import copy
from enum import Enum

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


class PythonEvaluator(OneReturnValueEvaluator):
    NAME = "Python"

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

    def __init__(self):
        super().__init__(self.NAME, [BuiltinConcepts.EVALUATION], 50)
        self.locals = {}

    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(f"Evaluating python node {node}.", self.name)

            # Do not evaluate if the ast refers to a concept (leave it to ConceptEvaluator)
            if isinstance(node.ast_, ast.Expression) and isinstance(node.ast_.body, ast.Name):
                c = context.sheerka.get(node.ast_.body.id)
                if not context.sheerka.isinstance(c, BuiltinConcepts.UNKNOWN_CONCEPT):
                    context.log("It's a simple concept. Not for me.", self.name)
                    not_for_me = context.sheerka.new(BuiltinConcepts.NOT_FOR_ME, body=node)
                    return sheerka.ret(self.name, False, not_for_me, parents=[return_value])

            # get locals
            my_globals = self.get_globals(context, node)
            my_locals = {}
            context.log(f"globals={my_globals}", self.name)

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

            context.log(f"{evaluated=}", self.name)
            return sheerka.ret(self.name, True, evaluated, parents=[return_value])

        except Exception as error:
            context.log_error(error, self.name)
            error = sheerka.new(BuiltinConcepts.ERROR, body=error)
            return sheerka.ret(self.name, False, error, parents=[return_value])

    def get_globals(self, context, node):
        my_locals = {
            "sheerka": context.sheerka,
            "desc": context.sheerka.dump_handler.dump_desc,
            "concepts": context.sheerka.dump_handler.dump_concepts,
            "definitions": context.sheerka.dump_handler.dump_definitions,
            "history": context.sheerka.dump_handler.dump_history,
            "state": context.sheerka.dump_handler.dump_state,
            "Concept": core.concept.Concept
        }
        if context.obj:
            context.log(f"Concept '{context.obj}' is in context. Adding it and its properties to locals.", self.name)

            for prop_name, prop_value in context.obj.props.items():
                if isinstance(prop_value.value, Concept):
                    my_locals[prop_name] = context.sheerka.value(prop_value.value)
                else:
                    my_locals[prop_name] = prop_value.value

            my_locals["self"] = context.obj.body

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

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

            if name in node.concepts:
                context.log(f"Using value from node.", self.name)
                concept = node.concepts[name]
                return_concept = False

            else:
                c_key, c_id, return_concept = self.resolve_name(name)

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

                context.log(f"Instantiating new concept with {c_key=}, {c_id=}.", self.name)
                new = context.sheerka.new
                concept = new((None, c_id)) if c_id else new(c_key)
                if context.sheerka.isinstance(concept, BuiltinConcepts.UNKNOWN_CONCEPT):
                    context.log(f"({c_key=}, {c_id=}) is not a concept. Skipping.", self.name)
                    continue

            context.log(f"Evaluating '{concept}'", self.name)
            with context.push(self.name, desc=f"Evaluating '{concept}'", obj=concept) as sub_context:
                evaluated = context.sheerka.evaluate_concept(sub_context, concept, True)
                sub_context.add_values(return_values=evaluated)

                if evaluated.key == concept.key:
                    my_locals[name] = evaluated if return_concept else context.sheerka.value(evaluated)

        if self.locals:  # when exta values are given. Add them
            my_locals.update(self.locals)

        return my_locals

    @staticmethod
    def resolve_name(to_resolve):
        """
        Try to match
        __C__concept_key__C__
        or
        __C__concept_key__concept_id__C__

        :param to_resolve:
        :return:
        """
        key, id_, use_concept = core.utils.decode_concept(to_resolve)
        if key or id_:
            return key, id_, use_concept
        else:
            return to_resolve, None, False


    @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_globals, 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_globals, my_locals)
        else:
            exec(compile(last_ast, "<ast>", "exec"), my_globals, my_locals)