from core.builtin_concepts import BuiltinConcepts
from core.tokenizer import Tokenizer, LexerError, TokenKind
from parsers.BaseParser import BaseParser, Node, ErrorNode
from dataclasses import dataclass, field
import ast
import logging

from parsers.ConceptLexerParser import ConceptNode

log = logging.getLogger(__name__)


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

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


class PythonNode(Node):

    def __init__(self, source, ast_, concepts=None):
        self.source = source
        self.ast_ = ast_
        self.concepts = concepts or {}  # when concepts are recognized in the expression

    # def __repr__(self):
    #     return "PythonNode(source='" + self.source + "', ast=" + self.get_dump(self.ast_) + ")"

    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

        self_dump = self.get_dump(self.ast_)
        other_dump = self.get_dump(other.ast_)

        return self_dump == other_dump

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

    @staticmethod
    def get_dump(ast_):
        dump = ast.dump(ast_)
        for to_remove in [", ctx=Load()", ", kind=None", ", type_ignores=[]"]:
            dump = dump.replace(to_remove, "")
        return dump


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

    def __init__(self, **kwargs):

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

    def parse(self, context, text):
        sheerka = context.sheerka
        tree = None

        python_switcher = {
            TokenKind.CONCEPT: lambda t: f"__C__USE_CONCEPT__{t.value}__C__"
        }

        try:
            if isinstance(text, str) and "c:" in text:
                source = self.get_text_from_tokens(list(Tokenizer(text)), python_switcher)
            elif isinstance(text, str):
                source = text
            else:
                source = self.get_text_from_tokens(text, python_switcher)
            source = source.strip()

            text = text if isinstance(text, str) else source

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

        except LexerError as e:
            self.has_error = True
            self.error_sink.append(e)

        ret = sheerka.ret(
            self.name,
            not self.has_error,
            sheerka.new(
                BuiltinConcepts.PARSER_RESULT,
                parser=self,
                source=text,
                body=self.error_sink if self.has_error else PythonNode(text, tree),
                try_parsed=None))

        self.log_result(context, 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


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 LexerNodeParserHelperForPython:
    """Helper class to parse mix of concepts and Python"""

    def __init__(self):
        self.identifiers = {}  # cache for already created identifier (the key is id(concept))
        self.identifiers_key = {}  # number of identifiers with the same root (prefix)

    def _get_identifier(self, concept):
        """
        Get an identifier for a concept.
        Make sure to return the same identifier if the same concept
        Make sure to return a different identifier if same name but different concept

        Internal function because I don't want identifiers, identifiers_key and python_ids_mappings
        to be instance variables
        I would like to keep this parser as stateless as possible
        :param concept:
        :return:
        """
        if id(concept) in self.identifiers:
            return self.identifiers[id(concept)]

        identifier = "__C__" + self._sanitize(concept.key or concept.name)
        if concept.id:
            identifier += "__" + concept.id

        if identifier in self.identifiers_key:
            self.identifiers_key[identifier] += 1
            identifier += f"_{self.identifiers_key[identifier]}"
        else:
            self.identifiers_key[identifier] = 0

        identifier += "__C__"

        self.identifiers[id(concept)] = identifier
        return identifier

    @staticmethod
    def _sanitize(identifier):
        res = ""
        for c in identifier:
            res += c if c.isalnum() else "0"
        return res

    def parse(self, context, nodes):
        source = ""
        to_parse = ""

        concepts = {}  # the key is the Python identifier

        for node in nodes:
            if isinstance(node, ConceptNode):
                source += node.source
                if to_parse:
                    to_parse += " "
                concept = node.concept
                python_id = self._get_identifier(concept)
                to_parse += python_id
                concepts[python_id] = concept
            else:
                source += node.source
                to_parse += node.source

        with context.push(self, desc="Trying Python for '" + to_parse + "'") as sub_context:
            sub_context.add_inputs(to_parse=to_parse)
            python_parser = PythonParser()
            result = python_parser.parse(sub_context, to_parse)
            sub_context.add_values(return_values=result)

        if result.status:
            python_node = result.body.body
            python_node.source = source
            python_node.concepts = concepts
            return python_node

        return result.body  # the error