# brk_grouper
UTXO and address cohort filtering for on-chain analytics.
## What It Enables
Slice the UTXO set and address population by age, amount, output type, halving epoch, or holder classification (STH/LTH). Build complex cohorts by combining filters for metrics like "realized cap of 1+ BTC UTXOs older than 155 days."
## Key Features
- **Age-based**: `TimeFilter::GreaterOrEqual(155)`, `TimeFilter::Range(30..90)`, `TimeFilter::LowerThan(7)`
- **Amount-based**: `AmountFilter::GreaterOrEqual(Sats::_1BTC)`, `AmountFilter::Range(Sats::_100K..Sats::_1M)`
- **Term classification**: `Term::Sth` (short-term holders, <155 days), `Term::Lth` (long-term holders)
- **Epoch filters**: Group by halving epoch
- **Type filters**: Segment by output type (P2PKH, P2TR, etc.)
- **Context-aware naming**: Automatic prefix generation (`utxos_`, `addrs_`) based on cohort context
- **Inclusion logic**: Filter hierarchy for aggregation (`Filter::includes`)
## Filter Types
```rust,ignore
pub enum Filter {
All,
Term(Term), // STH/LTH
Time(TimeFilter), // Age-based
Amount(AmountFilter), // Value-based
Epoch(HalvingEpoch), // Halving epoch
Type(OutputType), // P2PKH, P2TR, etc.
}
```
## Core API
```rust,ignore
let filter = Filter::Time(TimeFilter::GreaterOrEqual(155));
// Check membership
filter.contains_time(200); // true
filter.contains_amount(sats);
// Generate metric names
filter.to_full_name(CohortContext::Utxo); // "utxos_min_age_155d"
```
## Built On
- `brk_error` for error handling
- `brk_types` for `Sats`, `HalvingEpoch`, `OutputType`
- `brk_traversable` for data structure traversal