import { existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
import { dirname } from "node:path";
import type { WebUiPaths } from "../config/paths.ts";

export function readModelsConfig(paths: WebUiPaths): string {
	if (!existsSync(paths.modelsConfigFile)) return "{\n  \"providers\": {}\n}\n";
	return readFileSync(paths.modelsConfigFile, "utf8");
}

export function writeModelsConfig(paths: WebUiPaths, content: string): void {
	let parsed: unknown;
	try {
		parsed = JSON.parse(content);
	} catch (err) {
		const message = err instanceof Error ? err.message : String(err);
		throw new Error(`models.json 不是有效的 JSON: ${message}`);
	}
	if (parsed === null || typeof parsed !== "object" || Array.isArray(parsed)) {
		throw new Error("models.json 根节点必须是 JSON 对象");
	}
	const formatted = `${JSON.stringify(parsed, null, 2)}\n`;
	mkdirSync(dirname(paths.modelsConfigFile), { recursive: true });
	writeFileSync(paths.modelsConfigFile, formatted, "utf8");
}