import copy

from core.ast.visitors import UnreferencedNamesVisitor
from core.builtin_concepts import BuiltinConcepts, ParserResultConcept
from evaluators.BaseEvaluator import OneReturnValueEvaluator
from parsers.PythonParser import PythonNode
import ast
import core.ast.nodes


class PythonEvaluator(OneReturnValueEvaluator):
    NAME = "Python"

    """
    Evaluate a Python node, ie, evaluate some Python code
    """

    def __init__(self):
        super().__init__(self.NAME, [BuiltinConcepts.EVALUATION], 50)

    def matches(self, context, return_value):
        return return_value.status and \
               isinstance(return_value.value, ParserResultConcept) and \
               isinstance(return_value.value.value, PythonNode)

    def eval(self, context, return_value):
        sheerka = context.sheerka
        node = return_value.value.value
        try:
            context.log(self.verbose_log, f"Evaluating python node {node}.", self.name)

            my_locals = self.get_locals(context, node.ast_)
            context.log(self.verbose_log, f"locals={my_locals}", self.name)

            if isinstance(node.ast_, ast.Expression):
                context.log(self.verbose_log, "Evaluating using 'eval'.", self.name)
                compiled = compile(node.ast_, "<string>", "eval")
                evaluated = eval(compiled, {}, my_locals)
            else:
                context.log(self.verbose_log, "Evaluating using 'exec'.", self.name)
                evaluated = self.exec_with_return(node.ast_, my_locals)

            context.log(self.verbose_log, f"{evaluated=}", self.name)
            return sheerka.ret(self.name, True, evaluated, parents=[return_value])
        except Exception as error:
            context.log_error(self.verbose_log, error, self.name)
            error = sheerka.new(BuiltinConcepts.ERROR, body=error)
            return sheerka.ret(self.name, False, error, parents=[return_value])

    def get_locals(self, context, ast_):
        my_locals = {"sheerka": context.sheerka}
        if context.obj:
            context.log(self.verbose_log,
                        f"Concept '{context.obj}' is in context. Adding its properties to locals if any.", self.name)

            for prop_name, prop_value in context.obj.props.items():
                my_locals[prop_name] = prop_value.value

        node_concept = core.ast.nodes.python_to_concept(ast_)
        unreferenced_names_visitor = UnreferencedNamesVisitor(context.sheerka)
        unreferenced_names_visitor.visit(node_concept)

        for name in unreferenced_names_visitor.names:
            context.log(self.verbose_log, f"Resolving '{name}'.", self.name)

            if name in my_locals:
                context.log(self.verbose_log, f"Using value from property.", self.name)
                continue

            concept = context.sheerka.new(name)
            if context.sheerka.isinstance(concept, BuiltinConcepts.UNKNOWN_CONCEPT):
                context.log(self.verbose_log, f"'{name}' is not a concept. Skipping.", self.name)
                continue

            context.log(self.verbose_log, f"'{name}' is a concept. Evaluating.", self.name)
            sub_context = context.push(self.name, desc=f"Evaluating '{concept}'", obj=concept)
            sub_context.log_new(self.verbose_log)
            evaluated = context.sheerka.evaluate_concept(sub_context, concept, self.verbose_log)

            if evaluated.key == concept.key:
                my_locals[name] = evaluated.body or evaluated

        return my_locals

    @staticmethod
    def expr_to_expression(expr):
        expr.lineno = 0
        expr.col_offset = 0
        result = ast.Expression(expr.value, lineno=0, col_offset=0)

        return result

    def exec_with_return(self, code_ast, my_locals):

        init_ast = copy.deepcopy(code_ast)
        init_ast.body = code_ast.body[:-1]

        last_ast = copy.deepcopy(code_ast)
        last_ast.body = code_ast.body[-1:]

        exec(compile(init_ast, "<ast>", "exec"), {}, my_locals)
        if type(last_ast.body[0]) == ast.Expr:
            return eval(compile(self.expr_to_expression(last_ast.body[0]), "<ast>", "eval"), {}, my_locals)
        else:
            exec(compile(last_ast, "<ast>", "exec"), {}, my_locals)