#!/usr/bin/env python3
"""Schlüsselt auf, woraus sich jeder Kontostand zusammensetzt.

Saldo = Anfangssaldo + Einnahmen - Ausgaben - Transfers raus + Transfers rein.
Stimmt ein Kontostand nicht, liegt es fast immer an einer dieser fünf Zahlen –
oder an einem doppelt eingelesenen Auszug. Beides zeigt dieses Skript.

Aufruf:  pruefe_salden.py [pfad-zur-db]
"""
import sqlite3
import sys
from collections import Counter

DB = sys.argv[1] if len(sys.argv) > 1 else "/var/lib/certain-finance/app.db"
con = sqlite3.connect(f"file:{DB}?mode=ro", uri=True)
con.row_factory = sqlite3.Row


def eins(sql, *p):
    return con.execute(sql, p).fetchone()[0] or 0


def geld(c, w=""):
    return f"{c / 100:,.2f}".replace(",", "'") + (f" {w}" if w else "")


print(f"Datenbank: {DB}\n")

for a in con.execute("SELECT id, name, currency, opening_balance_cents FROM accounts "
                     "WHERE is_archived = 0 ORDER BY position, id"):
    ein = eins("SELECT SUM(amount_cents) FROM transactions WHERE account_id=? AND type='income'", a["id"])
    aus = eins("SELECT SUM(amount_cents) FROM transactions WHERE account_id=? AND type='expense'", a["id"])
    raus = eins("SELECT SUM(amount_cents) FROM transactions WHERE account_id=? AND type='transfer'", a["id"])
    rein = eins("SELECT SUM(COALESCE(to_amount_cents, amount_cents)) FROM transactions "
                "WHERE to_account_id=? AND type='transfer'", a["id"])
    saldo = a["opening_balance_cents"] + ein - aus - raus + rein
    anz = eins("SELECT COUNT(*) FROM transactions WHERE account_id=? OR to_account_id=?", a["id"], a["id"])
    spanne = con.execute("SELECT MIN(date), MAX(date) FROM transactions WHERE account_id=?", (a["id"],)).fetchone()

    print(f"=== {a['name']}  ({a['currency']}, id {a['id']}) ===")
    print(f"  Anfangssaldo     {geld(a['opening_balance_cents']):>14}")
    print(f"  + Einnahmen      {geld(ein):>14}")
    print(f"  - Ausgaben       {geld(aus):>14}")
    print(f"  - Transfers raus {geld(raus):>14}")
    print(f"  + Transfers rein {geld(rein):>14}")
    print(f"  = SALDO          {geld(saldo, a['currency']):>14}")
    print(f"  {anz} Buchungen, {spanne[0] or '–'} bis {spanne[1] or '–'}")

    # Doppelte Auszüge erkennen: gleicher Dateiname mehrfach gebucht.
    batches = con.execute(
        "SELECT filename, status, imported_count, created_at FROM import_batches "
        "WHERE account_id=? ORDER BY created_at", (a["id"],)).fetchall()
    namen = Counter(b["filename"] for b in batches if b["status"] == "committed")
    for b in batches:
        marke = "  <-- Datei mehrfach gebucht!" if b["status"] == "committed" and namen[b["filename"]] > 1 else ""
        print(f"    [{b['status']:<9}] {b['imported_count']:>4} aus {b['filename'][:44]}{marke}")

    # Buchungen, die sich in Datum+Betrag+Empfänger gleichen.
    dop = con.execute(
        "SELECT date, amount_cents, COALESCE(payee,''), COUNT(*) n FROM transactions "
        "WHERE account_id=? GROUP BY 1,2,3 HAVING n > 1 ORDER BY n DESC LIMIT 5", (a["id"],)).fetchall()
    if dop:
        summe = eins("SELECT SUM(amount_cents * (n-1)) FROM (SELECT amount_cents, COUNT(*) n "
                     "FROM transactions WHERE account_id=? GROUP BY date, amount_cents, COALESCE(payee,'') "
                     "HAVING n > 1)", a["id"])
        print(f"    Mehrfach vorhanden: {len(dop)} Kombinationen, Summe der Überzähligen {geld(summe)}")
        for d in dop:
            print(f"      {d[0]}  {geld(d[1]):>10}  {d[2][:34]:<34} x{d[3]}")
    print()