/**
 * kingdee-rule-router.ts — 每轮按产品画像与需求动态注入 1～3 条规则正文
 *
 * 注意：systemPrompt 注入默认不在聊天区展示；同时返回 display:true 的 message
 * 以便用户确认本轮已加载哪些规则。
 */
import * as path from "node:path";
import { fileURLToPath } from "node:url";
import type { ExtensionAPI, BeforeAgentStartEventResult } from "@kingdee-kcode/coding-agent";
import { inferProductLineIntentFromText } from "../src/project/product-line-registry";
import { readProductsFromProjectMd } from "../src/project/product-md";
import { routeRules } from "../src/rules/rule-router";

/** 扩展文件位于 packages/kcode-pi/extensions/ → 包根为上一级 */
function resolveKcodePiRootFromExtension(): string {
	return path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
}

export default function (pi: ExtensionAPI) {
	pi.on("before_agent_start", async (event, ctx): Promise<BeforeAgentStartEventResult | void> => {
		const packageRoot = resolveKcodePiRootFromExtension();
		const profileIds = readProductsFromProjectMd(ctx.cwd);
		const turn = inferProductLineIntentFromText(event.prompt);
		const productIds = profileIds.length > 0 ? profileIds : turn.productIds;

		const result = routeRules({
			prompt: event.prompt,
			productIds,
			packageRoot,
		});

		if (result.skipped || !result.injection) {
			if (result.skipped && /文档|无编码信号/.test(result.reason)) {
				const note = `本轮金蝶规则：${result.reason}`;
				return {
					systemPrompt: [...event.systemPrompt, `\n## 本轮金蝶规则\n- ${result.reason}\n`],
					message: {
						customType: "kingdee-rule-router",
						content: note,
						display: true,
						attribution: "agent",
					},
				};
			}
			return;
		}

		const ruleList = result.selected.map(n => `rule://${n}`).join(", ");
		const summary = `本轮金蝶编码规则已注入（${result.bytes} 字节）：${ruleList}`;
		const meta = `\n<!-- kingdee-rule-router: ${result.selected.join(",")} bytes=${result.bytes} ${result.reason} -->\n`;

		return {
			systemPrompt: [...event.systemPrompt, result.injection + meta],
			message: {
				customType: "kingdee-rule-router",
				content: summary,
				display: true,
				attribution: "agent",
			},
		};
	});
}