from codecs import decode
from csv import DictReader
from datetime import datetime
from typing import Any, Dict, List, Union

from bson import ObjectId

from classes.importer.abstract import Importer
from modules.database import col_entries


class ImporterCSV(Importer):
    """
    The ImporterCSV class represents the object with
    functionality to import/export garbage collection
    records and convert them to other object types
    from CSV files.
    """

    def __init__(self):
        super(Importer, self).__init__()

    async def import_data(self, data: bytes) -> List[ObjectId]:
        entries: List[Dict[str, Any]] = list(
            DictReader(decode(data).split("\n"), delimiter=";")
        )

        for entry in entries:
            entry["locations"] = (
                [int(entry["locations"])]
                if "," not in entry["locations"]
                else [int(id) for id in entry["locations"].split(",")]
            )
            entry["garbage_type"] = int(entry["garbage_type"])

            for key in ("locations", "garbage_type", "date"):
                if (
                    key not in entry
                    or (key == "garbage_type" and not isinstance(entry[key], int))
                    or (key == "locations" and not isinstance(entry[key], list))
                ):
                    raise ValueError

                if key == "date":
                    try:
                        datetime.fromisoformat(str(entry[key]))
                    except (ValueError, TypeError) as exc:
                        raise ValueError from exc

        entries_clean: List[Dict[str, Union[str, int, datetime]]] = [
            {
                "locations": entry["locations"],
                "garbage_type": entry["garbage_type"],
                "date": datetime.fromisoformat(str(entry["date"])),
            }
            for entry in entries
        ]

        inserted = await col_entries.insert_many(entries_clean)

        return [] if inserted is None else inserted.inserted_ids

    async def export_data(self, data: Any) -> Any:
        return None