            resizable=True
        )

    def init_ui(self, parent):
        """ Creates the Traits UI for displaying the array.
        """
        factory = self.factory
        if (factory.columns != []):
            columns = []
            for column in factory.columns:
                if isinstance(column, six.string_types):
                    title = column
                    column_id = column
                else:
                    title, column_id = column
                if column_id not in self.value.columns:
                    continue
                columns.append((title, column_id))
        else:
            columns = [(column_id, column_id)
                       for column_id in self.value.columns]

        if factory.show_index:
            index_name = self.value.index.name
            if index_name is None:
                index_name = ''
            columns.insert(0, (index_name, 'index'))

        if factory.adapter is not None:
            self.adapter = factory.adapter
            self.adapter._formats=factory.formats
            self.adapter._fonts=factory.fonts
            if not self.adapter.columns:
                self.adapter.columns = columns
        else:
            self.adapter = DataFrameAdapter(
                columns=columns,
                _formats=factory.formats,
                _fonts=factory.fonts
            )

        return self.edit_traits(
            view='_data_frame_view',
            parent=parent,
            kind='subpanel'
        )


class DataFrameEditor(BasicEditorFactory):
    """ Editor factory for basic data frame editor """

    #: The editor implementation class.
    klass = Property

    #: Should an index column be displayed.
    show_index = Bool(True)

    #: Should column headers be displayed.
    show_titles = Bool(True)

    #: Optional list of either column ID or pairs of (column title, column ID).
    columns = List()

    #: The format for each element, or a mapping column ID to format.
    formats = Either(Str, Dict, default='%s')

    #: The font for each element, or a mapping column ID to font.
    fonts = Either(Font, Dict, default='Courier 10')

    # The optional extended name of the trait to synchronize the selection
    # values with:
    selected = Str

    # The optional extended name of the trait to synchronize the selection rows
    # with:
    selected_row = Str

    # Whether or not to allow selection.
    selectable = Bool(True)

    # Whether or not to allow for multiple selections
    multi_select = Bool(False)

    # The optional extended name of the trait to synchronize the activated
    # value with:
    activated = Str

    # The optional extended name of the trait to synchronize the activated
    # value's row with:
    activated_row = Str

    # The optional extended name of the trait to synchronize left click data
    # with. The data is a TabularEditorEvent:
    clicked = Str

    # The optional extended name of the trait to synchronize left double click
    # data with. The data is a TabularEditorEvent:
    dclicked = Str

    # The optional extended name of the trait to synchronize right click data
    # with. The data is a TabularEditorEvent:
    right_clicked = Str

    # The optional extended name of the trait to synchronize right double
    # clicked data with. The data is a TabularEditorEvent:
    right_dclicked = Str

    # The optional extended name of the trait to synchronize column
    # clicked data with. The data is a TabularEditorEvent:
    column_clicked = Str

    # The optional extended name of the trait to synchronize column
    # right clicked data with. The data is a TabularEditorEvent:
    column_right_clicked = Str

    #: Whether or not the entries can be edited.
    editable = Bool(False)

    # What type of operations are allowed on the list:
    operations = List(Enum('delete', 'insert', 'append', 'edit', 'move'),
                      ['delete', 'insert', 'append', 'edit', 'move'])

    # The optional extended name of the trait used to indicate that a complete
    # table update is needed:
    update = Str

    # The optional extended name of the trait used to indicate that the table
    # just needs to be repainted.
    refresh = Str

    # Set to override the default dataframe adapter
    adapter = Instance(DataFrameAdapter)

    def _get_klass(self):
        """ The class used to construct editor objects.
        """
        return toolkit_object('data_frame_editor:_DataFrameEditor')