"use strict";

import path from 'path';
import fs from 'fs';

import sysinfo from 'systeminformation';

import log from '../../lib/io/NamespacedLog.mjs'; const l = log("infobroker");

// HACK: Make sure __dirname is defined when using es6 modules. I forget where I found this - a PR with a source URL would be great :D
const __dirname = import.meta.url.slice(7, import.meta.url.lastIndexOf("/"));


class InfoBroker {
	constructor(sysquery) {
		this.sysquery = sysquery;
		
		this.allowed_tables = {
			// name → sysinfo name
			cpu: "cpu",
			cpu_live: async () => {
				return {
					frequency: await sysinfo.cpuCurrentSpeed(),
					temperature: await sysinfo.cpuTemperature()
				};
			},
			meta: async () => await this.make_table_meta()
		};
	}
	
	/**
	 * Determines if the given table name is valid or not.
	 * @param	{string}	name	The table name to validate.
	 * @return	{Boolean}	Whether the table name is valid (true) or not (false).
	 */
	is_valid_table(name) {
		return Object.keys(this.allowed_tables).includes(name);
	}
	
	/**
	 * Returns a list of known table names.
	 * @return {string[]}	A list of known table names.
	 */
	list_tables() {
		return Object.keys(this.allowed_tables);
	}
	
	async make_table_meta() {
		return {
			version: `${this.sysquery.version}-${this.sysquery.commit.substring(0, 7)}`,
			versions_env: process.versions,
			pid: process.pid,
			uptime: process.uptime(),
			memory: process.memoryUsage(),
		};
	}
	
	async fetch_table(name) {
		if(!(typeof name === "string"))
			throw new Exception(`Error: Expected name to be of type string, but received value of type ${typeof name} instead.`);
		
		if(!this.is_valid_table(name)) {
			l.warn(`Unrecognised table '${name}' requested, returning null`);
			return null;
		}
		
		let name_translated = this.allowed_tables[name];
		
		if(typeof name_translated === "function")
			return await name_translated();
		
		return await sysinfo[name_translated]();
	}
}

export default InfoBroker;