import {
  createDemoSessionAdapter,
  createExternalAuthSessionAdapter,
  createUnavailableSessionAdapter,
  type ExternalSessionOwner,
} from "../adapters/auth/external-session-adapter.ts";
import { createDiagnosticsAdapter } from "../adapters/diagnostics/bounded-diagnostics.ts";
import { createHttpClient } from "../adapters/http/client.ts";
import {
  createContractHttpExecutor,
  type HttpExecutionObservation,
} from "../adapters/http/http-execution-v3.ts";
import {
  attemptBucket,
  durationBucket,
  statusGroup,
  type DiagnosticRecordInput,
} from "../contracts/diagnostics.ts";
import type { TelemetryEventName } from "../contracts/telemetry.ts";
import { createBrowserCrossContextInvalidationFromHost } from "../adapters/cross-context-invalidation/index.ts";
import {
  createTanStackCacheCoordinator,
} from "../adapters/query-cache/tanstack-cache-coordinator.ts";
import { createQueryClient } from "../adapters/query-cache/tanstack-query-cache.ts";
import { createServerStateScopeRuntime } from "../adapters/query-cache/server-state-scope-runtime.ts";
import { createConditionalValidatorStore } from "../adapters/query-cache/conditional-validator-store.ts";
import { createBrowserStorageAdapter } from "../adapters/storage/browser-storage-adapter.ts";
import { createBrowserMutationIntentFactory } from "../adapters/platform/browser-mutation-intent-factory.ts";
import { createTelemetryAdapter } from "../adapters/telemetry/best-effort-telemetry.ts";
import { createCsrfTokenProvider } from "../features/tech-log/adapters/http/studio-session-csrf.ts";
import {
  attachStudioSessionCredentials,
  invalidateTechLogCsrfOnOutcome,
} from "../features/tech-log/adapters/http/studio-session-credentials.ts";
import type { StudioOperationExecutor as TechLogStudioOperationExecutor } from "../features/tech-log/adapters/http/http-studio-gateway.ts";
import type { AuthSessionPort } from "../application/ports/auth-session-port.ts";
import type { ReleaseInfo } from "../application/ports/release-info-port.ts";
import {
  createRestProviderProfile,
  INSTALLED_REST_AUTH_PROFILES,
} from "../contracts/rest-profiles.ts";
import type { ClockPort } from "../application/ports/clock-port.ts";
import type { MutationIntent } from "../contracts/mutation-intent.ts";
import { createInstalledFeatureInputs } from "../features/installed-feature-adapters.ts";
import {
  INVALIDATION_REGISTRY,
  INVALIDATION_TOPIC_VERSIONS,
} from "../features/installed-feature-contracts.ts";
import { INSTALLED_RUNTIME_CAPABILITIES } from "../features/installed-runtime-capabilities.ts";
import {
  COMPILED_PRODUCT_FEATURE_IDS,
  INSTALLED_PRODUCT_FEATURE_IDS,
} from "../features/installed-product-manifest.ts";
import {
  activeProductFeatureIds,
  resolveProductFeatures,
} from "../contracts/product-features.ts";
import { describeRuntimeCapabilities } from "../contracts/runtime-capabilities.ts";
import {
  fetchReleaseManifest,
  type ReleaseManifest,
} from "./load-release-manifest.ts";
import type { RuntimeConfigLoadResult } from "./load-runtime-config.ts";
import { createServerStateGenerationStore } from "./server-state-generation-store.ts";
import { COMPOSED_CONTRACT_CONTRIBUTIONS } from "../features/installed-contract-contributions.ts";
import {
  indexInvalidationRegistry,
  indexInvalidationTopicVersions,
} from "../contracts/query-invalidation.ts";

type HttpClientDependencies = Parameters<typeof createHttpClient>[0];
export type RuntimeHttpContract = Pick<
  HttpClientDependencies,
  "getOperation" | "validatePayload" | "validateRequest" | "mapPayload"
>;

type RuntimeHttpContext = Readonly<{
  runtime: RuntimeConfigLoadResult;
  authSession: AuthSessionPort;
  fetcher?: typeof fetch;
  clock?: ClockPort;
  scheduler?: HttpClientDependencies["scheduler"];
  diagnostics?: HttpClientDependencies["diagnostics"];
  telemetry?: HttpClientDependencies["telemetry"];
}>;

export type RuntimeAdaptersContext = Readonly<{
  runtime: RuntimeConfigLoadResult;
  release: Readonly<ReleaseManifest>;
  host?: Record<string, unknown>;
  fetcher?: typeof fetch;
}>;

/**
 * §5.2. The composition root is where a manifest becomes release info. A V2
 * manifest states contract identity as a verified contract set and a V1
 * manifest as the legacy scalar; the application layer sees one shape and never
 * branches on the schema version to find the identity.
 */
function toReleaseInfo(manifest: Readonly<ReleaseManifest>): ReleaseInfo {
  const { contractSet, legacyApiContractVersion, ...rest } =
    structuredClone(manifest);
  return Object.freeze({
    ...rest,
    ...(legacyApiContractVersion === undefined
      ? {}
      : { apiContractVersion: legacyApiContractVersion }),
    ...(contractSet === null
      ? {}
      : { contractSetDigest: contractSet.setDigest }),
  });
}

const EXTERNAL_OWNER_METHODS = Object.freeze([
  "readState",
  "subscribe",
  "beginSignIn",
  "signOut",
  "attachCredential",
  "recoverSession",
  "notifyUnauthenticated",
] as const);

function isRecord(value: unknown): value is Record<string, unknown> {
  return Boolean(value) && typeof value === "object";
}

function externalOwnerFrom(
  host: Record<string, unknown>,
): ExternalSessionOwner | null {
  const candidate = host.__CA_FRONTEND_AUTH_OWNER__;
  if (!isRecord(candidate)) return null;
  return EXTERNAL_OWNER_METHODS.every(
    (name) => typeof candidate[name] === "function",
  )
    ? (candidate as ExternalSessionOwner)
    : null;
}

function hostValue(
  host: Record<string, unknown>,
  property: string,
): unknown {
  try {
    return Reflect.get(host, property);
  } catch {
    return undefined;
  }
}

function storageOrUndefined(value: unknown): Storage | undefined {
  if (!value || typeof value !== "object") return undefined;
  const candidate = value as Record<string, unknown>;
  try {
    return ["getItem", "setItem", "removeItem"].every(
      (method) => typeof Reflect.get(candidate, method) === "function",
    )
      ? (value as Storage)
      : undefined;
  } catch {
    return undefined;
  }
}

/**
 * Runtime-aware transport factory. Feature gateway composition calls this
 * factory when a registered API capability is installed.
 */
export function createRuntimeHttpClient(
  context: RuntimeHttpContext,
  contract: RuntimeHttpContract = {},
) {
  return createHttpClient({
    baseUrl: context.runtime.config.API_BASE_URL,
    timeoutMs: context.runtime.config.REQUEST_TIMEOUT_MS,
    maxRetryAttempts: context.runtime.config.MAX_RETRY_ATTEMPTS,
    authSession: context.authSession,
    providerProfile: createRestProviderProfile(
      "PRIMARY_API",
      context.runtime.config.API_BASE_URL,
      ["omit"],
    ),
    fetcher: context.fetcher,
    clock: context.clock,
    scheduler: context.scheduler,
    diagnostics: context.diagnostics,
    telemetry: context.telemetry,
    ...contract,
  });
}

/**
 * VD-07. Exactly one diagnostic per logical V3 execution and exactly one
 * `api.request.failed` telemetry event per terminal non-abort failure.
 *
 * The projection is closed: only registered context keys and bucketed values
 * reach the sinks, and neither sink can change the HTTP outcome, because the
 * caller invokes this inside the executor's isolated observation boundary.
 */
export function createHttpObservationProjector(
  sinks: Readonly<{
    diagnostics: Readonly<{ record(input: DiagnosticRecordInput): void }>;
    telemetry: Readonly<{
      emit(
        eventName: TelemetryEventName,
        attributes: Record<string, unknown>,
      ): void;
    }>;
  }>,
): (observation: HttpExecutionObservation) => void {
  return (observation) => {
    const safeAttributes = {
      route_id: observation.routeId,
      operation_id: observation.operationId,
      error_kind: observation.errorKind,
      http_status_group: statusGroup(observation.status),
      attempt_count_bucket: attemptBucket(observation.attemptCount),
      duration_bucket: durationBucket(observation.durationMs),
    };
    try {
      sinks.diagnostics.record({
        level: observation.outcome === "SUCCESS" ? "info" : "warn",
        eventId: "http.request.completed",
        context: {
          ...safeAttributes,
          operation: observation.diagnosticsOperation,
          outcome: observation.outcome,
        },
      });
    } catch {
      // Diagnostics cannot change a contract execution outcome.
    }
    if (!isTerminalNonAbortFailure(observation)) return;
    try {
      sinks.telemetry.emit("api.request.failed", { ...safeAttributes });
    } catch {
      // Telemetry cannot change a contract execution outcome.
    }
  };
}

/**
 * LIVE-05. Cancellation and scope fencing are caller- or generation-owned
 * decisions, not API failures: they produce a diagnostic once and never
 * `api.request.failed`.
 *
 * A `DEADLINE` owner is the opposite case. Nobody asked for it — the API did
 * not answer inside the contract's own budget — so excluding it would hide
 * exactly the outage this event exists to report.
 */
const CALLER_OWNED_CANCELLATION: ReadonlySet<string> = new Set([
  "CALLER",
  "ROUTE_TRANSITION",
  "SCOPE_FENCE",
  "APPLICATION_SHUTDOWN",
]);

function isTerminalNonAbortFailure(
  observation: HttpExecutionObservation,
): boolean {
  if (observation.outcome === "SUCCESS") return false;
  if (observation.outcome === "CANCELLED") return false;
  if (
    observation.cancellationOwner !== undefined &&
    CALLER_OWNED_CANCELLATION.has(observation.cancellationOwner)
  ) {
    return false;
  }
  return !(
    observation.outcome === "CONTRACT_VIOLATION" &&
    observation.errorKind === "SCOPE_FENCED"
  );
}

export async function createRuntimeAdapters(
  context: RuntimeAdaptersContext,
) {
  const host =
    context.host ?? (globalThis as unknown as Record<string, unknown>);
  const config = context.runtime.config;
  const mutationIntentFactory = createBrowserMutationIntentFactory();
  const externalOwner = externalOwnerFrom(host);
  const authSession =
    config.AUTH_MODE === "demo"
      ? createDemoSessionAdapter()
      : externalOwner
        ? createExternalAuthSessionAdapter(externalOwner)
        : createUnavailableSessionAdapter();
  const diagnostics = createDiagnosticsAdapter();
  const telemetry = createTelemetryAdapter({
    enabled: config.TELEMETRY_ENABLED,
    endpoint: config.TELEMETRY_ENDPOINT,
    fetcher: context.fetcher,
    onDrop(event) {
      const attributes =
        event.attributes && typeof event.attributes === "object"
          ? event.attributes
          : {};
      diagnostics.record({
        level: "warn",
        eventId: "telemetry.delivery.dropped",
        context: attributes,
      });
    },
  });
  const invalidationIndex = indexInvalidationRegistry(INVALIDATION_REGISTRY);
  const invalidationTopicVersions = indexInvalidationTopicVersions(
    INVALIDATION_REGISTRY,
    INVALIDATION_TOPIC_VERSIONS,
  );
  const conditionalValidators = createConditionalValidatorStore();
  const serverStateGeneration = createServerStateGenerationStore(() => {
    const queryClient = createQueryClient({ diagnostics });
    const crossContextInvalidation =
      createBrowserCrossContextInvalidationFromHost({
        ...(context.host === undefined ? {} : { host: context.host }),
        cacheEpoch: `release.${context.release.releaseId}`,
        topics: [...invalidationTopicVersions].map(([topic, topicVersion]) =>
          Object.freeze({
            topic,
            topicVersion,
          }),
        ),
        observe(observation) {
          if (
            observation.outcome !== "FAILED" &&
            observation.outcome !== "DEGRADED"
          ) {
            return;
          }
          diagnostics.record({
            level: "warn",
            eventId: "cache.operation.failed",
            context: {
              operation: observation.operation,
              outcome: observation.outcome,
              reason: observation.reason,
            },
          });
        },
      });
    const queryInvalidation = createTanStackCacheCoordinator({
      queryClient,
      invalidationIndex,
      topicVersions: invalidationTopicVersions,
      crossContext: crossContextInvalidation,
      diagnostics,
    });
    return Object.freeze({
      queryClient,
      queryInvalidation,
      crossContextStatus: () =>
        crossContextInvalidation?.getStatus() ?? "DEGRADED_LOCAL_ONLY",
    });
  });
  const serverStateScope = createServerStateScopeRuntime({
    session: authSession,
    queryInvalidation: {
      resetLocal: () => serverStateGeneration.resetCurrent(),
    },
    participants: [
      {
        order: 4,
        label: "conditional-validators",
        close: () => conditionalValidators.clear(),
      },
    ],
    activateNextGeneration: () => serverStateGeneration.activateNext(),
  });
  const storage = createBrowserStorageAdapter({
    localStorage: storageOrUndefined(hostValue(host, "localStorage")),
    sessionStorage: storageOrUndefined(
      hostValue(host, "sessionStorage"),
    ),
    diagnostics,
  });
  const releaseInfo = Object.freeze({
    async getCurrent() {
      return toReleaseInfo(context.release);
    },
    async refresh() {
      return toReleaseInfo(
        await fetchReleaseManifest(config.RELEASE_MANIFEST_URL, {
          fetcher: context.fetcher,
          buildId: context.release.buildId,
          releaseId: context.release.releaseId,
        }),
      );
    },
  });
  const runtimeCapabilities = Object.freeze({
    getSnapshot() {
      return describeRuntimeCapabilities(
        INSTALLED_RUNTIME_CAPABILITIES,
        config.CAPABILITY_OVERRIDES,
      );
    },
  });
  /**
   * §3.5. The two halves of the feature answer meet here and nowhere else: the
   * manifest says what the build compiled in, the runtime document says what is
   * switched off. Neither can add to the other.
   */
  const productFeatureStatuses = resolveProductFeatures(
    COMPILED_PRODUCT_FEATURE_IDS,
    INSTALLED_PRODUCT_FEATURE_IDS,
    config.FEATURE_OVERRIDES,
  );
  const activeFeatureIds = new Set(
    activeProductFeatureIds(productFeatureStatuses),
  );
  const productFeatures = Object.freeze({
    getSnapshot() {
      return productFeatureStatuses;
    },
    isActive(featureId: string) {
      return activeFeatureIds.has(featureId);
    },
  });
  const navigation = Object.freeze({
    reload() {
      const location = host.location;
      if (!isRecord(location) || typeof location.reload !== "function") {
        throw new Error("Browser reload is unavailable");
      }
      location.reload();
    },
  });
  /**
   * §7.7 / Task 7. There is exactly one CSRF provider per Studio session, and
   * it is owned by the composition root — not by the TechLog feature input —
   * because two collaborators share it: `attachCredentials` below (the only
   * path by which the CSRF header reaches the 17 JSON operations that
   * require it — every operation except `getStudioSession` itself) and the
   * multipart upload transport, which bypasses the platform executor
   * entirely and must set the header itself. If each built its own provider,
   * one Studio session would hold two different tokens.
   *
   * `execute` calls `getStudioSession` through `contractOperations`, which is
   * declared further below — a real ordering hazard, since `attachCredentials`
   * (needed to build `contractHttp`, needed to build `contractOperations`)
   * needs this provider first.
   *
   * Fix round 1 (C1). The original comment here claimed "`getStudioSession`
   * is a SAFE operation and needs no CSRF, so there is no true cycle" — that
   * was wrong. `retrySemantics: "SAFE"` and the auth profile's
   * `requiredCredentialHeaders` are orthogonal; every operation stamped with
   * `TECH_LOG_STUDIO_SESSION` (originally including `getStudioSession`
   * itself) required the CSRF header, so fetching the token required already
   * having it — an unconditional, deterministic cycle, reproduced against the
   * real composition root as unbounded recursion
   * (`RangeError: Maximum call stack size exceeded`), not a first-request
   * race. The real fix is `getStudioSession` now using the credential-free
   * `TECH_LOG_STUDIO_BOOTSTRAP` profile (`rest-profiles.ts`,
   * `tech-log-studio-contract-contribution.ts`), so its own
   * `attachCredentials` call never reaches this provider. `let` plus a
   * forward reference inside this closure still defers the read of
   * `contractOperations` to call time instead of declaration time — that part
   * of the original design was fine — but the binding below is a throwing
   * stub rather than a bare `let x!: T` definite-assignment assertion: `!`
   * silently accepts `undefined` forever if a future refactor inserts an
   * `await` between this declaration and the real assignment, where a stub
   * fails loudly instead.
   */
  let contractOperations: TechLogStudioOperationExecutor = Object.freeze({
    async execute() {
      throw new Error(
        "contractOperations used before assignment in createRuntimeAdapters — " +
          "construction order regressed.",
      );
    },
  });
  const techLogCsrf = createCsrfTokenProvider({
    async execute(options) {
      const outcome = await contractOperations.execute(
        "getStudioSession",
        {},
        {
          routeId: "TECH_LOG_STUDIO",
          ...(options?.signal ? { signal: options.signal } : {}),
        },
      );
      if (outcome.kind !== "SUCCESS") {
        throw new Error("studio session is unavailable");
      }
      const value = outcome.value as { csrfToken: string; csrfHeaderName: string };
      return { csrfToken: value.csrfToken, csrfHeaderName: value.csrfHeaderName };
    },
  });
  const contractHttp = createContractHttpExecutor({
    baseUrl: config.API_BASE_URL,
    maxRetryAttempts: config.MAX_RETRY_ATTEMPTS,
    // §6.1. `REQUEST_TIMEOUT_MS` was declared, validated and then dropped on the
    // floor here: every V3 operation ran on its contract's own 10s deadline and
    // the deployment dial did nothing. It is a ceiling, so it can tighten an
    // operation but never loosen one.
    requestDeadlineCeilingMs: config.REQUEST_TIMEOUT_MS,
    fetcher: context.fetcher,
    // §7.7. The installed registry owns Fetch credentials and the exact
    // credential-header sets; this collaborator only supplies proof headers.
    authProfiles: INSTALLED_REST_AUTH_PROFILES,
    async attachCredentials(operation, authContext) {
      if (serverStateScope.getPhase() !== "READY") {
        return Object.freeze({ kind: "SCOPE_FENCED" as const });
      }
      // Fix round 1 (C1, M4). Extracted to `studio-session-credentials.ts` so
      // this exact code — not a re-implementation of it — is what
      // `tests/features/tech-log/studio-csrf-composition.test.ts` exercises
      // against the real executor and provider.
      const studioOutcome = await attachStudioSessionCredentials(
        operation.authProfileId,
        authContext,
        techLogCsrf,
      );
      if (studioOutcome) return studioOutcome;
      const state = authSession.getState();
      if (state === "integration-failed") {
        return Object.freeze({ kind: "UNAVAILABLE" as const });
      }
      if (state !== "authenticated") {
        return Object.freeze({ kind: "UNAUTHENTICATED" as const });
      }
      try {
        const patch = await authSession.credentialPatch(
          {
            origin: new URL(config.API_BASE_URL).origin,
            method: operation.method,
            operationId: operation.operationId,
          },
          authContext,
        );
        if (serverStateScope.getPhase() !== "READY") {
          return Object.freeze({ kind: "SCOPE_FENCED" as const });
        }
        return Object.freeze({
          kind: "READY" as const,
          headers: patch.headers,
        });
      } catch {
        return Object.freeze({ kind: "UNAVAILABLE" as const });
      }
    },
    observe: createHttpObservationProjector({ diagnostics, telemetry }),
  });
  contractOperations = Object.freeze({
    async execute(
      operationId: string,
      input: unknown,
      executionContext: Readonly<{
        routeId: string;
        signal?: AbortSignal;
        intent?: MutationIntent;
      }>,
    ) {
      const operation =
        COMPOSED_CONTRACT_CONTRIBUTIONS.httpByOperationId.get(operationId);
      if (!operation) {
        return Object.freeze({
          kind: "CONTRACT_VIOLATION" as const,
          effect: "NOT_STARTED" as const,
          violation: Object.freeze({
            kind: "FINAL_REQUEST_INVARIANT_FAILED" as const,
            operation: "REQUEST" as const,
          }),
        });
      }
      const outcome = await contractHttp.execute(operation, input, {
        routeId: executionContext.routeId,
        scope: serverStateScope.getSnapshot(),
        ...(executionContext.signal === undefined
          ? {}
          : { signal: executionContext.signal }),
        ...(executionContext.intent === undefined
          ? {}
          : { intent: executionContext.intent }),
      });
      if (outcome.kind === "UNAUTHENTICATED") {
        authSession.onUnauthenticated();
      }
      // Fix round 2, item 1. `UNAUTHENTICATED` (401) and `FORBIDDEN` (403 —
      // the shape a CSRF-specific rejection normally takes) both leave a
      // stale token cached for every other in-flight and future Studio
      // request if nothing discards it. The cache owner discards it here,
      // not the gateway — the gateway has no way to know a rejection on one
      // operation invalidates a token shared across all of them. Same call
      // the composition test drives
      // (`tests/features/tech-log/studio-csrf-composition.test.ts`).
      // The auth profile scopes it to Studio operations: this executor serves
      // every installed feature, so without it an unrelated 403 discarded the
      // TechLog token.
      invalidateTechLogCsrfOnOutcome(
        outcome.kind,
        operation.frontend.authProfileId,
        techLogCsrf,
      );
      return outcome;
    },
  });
  const featureInputs = createInstalledFeatureInputs({
    contractOperations,
    studioSource: config.TECH_LOG_STUDIO_SOURCE,
    apiBaseUrl: config.API_BASE_URL,
    requestTimeoutMs: config.REQUEST_TIMEOUT_MS,
    csrf: techLogCsrf,
  });

  return Object.freeze({
    outputPorts: Object.freeze({
      session: authSession,
      preferences: storage,
      diagnostics,
      telemetry,
      releaseInfo,
      runtimeCapabilities,
      productFeatures,
      navigation,
    }),
    infrastructure: Object.freeze({
      get queryClient() {
        return serverStateGeneration.getSnapshot().queryClient;
      },
      get queryInvalidation() {
        return serverStateGeneration.getSnapshot().queryInvalidation;
      },
      serverStateGeneration,
      serverStateScope,
      mutationIntentFactory,
      conditionalValidators,
      crossContextInvalidationStatus: () =>
        serverStateGeneration.getSnapshot().crossContextStatus(),
      dispose() {
        // N-04. Telemetry is torn down first: it must stop scheduling and
        // delivering before the diagnostics and state dependencies it observes
        // are destroyed.
        telemetry.dispose();
        conditionalValidators.clear();
        serverStateScope.dispose();
        serverStateGeneration.dispose();
      },
    }),
    featureInputs,
  });
}