from smnp.error.runtime import RuntimeException
from smnp.runtime.evaluator import Evaluator, evaluate
from smnp.runtime.evaluators.expression import expressionEvaluator
from smnp.runtime.evaluators.iterable import abstractIterableEvaluator
from smnp.runtime.tools.error import updatePos
from smnp.runtime.tools.signature import argumentsNodeToMethodSignature


class FunctionCallEvaluator(Evaluator):

    @classmethod
    def evaluator(cls, node, environment):
        try:
            name = node.name.value
            arguments = abstractIterableEvaluator(expressionEvaluator(True))(node.arguments, environment)
            return environment.invokeFunction(name, arguments)
        except RuntimeException as e:
            raise updatePos(e, node)


class FunctionDefinitionEvaluator(Evaluator):

    @classmethod
    def evaluator(cls, node, environment):
        try:
            name = node.name.value
            signature = argumentsNodeToMethodSignature(node.arguments)
            arguments = [ arg.variable.value for arg in node.arguments ]
            body = node.body
            environment.addCustomFunction(name, signature, arguments, body)
        except RuntimeException as e:
            raise updatePos(e, node)


class BodyEvaluator(Evaluator):

    @classmethod
    def evaluator(cls, node, environment):
        for child in node.children:
            evaluate(child, environment)
            if environment.callStack[-1].value is not None:
                return environment.callStack[-1].value


class ReturnEvaluator(Evaluator):

    @classmethod
    def evaluator(cls, node, environment):
        if len(environment.callStack) > 0:
            returnValue = expressionEvaluator(doAssert=True)(node.value, environment)
            environment.callStack[-1].value = returnValue.value
        else:
            raise RuntimeException("Cannot use 'return' statement outside a function or method", node.pos, environment)