import ast
import logging
from dataclasses import dataclass

import core.utils
from core.builtin_concepts import BuiltinConcepts
from core.sheerka.services.SheerkaExecute import ParserInput
from core.tokenizer import TokenKind
from parsers.BaseParser import BaseParser, Node, ParsingError

log = logging.getLogger(__name__)


def get_python_node(obj):
    if isinstance(obj, PythonNode):
        return obj
    if hasattr(obj, "python_node"):
        return obj.python_node
    return None


@dataclass()
class PythonErrorNode(ParsingError):
    source: str
    exception: Exception

    # def __post_init__(self):
    #     self.log.debug("-> PythonErrorNode: " + str(self.exception))


@dataclass()
class ConceptDetectedError(ParsingError):
    name: str


class PythonNode(Node):

    def __init__(self, source, ast_=None, objects=None):
        self.source = source
        self.ast_ = ast_  # if ast_ else ast.parse(source, mode="eval") if source else None
        self.objects = objects or {}  # when objects (mainly concepts or rules) are recognized in the expression
        self.compiled = None
        self.ast_str = self.get_dump(self.ast_)

    def init_ast(self):
        if self.ast_ is None and self.source:
            self.ast_ = ast.parse(self.source, mode="eval")
            self.ast_str = self.get_dump(self.ast_)
        return self

    def get_compiled(self):
        if self.compiled is None:
            self.compiled = compile(self.ast_, "<string>", "eval")
        return self.compiled

    def __repr__(self):
        ast_type = "expr" if isinstance(self.ast_, ast.Expression) else "module"
        return "PythonNode(" + ast_type + "='" + self.source + "')"

    def __eq__(self, other):
        if not isinstance(other, PythonNode):
            return False

        if self.source != other.source:
            return False

        if self.ast_ and other.ast_:
            self_dump = self.get_dump(self.ast_)
            other_dump = self.get_dump(other.ast_)
            return self_dump == other_dump

        return True

    def __hash__(self):
        return hash((self.source, self.ast_.hash))

    @staticmethod
    def get_dump(ast_):
        if not ast_:
            return None
        dump = ast.dump(ast_)
        for to_remove in [", ctx=Load()", ", kind=None", ", type_ignores=[]"]:
            dump = dump.replace(to_remove, "")
        return dump


class PythonGetNamesVisitor(ast.NodeVisitor):
    """
    This visitor will find all the name declared in the ast
    """

    def __init__(self):
        self.names = set()

    def visit_Name(self, node):
        self.names.add(node.id)


class PythonParser(BaseParser):
    """
    Parse Python scripts
    """

    NAME = "Python"

    def __init__(self, **kwargs):

        BaseParser.__init__(self, PythonParser.NAME, 50)
        self.source = kwargs.get("source", "<undef>")

    def parse(self, context, parser_input: ParserInput):
        if not isinstance(parser_input, ParserInput):
            return None

        sheerka = context.sheerka
        tree = None
        tracker = {}  # to keep track of concept tokens (c:xxx:)

        python_switcher = {
            TokenKind.CONCEPT: lambda t: core.utils.encode_concept(t.value),
            TokenKind.RULE: lambda t: core.utils.encode_concept(t.value, "R")
        }

        if self.reset_parser(context, parser_input):
            source_code = parser_input.as_text(python_switcher, tracker)
            source_code = source_code.strip()

            #  first, try to parse an expression
            res, tree, error = self.try_parse_expression(source_code)
            if not res:
                # then try to parse a statement
                res, tree, error = self.try_parse_statement(source_code)
                if not res:
                    error_node = PythonErrorNode(parser_input.as_text(), error)
                    self.error_sink.append(error_node)

            # Python parser will refuse input that directly refers to a concept
            if isinstance(tree, ast.Expression) and isinstance(tree.body, ast.Name):
                if tree.body.id in tracker or context.sheerka.fast_resolve(tree.body.id, return_new=False) is not None:
                    context.log("It's a simple concept. Not for me.", self.name)
                    self.error_sink.append(ConceptDetectedError(tree.body.id))

        if self.has_error:
            ret = sheerka.ret(
                self.name,
                False,
                sheerka.new(
                    BuiltinConcepts.NOT_FOR_ME,
                    body=parser_input.as_text(),
                    reason=self.error_sink))
        else:
            ret = sheerka.ret(
                self.name,
                True,
                sheerka.new(
                    BuiltinConcepts.PARSER_RESULT,
                    parser=self,
                    source=parser_input.as_text(),
                    body=PythonNode(source_code, tree, tracker),
                    try_parsed=None))

        self.log_result(context, parser_input.as_text(), ret)
        return ret

    def try_parse_expression(self, text):
        try:
            return True, ast.parse(text, f"<{self.source}>", 'eval'), None
        except Exception as error:
            return False, None, error

    def try_parse_statement(self, text):
        try:
            return True, ast.parse(text, f"<{self.source}>", 'exec'), None
        except Exception as error:
            return False, None, error