from .tokens import Token
from .utils import *

SCOPES = ["static", "field", "var"]
PRIMITIVE_TYPES = ["int", "char", "boolean"]


class Class:
    def __init__(self, name: Token, variables: list, subroutines: list):
        self.name = name
        self.variables = variables
        self.subroutines = subroutines

    @classmethod
    def from_tokens(cls, tokens: list):
        """Construct a class from a list of tokens.

        In standard Jack, one file is exactly one class.

        Format:
        class <name> {
            <zero or more class variable declarations>
            <zero or more subroutines>
        }
        """
        if len(tokens) < 4:
            return None
        if tokens[0] != "class":
            raise JackSyntaxError(
                f"Expected `class`, got `{tokens[0]}` instead", tokens[0]
            )

        name = tokens[1]
        if name.type != "identifier":
            raise JackSyntaxError(f"You cannot name a class `{name}`", name)

        if tokens[2] != LEFT_BRACE:
            raise JackSyntaxError(
                f"Expected `{LEFT_BRACE}`, got `{tokens[2]}` instead", tokens[2]
            )

        tokens_consumed = 3

        while True:
            variables, token_cnt = Variable.from_tokens(
                tokens[tokens_consumed:], context="class"
            )
            if variables is None:
                break
            variables.print_verbose()
            tokens_consumed += token_cnt

        return Class(name, variables, [])


class Variable:
    def __init__(self, scope: Token, type: Token, names: list[Token]):
        self.scope = scope
        self.type = type
        self.names = names

    @classmethod
    def from_tokens(cls, tokens: list, context: str) -> tuple:
        """Construct variable declaration statement from a list of tokens.
        Return a tuple of an instance of Variable and number of tokens consumed.
        When `tokens` does not begin with a variable declaration, return (None, 0).

        context -- "class" (<scope> = static | field) or "subroutine" (<scope> = var)

        Format:
        <scope> <type> <one or more names, joined with a comma>;

        <scope> = static | field | var
        <type> = int | char | boolean | <class name>
        """
        if len(tokens) < 4 or tokens[0] not in SCOPES:
            # not variable declaration
            return (None, 0)

        scope = tokens[0]
        if scope in ["static", "field"] and context != "class":
            raise JackSyntaxError(
                f"You cannot declare a {scope} variable in a subroutine", scope
            )
        if scope == "var" and context != "subroutine":
            raise JackSyntaxError(
                f"You cannot declare a local variable outside of a subroutine",
                scope,
            )

        type = tokens[1]
        if type not in PRIMITIVE_TYPES and type.type != "identifier":
            raise JackSyntaxError(f"Expected datatype, got `{tokens[1]}` instead", type)

        tokens_consumed = 2
        names = []  # names of variables
        expecting_identifier = True

        for token in tokens[2:]:
            tokens_consumed += 1
            if token.type == "identifier":
                if expecting_identifier:
                    names.append(token)
                    expecting_identifier = False
                else:
                    raise JackSyntaxError(f"Expected `,`, got `{token}` instead", token)
            elif token == ",":
                if not expecting_identifier:
                    expecting_identifier = True
                else:
                    raise JackSyntaxError(
                        f"Expected variable name, got `,` instead", token
                    )
            elif token == ";":
                if expecting_identifier:
                    raise JackSyntaxError(
                        f"Expected variable name, got `;` instead", token
                    )
                break
            else:
                expected = "variable name" if expecting_identifier else "`,` or `;`"
                raise JackSyntaxError(
                    f"Expected {expected}, got `{token}` instead", token
                )

        return (Variable(scope, type, names), tokens_consumed)

    def print_verbose(self):
        print(f"Declare {len(self.names)} variable(s):")
        for name in self.names:
            print(self.scope, self.type, name)


class Subroutine:
    def __init__(self):
        pass


class Statement:
    def __init__(self):
        super().__init__()


class IfStatement(Statement):
    def __init__(self):
        super().__init__()