# Architecture

## Components
- `cmd/pxmon`: main CLI and TUI entrypoint.
- `cmd/pxmon-agent`: node-side agent binary.
- `internal/cli`: command parsing, TUI, bot integration, UX flows.
- `internal/cluster`: cluster model/store/service, SSH operations, alerts, reports, backup/runbooks/scheduler.
- `internal/history`: metrics history stores and chart helpers.
- `internal/agent`: agent API server and stats collection types.

## Data model
- Registry is encrypted and stored locally.
- Default path: `<user-config-dir>/pxmon/clusters.enc`
- Master key path defaults to `<user-config-dir>/pxmon/master.key`
- Supports environment overrides:
  - `PXMON_CONFIG`
  - `PXMON_MASTER_KEY`

## Runtime flow
1. User invokes CLI/TUI command.
2. `internal/cli` resolves cluster selector and command flags.
3. `internal/cluster.Service` performs SSH/agent calls.
4. Results are rendered in CLI tables/JSON or TUI panels.
5. Optional telemetry/history snapshots are persisted for trends.

## Security model
- Local registry encryption with a generated master key.
- Locker subsystem can block operational commands until unlock.
- Config export/import supports passphrase-protected bundles.