/**
 * sai-deci — the bundled Sai decisions extension.
 *
 * One entrypoint composes the Sai components so the host loads one extension instead of several:
 * the advisory routes own their input/lifecycle handlers, `ask_sai`/`sai_find` own their tools, the
 * tool ranker owns its `tool_search` registration and `session_shutdown` disposal. The components already share the single
 * client in `src/decisions.ts`; this file adds no transport, routing policy, or lifecycle of its own.
 *
 * It also contributes the Sai tools to pi-subagents' code-facing builtin agents. Children load
 * only the tool component, never the advisory routes or ranker.
 */
import { appendFileSync } from "node:fs";
import { fileURLToPath } from "node:url";
import type { ExtensionAPI } from "@selesai/code";
import saiAdvisoryRoutingExtension from "./src/advisory-routing.ts";
import saiAskToolExtension from "./src/ask-tool.ts";
import saiToolRankerExtension from "./src/tool-ranker.ts";

/** Compose the Sai components; each factory registers its own handlers, tools, and ranker. */
export default function saiDeciExtension(pi: ExtensionAPI): void {
	saiAdvisoryRoutingExtension(pi);
	saiAskToolExtension(pi);
	saiToolRankerExtension(pi);
	registerSubagentAugmentations(pi);
	// Debug sink: `SAI_ROUTING_LOG=/path/file.jsonl` appends the content-free `sai-routing` events
	// for `scripts/summarize-sai-routing.mjs`. Unset by default, so nothing is written or subscribed.
	const log = process.env.SAI_ROUTING_LOG;
	if (log) {
		pi.events.on("sai-routing", (event: unknown) => {
			try {
				appendFileSync(log, `${JSON.stringify({ t: Date.now(), ...(event as object) })}\n`);
			} catch {
				// Telemetry never changes behavior.
			}
		});
	}
}

type AugmentationRequest = {
	register(augmentation: { id: string; agentNames: readonly string[]; addTools: readonly string[]; subagentOnlyExtensions: readonly string[] }): void;
};

/**
 * `sai_find` only reads files, so every code-facing builtin gets it. `ask_sai` can run a shell
 * `command`, so it goes only to builtins that already have `bash`; `reviewer` has none.
 */
function registerSubagentAugmentations(pi: ExtensionAPI): void {
	pi.events.on("pi-subagents:request-builtin-agent-augmentations", (request: unknown) => {
		if (!request || typeof (request as Partial<AugmentationRequest>).register !== "function") return;
		const toolExtension = fileURLToPath(new URL("./src/ask-tool.ts", import.meta.url));
		const { register } = request as AugmentationRequest;
		register({
			id: "sai-deci-find",
			agentNames: ["scout", "reviewer", "worker", "delegate", "oracle"],
			addTools: ["sai_find"],
			subagentOnlyExtensions: [toolExtension],
		});
		register({
			id: "sai-deci-ask",
			agentNames: ["scout", "worker", "delegate", "oracle"],
			addTools: ["ask_sai"],
			subagentOnlyExtensions: [toolExtension],
		});
	});
}