# Lite Wallet Implementation Plan v2 — 2026-06-04

**Status:** Active. **Supersedes** `docs/full-lite-wallet-implementation-plan-2026-05-18.md` (archived).

## Context — why this plan replaces the v1 plan

The v1 ("Full Lite Wallet Implementation Plan", 2026-05-18) drove the lite effort for ~6 weeks and produced a large amount of code, but **zero end-to-end wallet functionality**. Its method — build every layer of every phase in a *typed-disabled* form and "promote one disabled scaffold at a time" through readiness/custody/handoff governance — generated ~160 dead `lite_wallet_*_plan`/`*_batch*` files (filenames up to 250 chars) and a 33k-line test file that exercised only disabled scaffolding. Those files were deleted on 2026-06-04 (branch `cleanup/lite-plan-churn`); a `scripts/check-source-hygiene.sh` pre-commit guard now blocks their regrowth.

A verified audit (8-agent review, 2026-06-04) established the real current state below. This plan keeps the v1 plan's **dependency ordering and ground rules** (which were sound) but discards its **method**: it switches from *horizontal disabled scaffolding* to *vertical working slices* — each milestone makes one capability work **end-to-end and demoable**, gated by a deterministic fake-backend test, before the next begins.

## Verified current state (2026-06-04)

**Real and working when enabled:**
- C-ABI bridge `lite_client_bridge.{h,cpp}` — makes real `litelib_*` calls via function pointers with copy-before-free Rust string ownership (`lite_client_bridge.cpp:120-183`). Gated by `#if DRAGONX_ENABLE_LITE_BACKEND` (default 0).
- CMake import contract — validates build coupling, imported-only link mode, ABI `sdxl-c-v1`, all 8 required symbols, optional signature (`CMakeLists.txt:62-145`).
- Capability gating — `wallet_capabilities.h` correctly gates lite features at compile + runtime.
- Result parsers + state mapper — `lite_result_parsers.{h,cpp}`, `lite_wallet_state_mapper.{h,cpp}` convert JSON → typed state (real, but never called).
- Backend artifact script — `scripts/build-lite-backend-artifact.sh` (reproducible; Rust source vendored at `external/SilentDragonXLite/`). Built Linux/Windows artifacts during dev, but `build/lite-backend/` is absent and CMake never invokes it.

**Real but unreachable (the core gap is integration):**
- `LiteWalletLifecycleService` (real `bridge_.initialize*`), `LiteSyncService`, `LiteConnectionService`, `LiteWalletGateway` (real `bridge_.execute`) — all contain real bridge calls but are **never constructed anywhere**, default to `allowBridgeCalls=false`, and the only wired UI path is a **validation-only adapter** that returns `RuntimeExecutionDisabled` for every real action.

**Not started / disabled:** sync loop (`startSync` returns "not implemented"), `WalletState` application (explicit `StateMutationDisabled`), send/import/export, wallet-file persistence, lite data UI, dynamic loading (only an unbuilt scaffold; imported-link only), macOS (operator-deferred).

**Known defects to fix while wiring:** (1) seed/passphrase flow through request structs but are only *flagged* redacted, never zeroed in memory; (2) the lifecycle bridge response JSON is discarded, never parsed, so `walletReady` is permanently false.

## Ground rules (carried over from v1 — still binding)

- Keep full-node runtime behavior unchanged; share only through narrow abstractions.
- Never fake balances, sync state, transactions, send results, wallet existence, or server connectivity. A disabled feature must look disabled, not fake-succeed.
- Never log seed phrases, passphrases, private keys, decrypted memos, or raw bridge responses. **Additionally: zero secret buffers (`sodium_memzero`) after use** — fixing the v1 gap.
- Copy Rust-returned strings before free; free exactly once; no raw pointer escape (already done in `lite_client_bridge`).
- Each milestone ships a deterministic test against an **injected fake backend** before any real-backend smoke test.
- Keep release packaging honest: lite artifacts bundle no daemon/Sapling/asmap assets; full-node artifacts stay intact.

## Architectural decisions (resolve up front)

1. **Canonical bridge seam = `lite_client_bridge`.** It already makes real `litelib_*` calls and is what the services use. The elaborate `lite_bridge_runtime` (~1.7 MB cpp, fake-only dry-dispatch + disabled phase-N scaffolds) is **not** the execution path. Keep only its genuinely-useful primitives (`LiteBridgeOwnedString` copy-before-free, idempotent teardown — already referenced by `lite_client_bridge.cpp:182`) and retire the disabled dispatch/promotion scaffolding (subject to the hygiene guard, same as the earlier churn cleanup). Do **not** invest further in `lite_bridge_runtime` dry-dispatch.

2. **App-owned `LiteWalletController`, mirroring the full-node ownership pattern.** The full-node path owns `WalletState state_` (`app.h:421`) as the single source of truth, driven by `NetworkRefreshService` + `RefreshScheduler` via enqueue → `RPCWorker` → callback → apply-to-`state_` (`app_network.cpp:912-944`, `refreshCoreData` ~`:1001-1043`), and every tab reads `app->state()` (`app.h:157-159`). The lite controller constructs `LiteClientBridge::linkedSdxl()` + the lite services with `allowBridgeCalls=true`, runs the same enqueue/worker/apply loop, and **feeds the same `WalletState`** — so the existing Balance/Send/Receive/Transactions tabs light up with no per-tab changes.

3. **Implement the existing `LiteWalletBackend` abstraction** (`wallet_backend.h:59-82`: `setServer/openWallet/startSync/cancelSync/sendTransaction`). It exists and is unused; the controller is its first implementation. Branch in `App::init()` on `supportsLiteBackend()` (`app.h:134-140`).

4. **`WalletState` is backend-agnostic and stays the single source of truth.** Lite-sourced data lands in the same fields the tabs already read: balances, `addresses` (`AddressInfo`), `transactions` (`TransactionInfo`), `sync` (`SyncInfo`) in `data/wallet_state.h`.

5. **Deterministic fake SDXL `.so`.** Build a tiny fake backend implementing the 8 `litelib_*` symbols with canned JSON, used to link a test target and drive every milestone's acceptance test without a real backend or network (satisfies the "injected fake bridge before real smoke test" rule). Real-backend smoke tests follow per milestone.

## Milestones (vertical slices)

Each milestone is independently demoable and gated by a fake-backend test. Order respects the v1 dependency chain (bridge → lifecycle → sync → state → UI → send → ship).

### M0 — Foundation: real artifact, linked build, fake-backend harness
**Goal:** A lite build that links a backend and a test harness that can drive the bridge deterministically.

> **Status (2026-06-04): mostly complete.**
> - ✅ Real Linux artifact built — `scripts/build-lite-backend-artifact.sh --platform linux` → `build/lite-backend/linux/libsilentdragonxlite.a` (126 MB) with all 8 `litelib_*` symbols + manifest (sha256 `c06f5679…`). `build/` is gitignored.
> - ✅ `build.sh --lite-backend` flag added (auto-discovers the artifact; `DRAGONX_LITE_BACKEND_DIR` override).
> - ✅ CMake import contract validated against the real artifact; `ObsidianDragonLite` (93 MB) **links** it (`nm` shows `litelib_execute/initialize_new/shutdown` as defined `T`).
> - ✅ Deterministic injectable fake harness — `tests/fake_lite_backend.h` (`makeFakeLiteApi()`, owned-string alloc/free accounting) + `testLiteBackendInjectableFakeBridge()` in the suite (`ctest` green). This is the harness M1 service tests reuse — it needs neither the real `.so` nor Rust.
> - ⏳ Deferred to a focused follow-up: (a) a standalone fake `.so` link-target for Rust-less CI (the real artifact covers the link path locally); (b) **retiring the `lite_bridge_runtime` disabled-dispatch scaffolding** — large/risky surgical cleanup, not required to unblock M1; do it with the same care as the churn cleanup.
- Run `scripts/build-lite-backend-artifact.sh` against `external/SilentDragonXLite` to produce a Linux `litelib` artifact + symbols file + manifest.
- Add a `build.sh --lite-backend` path that sets `-DDRAGONX_ENABLE_LITE_BACKEND=ON` with the library/symbols/manifest paths (today `--lite` only sets `DRAGONX_BUILD_LITE=ON`).
- Add a small fake SDXL `.so` (8 symbols, canned responses) + a CMake test target that links it; port the existing dry-dispatch tests toward real-symbol-table calls against the fake.
- Retire the `lite_bridge_runtime` disabled-dispatch scaffolding per decision (1).
- **Exit demo / test:** `ObsidianDragonLite` links the real artifact and `currentWalletCapabilities()` reports lite available; a test links the fake `.so` and the bridge reports `available()` and round-trips one `execute()` call.

### M1 — Wallet lifecycle end-to-end (create / open / restore)  ← highest-leverage spike
**Goal:** A user creates/opens/restores a **real** wallet from Settings.

> **Status (2026-06-04): implemented.**
> - ✅ New `src/wallet/lite_wallet_controller.{h,cpp}` — App-owned, constructs `LiteWalletLifecycleService` with `allowBridgeCalls=true`, executes real create/open/restore, **`sodium_memzero`-wipes seed/passphrase** after each call, tracks `walletOpen()`, fires a persist callback on success. `createLinked()` uses `LiteClientBridge::linkedSdxl()`; an injecting ctor takes a fake bridge for tests.
> - ✅ Response-discard defect fixed — `lite_wallet_lifecycle_service.cpp` `bridgeResult()` now sets `walletReady = nlohmann::json::accept(response)` instead of hardcoded `false`.
> - ✅ App wiring — `app.cpp::init()` constructs the controller when `supportsLiteBackend()` with `persist → settings_->save()`; `App::liteWallet()` accessor (null in full-node / unlinked-lite).
> - ✅ UI reroute — `settings_page.cpp` "Validate" handler calls the controller for real when present (shows "Wallet ready"; wipes the UI seed/passphrase buffers after submit), else falls back to the validation-only adapter.
> - ✅ Tests — `testLiteWalletControllerLifecycle()` on the M0 fake harness: create/restore → ready + `walletOpen()` + persist fires + no owned-string leak; empty-seed rejected pre-backend; `allowBridgeCalls=false` and full-node caps fail closed; secret-wipe helper verified. `ctest` green. Builds verified: lite+backend (`build/lite`), lite-no-backend (`build/linux`), and full-node (`build/fullnode`, clean, 0 litelib symbols linked — no regression).
> - ⏳ Deferred refinement: the controller is built at startup from saved connection settings, so a *live* in-session server change isn't honored until restart. Fold into M2/M3 (set the request's `serverUrl` from the field, or rebuild the controller on server-selection save).
>
> **Real-backend smoke (2026-06-04): PASS.** Added `tools/lite_smoke.cpp` + a backend-guarded `lite_smoke` CMake target (built in `build/lite`). Against the live `https://lite.dragonx.is`: `available()=true`, `walletExists(main)=false`, `checkServerOnline()=true`, and `initializeNew()` **created a real wallet** (`silentdragonxlite-wallet.dat`, "Starting Mempool"), seed never logged, isolated `HOME`, exit 0. The create path works end-to-end on the real `litelib`, not just the fake.
>
> Two findings from the smoke run:
> 1. **FIXED — chain-name bug.** Our default chain name was the ticker `"DRAGONX"`, but the SDXL backend hard-`panic!`s on anything outside `{main,test,regtest}` (`lightclient.rs:166`). Changed `kDragonXLiteChainName` and `Settings::lite_chain_name_` to `"main"`. **Migration landed** (`settings.cpp` load): any saved `chain_name` outside `{main,test,regtest}` is rewritten to `"main"` + flagged for re-save, so existing users with `"DRAGONX"` don't hit the panic. Covered by `testLiteChainNameMigration()`.
> 2. **OPEN — panic-across-FFI aborts the app (hardening).** The Rust backend uses `panic!` for error conditions; a panic across the C FFI boundary is UB and `SIGABRT`s the whole process (we saw a core dump). The C++ bridge cannot catch it. Before production: wrap the litelib FFI exports in `std::panic::catch_unwind` (rebuild the vendored lib) and/or validate all inputs before calling. Tracked in M5 (production enablement).
- Add `LiteWalletController` owned by `App` (construct in `App::init()` when `supportsLiteBackend()`), owning `LiteClientBridge::linkedSdxl()` + `LiteConnectionService` + `LiteWalletLifecycleService` with `allowBridgeCalls=true`.
- Reroute the Settings "Validate" button (`settings_page.cpp:1661-1663` → `evaluateLiteLifecycleRequestFromPageState` → validation-only `executeLiteWalletLifecycleUiRequest`, `:237`) to the controller's real `createWallet/openWallet/restoreWallet`. The request structs are already populated correctly (`settings_page.cpp:219-235`).
- Parse the lifecycle response JSON via `lite_result_parsers` and set wallet-ready state (fixes the discarded-response defect).
- Persist server selection + wallet path on success (wire to `config::Settings::save()`; today `settingsWriteRequested` is blocked).
- Zero seed/passphrase buffers after the bridge call (`sodium_memzero`) — fixes the secret-handling defect.
- **Exit demo / test:** Against the fake backend (then a real one), create a wallet → status shows ready; reopen after restart; restore-from-seed succeeds. Fake-backend test asserts the lifecycle path calls the bridge and produces a ready state.

### M2 — Sync loop + WalletState population
**Goal:** After open, balances/addresses/history populate the existing tabs.

> **Status (2026-06-04): data pipeline landed; live wiring (M2b) remains.**
> - ✅ **Last hop implemented + tested** — `applyLiteRefreshModelToWalletState(model, WalletState&)` in `lite_wallet_controller.{h,cpp}`: zatoshi→DRGX balances, z/t address split, transaction typing + confirmations (`chainHeight - blockHeight + 1`), sync progress. Mutates `WalletState` in place (it's non-copyable). `testLiteRefreshModelAppliesToWalletState()` drives a bundle through the existing `mapLiteWalletRefreshBundle` → apply → asserts the populated `WalletState`. `ctest` green.
> - ℹ️ The fetch/parse/assemble pipeline already exists and works: `LiteWalletGateway::refresh()` → `LiteWalletRefreshBundle` → `mapLiteWalletRefreshBundle()` → `LiteWalletAppRefreshModel`. M2 just needed the final `→ WalletState` hop (above) plus live wiring.
> - ✅ **M2b-1 — shared-bridge refactor (done).** `litelib` is a global singleton and every `LiteClientBridge` calls `litelib_shutdown()` on destruction, so services must not each own one. `LiteWalletLifecycleService`, `LiteWalletGateway`, and `LiteSyncService` now take a **non-owning `LiteClientBridge*`**; `LiteWalletController` owns the single bridge and passes `&bridge_`. Builds clean in all configs; existing tests stay green.
> - ✅ **M2b-2 — sync + controller refresh (done + tested).** `LiteSyncService::startSync` now executes the `sync` command (was a stub). `LiteWalletController` gained `startSync()` (auto-invoked when a wallet becomes ready) and `refreshWalletState(WalletState&)` which polls `syncstatus`, runs `gateway.refresh()`, maps the bundle, and applies it into `WalletState`. `testLiteWalletControllerRefreshPopulatesState()` drives the full path against the real-shape fake (balances/addresses/transactions/sync populated; no-op when no wallet open). The fake harness now returns command-shaped JSON per `tests/fixtures/lite/result_parsers.json`. (Surfaced a real bug: `info` requires `latest_block_height`, and the gateway aborts the whole refresh on the first command's parse failure — fixed in the fake; worth noting the gateway's abort-on-first-failure is fragile against partial backend responses.)
> - ⏳ **M2b-3 — threaded App hook (remaining).** Drive `refreshWalletState` from a controller-owned background worker (mirror `NetworkRefreshService`/`RefreshScheduler`): worker produces a copyable `LiteWalletAppRefreshModel`; `App::update()` applies it into `state_` on the main thread (WalletState is non-copyable, so pass the model, not the state, across threads). `litelib_execute` is `catch_unwind`-safe so the worker won't abort the app. Also: per-address balances (notes-correlation) and a real-backend refresh smoke (the real backend's JSON shapes may differ from the hand-built fixture).
- Implement `LiteSyncService::startSync` (replace the "not implemented" stub) + a background worker polling `syncstatus`, mirroring `NetworkRefreshService`/`RefreshScheduler` (enqueue → worker → apply on main thread).
- Drive `LiteWalletGateway` refresh (info/height/balance/addresses/notes/list/transactions) through `lite_result_parsers` → `lite_wallet_state_mapper` → `App` `WalletState` (`privateBalance`, `transparentBalance`, `addresses`, `transactions`, `sync`).
- Hook the controller into `App::update()`'s refresh dispatch alongside (not inside) the full-node path.
- **Exit demo / test:** After open, Balance/Receive/Transactions tabs show real lite data with no per-tab code changes (they already read `app->state()`); sync progress advances. Fake-backend test asserts a canned balance/tx set lands in `WalletState`.

### M3 — Wallet data UI completeness
**Goal:** A complete read-only wallet UX.
- Sync status/progress indicator; loading/empty states; new shielded/transparent address generation via the gateway (`receive_tab`); capability-gated surfaces verified (`isUiSurfaceAvailable`, `settings_page.cpp:1494` lite/full branch).
- **Exit demo / test:** Full read-only experience — balances, address book, history, live sync progress — against fake then real backend.

### M4 — Send / import / export / shield
**Goal:** A user can spend and back up.
- Wire `send_tab` (`:780-787` `sendTransaction`) to `litelib_execute` (`send`/`z_sendmany`) via the gateway, with fee + confirmation UI, result parsing, and tx-status polling that updates `WalletState`.
- Import (keys), export (wallet backup), shield (t→z).
- **Exit demo / test:** Send a transaction and watch it confirm; export a backup. Fake-backend test drives a send and asserts the result/tx-status flow.

### M5 — Persistence, recovery, packaging, production enablement
**Goal:** Shippable.
- Wallet-file durability + crash/recovery + error/retry UX.
- Lite release packaging (zip/AppImage/exe, no daemon assets — `build.sh:285`); build + (read-only-verify) sign the backend artifact in CI per `lite-wallet-backend-signing-policy`.
- Lift macOS deferral; optionally implement the dynamic-loader sublane if shared-library distribution is required (today imported-link only).
- Runtime kill-switch / feature flag / staged rollout.
- **Exit demo / test:** A downloadable `ObsidianDragonLite` that creates, syncs, sends, and persists against a real backend.

## What we explicitly drop from the v1 plan

- The "promote one disabled scaffold at a time" methodology and all `promotion → activation → post-closure → custody → handoff → stewardship → receipt` governance layers.
- Building disabled/typed-only versions of every stack layer ahead of real execution. (Vertical slices replace this.)
- Further investment in `lite_bridge_runtime` dry-dispatch as an execution path.
- "Readiness ceiling" / "Batch N" framing. Progress is measured by demoable capabilities, not batches.

We retain v1's ground rules, dependency ordering, and the artifact/ABI/signing reference docs (`lite-wallet-backend-artifact-link-contract`, `-production`, `-signing-policy`, `-source-signature-plan`).

## Verification

- **Per milestone:** a deterministic test linking the fake SDXL `.so` (no network) that asserts the new capability end-to-end, then a manual real-backend smoke test. Use `/verify` or `/run` to launch `ObsidianDragonLite` and confirm the exit demo.
- **Regression:** `cmake --build build/linux && (cd build/linux && ctest)` stays green; full-node build + behavior unchanged.
- **Hygiene:** `scripts/check-source-hygiene.sh` (pre-commit) keeps the churn from regrowing.

## References

- v1 (superseded/archived): `docs/full-lite-wallet-implementation-plan-2026-05-18.md`
- ABI / artifact / signing: `docs/lite-wallet-backend-artifact-link-contract-2026-05-18.md`, `docs/lite-wallet-backend-artifact-production-2026-05-18.md`, `docs/lite-wallet-backend-signing-policy-2026-05-22.md`, `docs/lite-wallet-backend-source-signature-plan-2026-05-20.md`
- Deferred runtime dynamic-loader design (only if M5 needs it): `docs/lite-wallet-phase2-runtime-bridge-dynamic-loader-sublane-plan-2026-05-23.md`, `docs/lite-wallet-phase2-runtime-bridge-loading-symbol-resolution-plan-2026-05-22.md`