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

from ee import EeException
from ee.xml import bomFile, indexFile
from ee.xml.bom_file_utils import find_pn, find_dpn, find_root_tag

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


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

        self.pn = find_pn(part)

    def dpn(self, uri: str):
        return find_dpn(self.part, uri)


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

    def add_entry(self, part: bomFile.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) -> Iterator[bomFile.Part]:
        return [e.part for e in self.parts]

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

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

    def find_by_dpn(self, distributor: str, pn: str) -> bomFile.Part:
        idx = self.dpn_indexes.get(distributor)

        if idx is None:
            tmp = [(find_dpn(entry.part, distributor), entry) for entry in self.parts]
            idx = {dpn: entry for dpn, entry in tmp if dpn is not None}
            self.dpn_indexes[distributor] = idx

        return idx[pn].part


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

    for file in dir_path.iterdir():
        if not file.is_file() or not file.name.endswith(".xml") or file.name == "index.xml":
            continue

        part = bomFile.parse(str(file), silence=True)  # type: bomFile.Part
        db.add_entry(part, False)

    return db


def save_db(dir_path: Path, db: PartDb):
    if dir_path.exists():
        if not dir_path.is_dir():
            raise EeException("The given db path is not a directory")

        idx_path = dir_path / "index.xml"
        if not idx_path.is_file():
            raise EeException("The given db directory exists, but does not look like a part db dir")

        for p in dir_path.iterdir():
            if not p.is_file():
                raise EeException("Non-file: {}".format(p))
            p.unlink()
        dir_path.rmdir()

    dir_path.mkdir(parents=True, exist_ok=True)

    idx = indexFile.IndexFile()
    idx.filesProp = indexFile.FileList()
    files = idx.filesProp.fileProp

    parts = db.iterparts()
    parts = sorted(parts, key=lambda p: p.idProp)

    for part in parts:
        id_ = part.id
        path = dir_path / "{}.xml".format(id_)
        with path.open("w") as f:
            part.export(outfile=f, level=0, name_=find_root_tag(part))

        files.append(indexFile.File(path=str(path)))

    with (dir_path / "index.xml").open("w") as f:
        idx.export(f, level=0, name_=find_root_tag(idx))