import { Injectable } from '@nestjs/common';
import type { HarnessSelection } from '@mosaicstack/types';
import type { ActorTenantScope } from '../auth/session-scope.js';

/**
 * TRANSITIONAL Slice-Zero selection store.
 *
 * This is an EXPLICITLY in-memory, owner-scoped store. It exists only so the
 * Slice-Zero HTTP surfaces round-trip a selection; it is NOT durable and does not
 * survive a process restart. Task Seven replaces it with the durable selection
 * repository backed by the database.
 *
 * The store is keyed STRICTLY by the server-derived scope (userId + tenantId).
 * There is no code path through which a client-supplied id chooses the key.
 */
@Injectable()
export class HarnessSelectionRepository {
  private readonly byOwner = new Map<string, HarnessSelection>();

  get(scope: ActorTenantScope): HarnessSelection | null {
    return this.byOwner.get(ownerKey(scope)) ?? null;
  }

  set(scope: ActorTenantScope, selection: HarnessSelection): HarnessSelection {
    // Store a normalized copy of exactly the tuple fields — nothing else is retained.
    const stored: HarnessSelection = {
      harnessId: selection.harnessId,
      providerId: selection.providerId,
      modelId: selection.modelId,
    };
    this.byOwner.set(ownerKey(scope), stored);
    return stored;
  }
}

/** Owner key from the server-derived scope only. NUL-separated to avoid collisions. */
function ownerKey(scope: ActorTenantScope): string {
  return `${scope.userId} ${scope.tenantId}`;
}