import { useCallback, useEffect, useState } from 'react'
import { api, Sample, SmartInfo, StorageDevice, ZFSInfo, ZFSSnapshot } from './api'
import { fmtBytes, fmtRate } from './Dashboard'
import TaskOutput from './TaskOutput'
import { Btn, Loading, Spinner, toast } from './ui'

const pct = (v: number) => `${Math.round(v)}%`
const KIND: Record<string, string> = { nvme: 'NVMe', ssd: 'SSD', hdd: 'HDD', usb: 'USB', other: 'disk' }
const hours = (h: number) => (h >= 24 * 365 ? `${(h / 8760).toFixed(1)} y` : h >= 48 ? `${Math.round(h / 24)} d` : `${h} h`)
const ago = (ms: number) => { const s = (Date.now() - ms) / 1000; return s < 3600 ? `${Math.round(s / 60)}m ago` : s < 86400 ? `${Math.round(s / 3600)}h ago` : `${Math.round(s / 86400)}d ago` }

function Meter({ frac, cls }: { frac: number; cls?: string }) {
  const c = cls ?? (frac >= 0.95 ? 'bad' : frac >= 0.85 ? 'warn' : '')
  return <div className="meter"><div className={'fill ' + c} style={{ width: `${Math.min(100, Math.max(0, frac * 100))}%` }} /></div>
}

// ---- SMART panel ----
function SmartPanel({ dev, rotational }: { dev: string; rotational: boolean }) {
  const [s, setS] = useState<SmartInfo | null>(null)
  const [err, setErr] = useState('')
  const load = useCallback(async (force = false) => {
    setS(null)
    try { setS(await api.smart(dev, force)); setErr('') } catch (e) { setErr(e instanceof Error ? e.message : 'failed') }
  }, [dev])
  useEffect(() => { load() }, [load])

  if (err) return <div className="error">{err}</div>
  if (!s) return <Loading label="Reading SMART…" />
  if (!s.available) return <div className="notice">smartmontools isn't installed, so there's no SMART data. Install it from the button above.</div>
  if (s.standby) return <div className="notice">Disk is spun down; SMART wasn't read so it stays asleep. <Btn className="btn" onClick={() => load(true)}>Wake and read</Btn></div>
  if (s.error) return <div className="notice">{s.error}</div>
  const ok = s.passed === true && s.warnings.length === 0
  return (
    <div className="smart">
      <div className="props">
        <div><span className="k">Health</span><span className={ok ? 'good' : 'warn-text'}>{s.passed === null ? 'unknown' : s.passed ? 'PASSED' : 'FAILED'}{s.warnings.length > 0 && ` · ${s.warnings.length} warning${s.warnings.length > 1 ? 's' : ''}`}</span></div>
        {s.temp > 0 && <div><span className="k">Temperature</span><span>{s.temp}°C</span></div>}
        {s.power_on_hours > 0 && <div><span className="k">Powered on</span><span>{hours(s.power_on_hours)} · {s.power_cycles} cycles</span></div>}
        {s.firmware && <div><span className="k">Firmware</span><span className="mono">{s.firmware}</span></div>}
        {s.serial && <div><span className="k">Serial</span><span className="mono">{s.serial}</span></div>}
        {s.self_test && <div><span className="k">Self-test</span><span>{s.self_test}{s.self_test_remaining ? ` (${s.self_test_remaining}% left)` : ''}</span></div>}
        <div><span className="k">Read</span><span className="muted">{ago(s.fetched_at)} <button className="link" onClick={() => load(true)}>refresh</button></span></div>
      </div>
      {s.warnings.length > 0 && <div className="notice attn">{s.warnings.join(' · ')}</div>}
      {s.nvme && (
        <div className="props">
          <div><span className="k">Endurance</span><span>{s.nvme.percentage_used}% used · spare {s.nvme.available_spare}% (threshold {s.nvme.spare_threshold}%)</span></div>
          <div><span className="k">Written</span><span>{fmtBytes(s.nvme.data_written_bytes)} · read {fmtBytes(s.nvme.data_read_bytes)}</span></div>
          <div><span className="k">Errors</span><span>{s.nvme.media_errors} media · {s.nvme.error_log_entries} logged · {s.nvme.unsafe_shutdowns} unsafe shutdowns</span></div>
        </div>
      )}
      {s.attrs.length > 0 && (
        <table className="attrs">
          <thead><tr><th>ID</th><th>Attribute</th><th>Raw</th><th>Value</th><th>Worst</th><th>Thresh</th></tr></thead>
          <tbody>
            {s.attrs.map((a) => (
              <tr key={a.id} className={a.warn ? 'warn' : ''}>
                <td className="num">{a.id}</td><td>{a.name.replace(/_/g, ' ')}{a.failed && <span className="badge bad">{a.failed}</span>}</td>
                <td className="num">{a.raw}</td><td className="num">{a.value}</td><td className="num">{a.worst}</td><td className="num">{a.thresh}</td>
              </tr>
            ))}
          </tbody>
        </table>
      )}
      <div className="svc-actions">
        <Btn className="btn" confirm={`Start a short self-test on ${dev}?`} onClick={async () => { if (await api.smartTest(dev, 'short').then(() => true, (e) => { toast(String(e.message ?? e), 'err'); return false })) { toast('short test started'); load(true) } }}>Short test</Btn>
        <Btn className="btn" confirm={`Start a long self-test on ${dev}? ${rotational ? 'This can take hours on a spinning disk.' : ''}`} onClick={async () => { if (await api.smartTest(dev, 'long').then(() => true, (e) => { toast(String(e.message ?? e), 'err'); return false })) { toast('long test started'); load(true) } }}>Long test</Btn>
      </div>
    </div>
  )
}

// ---- device card ----
function DeviceCard({ d, live }: { d: StorageDevice; live?: { read_bps: number; write_bps: number; util_pct: number } }) {
  const [open, setOpen] = useState(false)
  return (
    <section className="card disk">
      <div className="sub-head">
        <span className="badge">{KIND[d.kind] ?? d.kind}</span>
        <span className="dname">{d.name}</span>
        <span className="model">{[d.vendor, d.model].filter(Boolean).join(' ')}</span>
        <span className="spacer" />
        <span className="num">{fmtBytes(d.size)}{d.temp ? ` · ${d.temp.toFixed(0)}°C` : ''}</span>
      </div>
      {live && <div className="sub-head num muted">read {fmtRate(live.read_bps)} · write {fmtRate(live.write_bps)} · {pct(live.util_pct)} busy</div>}
      {d.parts.map((p) => (
        <div className="row" key={p.name}>
          <span className="k">{p.name}<small>{p.fstype || p.type}{p.label ? ` · ${p.label}` : ''}</small></span>
          {p.fs_size ? <Meter frac={(p.used ?? 0) / p.fs_size} /> : <span className="muted">{p.mount === '[SWAP]' ? 'swap' : p.mount ? '' : 'not mounted'}</span>}
          <span className="num">{p.fs_size ? `${fmtBytes(p.used ?? 0)} / ${fmtBytes(p.fs_size)} · ${p.mount}` : fmtBytes(p.size)}</span>
        </div>
      ))}
      {d.parts.length === 0 && <div className="muted">No partitions.</div>}
      <div className="svc-actions"><button className="btn" onClick={() => setOpen(!open)}>{open ? 'Hide SMART' : 'SMART'}</button></div>
      {open && <SmartPanel dev={d.name} rotational={d.rotational} />}
    </section>
  )
}

// ---- ZFS ----
function PoolCard({ p, onChanged }: { p: ZFSInfo['pools'][number]; onChanged: () => void }) {
  const scrubbing = /scrub in progress/i.test(p.scan ?? '')
  const paused = /scrub paused/i.test(p.scan ?? '')
  const [cfg, setCfg] = useState(false)
  const act = (a: 'start' | 'pause' | 'stop') => async () => {
    try { await api.zfsScrub(p.name, a); toast(`scrub ${a}: ok`); onChanged() } catch (e) { toast(e instanceof Error ? e.message : 'failed', 'err') }
  }
  return (
    <section className="card">
      <div className="sub-head">
        <span className={'dot ' + (p.health === 'ONLINE' ? 'ok' : p.health === 'DEGRADED' ? 'warn' : 'bad')} />
        <span className="dname">{p.name}</span>
        <span className="badge">{p.health}</span>
        <span className="spacer" />
        <span className="num">{fmtBytes(p.alloc)} / {fmtBytes(p.size)} · {p.cap}%</span>
      </div>
      <Meter frac={p.cap / 100} cls={p.cap >= 90 ? 'bad' : p.cap >= 80 ? 'warn' : ''} />
      <div className="props" style={{ marginTop: 8 }}>
        <div><span className="k">Free</span><span>{fmtBytes(p.free)} · fragmentation {p.frag}% · dedup {p.dedup}</span></div>
        {p.scan && <div><span className="k">Scan</span><span style={{ whiteSpace: 'normal' }}>{p.scan}</span></div>}
        {p.errors && <div><span className="k">Errors</span><span className={p.errors.startsWith('No known') ? '' : 'warn-text'}>{p.errors}</span></div>}
      </div>
      <div className="svc-actions">
        {!scrubbing && <Btn className="btn" confirm={`Start a scrub of ${p.name}? It reads the whole pool and can take many hours.`} onClick={act('start')}>{paused ? 'Resume scrub' : 'Scrub'}</Btn>}
        {scrubbing && <Btn className="btn" onClick={act('pause')}>Pause scrub</Btn>}
        {(scrubbing || paused) && <Btn className="btn" confirm="Stop the scrub?" onClick={act('stop')}>Stop scrub</Btn>}
        <button className="btn" onClick={() => setCfg(!cfg)}>{cfg ? 'Hide vdevs' : 'Vdevs'}</button>
      </div>
      {cfg && <pre className="unit-file">{p.config}</pre>}
    </section>
  )
}

function DatasetRow({ d, onChanged }: { d: ZFSInfo['datasets'][number]; onChanged: () => void }) {
  const [snaps, setSnaps] = useState<ZFSSnapshot[] | null>(null)
  const [open, setOpen] = useState(false)
  async function toggle() {
    setOpen(!open)
    if (!open && !snaps) { try { setSnaps(await api.zfsSnapshots(d.name)) } catch (e) { toast(e instanceof Error ? e.message : 'failed', 'err'); setSnaps([]) } }
  }
  async function snapshot() {
    const def = 'hamlab-' + new Date().toISOString().slice(0, 16).replace(/[-:T]/g, '').replace(/(\d{8})(\d{4})/, '$1-$2')
    const name = window.prompt(`Snapshot name for ${d.name}@`, def)
    if (!name) return
    try { await api.zfsSnapshot(d.name, name.trim()); toast(`${d.name}@${name.trim()} created`); setSnaps(null); onChanged() }
    catch (e) { toast(e instanceof Error ? e.message : 'failed', 'err') }
  }
  const depth = d.name.split('/').length - 1
  return (
    <>
      <div className="ds-row" style={{ paddingLeft: 12 + depth * 16 }}>
        <span className="ds-name" onClick={toggle}><span className="chev">{open ? '▾' : '▸'}</span>{d.name.split('/').pop()}{d.type === 'volume' && <span className="badge">zvol</span>}</span>
        <span className="num">{fmtBytes(d.used)}</span>
        <span className="num muted">{fmtBytes(d.refer)}</span>
        <span className="num muted">{d.used_by_snapshots ? fmtBytes(d.used_by_snapshots) : '—'}</span>
        <span className="num muted">{d.snapshots}</span>
        <span className="num muted">{d.compressratio}</span>
        <span className="ds-mount muted">{d.mount}</span>
      </div>
      {open && (
        <div className="ds-snaps">
          <div className="svc-actions"><Btn className="btn" onClick={snapshot}>Snapshot now</Btn><span className="muted">avail {fmtBytes(d.avail)}</span></div>
          {snaps === null ? <div className="muted"><Spinner /> listing…</div> : snaps.length === 0 ? <div className="muted">No snapshots.</div> : (
            <div className="snap-list">{snaps.slice().reverse().map((s) => <div key={s.name} className="snap"><span className="mono">{s.name.split('@')[1]}</span><span className="num muted">{new Date(s.created).toLocaleString()} · {fmtBytes(s.used)}</span></div>)}</div>
          )}
        </div>
      )}
    </>
  )
}

// ---- page ----
export default function Disks() {
  const [devs, setDevs] = useState<StorageDevice[] | null>(null)
  const [zfs, setZfs] = useState<ZFSInfo | null>(null)
  const [hasSmart, setHasSmart] = useState(true)
  const [live, setLive] = useState<Sample | null>(null)
  const [err, setErr] = useState('')
  const [task, setTask] = useState<string | null>(null)

  const load = useCallback(async () => {
    try {
      const r = await api.storage()
      setDevs(r.devices); setZfs(r.zfs); setHasSmart(r.smartctl); setErr('')
    } catch (e) { setErr(e instanceof Error ? e.message : 'failed') }
  }, [])
  useEffect(() => { load() }, [load])
  useEffect(() => {
    let stop = false
    const tick = async () => { if (!stop && document.visibilityState === 'visible') { try { setLive(await api.metrics()) } catch { /* ignore */ } } }
    tick()
    const t = setInterval(tick, 2000)
    return () => { stop = true; clearInterval(t) }
  }, [])

  if (!devs) return <div className="dash">{err ? <div className="error">{err}</div> : <Loading label="Scanning disks…" />}</div>
  const liveFor = (n: string) => live?.disks.find((d) => d.name === n)

  return (
    <div className="dash disks">
      {err && <div className="error">{err}</div>}
      <div className="dash-bar">
        <h2 className="section">Devices · {devs.length}</h2>
        <span className="spacer" />
        {!hasSmart && <Btn className="btn" onClick={async () => { try { const t = await api.installPackages(['smartmontools']); setTask(t.id) } catch (e) { toast(e instanceof Error ? e.message : 'failed', 'err') } }}>Install smartmontools</Btn>}
        <Btn className="btn" title="reload" onClick={load}>↻</Btn>
      </div>
      {!hasSmart && <div className="notice">SMART health needs smartmontools on this host. Install it with the button, then reload.</div>}
      {task && <TaskOutput id={task} onDone={(t) => { toast(`${t.title}: ${t.exit_code === 0 ? 'finished' : `exited ${t.exit_code}`}`, t.exit_code === 0 ? 'ok' : 'err'); load() }} />}
      <div className="cards">
        {devs.map((d) => <DeviceCard key={d.name} d={d} live={liveFor(d.name)} />)}
      </div>

      <div className="dash-bar"><h2 className="section">ZFS</h2></div>
      {zfs && !zfs.available && <div className="notice">{zfs.message || 'No ZFS pools on this host.'}</div>}
      {zfs?.available && zfs.pools.length === 0 && <div className="notice">ZFS is present but no pools are imported.</div>}
      {zfs?.available && zfs.pools.length > 0 && (
        <>
          <div className="cards">{zfs.pools.map((p) => <PoolCard key={p.name} p={p} onChanged={load} />)}</div>
          <section className="card datasets">
            <div className="ds-row head"><span>Dataset</span><span className="num">Used</span><span className="num">Refer</span><span className="num">In snaps</span><span className="num">Snaps</span><span className="num">Ratio</span><span>Mount</span></div>
            {zfs.datasets.map((d) => <DatasetRow key={d.name} d={d} onChanged={load} />)}
          </section>
        </>
      )}
    </div>
  )
}