import {performance} from 'node:perf_hooks';
import type {Bot} from '@wp2508/mineflayer';
import {instrument_bot, metadata, ResourceInfo} from '../resource_metrics.ts';

export interface CpuInfo {
    scope: 'bot_context';
    estimated: true;
    method: 'instrumented_sync_time';
    usage_percent: number | null;
    sampled_time_ms: number;
    interval_ms: number;
    coverage: string;
}

const coverage = '计量 Bot.emit 和初始 _client.emit 监听器的同步执行（包括数据包监听器和 physicsTick），'
    + '以及函数 run 的同步调用阶段；嵌套调用去重。不包含 emit 前的协议解析、异步等待及后续执行、'
    + '无关定时器、上述入口之外的插件执行和 BotContext 通知。'
    + '同步经过时间包含垃圾回收和操作系统调度暂停，因此该指标不是进程 CPU 使用率。';

export class init extends ResourceInfo<CpuInfo> {
    readonly name = 'used_cpu';
    readonly i18n = metadata('上下文 CPU 占用估算', coverage, {
        scope: ['归属范围', '指标归属于机器人上下文，固定为 bot_context'],
        estimated: ['是否为估算', '固定为 true，表示该指标始终是估算值'],
        method: ['计量方法', '通过插桩计量同步经过时间，不使用操作系统 CPU 计数器'],
        usage_percent: ['占用比例', '采样同步耗时除以实际经过时间再乘以 100，单位为百分比；首次采样前为 null'],
        sampled_time_ms: ['采样同步耗时', '本次采样间隔内去重后的同步执行耗时，单位为毫秒'],
        interval_ms: ['采样间隔', '通过单调时钟测得的实际经过时间，单位为毫秒'],
        coverage: ['计量覆盖范围', '同步执行计量包含的入口及未覆盖的执行阶段'],
    });
    private readonly meter: ReturnType<typeof instrument_bot>;
    constructor(bot: Bot) {
        super({scope: 'bot_context', estimated: true, method: 'instrumented_sync_time',
            usage_percent: null, sampled_time_ms: 0, interval_ms: 0, coverage});
        this.meter = instrument_bot(bot);
        let time = performance.now();
        let total = this.meter.total();
        this.start(1000, () => {
            const now = performance.now();
            const next = this.meter.total();
            const elapsed = now - time;
            const sampled = Math.max(0, next - total);
            time = now;
            total = next;
            this.publish({...this.info, usage_percent: elapsed > 0 ? sampled / elapsed * 100 : null,
                sampled_time_ms: sampled, interval_ms: elapsed});
        });
    }
    override dispose(): void {
        super.dispose();
        this.meter.dispose();
    }
}