# http://codeblog.dhananjaynene.com/2010/08/clojure-style-multi-methods-in-python/
def multi(switcher_func):
    """ Declares a multi map based method which will switch to the
    appropriate function based on the results of the switcher func"""
    def dispatcher(*args, **kwargs):
        key = switcher_func(*args, **kwargs)
        func = dispatcher.dispatch_map[key]
        if func :
            return func(*args,**kwargs)
        else :
            raise Exception("No function defined for dispatch key: %s" % key)
    dispatcher.dispatch_map = {}
    return dispatcher

def mmethod(dispatcher, result):
    """ The multi method decorator which allows one method at a time
    to be added to the broader switch for the given result value"""
    def inner(wrapped):
        dispatcher.dispatch_map[result] = wrapped
        # Change the method name from clashing with the multi and allowing
        # all multi methods to be written using the same name
        wrapped.__name__ = "_" + wrapped.__name__ + "_" + str(result)
        return dispatcher
    return inner

    
import utils.imutils as iu #TODO: make imutils minimal.
import utils.fp as fp
import numpy as np
import cv2
from PyQt5.QtGui import QImage

load = fp.multi(lambda p,s=None: s)
NDARR = 'ndarr'
IMAGE = 'image'
MASK  = 'mask' 

@fp.mmethod(load, None)
def load(path, type=None): return QImage(path)
@fp.mmethod(load, NDARR)
def load(path, type): return iu.imread(path)
@fp.mmethod(load, IMAGE)
def load(path, type): return iu.channel3img(iu.imread(path))
@fp.mmethod(load, MASK)
def load(path, type): return mask2segmap(iu.imread(path))