from pathlib import Path
from typing import List, MutableMapping, Optional, Iterator

from ee.xml import types, bom_file_utils

__all__ = [
    "PartDb",
    "load_db",
    "save_db",
]


class Entry(object):
    def __init__(self, new: bool, part: types.Part):
        self.new = new
        self.part = part

        self.pn = next((p.valueProp for p in bom_file_utils.part_numbers(part)), None)

    def dpn(self, uri: str):
        return [spn for spn in bom_file_utils.supplier_part_numbers(self.part) if spn.supplierProp == uri]


class PartDb(object):
    def __init__(self):
        self.parts: List[Entry] = []
        self.pn_index: MutableMapping[str, Entry] = {}
        self.new_entries = 0

    def add_entry(self, part: types.Part, new: bool):
        e = Entry(new, part)
        self.parts.append(e)

        if e.pn:
            self.pn_index[e.pn] = e

        if e.new:
            self.new_entries = self.new_entries + 1

    def iterparts(self, sort=False) -> Iterator[types.Part]:
        it = (e.part for e in self.parts)
        return sorted(it, key=lambda p: p.uriProp) if sort else it

    def size(self) -> int:
        return len(self.parts)

    def find_by_pn(self, pn: str) -> Optional[types.Part]:
        entry = self.pn_index.get(pn, None)
        return entry.part if entry else None


def load_db(path: Path) -> PartDb:
    db = PartDb()

    with path.open("r") as f:
        part_db: types.PartDb = types.parse(f, silence=True)

    part_db.partsProp = part_db.partsProp or types.PartList()

    for p in part_db.partsProp.part:
        db.add_entry(p, False)

    return db


def save_db(path: Path, db: PartDb, sort=False):
    part_db = types.PartDb()
    parts = part_db.parts = types.PartList()
    parts.partProp.extend(db.iterparts(sort=sort))

    with path.open("w") as f:
        part_db.export(outfile=f, level=0, name_=bom_file_utils.find_root_tag(part_db))