import arpeggio
from arpeggio.cleanpeg import ParserPEG
from typing import Union

from . import grammar, JobShopVisitor, JobShopProblem, ParseError


class JobShop2Visitor(JobShopVisitor):

    def visit_job_shop2(
            self, node: arpeggio.ParseTreeNode,
            children: arpeggio.SemanticActionResults) -> JobShopProblem:
        if self.debug:
            print("job_shop2:\nchildren:", children)
        problem = children[0]
        if self.debug:
            print("returning a", type(problem))
        return problem


def parse_string(inputdata: str) -> JobShopProblem:
    """parse string of jobshop2-formatted data
    (single problem instance, no name & description)
    and return JobShopProblem
    Raises a ParseError exception on errors"""
    try:
        parse_tree = parser.parse(inputdata)
    except arpeggio.NoMatch as e:
        raise ParseError(
                "Error while parsing problem input data at line {}, col {}:\n"
                "Rules {} did not match.".format(e.line, e.col, e.rules))
    return arpeggio.visit_parse_tree(parse_tree, JobShop2Visitor())


def parse_file(filename: Union[str, bytes]) -> JobShopProblem:
    """Open file with jobshop2-formatted data
    (single problem instance, no name & description),
    parse it and return JobShopProblem
    Raises a ParseError exception on errors"""

    with open(filename) as datafile:
        inputdata: str = datafile.read()
        return parse_string(inputdata)


def main():
    print(parse_file('../inputdata/jobshop2/ta13'))


parser = ParserPEG(grammar, "job_shop2", skipws=False)

if __name__ == "__main__":
    main()