__author__ = 'RemiZOffAlex'
__email__ = 'remizoffalex@mail.ru'

from uuid import uuid4


def closure_include(name):
    def closure_filter(closure):
        return closure['child']==name
    return closure_filter


def closure_exclude(name):
    def closure_filter(closure):
        return closure['child']!=name
    return closure_filter


def scope_addition(context, parent = None):
    name = str(uuid4())
    context.scopes[name] = {}
    if parent:
        context.closures.append({
            'parent': parent,
            'child': name
        })
    else:
        context.closures.append({
            'parent': context.current,
            'child': name
        })
    return name

# def scope_del(context, name):
#     closures = []
#     for item in context.closures:
#         if item['child'] != name:
#             closures.append(item)
#     context.closures = closures
#     del context.scopes[name]

def scope_del(context, name):
    if name in context.scopes:
        context.closures = list(
            filter(
                closure_exclude,
                context.closures
            )
        )
        del context.scopes[name]
        return
    raise Exception('Область видимости {} не найдена'.format(name))

def variable_addition(context, name, value = None):
    current = context.scopes[context.current]
    if name in current:
        raise Exception('Double declaration of the variable %s' % name)
    current[name] = value


def variable_delete(context, name):
    current = context.scopes[context.current]
    if name in current:
        del current[name]
    raise Exception('Переменная {} не найдена'.format(name))


def variable_exist(context, name):
    current = context.scopes[context.current]
    return name in current


def variable_get(context, name):
    scope = context.scopes[context.current]
    if name in scope:
        result = scope[name]
        return result
    stack = []
    if context.current != 'root':
        stack.append(context.current)
    while len(stack) > 0:
        scope_name = stack.pop()
        closures = list(
            filter(
                closure_include(scope_name),
                context.closures
            )
        )
        for closure in closures:
            stack.append(closure['parent'])
        scope = context.scopes[scope_name]
        if name in scope:
            result = scope[name]
            return result

    raise Exception('Переменная {} не найдена'.format(name))


def variable_set(context, name, value):
    current = context.scopes[context.current]
    if name in current:
        current[name] = value
        return
    raise Exception('Переменная {} не найдена'.format(name))