/**
 * Read-only memory lookup for pi-subagents child sessions.
 *
 * The full extension also indexes sessions, injects memory policy, runs background review,
 * consolidation and correction detection, and registers write tools. A delegated child must
 * not do any of that. This entrypoint registers only `memory_search` and `session_search` over
 * the parent's database, records no usage hits, and never migrates, backfills or indexes.
 */
import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { loadConfig } from "./config.js";
import { isDatabaseMigrationPending } from "./extension-root-migration.js";
import { AGENT_ROOT, resolveMemoryRoots } from "./paths.js";
import { DatabaseManager } from "./store/db.js";
import { registerMemorySearchTool } from "./tools/memory-search-tool.js";
import { registerSessionSearchTool } from "./tools/session-search-tool.js";
import type { MemoryConfig } from "./types.js";

export const CHILD_SEARCH_TOOLS = ["memory_search", "session_search"] as const;

export interface ChildSearchOptions {
  /** Defaults to the user's memory config; tests pass their own. */
  config?: MemoryConfig;
  agentRoot?: string;
}

export default function hermesMemoryChildSearch(pi: ExtensionAPI, options: ChildSearchOptions = {}): void {
  const config = options.config ?? loadConfig();
  const agentRoot = options.agentRoot ?? AGENT_ROOT;
  const { legacyGlobalDir, globalDir, shouldMigrateExtensionRoot } = resolveMemoryRoots(config.memoryDir, agentRoot);
  const dbManager = new DatabaseManager(globalDir);
  // The parent session owns the full-database scan; a child only reads.
  dbManager.setQuickCheckOnOpen(false);
  let closed = false;
  dbManager.setOpenGuard(() => {
    if (closed) throw new Error("Memory session has shut down");
    // Only the parent migrates; opening first would create an empty database in the new root.
    if (shouldMigrateExtensionRoot && isDatabaseMigrationPending(legacyGlobalDir, globalDir)) {
      throw new Error("Legacy sessions.db migration is pending; the parent session completes it");
    }
  });

  registerSessionSearchTool(pi, dbManager, config.sessionSearch ?? { variant: "legacy" });
  registerMemorySearchTool(pi, dbManager, { usageTrackingEnabled: false });

  pi.on("session_shutdown", async () => {
    closed = true;
    dbManager.close();
  });
}