from enum import Enum
from tclint.syntax_tree import Visitor, BareWord, Command
from tclint.violations import Violation, Rule


class Rules(Enum):
    VALIDATION = "validation"
    OPTIONAL_ARG_POSITION = "optinal_args"

    def __str__(self):
        return self.value


class CommandArgsCheck(Visitor):
    def __init__(self):
        self._violations = []

    def check(self, _, tree):
        self._violations.clear()
        tree.accept(self, recurse=True)
        return self._violations

    def visit_command(self, command: Command):
        if (
            not hasattr(command.routine, "contents")
            or command.routine.contents != "proc"
        ):
            return
        if len(command.args) < 2:
            return

        args_node = command.args[1]
        if not hasattr(args_node, "children"):
            return

        found_optional = False
        for arg in args_node.children:
            # Required argument
            if isinstance(arg, BareWord):
                if found_optional:
                    self._violations.append(
                        Violation(
                            Rules.OPTIONAL_ARG_POSITION,
                            "Required argument follows optional one",
                            arg.pos,
                            arg.end_pos,
                        )
                    )
            # Optional argument
            elif hasattr(arg, "children") and len(arg.children) >= 2:
                found_optional = True


def get_checkers():
    checkers = (CommandArgsCheck(),)

    return checkers