# Source code for urwidtrees.decoration

    # Copyright (C) 2013  Patrick Totzke <patricktotzke@gmail.com>
    # This file is released under the GNU GPL, version 3 or a later revision.
    from .tree import Tree, SimpleTree
    import urwid
    import logging

    NO_SPACE_MSG = 'too little space for requested decoration'

    class TreeDecorationError(Exception):
        pass

    class DecoratedTree(Tree):
        """
        :class:`Tree` that wraps around another :class:`Tree` and allows to read
        original content as well as decorated versions thereof.
        """
        def __init__(self, content):
            if not isinstance(content, Tree):
                # do we need this?
                content = SimpleTree(content)
            self._tree = content
            self.root = self._tree.root

        def get_decorated(self, pos):
            """
            return widget that consists of the content of original tree at given
            position plus its decoration.
            """
            return self.decorate(pos, self[pos])

        def decorate(self, pos, widget, is_first=True):
            """
            decorate `widget` according to a position `pos` in the original tree.
            setting `is_first` to False indicates that we are decorating a line
            that is *part* of the (multi-line) content at this position, but not
            the first part. This allows to omit incoming arrow heads for example.
            """
            return widget

        # pass on everything else to the original tree.

        def parent_position(self, pos):
            return self._tree.parent_position(pos)

        def first_child_position(self, pos):
            return self._tree.first_child_position(pos)

        def last_child_position(self, pos):
            return self._tree.last_child_position(pos)

        def next_sibling_position(self, pos):
            return self._tree.next_sibling_position(pos)

        def prev_sibling_position(self, pos):
            return self._tree.prev_sibling_position(pos)

        def __getitem__(self, pos):
            return self._tree[pos]

    class CollapseMixin(object):
        """
        Mixin for :class:`Tree` that allows to collapse subtrees.

        This works by overwriting
        :meth:`[first|last]_child_position <first_child_position>`, forcing them to
        return `None` if the given position is considered collapsed. We use a
        (given) callable `is_collapsed` that accepts positions and returns a
        boolean to determine which node is considered collapsed.
        """
        def __init__(self, is_collapsed=lambda pos: False,
                     **kwargs):
            self._initially_collapsed = is_collapsed
            self._divergent_positions = []

        def is_collapsed(self, pos):
            """checks if given position is currently collapsed"""
            collapsed = self._initially_collapsed(pos)
            if pos in self._divergent_positions:
                collapsed = not collapsed
            return collapsed

        # implement functionality by overwriting local position transformations

        # TODO: ATM this assumes we are in a wrapper: it uses self._tree.
        # This is not necessarily true, for example for subclasses of SimpleTree!
        # maybe define this whole class as a wrapper?

        def last_child_position(self, pos):
            if self.is_collapsed(pos):
                return None
            return self._tree.last_child_position(pos)

        def first_child_position(self, pos):
            if self.is_collapsed(pos):
                return None
            return self._tree.first_child_position(pos)

        def collapsible(self, pos):
            return not self._tree.is_leaf(pos)

        def set_position_collapsed(self, pos, is_collapsed):
            if self.collapsible(pos):
                if self._initially_collapsed(pos) == is_collapsed:
                    if pos in self._divergent_positions:
                        self._divergent_positions.remove(pos)
                else:
                    if pos not in self._divergent_positions:
                        self._divergent_positions.append(pos)

        def toggle_collapsed(self, pos):
            self.set_position_collapsed(pos, not self.is_collapsed(pos))

        def collapse(self, pos):
            self.set_position_collapsed(pos, True)

        def collapse_all(self):
            self.set_collapsed_all(True)

        def expand_all(self):
            self.set_collapsed_all(False)

        def set_collapsed_all(self, is_collapsed):
            self._initially_collapsed = lambda x: is_collapsed
            self._divergent_positions = []

        def expand(self, pos):
            self.set_position_collapsed(pos, False)

    class CollapseIconMixin(CollapseMixin):
        """
        Mixin for :class:`Tree` that allows to collapse subtrees and use
        an indicator icon in line decorations.
        This Mixin adds the ability to construct collapse-icon for a
        position, indicating its collapse status to :class:`CollapseMixin`.
        """
        def __init__(self,
                     is_collapsed=lambda pos: False,
                     icon_collapsed_char='+',
                     icon_expanded_char='-',
                     icon_collapsed_att=None,
                     icon_expanded_att=None,
                     icon_frame_left_char='[',
                     icon_frame_right_char=']',
                     icon_frame_att=None,
                     icon_focussed_att=None,
                     **kwargs):
            """TODO: docstrings"""
            CollapseMixin.__init__(self, is_collapsed, **kwargs)
            self._icon_collapsed_char = icon_collapsed_char
            self._icon_expanded_char = icon_expanded_char
            self._icon_collapsed_att = icon_collapsed_att
            self._icon_expanded_att = icon_expanded_att
            self._icon_frame_left_char = icon_frame_left_char
            self._icon_frame_right_char = icon_frame_right_char
            self._icon_frame_att = icon_frame_att
            self._icon_focussed_att = icon_focussed_att

        def _construct_collapse_icon(self, pos):
            width = 0
            widget = None
            char = self._icon_expanded_char
            charatt = self._icon_expanded_att
            if self.is_collapsed(pos):
                char = self._icon_collapsed_char
                charatt = self._icon_collapsed_att
            if char is not None:

                columns = []
                if self._icon_frame_left_char is not None:
                    lchar = self._icon_frame_left_char
                    charlen = len(lchar)
                    leftframe = urwid.Text((self._icon_frame_att, lchar))
                    columns.append((charlen, leftframe))
                    width += charlen

                # next we build out icon widget: we feed all markups to a Text,
                # make it selectable (to toggle collapse) if requested
                markup = (charatt, char)
                widget = urwid.Text(markup)
                charlen = len(char)
                columns.append((charlen, widget))
                width += charlen

                if self._icon_frame_right_char is not None:
                    rchar = self._icon_frame_right_char
                    charlen = len(rchar)
                    rightframe = urwid.Text((self._icon_frame_att, rchar))
                    columns.append((charlen, rightframe))
                    width += charlen

                widget = urwid.Columns(columns)
            return width, widget

    class CollapsibleTree(CollapseMixin, DecoratedTree):
        """Undecorated Tree that allows to collapse subtrees"""
        def __init__(self, tree, **kwargs):
            DecoratedTree.__init__(self, tree)
            CollapseMixin.__init__(self, **kwargs)

    class IndentedTree(DecoratedTree):
        """Indent tree nodes according to their depth in the tree"""
        def __init__(self, tree, indent=2):
            """
            :param tree: tree of widgets to be displayed
            :type tree: Tree
            :param indent: indentation width
            :type indent: int
            """
            self._indent = indent
            DecoratedTree.__init__(self, tree)

        def decorate(self, pos, widget, is_first=True):
            line = None
            indent = self._tree.depth(pos) * self._indent
            cols = [(indent, urwid.SolidFill(' ')), widget]
            # construct a Columns, defining all spacer as Box widgets
            line = urwid.Columns(cols, box_columns=range(len(cols))[:-1])
            return line

    class CollapsibleIndentedTree(CollapseIconMixin, IndentedTree):
        """
        Indent collapsible tree nodes according to their depth in the tree and
        display icons indicating collapse-status in the gaps.
        """
        def __init__(self, walker, icon_offset=1, indent=4, **kwargs):
            """
            :param walker: tree of widgets to be displayed
            :type walker: Tree
            :param indent: indentation width
            :type indent: int
            :param icon_offset: distance from icon to the eginning of the tree
                                node.
            :type icon_offset: int
            """
            self._icon_offset = icon_offset
            IndentedTree.__init__(self, walker, indent=indent)
            CollapseIconMixin.__init__(self, **kwargs)

        def decorate(self, pos, widget, is_first=True):
            """
            builds a list element for given position in the tree.
            It consists of the original widget taken from the Tree and some
            decoration columns depending on the existence of parent and sibling
            positions. The result is a urwid.Culumns widget.
            """
            void = urwid.SolidFill(' ')
            line = None
            cols = []
            depth = self._tree.depth(pos)

            # add spacer filling all but the last indent
            if depth > 0:
                cols.append((depth * self._indent, void)),  # spacer

            # construct last indent
            # TODO
            iwidth, icon = self._construct_collapse_icon(pos)
            available_space = self._indent
            firstindent_width = self._icon_offset + iwidth

            # stop if indent is too small for this decoration
            if firstindent_width > available_space:
                raise TreeDecorationError(NO_SPACE_MSG)

            # add icon only for non-leafs
            is_leaf = self._tree.is_leaf(pos)
            if not is_leaf:
                if icon is not None:
                    # space to the left
                    cols.append((available_space - firstindent_width,
                                 urwid.SolidFill(' ')))
                    # icon
                    icon_pile = urwid.Pile([('pack', icon), void])
                    cols.append((iwidth, icon_pile))
                    # spacer until original widget
                    available_space = self._icon_offset
                cols.append((available_space, urwid.SolidFill(' ')))
            else:  # otherwise just add another spacer
                cols.append((self._indent, urwid.SolidFill(' ')))

            cols.append(widget)  # original widget ]
            # construct a Columns, defining all spacer as Box widgets
            line = urwid.Columns(cols, box_columns=range(len(cols))[:-1])

            return line

    class ArrowTree(IndentedTree):
        """
        Decorates the tree by indenting nodes according to their depth and using
        the gaps to draw arrows indicate the tree structure.
        """
        def __init__(self, walker,
                     indent=3,
                     childbar_offset=0,
                     arrow_hbar_char=u'\u2500',
                     arrow_hbar_att=None,
                     arrow_vbar_char=u'\u2502',
                     arrow_vbar_att=None,
                     arrow_tip_char=u'\u27a4',
                     arrow_tip_att=None,
                     arrow_att=None,
                     arrow_connector_tchar=u'\u251c',
                     arrow_connector_lchar=u'\u2514',
                     arrow_connector_att=None, **kwargs):
            """
            :param walker: tree of widgets to be displayed
            :type walker: Tree
            :param indent: indentation width
            :type indent: int
            """
            IndentedTree.__init__(self, walker, indent)
            self._childbar_offset = childbar_offset
            self._arrow_hbar_char = arrow_hbar_char
            self._arrow_hbar_att = arrow_hbar_att
            self._arrow_vbar_char = arrow_vbar_char
            self._arrow_vbar_att = arrow_vbar_att
            self._arrow_connector_lchar = arrow_connector_lchar
            self._arrow_connector_tchar = arrow_connector_tchar
            self._arrow_connector_att = arrow_connector_att
            self._arrow_tip_char = arrow_tip_char
            self._arrow_tip_att = arrow_tip_att
            self._arrow_att = arrow_att

        def _construct_spacer(self, pos, acc):
            """
            build a spacer that occupies the horizontally indented space between
            pos's parent and the root node. It will return a list of tuples to be
            fed into a Columns widget.
            """
            parent = self._tree.parent_position(pos)
            if parent is not None:
                grandparent = self._tree.parent_position(parent)
                if self._indent > 0 and grandparent is not None:
                    parent_sib = self._tree.next_sibling_position(parent)
                    draw_vbar = parent_sib is not None and \
                        self._arrow_vbar_char is not None
                    space_width = self._indent - 1 * (draw_vbar) - self._childbar_offset
                    if space_width > 0:
                        void = urwid.AttrMap(urwid.SolidFill(' '), self._arrow_att)
                        acc.insert(0, ((space_width, void)))
                    if draw_vbar:
                        barw = urwid.SolidFill(self._arrow_vbar_char)
                        bar = urwid.AttrMap(barw, self._arrow_vbar_att or
                                            self._arrow_att)
                        acc.insert(0, ((1, bar)))
                return self._construct_spacer(parent, acc)
            else:
                return acc

        def _construct_connector(self, pos):
            """
            build widget to be used as "connector" bit between the vertical bar
            between siblings and their respective horizontal bars leading to the
            arrow tip
            """
            # connector symbol, either L or |- shaped.
            connectorw = None
            connector = None
            if self._tree.next_sibling_position(pos) is not None:  # |- shaped
                if self._arrow_connector_tchar is not None:
                    connectorw = urwid.Text(self._arrow_connector_tchar)
            else:  # L shaped
                if self._arrow_connector_lchar is not None:
                    connectorw = urwid.Text(self._arrow_connector_lchar)
            if connectorw is not None:
                att = self._arrow_connector_att or self._arrow_att
                connector = urwid.AttrMap(connectorw, att)
            return connector

        def _construct_arrow_tip(self, pos):
            """returns arrow tip as (width, widget)"""
            arrow_tip = None
            width = 0
            if self._arrow_tip_char:
                txt = urwid.Text(self._arrow_tip_char)
                arrow_tip = urwid.AttrMap(
                    txt, self._arrow_tip_att or self._arrow_att)
                width = len(self._arrow_tip_char)
            return width, arrow_tip

        def _construct_first_indent(self, pos):
            """
            build spacer to occupy the first indentation level from pos to the
            left. This is separate as it adds arrowtip and sibling connector.
            """
            cols = []
            void = urwid.AttrMap(urwid.SolidFill(' '), self._arrow_att)
            available_width = self._indent

            if self._tree.depth(pos) > 0:
                connector = self._construct_connector(pos)
                if connector is not None:
                    width = connector.pack()[0]
                    if width > available_width:
                        raise TreeDecorationError(NO_SPACE_MSG)
                    available_width -= width
                    if self._tree.next_sibling_position(pos) is not None:
                        barw = urwid.SolidFill(self._arrow_vbar_char)
                        below = urwid.AttrMap(barw, self._arrow_vbar_att or
                                              self._arrow_att)
                    else:
                        below = void
                    # pile up connector and bar
                    spacer = urwid.Pile([('pack', connector), below])
                    cols.append((width, spacer))

                #arrow tip
                awidth, at = self._construct_arrow_tip(pos)
                if at is not None:
                    if awidth > available_width:
                        raise TreeDecorationError(NO_SPACE_MSG)
                    available_width -= awidth
                    at_spacer = urwid.Pile([('pack', at), void])
                    cols.append((awidth, at_spacer))

                # bar between connector and arrow tip
                if available_width > 0:
                    barw = urwid.SolidFill(self._arrow_hbar_char)
                    bar = urwid.AttrMap(
                        barw, self._arrow_hbar_att or self._arrow_att)
                    hb_spacer = urwid.Pile([(1, bar), void])
                    cols.insert(1, (available_width, hb_spacer))
            return cols

        def decorate(self, pos, widget, is_first=True):
            """
            builds a list element for given position in the tree.
            It consists of the original widget taken from the Tree and some
            decoration columns depending on the existence of parent and sibling
            positions. The result is a urwid.Culumns widget.
            """
            line = None
            if pos is not None:
                original_widget = widget
                cols = self._construct_spacer(pos, [])

                # Construct arrow leading from parent here,
                # if we have a parent and indentation is turned on
                if self._indent > 0:
                    if is_first:
                        indent = self._construct_first_indent(pos)
                        if indent is not None:
                            cols = cols + indent
                    else:
                        parent = self._tree.parent_position(pos)
                        if self._indent > 0 and parent is not None:
                            parent_sib = self._tree.next_sibling_position(pos)
                            draw_vbar = parent_sib is not None
                            void = urwid.AttrMap(urwid.SolidFill(' '),
                                                 self._arrow_att)
                            if self._childbar_offset > 0:
                                cols.append((self._childbar_offset, void))
                            if draw_vbar:
                                barw = urwid.SolidFill(self._arrow_vbar_char)
                                bar = urwid.AttrMap(
                                    barw, self._arrow_vbar_att or self._arrow_att)
                                rspace_width = self._indent - \
                                    1 - self._childbar_offset
                                cols.append((1, bar))
                                cols.append((rspace_width, void))
                            else:
                                cols.append((self._indent, void))

                # add the original widget for this line
                cols.append(original_widget)
                # construct a Columns, defining all spacer as Box widgets
                line = urwid.Columns(cols, box_columns=range(len(cols))[:-1])
            return line

    class CollapsibleArrowTree(CollapseIconMixin, ArrowTree):
        """Arrow-decoration that allows collapsing subtrees"""
        def __init__(self, treelistwalker, icon_offset=0, indent=5, **kwargs):
            self._icon_offset = icon_offset
            ArrowTree.__init__(self, treelistwalker, indent, **kwargs)
            CollapseIconMixin.__init__(self, **kwargs)

        def _construct_arrow_tip(self, pos):

            cols = []
            overall_width = self._icon_offset

            if self._icon_offset > 0:
                # how often we repeat the hbar_char until width icon_offset is
                # reached
                hbar_char_count = len(self._arrow_hbar_char) / self._icon_offset
                barw = urwid.Text(self._arrow_hbar_char * hbar_char_count)
                bar = urwid.AttrMap(barw, self._arrow_hbar_att or self._arrow_att)
                cols.insert(1, (self._icon_offset, bar))

            # add icon only for non-leafs
            if self.collapsible(pos):
                iwidth, icon = self._construct_collapse_icon(pos)
                if icon is not None:
                    cols.insert(0, (iwidth, icon))
                    overall_width += iwidth

            # get arrow tip
            awidth, tip = ArrowTree._construct_arrow_tip(self, pos)
            if tip is not None:
                cols.append((awidth, tip))
                overall_width += awidth

            return overall_width, urwid.Columns(cols)