from tuikit.core.coords import Point, Size

from tuikit.core.theme import default_theme

from tuikit.core.signal import Signal

import logging

class Widget:

    """Base class for all widgets."""

    _num_instances = 0

    def __init__(self):

        self._num_instances += 1

        #: Widget name is used for logging etc. Not visible anywhere.

        self.name = '{}{}'.format(

            self.__class__.__name__,

            self._num_instances)

        #: Parent Widget

        self.parent = None

        #: Window owning this Widget

        self.window = None

        #: Theme

        self.theme = default_theme

        #: Position inside parent widget. Modified by layout manager.

        self.pos = Point()

        #: Actual size. Modified by layout manager.

        self._size = Size(10, 10)

        #: Requested size. Layout manager will use this when placing the widget.

        self.sizereq = Size(1, 1)

        #: Minimal size of widget. Widget will never be sized smaller than this.

        self.sizemin = Size(1, 1)

        #: Maximum size of widget. Widget will never be sized bigger than this.

        #: None means no maximum size (infinite).

        self.sizemax = Size(None, None)

        #: Cursor is position where text input will occur.

        #: Hidden widget does not affect layout.

        self.hidden = False

        #: Allow keyboard focus for this widget.

        self.allow_focus = False

        self.sig_keypress = Signal(allow_stop=True)

    ## position and size ##

    @property

    def x(self):

        return self.pos.x

    @property

    def y(self):

        return self.pos.y

    @property

    def width(self):

        return self.size.w

    @property

    def height(self):

        return self.size.h

    @property

    def size(self):

        return self._size.readonly()

    def resize(self, w, h):

        self._size.update(w, h)

    ## drawing, looks ##

    def draw(self, buffer):

        """Draw self into buffer."""

        self.log.debug('Draw into %r at %s (exposed %s)',

                       buffer, buffer.origin, self.exposed(buffer))

    def set_theme(self, theme):

        self.theme = theme

    @staticmethod

    def exposed(buffer):

        """Exposed part of widget.

        Only this area needs to be drawn.

        Returns exposed Rect in widget's local coordinates,

        where 0,0 is left top corner of widget to be drawn.

        """

        return buffer.clip_rect.moved(-buffer.origin.x, -buffer.origin.y)

    @property

    def cursor(self):

    ## events ##

    def resize_event(self, ev):

        self.resize(ev.w, ev.h)

    def keypress_event(self, ev):

        """Keypress event handler.

        Override to accept keyboard input.

        Returns True if event was consumed.

        Call this implementation from inherited classes

        if it does not consume the event.

        """

        if self.sig_keypress(ev):

            return True

        self.log.debug('Not consumed: %s', ev)

    ## timeouts ##

    def add_timeout(self, delay, callback, *args):

        """Register `callback` to be called after `delay` seconds."""

        self.parent.add_timeout(self, delay, callback, *args)

    def remove_timeout(self, callback, *args):

        """Unregister callback previously registered with add_timeout.

        Removes all timeouts with the `callback` and `args`.

        """

        self.parent.remove_timeout(self, callback, *args)

    ## focus ##

    def can_focus(self):

        return not self.hidden and self.allow_focus

    def has_focus(self):

        if self.parent is None:

            return True

        return (self.parent.has_focus()

            and self.parent.focus_widget == self)

    ## utilities ##

    @property

    def log(self):

        return logging.getLogger('tuikit.' + self.name)