/**
 * UptimeRobot 只读数据源（API v2）—— Cloudflare Workers 版
 *
 * 与 prober/node/lib/uptimerobot.js 共用同一份语义（术语对齐见该文件顶部注释），
 * 但按 Workers 环境改了两处：
 *   1. 没有 node:crypto / node:fs，API Key 从 env（wrangler secret）读取
 *   2. 限流改为「按 KV 里记录的上次同步时间判断」，KV 最终一致对分钟级同步无影响
 *
 * 只读：仅调用 getMonitors，不做任何写操作，因此用 ur* 开头的只读 Key 即可。
 */

const API_URL = 'https://api.uptimerobot.com/v2/getMonitors';
const TYPE_LABEL = { 1: 'HTTP', 2: 'KEYWORD', 3: 'PING', 4: 'PORT' };

// 暂停/未检测都归入 pending：否则会被误报成「离线」
const STATUS_MAP = { 0: 'pending', 1: 'pending', 2: 'up', 8: 'down', 9: 'down' };

function splitNums(value) {
  return String(value ?? '').split('-').map(Number).filter(Number.isFinite);
}

function ratiosToObject(value, ratios) {
  const nums = splitNums(value);
  const out = {};
  ratios.forEach((r, i) => { if (Number.isFinite(nums[i])) out[r] = nums[i]; });
  return out;
}

function targetOf(m) {
  if (m.type === 4 && m.port) return `${m.url ? `${m.url}:` : ''}${m.port}`;
  return m.url || '';
}

function latestDownReason(logs) {
  const down = (logs ?? []).find((l) => l.type === 1);
  const reason = down?.reason;
  if (!reason) return null;
  const code = String(reason.code ?? '').trim();
  const detail = String(reason.detail ?? '').trim();
  return { code: code || null, text: [code, detail].filter(Boolean).join(' ') || null };
}

/** 把 UptimeRobot 的 getMonitors 响应映射成内部结构（纯函数，可离线单测） */
export function mapUptimeRobotMonitors(payload, options = {}) {
  const group = options.group || 'UptimeRobot';
  const ratios = options.ratios ?? [1, 7, 30, 90];
  const now = options.now ?? Date.now();
  const historyLimit = options.historyLimit ?? 48;
  const monitors = [];

  for (const m of payload?.monitors ?? []) {
    const status = STATUS_MAP[m.status] ?? 'pending';
    const samples = Array.isArray(m.response_times) ? m.response_times : [];
    const logs = Array.isArray(m.logs) ? m.logs : [];
    // UR 侧的真实检测时刻：正常取最新响应样本，故障取最近一次故障日志
    const lastCheckSec = status === 'down' ? logs.find((l) => l.type === 1)?.datetime : samples[0]?.datetime;
    const lastCheckIso = new Date((Number(lastCheckSec) || Math.floor(now / 1000)) * 1000).toISOString();

    const history = samples
      .slice(0, historyLimit)
      .map((s) => ({ t: new Date(s.datetime * 1000).toISOString(), ok: Number(s.value) > 0, ms: Math.max(0, Number(s.value) || 0) }))
      .reverse();
    if (status === 'down') history.push({ t: lastCheckIso, ok: false, ms: 0 });

    const last = samples[0]?.value;
    const avg = m.average_response_time;
    const latency = Number.isFinite(Number(last)) && Number(last) > 0
      ? Math.round(Number(last))
      : Number.isFinite(Number(avg)) ? Math.round(Number(avg)) : null;

    const reason = latestDownReason(logs);
    let detail;
    if (status === 'up') detail = 'UptimeRobot：运行正常';
    else if (status === 'down') detail = `UptimeRobot：${reason?.text ?? '连接失败'}`;
    else detail = m.status === 0 ? 'UptimeRobot：监控已暂停' : 'UptimeRobot：尚未检测';

    monitors.push({
      id: `ur-${m.id}`,
      name: m.friendly_name || `UptimeRobot #${m.id}`,
      group,
      type: 'ur',
      url: targetOf(m),
      source: 'uptimerobot',
      sourceId: m.id,
      sourceType: m.type,
      sourceLabel: TYPE_LABEL[m.type] ?? `TYPE${m.type}`,
      interval: Number(m.interval) || 300,
      status,
      latency,
      code: status === 'down' && reason?.code ? Number(reason.code) || null : null,
      detail,
      lastCheckIso,
      history,
      uptimeRatios: ratiosToObject(m.custom_uptime_ratio, ratios),
      downSeconds: ratiosToObject(m.custom_down_durations, ratios),
    });
  }
  return monitors;
}

/**
 * 拉取 UptimeRobot 监控列表。
 * @param {string} apiKey
 * @param {{ratios?: number[], timeoutMs?: number}} [options]
 */
export async function fetchUptimeRobotMonitors({ apiKey, ratios = [1, 7, 30, 90], timeoutMs = 15000 }) {
  if (!apiKey) throw new Error('缺少 UptimeRobot API Key');
  const body = new URLSearchParams({
    api_key: apiKey,
    format: 'json',
    response_times: '1',
    response_times_average: '30',
    custom_uptime_ratios: ratios.join('-'),
    logs: '1',
    log_types: '1-2',
    // 注意：custom_down_durations 不能作为请求参数传入（v2 会返回 invalid_parameter）
  });
  const res = await fetch(API_URL, {
    method: 'POST',
    headers: { 'content-type': 'application/x-www-form-urlencoded', accept: 'application/json' },
    body,
    signal: AbortSignal.timeout(timeoutMs),
  });
  if (!res.ok) throw new Error(`UptimeRobot HTTP ${res.status}`);
  const payload = await res.json();
  if (payload.stat !== 'ok') throw new Error(`UptimeRobot 返回错误：${payload.error?.message || payload.error?.type || 'unknown'}`);
  return mapUptimeRobotMonitors(payload, { ratios });
}