path: root/ranger/gui/displayable.py

# This file is part of ranger, the console file manager.
# License: GNU GPL version 3, see the file "AUTHORS" for details.

from __future__ import (absolute_import, division, print_function)

import curses

from ranger.core.shared import FileManagerAware
from ranger.gui.curses_shortcuts import CursesShortcuts


class Displayable(  # pylint: disable=too-many-instance-attributes
        FileManagerAware, CursesShortcuts):
    """Displayables are objects which are displayed on the screen.

    This is just the abstract class, defining basic operations
    such as resizing, printing, changing colors.
    Subclasses of displayable can extend these methods:

    draw() -- draw the object. Is only called if visible.
    poke() -- is called just before draw(), even if not visible.
    finalize() -- called after all objects finished drawing.
    click(event) -- called with a MouseEvent. This is called on all
        visible objects under the mouse, until one returns True.
    press(key) -- called after a key press on focused objects.
    destroy() -- called before destroying the displayable object

    Additionally, there are these methods:

    __contains__(item) -- is the item (y, x) inside the widget?

    These attributes are set:

    Modifiable:
        focused -- Focused objects receive press() calls.
        visible -- Visible objects receive draw() and finalize() calls
        need_redraw -- Should the widget be redrawn? This variable may
            be set at various places in the script and should eventually be
            handled (and unset) in the draw() method.

    Read-Only: (i.e. recommended not to change manually)
        win -- the own curses window object
        parent -- the parent (DisplayableContainer) object or None
        x, y, wid, hei -- absolute coordinates and boundaries
        settings, fm -- inherited shared variables
    """

    def __init__(self, win,  # pylint: disable=super-init-not-called
                 env=None, fm=None, settings=None):
        from ranger.gui.ui import UI

        if env is not None:
            self.env = env
        if fm is not None:
            self.fm = fm
        if settings is not None:
            self.settings = settings

        self.need_redraw = True
        self.focused = False
        self.visible = True
        self.x = 0
        self.y = 0
        self.wid = 0
        self.hei = 0
        self.paryx = (0, 0)
        self.parent = None

        self._old_visible = self.visible

        if win is not None:
            if isinstance(self, UI):
                self.win = win
            else:
                self.win = win.derwin(1, 1, 0, 0)

    def __nonzero__(self):
        """Always True"""
        return True
    __bool__ = __nonzero__

    def __contains__(self, item):
        """Checks if item is inside the boundaries.

        item can be an iterable like [y, x] or an object with x and y methods.
        """
        try:
            y, x = item.y, item.x
        except AttributeError:
            try:
                y, x = item
            except (ValueError, TypeError):
                return False

        return self.contains_point(y, x)

    def draw(self):
        """Draw the oject.

        Called on every main iteration if visible.  Containers should call
        draw() on their contained objects here.  Override this!
        """

    def destroy(self):
        """Called when the object is destroyed."""
        self.win = None

    def contains_point(self, y, x):
        """Test whether the point lies inside this object.

        x and y should be absolute coordinates.
        """
        return (x >= self.x and x < self.x + self.wid) and \
            (y >= self.y and y < self.y + self.hei)

    def click(self, event):
        """Called when a mouse key is pressed and self.focused is True.

        Override this!
        """
        pass

    def press(self, key):
        """Called when a key is pressed and self.focused is True.

        Override this!
        """
        pass

    def poke(self):
        """Called before drawing, even if invisible"""
        if self._old_visible != self.visible:
            self._old_visible = self.visible
            self.need_redraw = True

            if not self.visible:
                self.win.erase()

    def finalize(self):
        """Called after every displayable is done drawing.

        Override this!
        """
        pass

    def resize(self, y, x, hei=None, wid=None):
        """Resize the widget"""
        do_move = True
        try:
            maxy, maxx = self.fm.ui.termsize
        except TypeError:
            pass
        else:
            if hei is None:
                hei = maxy - y

            if wid is None:
                wid = maxx - x

            if x < 0 or y < 0:
                self.fm.notify("Warning: Subwindow origin below zero for <%s> "
                               "(x = %d, y = %d)" % (self, x, y), bad=True)

            if x + wid > maxx or y + hei > maxy:
                self.fm.notify(
                    "Warning: Subwindow size out of bounds for <%s> "
                    "(x = %d, y = %d, hei = %d, wid = %d)" % (self, x, y, hei, wid),
                    bad=True,
                )

        window_is_cleared = False

        if hei != self.hei or wid != self.wid:
            # log("resizing " + str(self))
            self.win.erase()
            self.need_redraw = True
            window_is_cleared = True
            try:
                self.win.resize(hei, wid)
            except curses.error:
                # Not enough space for resizing...
                try:
                    self.win.mvderwin(0, 0)
                    do_move = True
                    self.win.resize(hei, wid)
                except curses.error:
                    pass
                    # raise ValueError("Resizing Failed!")

            self.hei, self.wid = self.win.getmaxyx()

        if do_move or y != self.paryx[0] or x != self.paryx[1]:
            if not window_is_cleared:
                self.win.erase()
                self.need_redraw = True
            # log("moving " + str(self))
            try:
                self.win.mvderwin(y, x)
            except curses.error:
                pass

            self.paryx = self.win.getparyx()
            self.y, self.x = self.paryx
            if self.parent:
                self.y += self.parent.y
                self.x += self.parent.x

    def __str__(self):
        return self.__class__.__name__


class DisplayableContainer(Displayable):
    """DisplayableContainers are Displayables which contain other Displayables.

    This is also an abstract class. The methods draw, poke, finalize,
    click, press and destroy are extended here and will recursively
    call the function on all contained objects.

    New methods:

    add_child(object) -- add the object to the container.
    replace_child(old_obj, new_obj) -- replaces old object with new object.
    remove_child(object) -- remove the object from the container.

    New attributes:

    container -- a list with all contained objects (rw)
    """

    def __init__(self, win, env=None, fm=None, settings=None):
        if env is not None:
            self.env = env
        if fm is not None:
            self.fm = fm
        if settings is not None:
            self.settings = settings

        self.container = []

        Displayable.__init__(self, win)

    # ------------------------------------ extended or overidden methods

    def poke(self):
        """Recursively called on objects in container"""
        Displayable.poke(self)
        for displayable in self.container:
            displayable.poke()

    def draw(self):
        """Recursively called on visible objects in container"""
        for displayable in self.container:
            if self.need_redraw:
                displayable.need_redraw = True
            if displayable.visible:
                displayable.draw()

        self.need_redraw = False

    def finalize(self):
        """Recursively called on visible objects in container"""
        for displayable in self.container:
            if displayable.visible:
                displayable.finalize()

    def press(self, key):
        """Recursively called on objects in container"""
        focused_obj = self._get_focused_obj()

        if focused_obj:
            focused_obj.press(key)
            return True
        return False

    def click(self, event):
        """Recursively called on objects in container"""
        focused_obj = self._get_focused_obj()
        if focused_obj and focused_obj.click(event):
            return True

        for displayable in self.container:
            if displayable.visible and event in displayable:
                if displayable.click(event):
                    return True

        return False

    def destroy(self):
        """Recursively called on objects in container"""
        for displayable in self.container:
            displayable.destroy()

    # ----------------------------------------------- new methods

    def add_child(self, obj):
        """Add the objects to the container."""
        if obj.parent:
            obj.parent.remove_child(obj)
        self.container.append(obj)
        obj.parent = self

    def replace_child(self, old_obj, new_obj):
        """Replace the old object with the new instance in the container."""
        self.container[self.container.index(old_obj)] = new_obj
        new_obj.parent = self

    def remove_child(self, obj):
        """Remove the object from the container."""
        try:
            self.container.remove(obj)
        except ValueError:
            pass
        else:
            obj.parent = None

    def _get_focused_obj(self):
        # Finds a focused displayable object in the container.
        for displayable in self.container:
            if displayable.focused:
                return displayable
            try:
                obj = displayable._get_focused_obj()  # pylint: disable=protected-access
            except AttributeError:
                pass
            else:
                if obj is not None:
                    return obj
        return None