# Economy module

This area is split across three services:

- `economy.service.ts`
- `exam.service.ts`
- `lootdrop.service.ts`

## Core rules

- Currency values are `bigint`
- `modifyUserBalance()` is the canonical balance mutator for most features because it logs a transaction and emits `BALANCE_CHANGED`
- direct balance updates still exist in a few flows where the service owns the full transaction, such as trivia entry/win and exam payout

## Daily rewards

- `claimDaily()` uses a UTC-midnight cooldown, not a rolling 24-hour timer
- streak bonus is linear from `config.economy.daily.streakBonus`
- weekly bonus applies every seventh claim
- total daily reward is capped at `500n`
- missing more than 24 hours after the cooldown expired resets the streak

## Weekly exam

- stored in `user_timers` with type `EXAM_SYSTEM`
- registration locks the user to the current weekday
- payout is based on XP gained since the previous exam snapshot
- missing the assigned weekday rolls the timer forward and pays nothing

## Lootdrops

- channel activity and cooldowns are kept in memory
- spawned drops are persisted in the `lootdrops` table
- claiming uses an atomic update where `claimedBy IS NULL`
- expired drops and stale activity are cleaned every 60 seconds
- spawned drops expire after 10 minutes
