/** * ProviderInstanceRegistryHydration — derive a `ProviderInstanceConfigMap` * from `ServerSettings` and keep `ProviderInstanceRegistry` in sync with it. * * The server still reads two shapes: * *   1. `settings.providerInstances` — the new driver-agnostic map the *      registry expects. Keyed by `ProviderInstanceId`, values are *      `ProviderInstanceConfig` envelopes. *   2. `settings.providers.<kind>` — the legacy single-instance-per-driver *      fields (`providers.codex`, `providers.claudeAgent`, …). These are *      the source of truth for every deployment that hasn't been migrated *      yet to an explicit `providerInstances` entry. * * This module bridges (2) into (1) and wires the resulting map into a * mutable registry. For every built-in driver whose id is not already * present in `providerInstances` (keyed on * `defaultInstanceIdForDriver(driverKind)` — literally the driver kind as a * routing slug), we synthesize an envelope from the legacy field. The * registry decodes both flavours through the same `configSchema` and ends * up with one uniform `ProviderInstance` per entry. * * Explicit `providerInstances` entries always win — users can already * override the legacy `providers.<kind>` blob by authoring a * `providerInstances.codex` entry with a matching driver, and we don't * want the synthesized envelope to silently stomp their config. * * Hot-reload * ---------- * On layer build we: *   1. Read the current `ServerSettings` once and use it to seed the *      registry's initial state via `ProviderInstanceRegistryMutableLayer`. *   2. Fork a daemon fiber (lifetime tied to the layer's scope) that *      subscribes to `ServerSettingsService.streamChanges` and calls *      `ProviderInstanceRegistryMutator.reconcile` on every emission. * * Failures inside the watcher are logged and swallowed so a single bad * settings emission cannot kill the registry. Unknown drivers and invalid * configs already round-trip through the registry's own "unavailable" * shadow bucket. * * @module provider/Layers/ProviderInstanceRegistryHydration */import {  defaultInstanceIdForDriver,  type ProviderInstanceConfig,  type ProviderInstanceConfigMap,  ServerSettings,} from "@t3tools/contracts";import * as Effect from "effect/Effect";import * as Layer from "effect/Layer";import * as Stream from "effect/Stream"; import { ServerSettingsService } from "../../serverSettings.ts";import { BUILT_IN_DRIVERS, type BuiltInDriversEnv } from "../builtInDrivers.ts";import { ProviderInstanceRegistry } from "../Services/ProviderInstanceRegistry.ts";import { ProviderInstanceRegistryMutator } from "../Services/ProviderInstanceRegistryMutator.ts";import { ProviderInstanceRegistryMutableLayer } from "./ProviderInstanceRegistryLive.ts"; /** * Synthesize a `ProviderInstanceConfigMap` from a `ServerSettings` snapshot. * * Strategy: *   1. Copy all explicit `settings.providerInstances` entries verbatim. *   2. For each built-in driver whose `defaultInstanceIdForDriver(id)` key *      is *not* already in the explicit map, synthesize an entry from the *      matching legacy `settings.providers.<kind>` blob. * * The returned map is the input the registry consumes; pure & exported * separately so the hydration logic can be exercised by unit tests * without layering. */export const deriveProviderInstanceConfigMap = (  settings: ServerSettings,): ProviderInstanceConfigMap => {  const merged: Record<string, ProviderInstanceConfig> = { ...settings.providerInstances };   for (const driver of BUILT_IN_DRIVERS) {    const instanceId = defaultInstanceIdForDriver(driver.driverKind);    if (instanceId in merged) {      // Explicit `providerInstances` entry for this slot — user-authored      // config always wins over the legacy mirror.      continue;    }     // Only built-in drivers have a legacy mirror; the registry's    // `providers` struct is keyed on the same literal slug as    // `driverKind`. Access is dynamic (the driver kind is a branded string),    // but it's constrained to `keyof settings.providers` by the union of    // built-in driver kinds.    const legacyKey = driver.driverKind as keyof ServerSettings["providers"];    const legacyConfig = settings.providers[legacyKey];    if (legacyConfig === undefined) {      continue;    }     merged[instanceId] = {      driver: driver.driverKind,      config: legacyConfig,    };  }   return merged as ProviderInstanceConfigMap;}; /** * Layer that consumes `ProviderInstanceRegistryMutator` and forks a * settings-watcher fiber. The fiber's lifetime is tied to the enclosing * layer scope (process lifetime in production), so it is interrupted on * shutdown without leaking. * * Errors inside the watcher are logged and swallowed — the registry's own * "unavailable" bucket already absorbs unknown drivers and invalid * configs, so the only way the watcher could fail is a settings stream * tear-down, which logs and exits cleanly. */const SettingsWatcherLive: Layer.Layer<  never,  never,  ProviderInstanceRegistryMutator | ServerSettingsService> = Layer.effectDiscard(  Effect.gen(function* () {    const mutator = yield* ProviderInstanceRegistryMutator;    const serverSettings = yield* ServerSettingsService;    yield* serverSettings.streamChanges.pipe(      Stream.runForEach((next) =>        mutator          .reconcile(deriveProviderInstanceConfigMap(next))          .pipe(            Effect.catchCause((cause) =>              Effect.logError("ProviderInstanceRegistry reconcile failed", cause),            ),          ),      ),      Effect.forkScoped,    );  }),); /** * Hydrate `ProviderInstanceRegistry` from `ServerSettings` and keep it in * sync with subsequent `streamChanges` emissions. * * The Layer's two halves: *   - `ProviderInstanceRegistryMutableLayer` produces the registry + *     mutator from the initial config map. Its scope owns every *     per-instance child scope created during reconcile. *   - `SettingsWatcherLive` consumes the mutator and runs a daemon fiber *     in the same scope. * * Composing via `Layer.provideMerge` makes the watcher's deps available * from the mutable layer while still surfacing the registry as an output. * The mutator tag is technically also exposed; only this module imports * it, so the visibility leak is harmless in practice. */export const ProviderInstanceRegistryHydrationLive: Layer.Layer<  ProviderInstanceRegistry,  never,  BuiltInDriversEnv | ServerSettingsService> = Layer.unwrap(  Effect.gen(function* () {    const serverSettings = yield* ServerSettingsService;    const initialSettings: ServerSettings | undefined = yield* serverSettings.getSettings.pipe(      Effect.orElseSucceed(() => undefined),    );    const initialConfigMap =      initialSettings === undefined        ? ({} as ProviderInstanceConfigMap)        : deriveProviderInstanceConfigMap(initialSettings);     const mutableLayer = ProviderInstanceRegistryMutableLayer({      drivers: BUILT_IN_DRIVERS,      configMap: initialConfigMap,    });     return SettingsWatcherLive.pipe(Layer.provideMerge(mutableLayer));  }),) as Layer.Layer<ProviderInstanceRegistry, never, BuiltInDriversEnv | ServerSettingsService>;