from copy import deepcopy


def diff_rev(_old, _new):
	delta = {}
	if not isinstance(_old, dict):
		return delta
	for k in _new.keys():
		if k in _old:
			if isinstance(_new[k], dict):
				res = diff_rev(_old[k], _new[k])
				if len(res.keys()):
					delta[k] = res
		else:
			_old[k] = _new[k]
			delta[k] = _new[k]

	return delta


def diff_add(_old, _new):
	__old = deepcopy(_old)
	delta = diff_rev(__old, _new)
	return delta


def diff_del(_old, _new):
	delta = {}
	for k in _old:
		if k in _new:
			if isinstance(_old[k], dict) and isinstance(_new[k], dict):
				sub = diff_del(_old[k], _new[k])
				if sub:
					delta[k] = sub
		else:
			# key absent from _new: None signals "delete entire key" for dicts
			delta[k] = None if isinstance(_old[k], dict) else _old[k]
	return delta


def diff_upd(_old, _new, add_if_not_exist=False):
	delta = {}
	for k in _new.keys():
		if k in _old:
			if isinstance(_new[k], dict):
				res = diff_upd(_old[k], _new[k], add_if_not_exist)
				if len(res.keys()):
					delta[k] = res
			elif _new[k] != _old[k]:
				delta[k] = _new[k]
		elif add_if_not_exist:
			delta[k] = _new[k]

	return delta


def diff_upd_add(_old, _new):
	return diff_upd(_old, _new, add_if_not_exist=True)


def diff_full(_old, _new, combine_upd_add=True):
	diff = {}
	if combine_upd_add:
		res = diff_upd_add(_old, _new)
		if len(res.keys()):
			diff['update_add'] = res
		res = diff_del(_old, _new)
		if len(res.keys()):
			diff['delete'] = res
	else:
		res = diff_upd(_old, _new)
		if len(res.keys()):
			diff['update'] = res
		res = diff_add(_old, _new)
		if len(res.keys()):
			diff['add'] = res
		res = diff_del(_old, _new)
		if len(res.keys()):
			diff['delete'] = res

	return diff

def _legacy_assertions() -> None:
	result = diff_add({}, {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}})
	assert result == {'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}

	result = diff_add({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'})
	assert result == {}

	result = diff_add({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'})
	assert result == {}

	result = diff_add({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'd': 'icecream', 'c': 'coke'})
	assert result == {'d':'icecream'}

	result = diff_add({'a': 'hamburger', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'})
	assert result == {'b':'fries'}

	result = diff_add({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke'}}, {'c': {'f': 'coffee'}})
	assert result == {'c': {'f': 'coffee'}}

	result = diff_add({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a': 'hamburger', 'b': 'fries', 'c': {'f': 'coffee'}})
	assert result == {}

	result = diff_del({'a': 'hamburger', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'})
	assert result == {'d':'icecream'}

	result = diff_del({'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'})
	assert result == {}

	result = diff_del({'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, {'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'})
	assert result == {}

	result = diff_del({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'b': 'fries'})
	assert result == {'c':'pepsi'}

	result = diff_del({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'})
	assert result == {}

	result = diff_del({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a': 'hamburger', 'b': 'fries'})
	assert result == {'c': None}

	result = diff_del({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'coke'}})
	assert result == {'a':'hamburger', 'b':'fries', 'c': {'f': 'coffee'}}

	result = diff_del({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee'}})
	assert result == {}

	result = diff_upd({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'potatoes'})
	assert result == {'a':'hotdog', 'b':'potatoes'}

	result = diff_upd({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'pepsi'}})
	assert result == {'c': {'e': 'pepsi'}}

	result = diff_upd({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'fries'})
	assert result == {'a':'hotdog'}

	result = diff_upd({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'd': 'icecream', 'c': 'coke'})
	assert result == {'c':'coke'}

	result = diff_upd({'a': 'hamburger', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'})
	assert result == {'c':'coke'}

	result = diff_upd({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke'}}, {'c': {'f': 'coffee'}})
	assert result == {}

	result = diff_upd({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee'}})
	assert result == {'c': {'e': 'pepsi'}}

	# Update/add
	result = diff_upd_add({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'potatoes', 'd': 'icecream'})
	assert result == {'a':'hotdog', 'b':'potatoes', 'd': 'icecream'}

	result = diff_upd_add({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'pepsi', 'g': 'tea', 'h': 'cake'}, 'b':'potatoes'})
	assert result == {'b':'potatoes', 'c': {'e': 'pepsi', 'g': 'tea', 'h': 'cake'}}

	result = diff_upd_add({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'fries'})
	assert result == {'a':'hotdog'}

	result = diff_upd_add({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee'}})
	assert result == {'c': {'e': 'pepsi'}}

	#####################
	result = diff_upd_add({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'potatoes'})
	assert result == {'a':'hotdog', 'b':'potatoes'}

	result = diff_upd_add({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'pepsi'}})
	assert result == {'c': {'e': 'pepsi'}}

	result = diff_upd_add({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'fries'})
	assert result == {'a':'hotdog'}

	result = diff_upd_add({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'd': 'icecream', 'c': 'coke'})
	assert result == {'c': 'coke', 'd': 'icecream'}

	result = diff_upd_add({'a': 'hamburger', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'})
	assert result == {'b': 'fries', 'c': 'coke'}

	result = diff_upd_add({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke'}}, {'c': {'f': 'coffee'}})
	assert result == {'c': {'f': 'coffee'}}

	result = diff_upd_add({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee'}})
	assert result == {'c': {'e': 'pepsi'}}

	result = diff_upd_add({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee', 'h': 'cake'}})
	assert result == {'c': {'e': 'pepsi', 'h': 'cake'}}

	# diff_full
	combine_upd_add = False

	result = diff_full({}, {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, combine_upd_add)
	assert result == {'add': {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {'update': {'c': 'coke'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, combine_upd_add)
	assert result == {'delete': {'d': 'icecream'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'd': 'icecream', 'c': 'coke'}, combine_upd_add)
	assert result == {'add': {'d': 'icecream'}, 'delete': {'b': 'fries'}, 'update': {'c': 'coke'}}

	result = diff_full({'a': 'hamburger', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {'add': {'b': 'fries'}, 'delete': {'d': 'icecream'}, 'update': {'c': 'coke'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke'}}, {'c': {'f': 'coffee'}}, combine_upd_add)
	assert result == {'add': {'c': {'f': 'coffee'}}, 'delete': {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke'}}}

	result = diff_full({'a': 'hamburger', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {'add': {'b': 'fries'}, 'delete': {'d': 'icecream'}, 'update': {'c': 'coke'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, {'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, combine_upd_add)
	assert result == {'update': {'c': 'pepsi'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'b': 'fries'}, combine_upd_add)
	assert result == {'delete': {'c': 'pepsi'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {'update': {'c': 'coke'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a': 'hamburger', 'b': 'fries'}, combine_upd_add)
	assert result == {'delete': {'c': None}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a': 'hamburger', 'b': 'fries', 'c': {'f': 'coffee'}}, combine_upd_add)
	assert result == {'delete': {'c': {'e': 'coke'}}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'coke'}}, combine_upd_add)
	assert result == {'delete': {'a': 'hamburger', 'b': 'fries', 'c': {'f': 'coffee'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'potatoes'}, combine_upd_add)
	assert result == {'delete': {'c': None}, 'update': {'a': 'hotdog', 'b': 'potatoes'}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'pepsi'}}, combine_upd_add)
	assert result == {'delete': {'a': 'hamburger', 'b': 'fries', 'c': {'f': 'coffee'}}, 'update': {'c': {'e': 'pepsi'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'fries'}, combine_upd_add)
	assert result == {'delete': {'c': None}, 'update': {'a': 'hotdog'}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee'}}, combine_upd_add)
	assert result == {'update': {'c': {'e': 'pepsi'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'potatoes', 'd': 'icecream'}, combine_upd_add)
	assert result == {'add': {'d': 'icecream'}, 'delete': {'c': None}, 'update': {'a': 'hotdog', 'b': 'potatoes'}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'pepsi', 'g': 'tea', 'h': 'cake'}, 'b':'potatoes'}, combine_upd_add)
	assert result == {'add': {'c': {'g': 'tea', 'h': 'cake'}}, 'delete': {'a': 'hamburger', 'c': {'f': 'coffee'}}, 'update': {'b': 'potatoes', 'c': {'e': 'pepsi'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'fries'}, combine_upd_add)
	assert result == {'delete': {'c': None}, 'update': {'a': 'hotdog'}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee'}}, combine_upd_add)
	assert result == {'update': {'c': {'e': 'pepsi'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee', 'h': 'cake'}}, combine_upd_add)
	assert result == {'add': {'c': {'h': 'cake'}}, 'update': {'c': {'e': 'pepsi'}}}

	# ToDo: diff_full
	combine_upd_add = True

	result = diff_full({}, {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, combine_upd_add)
	assert result == {'update_add': {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {'update_add': {'c': 'coke'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, combine_upd_add)
	assert result == {'delete': {'d': 'icecream'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'd': 'icecream', 'c': 'coke'}, combine_upd_add)
	assert result == {'delete': {'b': 'fries'}, 'update_add': {'c': 'coke', 'd': 'icecream'}}

	result = diff_full({'a': 'hamburger', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {'delete': {'d': 'icecream'}, 'update_add': {'b': 'fries', 'c': 'coke'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke'}}, {'c': {'f': 'coffee'}}, combine_upd_add)
	assert result == {'update_add': {'c': {'f': 'coffee'}}, 'delete': {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke'}}}

	result = diff_full({'a': 'hamburger', 'c': 'pepsi', 'd': 'icecream'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {'delete': {'d': 'icecream'}, 'update_add': {'b': 'fries', 'c': 'coke'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, {'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, combine_upd_add)
	assert result == {'update_add': {'c': 'pepsi'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'b': 'fries'}, combine_upd_add)
	assert result == {'delete': {'c': 'pepsi'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': 'pepsi'}, {'a': 'hamburger', 'b': 'fries', 'c': 'coke'}, combine_upd_add)
	assert result == {'update_add': {'c': 'coke'}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a': 'hamburger', 'b': 'fries'}, combine_upd_add)
	assert result == {'delete': {'c': None}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a': 'hamburger', 'b': 'fries', 'c': {'f': 'coffee'}}, combine_upd_add)
	assert result == {'delete': {'c': {'e': 'coke'}}}

	result = diff_full({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'coke'}}, combine_upd_add)
	assert result == {'delete': {'a': 'hamburger', 'b': 'fries', 'c': {'f': 'coffee'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'potatoes'}, combine_upd_add)
	assert result == {'delete': {'c': None}, 'update_add': {'a': 'hotdog', 'b': 'potatoes'}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'pepsi'}}, combine_upd_add)
	assert result == {'delete': {'a': 'hamburger', 'b': 'fries', 'c': {'f': 'coffee'}}, 'update_add': {'c': {'e': 'pepsi'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'fries'}, combine_upd_add)
	assert result == {'delete': {'c': None}, 'update_add': {'a': 'hotdog'}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee'}}, combine_upd_add)
	assert result == {'update_add': {'c': {'e': 'pepsi'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'potatoes', 'd': 'icecream'}, combine_upd_add)
	assert result == {'delete': {'c': None}, 'update_add': {'a': 'hotdog', 'b': 'potatoes', 'd': 'icecream'}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'c': {'e': 'pepsi', 'g': 'tea', 'h': 'cake'}, 'b':'potatoes'}, combine_upd_add)
	assert result == {'delete': {'a': 'hamburger', 'c': {'f': 'coffee'}}, 'update_add': {'b': 'potatoes', 'c': {'e': 'pepsi', 'g': 'tea', 'h': 'cake'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hotdog', 'b':'fries'}, combine_upd_add)
	assert result == {'delete': {'c': None}, 'update_add': {'a': 'hotdog'}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee'}}, combine_upd_add)
	assert result == {'update_add': {'c': {'e': 'pepsi'}}}

	result = diff_full({'a':'hamburger', 'b':'fries', 'c': {'e': 'coke', 'f': 'coffee'}}, {'a':'hamburger', 'b':'fries', 'c': {'e': 'pepsi', 'f': 'coffee', 'h': 'cake'}}, combine_upd_add)
	assert result == {'update_add': {'c': {'e': 'pepsi', 'h': 'cake'}}}

if __name__ == '__main__':
	_legacy_assertions()