# Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

from abc import ABC, abstractmethod
from dataclasses import dataclass
from typing import Dict, Iterable, Type

from pants.engine.load_statements import LoadStatementWithContent
from pants.engine.struct import Struct


class ParseError(Exception):
    """Indicates an error parsing BUILD configuration."""


@dataclass(frozen=True)
class SymbolTable:
    """A symbol table dict mapping symbol name to implementation class."""

    table: Dict[str, Type]


@dataclass(frozen=True)
class HydratedStruct:
    """A wrapper around a Struct subclass post hydration.

    This exists so that the rule graph can statically provide a struct for a target, and rules can
    depend on this without needing to depend on having a concrete instance of SymbolTable to
    register their input selectors.
    """

    value: Struct


class Parser(ABC):
    @abstractmethod
    def parse(
        self, filepath: str, filecontent: bytes, load_statements: Iterable[LoadStatementWithContent]
    ):
        """
        :param filepath: The name of the file being parsed. The parser should not assume that the path
                         is accessible, and should consume the filecontent.
        :param filecontent: The raw byte content to parse.
        :returns: A list of decoded addressable, Serializable objects. The callable will
                  raise :class:`ParseError` if there were any problems encountered parsing the filecontent.
        :rtype: :class:`collections.Callable`
        """