"""One-time script: Import all cases from Abrechnung_DAK.xlsx into DB.

Usage:
    cd /home/frontend/dak_c2s/backend
    source venv/bin/activate
    python -m scripts.import_historical [path_to_xlsx]

    Default path: ../data/Abrechnung_DAK.xlsx

Options:
    --dry-run    Parse and validate without writing to DB
    --sheet NAME Import only the named sheet (can repeat)
    --verbose    Show per-row errors in output
"""

import argparse
import logging
import os
import sys

# Ensure the backend package is importable
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from app.database import SessionLocal
from app.services.excel_import import (
    YEAR_SHEETS,
    import_abrechnung_sheet,
    import_full_abrechnung,
)


def main() -> None:
    parser = argparse.ArgumentParser(
        description="Import historical cases from Abrechnung_DAK.xlsx"
    )
    parser.add_argument(
        "filepath",
        nargs="?",
        default=os.path.join(
            os.path.dirname(  # dak_c2s/
                os.path.dirname(  # dak_c2s/backend/
                    os.path.dirname(os.path.abspath(__file__))  # dak_c2s/backend/scripts/
                )
            ),
            "data",
            "Abrechnung_DAK.xlsx",
        ),
        help="Path to the Excel file (default: ../../data/Abrechnung_DAK.xlsx)",
    )
    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="Parse and validate without writing to DB",
    )
    parser.add_argument(
        "--sheet",
        action="append",
        dest="sheets",
        help="Import only specific sheet(s); can be repeated",
    )
    parser.add_argument(
        "--verbose", "-v",
        action="store_true",
        help="Show per-row errors in output",
    )
    args = parser.parse_args()

    # Configure logging
    log_level = logging.DEBUG if args.verbose else logging.INFO
    logging.basicConfig(
        level=log_level,
        format="%(asctime)s %(levelname)-8s %(name)s: %(message)s",
        datefmt="%H:%M:%S",
    )

    filepath = args.filepath
    if not os.path.exists(filepath):
        print(f"ERROR: File not found: {filepath}")
        sys.exit(1)

    print(f"Importing from: {filepath}")
    if args.dry_run:
        print("*** DRY RUN -- no changes will be committed ***")
    print()

    db = SessionLocal()
    try:
        if args.sheets:
            # Import specific sheets only
            from openpyxl import load_workbook

            wb = load_workbook(filepath, read_only=True, data_only=True)
            try:
                for sheet_name in args.sheets:
                    if sheet_name not in wb.sheetnames:
                        print(f"  WARNING: Sheet '{sheet_name}' not found, skipping")
                        continue

                    # Determine default year
                    if sheet_name == "2020-2022":
                        default_year = None
                    else:
                        try:
                            default_year = int(sheet_name)
                        except ValueError:
                            default_year = None

                    ws = wb[sheet_name]
                    result = import_abrechnung_sheet(
                        db=db,
                        ws=ws,
                        sheet_name=sheet_name,
                        default_year=default_year,
                    )
                    _print_result(sheet_name, result, args.verbose)

                if args.dry_run:
                    db.rollback()
                    print("\nDry run complete -- rolled back all changes.")
                else:
                    db.commit()
                    print("\nImport committed to database.")
            finally:
                wb.close()
        else:
            # Import all year sheets
            if args.dry_run:
                # For dry run, we do the same import but rollback at the end
                from openpyxl import load_workbook

                wb = load_workbook(filepath, read_only=True, data_only=True)
                try:
                    for sheet_name in YEAR_SHEETS:
                        if sheet_name not in wb.sheetnames:
                            print(f"  Sheet '{sheet_name}' not found, skipping")
                            continue

                        if sheet_name == "2020-2022":
                            default_year = None
                        else:
                            try:
                                default_year = int(sheet_name)
                            except ValueError:
                                default_year = None

                        ws = wb[sheet_name]
                        result = import_abrechnung_sheet(
                            db=db,
                            ws=ws,
                            sheet_name=sheet_name,
                            default_year=default_year,
                        )
                        _print_result(sheet_name, result, args.verbose)
                finally:
                    wb.close()

                db.rollback()
                print("\nDry run complete -- rolled back all changes.")
            else:
                result = import_full_abrechnung(db, filepath)
                print("Import results:")
                for sheet_name, stats in result.items():
                    _print_result(sheet_name, stats, args.verbose)
                print("\nImport committed to database.")

    except Exception as e:
        db.rollback()
        print(f"\nERROR: Import failed: {e}")
        logging.exception("Import failed")
        sys.exit(1)
    finally:
        db.close()


def _print_result(sheet_name: str, result: dict, verbose: bool) -> None:
    """Print import result for a single sheet."""
    imported = result["imported"]
    skipped = result["skipped"]
    error_count = len(result["errors"])

    status = "OK" if error_count == 0 else f"{error_count} errors"
    print(f"  {sheet_name:12s}: {imported:4d} imported, {skipped:4d} skipped  [{status}]")

    if verbose and result["errors"]:
        for err in result["errors"]:
            print(f"    - {err}")


if __name__ == "__main__":
    main()