import csv
import io
from decimal import Decimal
from fastapi import APIRouter
from fastapi.responses import StreamingResponse
from database import connect
from models import CATEGORIES

router = APIRouter()


def safe_cell(value):
    text = str(value or '')
    return "'" + text if text.lstrip().startswith(('=', '+', '-', '@')) or text.startswith(('\t', '\r', '\n')) else text


def csv_rows():
    stream = io.StringIO(newline='')
    writer = csv.writer(stream, delimiter=';', lineterminator='\r\n')
    yield '\ufeff'
    writer.writerow(['Datum', 'Position', 'Kategorie', 'Betrag', 'Notiz', 'Erwartet', 'Erhalten'])
    yield stream.getvalue()
    stream.seek(0); stream.truncate(0)
    with connect() as db:
        for row in db.execute('SELECT i.*, a.name FROM income_entries i JOIN assets a ON a.id=i.asset_id ORDER BY date DESC, i.id DESC'):
            writer.writerow([row['date'], safe_cell(row['name']), CATEGORIES[row['category']],
                             f"{Decimal(row['amount'])/100:.2f}".replace('.', ','), safe_cell(row['note']),
                             'Ja' if row['expected'] else 'Nein', 'Ja' if row['received'] else 'Nein'])
            yield stream.getvalue()
            stream.seek(0); stream.truncate(0)


@router.get('/export/income.csv')
def export():
    return StreamingResponse(csv_rows(), media_type='text/csv; charset=utf-8', headers={'Content-Disposition': 'attachment; filename="income.csv"'})