from tuikit.core.coords import Point, Size, Rect
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 = '%s#%s' % (self.__class__.__name__, self._num_instances)

        #: Parent Widget
        self.parent = None
        #: Window owning this Widget
        self.window = None
        #: Theme
        self.theme = default_theme
        #: Timer
        self.timer = None

        #: 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.
        #: The cursor coordinates are relative to widget.
        self._cursor = Point()
        #: Cursor is displayed on screen only when the widget is focused.
        self._cursor_visible = False

        #: True if this widget requests redraw
        self.need_draw = True
        #: 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

    def move(self, x, y):
        """Should be called only by layout manager."""
        self.pos.update(x, y)

    @property
    def width(self):
        return self.size.w

    @property
    def height(self):
        return self.size.h

    @property
    def size(self):
        return self._size.immutable()

    def resize(self, w, h):
        """Should be called only by layout manager."""
        self._size.update(w, h)

    @property
    def boundaries(self):
        return Rect(self.pos, self._size)

    # -------------------------------------------------------------------------
    #   Presentation

    def draw_if_needed(self, buffer):
        if self.need_draw:
            self.draw(buffer)

    def draw(self, buffer):
        """Draw self into buffer."""
        self.log.debug('Draw into %r at %s (exposed %s)',
                       buffer, buffer.origin, self.exposed(buffer))
        self.need_draw = False

    def redraw(self):
        """Request redraw."""
        self.need_draw = True

    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):
        """Return cursor coordinates.
        
        Returns None if cursor is set outside of widget boundaries.
        
        """
        if self._cursor in Rect(0, 0, *self._size):
            return self._cursor

    @property
    def cursor_visible(self):
        return self._cursor_visible

    # -------------------------------------------------------------------------
    #   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.

        Return True if event was consumed.

        Call parent implementation from inherited classes
        when not consuming the event.

        """
        if self.sig_keypress(ev):
            return True
        self.log.debug('Not consumed: %s', ev)

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

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

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

    # -------------------------------------------------------------------------
    #   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):
        """Logger for widget debugging.
        
        Logger name contains full module name, class name and instance number.
        
        """
        return logging.getLogger('%s.%s' % (self.__module__, self.name))