#!/usr/bin/env python3
"""Apply 'Büromiete ab Sep 2027 → 1000€/Monat' to Finanzplan-Wandeldarlehen-400k
Base/Bull/Bear scenarios.

Updates row 27 (raumkosten) in 'Betriebliche Aufwendungen' sheet of each file.
Existing label is renamed to 'Büromiete (ab Sep 2027)'.

Usage:
    python3 pitch-deck/scripts/apply-bueromiete.py
    python3 pitch-deck/scripts/apply-bueromiete.py --dry-run
"""

from __future__ import annotations

import argparse
import shutil
import sys
from datetime import datetime
from pathlib import Path

from openpyxl import load_workbook
from openpyxl.utils import get_column_letter

EXPORTS = Path(__file__).resolve().parent.parent / "exports"

TARGETS = [
    "Finanzplan-Wandeldarlehen-400k.xlsx",
    "Finanzplan-Wandeldarlehen-400k-Bull.xlsx",
    "Finanzplan-Wandeldarlehen-400k-Bear.xlsx",
]

RENT_ROW = 27
RENT_AMOUNT = 1000
START_YEAR = 2027
START_MONTH = 9
NEW_LABEL = "Büromiete (ab Sep 2027)"


def find_start_col(ws) -> int:
    for c in range(2, ws.max_column + 1):
        if ws.cell(row=1, column=c).value == START_YEAR and ws.cell(row=2, column=c).value == START_MONTH:
            return c
    raise RuntimeError(f"Could not find {START_MONTH}/{START_YEAR} in header rows")


def process_file(path: Path, dry_run: bool) -> tuple[int, int, int]:
    wb = load_workbook(path)
    if "Betriebliche Aufwendungen" not in wb.sheetnames:
        raise RuntimeError(f"{path.name}: missing 'Betriebliche Aufwendungen' sheet")
    ws = wb["Betriebliche Aufwendungen"]

    current_label = ws.cell(row=RENT_ROW, column=1).value
    if current_label is None or "raumkosten" not in str(current_label).lower() and "raum" not in str(current_label).lower() and "miete" not in str(current_label).lower() and "büro" not in str(current_label).lower():
        raise RuntimeError(f"{path.name}: row {RENT_ROW} label is {current_label!r}, expected raumkosten/raum/miete/büro")

    ws.cell(row=RENT_ROW, column=1).value = NEW_LABEL

    start_col = find_start_col(ws)
    end_col = ws.max_column
    for c in range(start_col, end_col + 1):
        ws.cell(row=RENT_ROW, column=c).value = RENT_AMOUNT

    if not dry_run:
        wb.save(path)

    return start_col, end_col, end_col - start_col + 1


def backup(path: Path) -> Path:
    ts = datetime.now().strftime("%Y%m%d-%H%M%S")
    bk = path.with_name(f"{path.stem}.BACKUP-pre-bueromiete-{ts}{path.suffix}")
    shutil.copy2(path, bk)
    return bk


def main() -> int:
    ap = argparse.ArgumentParser(description=__doc__)
    ap.add_argument("--dry-run", action="store_true")
    ap.add_argument("--no-backup", action="store_true")
    args = ap.parse_args()

    for name in TARGETS:
        path = EXPORTS / name
        if not path.exists():
            print(f"  ⚠ skip (not found): {name}", file=sys.stderr)
            continue
        if not args.dry_run and not args.no_backup:
            bk = backup(path)
            print(f"  ✓ backup: {bk.name}")
        start_col, end_col, n = process_file(path, dry_run=args.dry_run)
        print(
            f"  {name}: row {RENT_ROW} → '{NEW_LABEL}', "
            f"cols {get_column_letter(start_col)}..{get_column_letter(end_col)} = {RENT_AMOUNT}€ ({n} months)"
        )
    return 0


if __name__ == "__main__":
    sys.exit(main())