import { useEffect, useState, useCallback } from 'react'
import {
  fetchDataSourceStatuses,
  fetchIngestStatus,
  fetchAdminStats,
  fetchKeyRingStatus,
  resetKeyRingCooldown,
  updateSetting,
  clearSetting,
  testDataSourceConnection,
} from '../dal'
import type { DataSourceStatus, DataSourceTestResult, IngestSourceStatus, AdminStats } from '../types'
import type { KeyRingStatusResponse } from '../dal'
import SettingRow from '../SettingRow'
import { Card, CardBody, CardHeader, Badge, SectionHeader, Alert, Spinner, SkeletonBlock } from '../components'

function formatTime(iso: string | null): string {
  if (!iso) return '暂无记录'
  try {
    return new Date(iso).toLocaleString('zh-CN', { hour12: false })
  } catch {
    return iso
  }
}

export default function DataSourcesPage() {
  const [sources, setSources] = useState<DataSourceStatus[]>([])
  const [loading, setLoading] = useState(true)
  const [loadError, setLoadError] = useState('')
  const [ingestStats, setIngestStats] = useState<Record<string, IngestSourceStatus>>({})
  const [ingestLoading, setIngestLoading] = useState(true)
  const [stats, setStats] = useState<AdminStats | null>(null)

  const [testingSource, setTestingSource] = useState<string | null>(null)
  const [testResults, setTestResults] = useState<Record<string, DataSourceTestResult>>({})

  const [editingKey, setEditingKey] = useState<string | null>(null)
  const [busyKey, setBusyKey] = useState<string | null>(null)
  const [rowNotice, setRowNotice] = useState<{ key: string; ok: boolean; text: string } | null>(null)
  const [keyRing, setKeyRing] = useState<KeyRingStatusResponse | null>(null)
  const [ringLoading, setRingLoading] = useState(false)

  const loadSources = useCallback(async () => {
    setLoading(true)
    setLoadError('')
    try {
      setSources(await fetchDataSourceStatuses())
    } catch (err) {
      setLoadError(err instanceof Error ? err.message.split('\n')[0] : '加载失败')
      setSources([])
    } finally {
      setLoading(false)
    }
  }, [])

  // 健康状态(只读,与配置加载并行;失败不阻塞配置页)
  const loadIngest = useCallback(async () => {
    setIngestLoading(true)
    try {
      const { sources } = await fetchIngestStatus()
      setIngestStats(Object.fromEntries(sources.map(x => [x.name, x])))
    } catch {
      /* ignore */
    } finally {
      setIngestLoading(false)
    }
  }, [])

  // 管理区统计(只读)
  const loadStats = useCallback(async () => {
    try {
      setStats(await fetchAdminStats())
    } catch {
      /* ignore */
    }
  }, [])

  // Key Ring 状态(只读)
  const loadKeyRing = useCallback(async () => {
    setRingLoading(true)
    try {
      setKeyRing(await fetchKeyRingStatus())
    } catch {
      /* ignore */
    } finally {
      setRingLoading(false)
    }
  }, [])

  useEffect(() => {
    loadSources()
    loadIngest()
    loadStats()
    loadKeyRing()
  }, [loadSources, loadIngest, loadStats, loadKeyRing])

  async function handleTest(sourceName: string) {
    setTestingSource(sourceName)
    setTestResults(prev => ({ ...prev, [sourceName]: { ok: false, status: null, latency_ms: 0, detail: '测试中...' } }))
    try {
      const result = await testDataSourceConnection(sourceName)
      setTestResults(prev => ({ ...prev, [sourceName]: result }))
    } catch (err: unknown) {
      const msg = err instanceof Error ? err.message.split('\n')[0] : '连接失败'
      setTestResults(prev => ({ ...prev, [sourceName]: { ok: false, status: null, latency_ms: 0, detail: msg } }))
    } finally {
      setTestingSource(null)
    }
  }

  // 渲染数据源健康块(最近采集 + 异常提示)
  function renderHealth(sourceName: string) {
    const st = ingestStats[sourceName]
    if (!st) {
      return (
        <div className="flex items-center justify-between text-xs">
          <span className="text-ink-400">最近成功采集</span>
          <span className="text-ink-400">{ingestLoading ? '加载中...' : '暂无数据'}</span>
        </div>
      )
    }
    const ago = st.last_success_at ? formatTime(st.last_success_at) : '暂无记录'
    const issues: string[] = []
    if (st.status === 'key_not_configured') issues.push('未配置 API Key')
    else if (st.status === 'no_data') issues.push('本地无数据,建议补采')
    if (st.last_failure) issues.push('近期有采集失败')
    return (
      <div className="space-y-1.5 border-t border-ink-200 pt-3">
        <div className="flex items-center justify-between text-xs">
          <span className="text-ink-400">最近成功采集</span>
          <span className="text-ink-600">{ago}</span>
        </div>
        <div className="flex items-center justify-between text-xs">
          <span className="text-ink-400">已入库(近期)</span>
          <span className="text-ink-600">{st.recent_count.toLocaleString()} 条</span>
        </div>
        {st.note && <p className="text-2xs leading-relaxed text-ink-400">{st.note}</p>}
        {issues.length > 0 && (
          <p className="border-l-2 border-press bg-press-wash/40 px-2 py-1 text-2xs leading-relaxed text-press-dark">
            {issues.join(' / ')} — 请前往「数据采集」补采
          </p>
        )}
        {st.last_failure && (
          <p className="truncate text-2xs text-ink-400" title={st.last_failure.detail}>
            最近失败: {st.last_failure.detail.slice(0, 60)}
          </p>
        )}
      </div>
    )
  }

  async function handleSave(key: string, value: string) {
    setBusyKey(key)
    setRowNotice(null)
    try {
      await updateSetting(key, value)
      setRowNotice({ key, ok: true, text: '已保存,立即生效' })
      setEditingKey(null)
      await loadSources()
    } catch (err) {
      setRowNotice({ key, ok: false, text: err instanceof Error ? err.message.split('\n')[0] : '保存失败' })
    } finally {
      setBusyKey(null)
    }
  }

  async function handleClear(key: string) {
    setBusyKey(key)
    setRowNotice(null)
    try {
      await clearSetting(key)
      setRowNotice({ key, ok: true, text: '已清除数据库覆盖,回落 .env 默认值' })
      await loadSources()
    } catch (err) {
      setRowNotice({ key, ok: false, text: err instanceof Error ? err.message.split('\n')[0] : '清除失败' })
    } finally {
      setBusyKey(null)
    }
  }

  async function handleResetCooldown() {
    if (!window.confirm('确定重置所有 key 的冷却状态?这可能使被限流的 key 立即恢复请求。')) return
    try {
      const res = await resetKeyRingCooldown()
      setKeyRing(res.stats)
      setRowNotice({ key: "__ring", ok: true, text: res.message })
    } catch (err) {
      setRowNotice({ key: "__ring", ok: false, text: err instanceof Error ? err.message.split('\n')[0] : '重置失败' })
    }
  }


  return (
    <div className="space-y-6">
      <SectionHeader
        title="数据源管理"
        description="数据采集源的 API 配置、健康状态与连通性测试。"
      />

      {loadError && (
        <Alert kind="error" title="无法加载数据源配置" message={loadError} />
      )}

      {/* 数据源卡片 */}
      {loading ? (
        <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
          {[1, 2, 3].map(i => (
            <Card key={i}>
              <CardBody>
                <div className="space-y-3">
                  <SkeletonBlock className="h-4 w-24" />
                  <SkeletonBlock className="h-3 w-32" />
                  <SkeletonBlock className="h-8 w-full" />
                </div>
              </CardBody>
            </Card>
          ))}
        </div>
      ) : (
        <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
          {sources.map(source => {
            const result = testResults[source.name]
            const cardKeys = source.settings.map(s => s.key)
            return (
              <Card key={source.name}>
                <CardBody className="space-y-4">
                  <div className="flex flex-wrap items-center justify-between gap-x-2 gap-y-1 border-b border-ink-200 pb-3">
                    <h3 className="font-serif text-sm font-bold text-ink-900">{source.label}</h3>
                    <Badge status={source.key_configured ? 'success' : 'error'}>
                      {source.key_configured ? '已就绪' : '缺配置'}
                    </Badge>
                  </div>

                  <p className="text-2xs leading-relaxed text-ink-500">{source.description}</p>

                  {source.settings.length > 0 ? (
                    <div>
                      {source.settings.map(setting => (
                        <SettingRow
                          key={setting.key}
                          setting={setting}
                          editing={editingKey === setting.key}
                          busy={busyKey === setting.key}
                          onEdit={() => { setEditingKey(setting.key); setRowNotice(null) }}
                          onCancel={() => setEditingKey(null)}
                          onSave={v => handleSave(setting.key, v)}
                          onClear={() => handleClear(setting.key)}
                        />
                      ))}
                    </div>
                  ) : (
                    <p className="text-2xs text-ink-400">无需 API Key</p>
                  )}

                  {rowNotice && cardKeys.includes(rowNotice.key) && (
                    <Alert kind={rowNotice.ok ? 'ok' : 'error'} title={rowNotice.text} />
                  )}

                  {/* 数据源健康:最近采集 + 异常提示 */}
                  {renderHealth(source.name)}

                  {result && testingSource !== source.name && (
                    <Alert
                      kind={result.ok ? 'ok' : 'error'}
                      title={result.ok ? `连接成功(${result.latency_ms}ms)` : result.status ? `HTTP ${result.status}` : '连接失败'}
                      message={result.ok ? undefined : result.detail}
                    />
                  )}

                  <button
                    onClick={() => handleTest(source.name)}
                    disabled={testingSource === source.name}
                    className="btn btn-sm w-full"
                  >
                    {testingSource === source.name ? (<><Spinner /> 测试中</>) : '测试连接'}
                  </button>
                </CardBody>
              </Card>
            )
          })}
        </div>
      )}

      {/* API Key 轮换环状态 */}
      <Card>
        <CardHeader
          title="API Key 轮换环"
          description={keyRing?.has_multiple
            ? `已配置 ${keyRing.total} 个 key,遇到限流(429)自动切换;冷却 ${keyRing.cooldown_seconds}s`
            : '当前仅 1 个 key,无法轮换。建议配置多个 key 以提高限流容忍度'
          }
          action={
            <button
              onClick={handleResetCooldown}
              disabled={ringLoading}
              className="btn-sm btn-outline"
            >
              重置冷却
            </button>
          }
        />
        <CardBody>
          {ringLoading && !keyRing ? (
            <SkeletonBlock className="h-10 w-full" />
          ) : keyRing && keyRing.total > 0 ? (
            <div className="space-y-2">
              {keyRing.keys.map((k, i) => {
                const isBlocked = k.blocked_remaining > 0
                return (
                  <div key={i} className={`flex items-center justify-between gap-3 border-b border-ink-100 py-2 last:border-b-0 ${isBlocked ? 'opacity-70' : ''}`}>
                    <div className="flex items-center gap-2">
                      <span className={`inline-block h-2 w-2 rounded-full ${isBlocked ? 'bg-amber-500' : 'bg-emerald-500'}`} />
                      <span className="font-mono text-xs text-ink-700">{k.masked}</span>
                      {i === keyRing.active_index && (
                        <span className="rounded bg-ink-900 px-1.5 py-0.5 text-2xs text-paper-500">当前</span>
                      )}
                    </div>
                    <span className={`text-2xs tabular-nums ${isBlocked ? 'text-amber-600' : 'text-ink-400'}`}>
                      {isBlocked ? `冷却中 ${k.blocked_remaining.toFixed(0)}s` : '可用'}
                    </span>
                  </div>
                )
              })}
            </div>
          ) : (
            <p className="text-xs text-ink-400">暂无 key 配置</p>
          )}
          <p className="mt-3 border-l-2 border-ink-300 pl-3 text-2xs leading-relaxed text-ink-500">
            在「Bzzoiro」配置项中用<b>逗号 / 分号 / 换行</b>分隔多个 key 即可启用轮换。遇到 429 自动标记当前 key 为冷却并立即切换到下一个 key;
            全部 key 冷却时等待最早恢复的 key。「重置冷却」可紧急恢复所有 key。
          </p>
        </CardBody>
      </Card>

      {/* 近期活动统计(只读) */}
      {stats && stats.predictions && (
        <Card>
          <CardHeader title="近期预测活动" description="过去 24 小时 / 7 天的预测次数" />
          <CardBody>
            <div className="grid grid-cols-3 gap-4 text-center">
              <div>
                <div className="font-serif text-2xl font-bold tabular-nums text-ink-900">{stats.predictions.last_24h}</div>
                <div className="mt-1 text-2xs text-ink-400">近 24 小时</div>
              </div>
              <div>
                <div className="font-serif text-2xl font-bold tabular-nums text-ink-900">{stats.predictions.last_7d}</div>
                <div className="mt-1 text-2xs text-ink-400">近 7 天</div>
              </div>
              <div>
                <div className="font-serif text-2xl font-bold tabular-nums text-ink-900">{stats.predictions.total}</div>
                <div className="mt-1 text-2xs text-ink-400">总计</div>
              </div>
            </div>
          </CardBody>
        </Card>
      )}

      <Card>
        <CardHeader title="配置说明" />
        <CardBody>
          <div className="space-y-3 text-xs leading-relaxed text-ink-600">
            <p className="border-l-2 border-ink-300 pl-3">
              保存的配置存于数据库 <code className="font-mono">app_settings</code> 并<b>立即生效</b>,优先于 <code className="font-mono">.env</code>;「回落 .env」删除覆盖值。
            </p>
            <p className="border-l-2 border-ink-300 pl-3">
              「最近成功采集」为只读健康快照(不触发采集);近似数据已在行内标注。伤停源会区分「未配置 Key / 无数据 / 有数据」。
            </p>
            <p className="border-l-2 border-ink-300 pl-3">
              「测试连接」真实请求上游一次;异常提示会引导前往「数据采集」补采,避免在空数据上误操作。
            </p>
          </div>
        </CardBody>
      </Card>
    </div>
  )
}