/**
 * CodexDriver — first concrete `ProviderDriver` in the new per-instance model.
 *
 * A driver is a plain value (not a Context.Service) whose `create()` returns
 * one `ProviderInstance` bundling:
 *   - `snapshot`   — the live `ServerProviderShape` for this instance;
 *   - `adapter`    — the Codex session/turn/approval runtime;
 *   - `textGeneration` — commit/PR/branch/title generation via `codex exec`.
 *
 * Each call to `create()` captures the `codexConfig` argument in closures
 * owned by the returned instance. Two instances created with different
 * `homePath`s (e.g. `codex_personal` + `codex_work`) therefore run with
 * fully independent Codex app-server processes and `CODEX_HOME`
 * environments — no shared mutable state.
 *
 * Resource lifecycle: `create()` runs in a scope handed in by the registry.
 * Closing that scope releases the adapter's child processes, the managed
 * snapshot's refresh fibre, and the text-generation binaries' transient
 * scratch files. The registry uses this to tear down an instance when its
 * `providerInstances` entry disappears or its config changes.
 *
 * @module provider/Drivers/CodexDriver
 */
import { CodexSettings, ProviderDriverKind, type ServerProvider } from "@belweave/contracts";
import * as Duration from "effect/Duration";
import * as Effect from "effect/Effect";
import * as FileSystem from "effect/FileSystem";
import * as Path from "effect/Path";
import * as Schema from "effect/Schema";
import * as Stream from "effect/Stream";
import { HttpClient } from "effect/unstable/http";
import { ChildProcessSpawner } from "effect/unstable/process";

import { makeCodexTextGeneration } from "../../textGeneration/CodexTextGeneration.ts";
import { ServerConfig } from "../../config.ts";
import { ProviderDriverError } from "../Errors.ts";
import { makeCodexAdapter } from "../Layers/CodexAdapter.ts";
import { checkCodexProviderStatus, makePendingCodexProvider } from "../Layers/CodexProvider.ts";
import { ProviderEventLoggers } from "../Layers/ProviderEventLoggers.ts";
import { makeManagedServerProvider } from "../makeManagedServerProvider.ts";
import type { ProviderDriver, ProviderInstance } from "../ProviderDriver.ts";
import type { ServerProviderDraft } from "../providerSnapshot.ts";
import { mergeProviderInstanceEnvironment } from "../ProviderInstanceEnvironment.ts";
import {
  enrichProviderSnapshotWithVersionAdvisory,
  makePackageManagedProviderMaintenanceResolver,
  resolveProviderMaintenanceCapabilitiesEffect,
} from "../providerMaintenance.ts";
import {
  codexContinuationIdentity,
  materializeCodexShadowHome,
  resolveCodexHomeLayout,
} from "./CodexHomeLayout.ts";
const decodeCodexSettings = Schema.decodeSync(CodexSettings);

const DRIVER_KIND = ProviderDriverKind.make("codex");
const SNAPSHOT_REFRESH_INTERVAL = Duration.minutes(5);
const UPDATE = makePackageManagedProviderMaintenanceResolver({
  provider: DRIVER_KIND,
  npmPackageName: "@openai/codex",
  homebrewFormula: "codex",
  nativeUpdate: null,
});

/**
 * Services the driver needs to materialize an instance. Surfaced as the
 * driver's `R` so the registry layer aggregates these across every
 * registered driver and the runtime satisfies them once.
 */
export type CodexDriverEnv =
  | ChildProcessSpawner.ChildProcessSpawner
  | FileSystem.FileSystem
  | HttpClient.HttpClient
  | Path.Path
  | ProviderEventLoggers
  | ServerConfig;

/**
 * Stamp instance identity onto a `ServerProvider` snapshot produced by the
 * driver-kind-only codex helpers. Once `buildServerProvider` in
 * `providerSnapshot.ts` is widened to accept `instanceId`/`driver`, this
 * wrapper disappears.
 */
const withInstanceIdentity =
  (input: {
    readonly instanceId: ProviderInstance["instanceId"];
    readonly displayName: string | undefined;
    readonly accentColor: string | undefined;
    readonly continuationGroupKey: string;
  }) =>
  (snapshot: ServerProviderDraft): ServerProvider => ({
    ...snapshot,
    instanceId: input.instanceId,
    driver: DRIVER_KIND,
    ...(input.displayName ? { displayName: input.displayName } : {}),
    ...(input.accentColor ? { accentColor: input.accentColor } : {}),
    continuation: { groupKey: input.continuationGroupKey },
  });

export const CodexDriver: ProviderDriver<CodexSettings, CodexDriverEnv> = {
  driverKind: DRIVER_KIND,
  metadata: {
    displayName: "Codex",
    supportsMultipleInstances: true,
  },
  configSchema: CodexSettings,
  defaultConfig: (): CodexSettings => decodeCodexSettings({}),
  create: ({ instanceId, displayName, accentColor, environment, enabled, config }) =>
    Effect.gen(function* () {
      const spawner = yield* ChildProcessSpawner.ChildProcessSpawner;
      const httpClient = yield* HttpClient.HttpClient;
      const eventLoggers = yield* ProviderEventLoggers;
      const processEnv = mergeProviderInstanceEnvironment(environment);
      const homeLayout = yield* resolveCodexHomeLayout(config);
      const continuationIdentity = codexContinuationIdentity(homeLayout);
      const stampIdentity = withInstanceIdentity({
        instanceId,
        displayName,
        accentColor,
        continuationGroupKey: continuationIdentity.continuationKey,
      });
      yield* materializeCodexShadowHome(homeLayout).pipe(
        Effect.mapError(
          (cause) =>
            new ProviderDriverError({
              driver: DRIVER_KIND,
              instanceId,
              detail: cause.message,
              cause,
            }),
        ),
      );
      const effectiveConfig = {
        ...config,
        enabled,
        homePath: homeLayout.effectiveHomePath ?? "",
      } satisfies CodexSettings;
      const maintenanceCapabilities = yield* resolveProviderMaintenanceCapabilitiesEffect(UPDATE, {
        binaryPath: effectiveConfig.binaryPath,
        env: processEnv,
      });

      // `makeCodexAdapter` and `makeCodexTextGeneration` have `never` error
      // channels at construction time — their failure modes are all on the
      // per-operation closures they return. No `mapError` wrapper is needed
      // here; the registry only has to worry about snapshot-build and
      // spawner-availability failures surfaced from `checkCodexProviderStatus`
      // below.
      const adapter = yield* makeCodexAdapter(effectiveConfig, {
        instanceId,
        environment: processEnv,
        ...(eventLoggers.native ? { nativeEventLogger: eventLoggers.native } : {}),
      });
      const textGeneration = yield* makeCodexTextGeneration(effectiveConfig, processEnv);

      // Build a managed snapshot whose settings never change — mutations come
      // in as instance rebuilds from the registry rather than in-place
      // updates. Pre-provide `ChildProcessSpawner` so the check fits
      // `makeManagedServerProvider.checkProvider`'s `R = never`.
      const checkProvider = checkCodexProviderStatus(effectiveConfig, undefined, processEnv).pipe(
        Effect.map(stampIdentity),
        Effect.provideService(ChildProcessSpawner.ChildProcessSpawner, spawner),
      );
      const snapshot = yield* makeManagedServerProvider<CodexSettings>({
        maintenanceCapabilities,
        getSettings: Effect.succeed(effectiveConfig),
        streamSettings: Stream.never,
        haveSettingsChanged: () => false,
        initialSnapshot: (settings) =>
          makePendingCodexProvider(settings).pipe(Effect.map(stampIdentity)),
        checkProvider,
        enrichSnapshot: ({ snapshot, publishSnapshot }) =>
          enrichProviderSnapshotWithVersionAdvisory(snapshot, maintenanceCapabilities).pipe(
            Effect.provideService(HttpClient.HttpClient, httpClient),
            Effect.flatMap((enrichedSnapshot) => publishSnapshot(enrichedSnapshot)),
          ),
        refreshInterval: SNAPSHOT_REFRESH_INTERVAL,
      }).pipe(
        Effect.mapError(
          (cause) =>
            new ProviderDriverError({
              driver: DRIVER_KIND,
              instanceId,
              detail: `Failed to build Codex snapshot: ${cause.message ?? String(cause)}`,
              cause,
            }),
        ),
      );

      return {
        instanceId,
        driverKind: DRIVER_KIND,
        continuationIdentity,
        displayName,
        accentColor,
        enabled,
        snapshot,
        adapter,
        textGeneration,
      } satisfies ProviderInstance;
    }),
};
