import os
import util

# default callbacks
def none(window):
    return None

def last_buffer(window):
    bl = window.application.bufferlist
    if bl.hidden_buffers:
        return bl.hidden_buffers[0].name()
    else:
        return ''

def current_buffer(window):
    return window.buffer.name()

def last_replace_before(window):
    return None #XYZ
    if window.application.last_replace_before:
        return window.application.last_replace_before
    else:
        return None

def last_replace_after(window):
    return None #XYZ
    if window.application.last_replace_after:
        return window.application.last_replace_after
    else:
        return None

def current_working_dir(window):
    return util.normal_path(os.getcwd())

def path_dirname(window):
    if hasattr(window.buffer, 'path'):
        path = os.path.dirname(window.buffer.path)
        return util.normal_path(path) + '/'
    else:
        return current_working_dir(window)

# default callback builders
def build_constant(c):
    return lambda w: c

def build_mode_var(name):
    return lambda w: hasattr(w.mode, name) and getattr(w.mode, name) or ''