#!/usr/bin/env python3
"""Clean up Finanzplan Excel files:

Strip 'category — ' prefix from column-A labels in 'Betriebliche Aufwendungen'
and 'Liquidität' sheets.

Runs against ALL Finanzplan-*.xlsx files in pitch-deck/exports/ (except BACKUPs).
Creates a single timestamped backup per file before modification.

Usage:
    python3 pitch-deck/scripts/cleanup-finanzplan-labels.py
    python3 pitch-deck/scripts/cleanup-finanzplan-labels.py --dry-run
    python3 pitch-deck/scripts/cleanup-finanzplan-labels.py --only Finanzplan-Wandeldarlehen-400k.xlsx
"""

from __future__ import annotations

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

from openpyxl import load_workbook

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


def strip_prefix(value):
    """Drop a lowercase 'kategorie — ' prefix from a label."""
    if not value:
        return value
    s = str(value)
    if " — " not in s:
        return s
    prefix, rest = s.split(" — ", 1)
    # Only strip if prefix looks like a single-word lowercase category tag
    if prefix.islower() and prefix.replace("/", "").replace("-", "").isalpha():
        return rest
    return s


def clean_labels(ws, start_row: int = 4) -> int:
    n = 0
    for r in range(start_row, ws.max_row + 1):
        before = ws.cell(row=r, column=1).value
        after = strip_prefix(before)
        if after != before:
            ws.cell(row=r, column=1).value = after
            n += 1
    return n


def process_file(path: Path, dry_run: bool = False) -> dict:
    wb = load_workbook(path)
    stats = {"liq_labels": 0, "ba_labels": 0}

    if "Liquidität" in wb.sheetnames:
        stats["liq_labels"] = clean_labels(wb["Liquidität"], start_row=4)

    if "Betriebliche Aufwendungen" in wb.sheetnames:
        stats["ba_labels"] = clean_labels(wb["Betriebliche Aufwendungen"], start_row=4)

    if not dry_run:
        wb.save(path)

    return stats


def backup(path: Path, tag: str) -> Path:
    """Make a single timestamped backup. Returns the backup path."""
    ts = datetime.now().strftime("%Y%m%d-%H%M%S")
    bk = path.with_name(f"{path.stem}.BACKUP-{tag}-{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", help="Show what would change, do not write")
    ap.add_argument("--only", help="Process only a specific filename")
    ap.add_argument("--no-backup", action="store_true", help="Skip backup (default: backup once)")
    args = ap.parse_args()

    files = sorted(EXPORTS.glob("Finanzplan-*.xlsx"))
    files = [f for f in files if "BACKUP" not in f.name]
    if args.only:
        files = [f for f in files if f.name == args.only]
    if not files:
        print("No files matched", file=sys.stderr)
        return 1

    print(f"{'DRY-RUN — ' if args.dry_run else ''}{len(files)} file(s) to process")
    for path in files:
        if not args.dry_run and not args.no_backup:
            bk = backup(path, "pre-label-cleanup")
            print(f"  ✓ backup: {bk.name}")
        stats = process_file(path, dry_run=args.dry_run)
        print(
            f"  {path.name}: "
            f"Liq labels={stats['liq_labels']}  BA labels={stats['ba_labels']}"
        )
    return 0


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