import { useEffect, useRef, useState } from 'react'
import { api, type HostMetrics as HostMetricsData, type Integration } from '../lib/api'

const TEXT_SECONDARY = '#7A7D85'
const TEXT_PRIMARY = '#E8E6E0'
const GOLD = '#C8A434'

const cardBase: React.CSSProperties = {
  backgroundColor: 'rgba(10, 10, 12, 0.92)',
  border: '1px solid rgba(200, 164, 52, 0.08)',
  borderRadius: '12px',
  padding: '16px',
  boxShadow: '0 0 20px rgba(200, 164, 52, 0.03)',
}

const sectionTitle: React.CSSProperties = {
  fontSize: '11px',
  textTransform: 'uppercase',
  letterSpacing: '1.5px',
  color: TEXT_SECONDARY,
  fontWeight: 500,
  marginBottom: '12px',
}

function percentColor(p: number | null): string {
  if (p === null) return TEXT_SECONDARY
  if (p >= 90) return '#E74C3C'
  if (p >= 75) return '#E67E22'
  return '#2ECC71'
}

function Gauge({ label, percent, sub }: { label: string; percent: number | null; sub?: string }) {
  return (
    <div style={cardBase}>
      <h3 style={sectionTitle}>{label}</h3>
      <div className="flex items-end gap-2">
        <span style={{ fontSize: '28px', fontWeight: 700, color: percentColor(percent) }}>
          {percent !== null ? `${percent}%` : '—'}
        </span>
      </div>
      <div className="mt-2 h-1.5 w-full overflow-hidden rounded-full" style={{ backgroundColor: 'rgba(255,255,255,0.06)' }}>
        <div
          className="h-full rounded-full transition-all"
          style={{ width: `${percent ?? 0}%`, backgroundColor: percentColor(percent) }}
        />
      </div>
      {sub && <p className="mt-2" style={{ fontSize: '11px', color: TEXT_SECONDARY }}>{sub}</p>}
    </div>
  )
}

export default function HostMetrics() {
  const [hosts, setHosts] = useState<Integration[]>([])
  const [hostId, setHostId] = useState<number | null>(null)
  const [metrics, setMetrics] = useState<HostMetricsData | null>(null)
  const [error, setError] = useState<string | null>(null)
  const [loading, setLoading] = useState(false)
  const pollRef = useRef<ReturnType<typeof setInterval> | null>(null)

  useEffect(() => {
    api.listIntegrations().then(({ integrations }) => {
      setHosts(integrations.filter((i) => i.type === 'ssh'))
    })
  }, [])

  useEffect(() => {
    return () => {
      if (pollRef.current) clearInterval(pollRef.current)
    }
  }, [])

  function fetchMetrics(id: number) {
    setLoading(true)
    api
      .getHostMetrics(id)
      .then((data) => {
        setMetrics(data)
        setError(null)
      })
      .catch((err) => setError(err instanceof Error ? err.message : 'Failed to load metrics'))
      .finally(() => setLoading(false))
  }

  function handleSelect(id: number) {
    setHostId(id)
    setMetrics(null)
    setError(null)
    if (pollRef.current) clearInterval(pollRef.current)
    fetchMetrics(id)
    pollRef.current = setInterval(() => fetchMetrics(id), 5000)
  }

  const host = hosts.find((h) => h.id === hostId)

  return (
    <div className="flex h-full gap-4">
      <div className="w-56 shrink-0 overflow-y-auto rounded-lg border border-white/10 bg-white/5 p-3">
        <p className="mb-2 text-xs font-medium uppercase tracking-wide" style={{ color: TEXT_SECONDARY }}>
          SSH Hosts
        </p>
        {hosts.length === 0 && (
          <p className="text-xs" style={{ color: TEXT_SECONDARY }}>
            No SSH integrations configured. Add one in Settings → Integrations.
          </p>
        )}
        {hosts.map((h) => (
          <button
            key={h.id}
            onClick={() => handleSelect(h.id)}
            className="mb-1 w-full rounded-md px-2 py-1.5 text-left text-sm transition"
            style={{
              background: hostId === h.id ? 'rgba(200,164,52,0.15)' : 'transparent',
              color: hostId === h.id ? GOLD : TEXT_PRIMARY,
            }}
          >
            {h.name}
          </button>
        ))}
      </div>

      <div className="flex flex-1 flex-col gap-4 overflow-y-auto pr-1">
        <div className="flex items-center justify-between">
          <p style={{ fontSize: '13px', color: TEXT_PRIMARY, fontWeight: 500 }}>
            {host ? host.name : 'Select a host to view live metrics'}
          </p>
          <p style={{ fontSize: '11px', color: error ? '#E74C3C' : TEXT_SECONDARY }}>
            {error ?? (loading ? 'Refreshing…' : metrics ? 'Live · updates every 5s' : '')}
          </p>
        </div>

        {metrics && (
          <>
            <div className="grid grid-cols-4 gap-4">
              <Gauge label="CPU" percent={metrics.cpu.percent} sub={metrics.cpu.cores ? `${metrics.cpu.cores} cores · load ${metrics.cpu.load?.map((l) => l.toFixed(2)).join(' / ') ?? '—'}` : undefined} />
              <Gauge label="Memory" percent={metrics.memory.percent} sub={metrics.memory.usedGiB !== null ? `${metrics.memory.usedGiB} / ${metrics.memory.totalGiB} GiB` : undefined} />
              <Gauge label="Disk (/)" percent={metrics.disk.percent} sub={metrics.disk.usedHuman ? `${metrics.disk.usedHuman} / ${metrics.disk.totalHuman} used` : undefined} />
              <div style={cardBase}>
                <h3 style={sectionTitle}>Uptime</h3>
                <p style={{ fontSize: '22px', fontWeight: 700, color: TEXT_PRIMARY }}>{metrics.uptime.formatted ?? '—'}</p>
                <p className="mt-2" style={{ fontSize: '11px', color: TEXT_SECONDARY }}>
                  {metrics.system.hostname ?? ''} {metrics.system.os ? `· ${metrics.system.os}` : ''}
                </p>
              </div>
            </div>

            <div className="grid grid-cols-2 gap-4">
              <div style={cardBase}>
                <h3 style={sectionTitle}>Network Interfaces</h3>
                {metrics.network.interfaces.length === 0 ? (
                  <p style={{ fontSize: '12px', color: TEXT_SECONDARY }}>No interfaces reported.</p>
                ) : (
                  <div className="flex flex-col gap-1.5">
                    {metrics.network.interfaces.map((iface) => (
                      <div key={iface.name} className="flex items-center justify-between" style={{ fontSize: '12px' }}>
                        <span style={{ color: TEXT_PRIMARY }}>{iface.name}</span>
                        <span style={{ color: TEXT_SECONDARY }}>{iface.ip || '—'}</span>
                        <span style={{ color: iface.state === 'UP' ? '#2ECC71' : TEXT_SECONDARY }}>{iface.state}</span>
                      </div>
                    ))}
                  </div>
                )}
              </div>

              <div style={cardBase}>
                <h3 style={sectionTitle}>Listening Ports ({metrics.ports.ports.length})</h3>
                {metrics.ports.ports.length === 0 ? (
                  <p style={{ fontSize: '12px', color: TEXT_SECONDARY }}>None detected.</p>
                ) : (
                  <div className="flex max-h-40 flex-col gap-1.5 overflow-y-auto">
                    {metrics.ports.ports.slice(0, 12).map((p, i) => (
                      <div key={i} className="flex items-center justify-between" style={{ fontSize: '12px' }}>
                        <span style={{ color: TEXT_PRIMARY }}>{p.protocol}/{p.localPort}</span>
                        <span style={{ color: TEXT_SECONDARY }}>{p.process ?? '—'}</span>
                      </div>
                    ))}
                  </div>
                )}
              </div>
            </div>

            <div style={cardBase}>
              <h3 style={sectionTitle}>Top Processes</h3>
              {metrics.processes.top.length === 0 ? (
                <p style={{ fontSize: '12px', color: TEXT_SECONDARY }}>No process data.</p>
              ) : (
                <table className="w-full" style={{ fontSize: '12px' }}>
                  <thead>
                    <tr style={{ color: TEXT_SECONDARY, textAlign: 'left' }}>
                      <th className="pb-1">PID</th>
                      <th className="pb-1">User</th>
                      <th className="pb-1">CPU%</th>
                      <th className="pb-1">Mem%</th>
                      <th className="pb-1">Command</th>
                    </tr>
                  </thead>
                  <tbody>
                    {metrics.processes.top.map((p) => (
                      <tr key={p.pid} style={{ color: TEXT_PRIMARY }}>
                        <td className="py-0.5">{p.pid}</td>
                        <td className="py-0.5">{p.user}</td>
                        <td className="py-0.5">{p.cpu}</td>
                        <td className="py-0.5">{p.mem}</td>
                        <td className="py-0.5" style={{ color: TEXT_SECONDARY }}>{p.command}</td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              )}
              {metrics.processes.total !== null && (
                <p className="mt-2" style={{ fontSize: '11px', color: TEXT_SECONDARY }}>
                  {metrics.processes.total} total · {metrics.processes.running ?? '—'} running
                </p>
              )}
            </div>

            <div className="grid grid-cols-2 gap-4">
              <div style={cardBase}>
                <h3 style={sectionTitle}>Firewall ({metrics.firewall.type})</h3>
                {metrics.firewall.type === 'none' ? (
                  <p style={{ fontSize: '12px', color: TEXT_SECONDARY }}>No firewall data available (requires root, or none configured).</p>
                ) : (
                  <div className="flex flex-col gap-1.5">
                    {metrics.firewall.chains.map((c) => (
                      <div key={c.name} className="flex items-center justify-between" style={{ fontSize: '12px' }}>
                        <span style={{ color: TEXT_PRIMARY }}>{c.name}</span>
                        <span style={{ color: TEXT_SECONDARY }}>{c.policy} · {c.rules.length} rules</span>
                      </div>
                    ))}
                  </div>
                )}
              </div>

              <div style={cardBase}>
                <h3 style={sectionTitle}>Login Activity</h3>
                {metrics.loginStats.recentLogins.length === 0 && metrics.loginStats.failedLogins.length === 0 ? (
                  <p style={{ fontSize: '12px', color: TEXT_SECONDARY }}>No login history readable.</p>
                ) : (
                  <p style={{ fontSize: '12px', color: TEXT_PRIMARY }}>
                    {metrics.loginStats.totalLogins} recent logins · {metrics.loginStats.failedLogins.length} failed attempts · {metrics.loginStats.uniqueIPs} unique IPs
                  </p>
                )}
              </div>
            </div>
          </>
        )}

        {!metrics && !error && host && <p style={{ fontSize: '12px', color: TEXT_SECONDARY }}>Loading metrics…</p>}
      </div>
    </div>
  )
}