import argparse
import pydoc
from pathlib import Path
from typing import List

from ee import tools, EeException
from ee.part import Part, PartDb, load_db, save_db
from ee.project import Project


def load_functions(function_names):
    functions = []
    for fn in function_names:
        f = pydoc.locate(fn)

        if f is None:
            raise EeException("Could not load function: {}".format(fn))

        if not callable(f):
            raise EeException("Not a callable: {}, is a {}".format(fn, type(f)))

        functions.append((fn, f))
    return functions


def work(in_path: Path, out_path: Path, report_path: Path, function_names: List[str]):
    functions = load_functions(function_names)

    in_parts = load_db(in_path)

    parts = PartDb()

    tools.mk_parents(report_path)
    with report_path.open("w") as rpt:
        for xml in in_parts.iterparts():
            part = Part(xml)

            for name, f in functions:
                part = f(part)

    save_db(out_path, in_parts)


parser = argparse.ArgumentParser()

parser.add_argument("--in",
                    dest="in_path",
                    required=True,
                    metavar="PART DB")

parser.add_argument("--out",
                    required=True,
                    metavar="REQUIREMENTS")

parser.add_argument("--function",
                    required=True,
                    nargs="*",
                    metavar="FUNCTION")

parser.add_argument("--execution",
                    default="default")

args = parser.parse_args()

project = Project.load()
report = project.report_dir / "apply-function" / (args.execution + ".rst")
work(Path(args.in_path), Path(args.out), report, args.function)