/**
 * Admin 后台 - 监控面板(报刊风)
 *
 * 功能:
 * - /health 存活检查(自动:30 秒一轮;可手动刷新)
 * - /health/ready 数据库就绪检查
 * - 服务名 / 版本 / 运行时间 / 检查项(后端返回什么就展示什么)
 */

import { useCallback, useEffect, useState } from 'react'
import { fetchHealth } from '../dal'
import { api } from '../api'
import { Card, CardBody, CardHeader, SectionHeader, Alert, Spinner, Badge } from '../components'

export default function MonitoringPage() {
  const [health, setHealth] = useState<any>(null)
  const [ready, setReady] = useState<'ready' | 'not_ready' | null>(null)
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [lastCheck, setLastCheck] = useState<string>('')

  const refresh = useCallback(async () => {
    setLoading(true)
    setError(null)
    try {
      const [h, r] = await Promise.allSettled([
        fetchHealth(),
        api.get<{ status: string }>('/health/ready'),
      ])
      setHealth(h.status === 'fulfilled' ? h.value : null)
      setReady(r.status === 'fulfilled' ? (r.value?.status as 'ready' | 'not_ready') : null)
      if (h.status === 'rejected') {
        setError(h.reason instanceof Error ? h.reason.message : '无法连接到后端')
      }
      setLastCheck(new Date().toLocaleTimeString('zh-CN', { hour12: false }))
    } finally {
      setLoading(false)
    }
  }, [])

  useEffect(() => {
    refresh()
    const t = setInterval(refresh, 30_000)
    return () => clearInterval(t)
  }, [refresh])

  const alive = health?.status === 'healthy' || health?.status === 'ok'

  return (
    <div className="space-y-6">
      <SectionHeader
        title="系统监控"
        description="存活与数据库就绪检查,每 30 秒自动巡检一次。"
      />

      <div className="flex items-center justify-between">
        <span className="text-2xs text-ink-400">
          {lastCheck && `最近巡检 ${lastCheck}`}
        </span>
        <button onClick={refresh} disabled={loading} className="btn btn-sm">
          {loading ? (<><Spinner /> 检查中</>) : '立即巡检'}
        </button>
      </div>

      {error && (
        <Alert
          kind="error"
          title="无法连接到后端"
          message={`${error}\n请确认服务是否正常运行,以及登录会话是否已过期。`}
        />
      )}

      <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
        {/* 存活状态 */}
        <div className="border border-ink-900 bg-paper-50 p-5">
          <div className="text-2xs tracking-[0.2em] text-ink-400">存活状态</div>
          <div className="mt-2 flex items-center gap-2">
            <span
              className={`inline-block h-2 w-2 ${alive ? 'bg-ink-900' : 'bg-press'}`}
              aria-hidden="true"
            />
            <span className={`font-serif text-xl font-bold ${alive ? 'text-ink-900' : 'text-press'}`}>
              {health ? (alive ? '正常' : String(health.status)) : '—'}
            </span>
          </div>
        </div>

        {/* 数据库就绪 */}
        <div className="border border-ink-900 bg-paper-50 p-5">
          <div className="text-2xs tracking-[0.2em] text-ink-400">数据库就绪</div>
          <div className="mt-2 flex items-center gap-2">
            <span
              className={`inline-block h-2 w-2 ${ready === 'ready' ? 'bg-ink-900' : ready === null ? 'bg-ink-300' : 'bg-press'}`}
              aria-hidden="true"
            />
            <span
              className={`font-serif text-xl font-bold ${ready === 'not_ready' ? 'text-press' : 'text-ink-900'}`}
            >
              {ready === 'ready' ? '就绪' : ready === 'not_ready' ? '未就绪' : '—'}
            </span>
          </div>
        </div>

        {/* 服务名 */}
        <div className="border border-ink-900 bg-paper-50 p-5">
          <div className="text-2xs tracking-[0.2em] text-ink-400">服务</div>
          <div className="mt-2 font-serif text-xl font-bold text-ink-900">
            {health?.service || 'profeto'}
          </div>
        </div>

        {/* 版本 */}
        {health?.version && (
          <div className="border border-ink-900 bg-paper-50 p-5">
            <div className="text-2xs tracking-[0.2em] text-ink-400">版本</div>
            <div className="mt-2 font-serif text-xl font-bold tabular-nums text-ink-900">
              {health.version}
            </div>
          </div>
        )}

        {/* 运行时间 */}
        {health?.uptime_seconds != null && (
          <div className="border border-ink-900 bg-paper-50 p-5">
            <div className="text-2xs tracking-[0.2em] text-ink-400">运行时间</div>
            <div className="mt-2 font-serif text-xl font-bold tabular-nums text-ink-900">
              {Math.floor(health.uptime_seconds / 3600)}h{' '}
              {Math.floor((health.uptime_seconds % 3600) / 60)}m
            </div>
          </div>
        )}

        {/* 检查项 */}
        {health?.checks && Object.keys(health.checks).length > 0 && (
          <div className="border border-ink-900 bg-paper-50 p-5 sm:col-span-2 lg:col-span-1">
            <div className="text-2xs tracking-[0.2em] text-ink-400">健康检查</div>
            <div className="mt-2 space-y-1">
              {Object.entries(health.checks).map(([key, val]) => (
                <div key={key} className="flex items-center justify-between text-sm">
                  <span className="text-2xs text-ink-500">{key}</span>
                  <Badge status={String(val) === 'pass' ? 'success' : 'error'}>
                    {String(val)}
                  </Badge>
                </div>
              ))}
            </div>
          </div>
        )}
      </div>
    </div>
  )
}