import sys
from typing import Any
from pathlib import Path

from django.core.management.base import BaseCommand, CommandParser

from todo.operations.csv_importer import CSVImporter


class Command(BaseCommand):
    help = """Import specifically formatted CSV file containing incoming tasks to be loaded.
    For specfic format of inbound CSV, see data/import_example.csv.
    For documentation on upsert logic and required fields, see README.md.
    """

    def add_arguments(self, parser: CommandParser) -> None:

        parser.add_argument(
            "-f", "--file", dest="file", default=None, help="File to to inbound CSV file."
        )

    def handle(self, *args: Any, **options: Any) -> None:
        # Need a file to proceed
        if not options.get("file"):
            print("Sorry, we need a filename to work from.")
            sys.exit(1)

        filepath = Path(options["file"])

        if not filepath.exists():
            print(f"Sorry, couldn't find file: {filepath}")
            sys.exit(1)

        # Encoding "utf-8-sig" means "ignore byte order mark (BOM), which Excel inserts when saving CSVs."
        with filepath.open(mode="r", encoding="utf-8-sig") as fileobj:
            importer = CSVImporter()
            results = importer.upsert(fileobj, as_string_obj=True)

        # Report successes, failures and summaries
        print()
        if results["upserts"]:
            for upsert_msg in results["upserts"]:
                print(upsert_msg)

        # Stored errors has the form:
        # self.errors = [{3: ["Incorrect foo", "Non-existent bar"]}, {7: [...]}]
        if results["errors"]:
            for error_dict in results["errors"]:
                for k, error_list in error_dict.items():
                    print(f"\nSkipped CSV row {k}:")
                    for msg in error_list:
                        print(f"- {msg}")

        print()
        if results["summaries"]:
            for summary_msg in results["summaries"]:
                print(summary_msg)