from dataclasses import dataclass
from enum import Enum, auto
from typing import Any
from .typeclass import TypeEnum
from .exceptions import NebPanic
#from . import Function

# tokens and types
# NOTE: this can probably be simplified
class TokenType(Enum):

    OPEN_PAREN = auto()
    CLOSE_PAREN = auto()

    EOF = auto()

    # literals
    INT = auto()
    FLOAT = auto()
    STRING = auto()
    TRUE = auto()
    FALSE = auto()

    # keywords
    IF = auto()
    FOR_COUNT = auto()
    DEF = auto()
    LAMBDA = auto()
    FUNC = auto()

    # symbols
    SYMBOL = auto()

    # types
    INT_TYPE = auto()
    FLOAT_TYPE = auto()
    NUMBER_TYPE = auto()
    STRING_TYPE = auto()
    ANY_TYPE = auto()
    LIST_TYPE = auto()
    LITERAL_TYPE = auto()
    BOOL_TYPE = auto()
    USER_TYPE = auto()

    MANY = auto()

@dataclass
class Token:
    type_: TokenType
    text: str
    value: Any
    line: int

    def __str__(self):
        return f"{self.type_.name} {self.text} {self.line}"

class Literal:
    def __init__(self, value, type_=None):
        self.value = value
        if type_ is None:
            self.type_ = TypeEnum.ANY
        else:
            self.type_ = type_
    def __str__(self):
        return f"{self.value}:literal"

class Int(Literal):
    def __init__(self, value):
        super().__init__(value, TypeEnum.INT)
    def __str__(self):
        return f"{self.value}"

class Float(Literal):
    def __init__(self, value):
        super().__init__(value, TypeEnum.FLOAT)
    def __str__(self):
        return f"{self.value}"

class Bool(Literal):
    def __init__(self, value):
        super().__init__(value, TypeEnum.BOOL)
    def __str__(self):
        return f"#{str(self.value).lower()}"

class String(Literal):
    def __init__(self, value):
        super().__init__(value, TypeEnum.STRING)
    def __str__(self):
        return f'"{repr(self.value)[1:-1]}"'

class Type:
    def __init__(self, name):
        self.name = name
    def __str__(self):
        return self.name

class Symbol:
    def __init__(self, name, line):
        self.name = name
        self.line = line
        self.type_ = TypeEnum.ANY  # TODO no it's not
    def __str__(self):
        return f"{self.name}"

class Expr:
    def __init__(self, args):
        self.args = args
        self.type_ = TypeEnum.ANY  # TODO no it's not
    def __str__(self):
        return "(" +  " ".join(f"{arg}" for arg in self.args) + ")"

class List:
    def __init__(self, args):
        self.args = args
        self.type_ = TypeEnum.LIST
    def __str__(self):
        return "(" +  " ".join(f"{arg}" for arg in self.args) + ")"

# function things
class Arg:

    def __init__(self, name, type_, *, optional=False, lazy=False):
        self.name = name
        self.type_ = type_
        self.optional = optional
        self.lazy = lazy

    def __str__(self):
        opt = "?" if self.optional else ""
        lazy = "~" if self.lazy else ""
        return f"{lazy}{opt}{self.name} {self.type_}"

def string_args(args, many):
    out = [f"{arg}" for arg in args]
    if many is not None:
        many.name = "&"
        out.append(f"{many}")
    return " ".join(out).strip()

class Environment:

    def __init__(self, parent=None):
        self.parent = parent
        self.environment = {}

    def register(self, key, value):
        self.environment[key] = value

    def reregister(self, key, value):
        if not self.contains(key):
            raise NebPanic(f"undefined symbol: '{key}")
        if key in self.environment:
            self.register(key, value)
        else:
            self.parent.reregister(key, value)

    def contains(self, key):
        if key in self.environment:
            return True
        elif self.parent is not None:
            return self.parent.contains(key)
        else:
            return False

    def get(self, key):
        if not self.contains(key):
            raise NebPanic(f"undefined symbol: '{key}")
        if key in self.environment:
            return self.environment[key]
        else:
            return self.parent.get(key)

    def __str__(self):
        out = ""
        for k, v in self.environment.items():
            out += f"{k}: {v}, "
        return out

'''
class Function:

    def __init__(self, name, params, body, args=None, many=None):
        self.name = name
        self.params = params
        self.body = body
        self.args = args
        self.many = many
        self.type_ = TypeEnum.ANY  # TODO no it's not

    def describe(self, name=None):
        if name is None:
            name = self.name
        out = [f"({name}"]
        if self.args is not None:
            for arg in self.args:
                out.append(f"{arg}")
        if self.many is not None:
            out.append(f"{self.many}")
        return " ".join(out) + ")"

    def arity_check(self, symbol, params):
        min_arity = len([a for a in self.args if not a.optional])
        max_arity = -1 if self.many is not None else len(self.args)

        if len(params) < min_arity or (max_arity >= 0 and len(params) > max_arity):
            if max_arity < 0:
                fmt = f"{min_arity}+"
            elif min_arity != max_arity: 
                fmt = f"{min_arity}-{max_arity}"
            else:
                fmt = f"{min_arity}"
            raise InterpretPanic(symbol, f"expected [{fmt}] arguments, received {len(params)}")
        return True

    def evaluate_args(self, symbol, params, env, ns):
        self.arity_check(symbol, params)
        ret = []

        for idx, param in enumerate(params):
            if idx < len(self.args):
                arg = self.args[idx]
            else:
                arg = self.many
            if arg.lazy:
                ret.append(param)
                continue
            ev = evaluate(param, env, ns)
            if not is_subtype_of(ev.type_, arg.type_):
                exp = f"{arg.type_}"
                rec = f"{ev.type_}"
                raise InterpretPanic(symbol, f"received {rec}, expected {exp}", ev)
            ret.append(ev)
        return ret

    def call(self, expr, env):
        pass
'''

'''
class Builtin(Function):
    
    def __init__(self, callable_, args=None, many=None):
        super().__init__("<builtin>", None, callable_, args, many)

    def __str__(self):
        return f"builtin function {self.name}"

    def call(self, expr, env, ns):
        self.arity_check(expr.args[0], expr.args[1:])
        evaluated_args = self.evaluate_args(expr.args[0], expr.args[1:], env, ns)
        return self.body(expr.args[0], evaluated_args, env, ns)


class UserFunction(Function):
    
    def __init__(self, name, params, body):
        newparams, args, many = self.process_params(name, params)
        super().__init__(name, newparams, body, args, many)

    def __str__(self):
        out = f"(func {self.name} ("
        args_list = [f"{a.name} {a.type_}" for a in self.args]
        if self.many:
            args_list.append(f"{self.many.name} {self.many.type_}")
        out = out + " ".join(args_list) + ") "
        for expr in self.body:
            out = out + f"{expr} "
        return out.strip() + ")"


    def process_params(self, name, params):
        newparams = []
        args = []
        many = None
        prev_type = False
        first = True
        for param in params:
            if isinstance(param, Symbol):
                if many is not None:
                    raise NebPanic("& must be last argument")
                if param.name == "&":
                    many = Arg(param.name, TypeEnum.ANY)
                else:
                    newparams.append(param)
                    args.append(Arg(param.name, TypeEnum.ANY))
                prev_type = False
            elif isinstance(param, Type) and not prev_type and not first:
                typ = TypeEnum.__getattr__(param.name[1:].upper())
                if many is None:
                    args[-1].type_ = typ
                else:
                    many.type_ = typ
                prev_type = True
            else:
                raise NebPanic("invalid :func signature", param)
            first = False
        return newparams, args, many

    def call(self, expr, env, ns):
        self.arity_check(expr.args[0], expr.args[1:])
        evaluated_args = self.evaluate_args(expr.args[0], expr.args[1:], env, ns)
        this_env = Environment(env)
        for idx, param in enumerate(self.params):
            this_env.register(param.name, evaluated_args[idx])

        # if we got "many", wrap the rest in a list
        if self.many:
            this_env.register(self.many.name, List(evaluated_args[len(self.params):]))

        return interpret(self.body, env=this_env, ns=ns)
'''