import { useCallback, useEffect, useRef, useState } from 'react'
import { api, TaskInfo, UpdatePackage, UpdatesStatus } from './api'
import TaskOutput from './TaskOutput'
import { Btn, Loading, Spinner, toast } from './ui'

function ago(ms?: number): string {
  if (!ms) return 'never'
  const s = Math.max(0, (Date.now() - ms) / 1000)
  const d = Math.floor(s / 86400), h = Math.floor((s % 86400) / 3600), m = Math.floor((s % 3600) / 60)
  return (d > 0 ? `${d}d ${h}h` : h > 0 ? `${h}h ${m}m` : `${m}m`) + ' ago'
}

export default function Updates() {
  const [st, setSt] = useState<UpdatesStatus | null>(null)
  const [err, setErr] = useState('')
  const [reloading, setReloading] = useState(false)
  const [sel, setSel] = useState<Set<string>>(new Set())
  const [task, setTask] = useState<string | null>(null)
  const [taskRunning, setTaskRunning] = useState(false)
  const [open, setOpen] = useState<string | null>(null)
  const [changelog, setChangelog] = useState<Record<string, string>>({})
  const taskBox = useRef<HTMLDivElement>(null)

  const load = useCallback(async () => {
    setReloading(true)
    try {
      const s = await api.updates()
      setSt(s); setErr('')
      if (s.running_task) { setTask(s.running_task); setTaskRunning(true) }
      setSel((prev) => new Set([...prev].filter((n) => s.packages.some((p) => p.name === n))))
    } catch (e) { setErr(e instanceof Error ? e.message : 'failed') }
    finally { setReloading(false) }
  }, [])
  useEffect(() => { load() }, [load])

  async function start(fn: () => Promise<TaskInfo>) {
    setErr('')
    try {
      const t = await fn()
      setTask(t.id); setTaskRunning(true)
      window.setTimeout(() => taskBox.current?.scrollIntoView({ behavior: 'smooth', block: 'nearest' }), 50)
    } catch (e) { toast(e instanceof Error ? e.message : 'failed', 'err') }
  }
  function done(t: TaskInfo) {
    setTaskRunning(false)
    const ok = t.exit_code === 0 && !t.error
    toast(`${t.title}: ${ok ? 'finished' : t.error || `exited ${t.exit_code}`}`, ok ? 'ok' : 'err')
    load()
  }
  async function showChangelog(p: UpdatePackage) {
    if (open === p.name) { setOpen(null); return }
    setOpen(p.name)
    if (!changelog[p.name]) {
      try { const r = await api.changelog(p.name); setChangelog((c) => ({ ...c, [p.name]: r.text || '(empty)' })) }
      catch (e) { setChangelog((c) => ({ ...c, [p.name]: e instanceof Error ? e.message : 'unavailable' })) }
    }
  }
  const toggle = (n: string) => setSel((s) => { const x = new Set(s); if (x.has(n)) x.delete(n); else x.add(n); return x })

  if (!st) return <div className="dash">{err ? <div className="error">{err}</div> : <Loading label="Checking packages…" />}</div>
  const canAct = st.can_upgrade && !taskRunning

  return (
    <div className="dash updates">
      {!st.manager && <div className="notice">No supported package manager found (looked for apt, dnf, zypper, pacman, apk).</div>}
      {st.manager && !st.sudo && <div className="notice">Read-only: refreshing and upgrading need root. Run Ham Lab as root, or give its user passwordless sudo or doas.</div>}
      {st.reboot_needed && (
        <div className="notice attn">
          <b>Reboot required</b>{st.reboot_pkgs.length > 0 && <> · {st.reboot_pkgs.join(', ')}</>} — use the power button in the header.
        </div>
      )}
      {err && <div className="error">{err}</div>}

      <div className="kpis">
        <div className="tile"><div className="label">Upgradable</div><div className="value">{st.packages.length}</div><div className="sub">{st.security_count ? `${st.security_count} security` : 'no security updates'}</div></div>
        <div className="tile"><div className="label">Index refreshed</div><div className="value">{ago(st.last_refresh)}</div><div className="sub">{st.manager}</div></div>
        <div className="tile"><div className="label">Last upgrade</div><div className="value">{ago(st.last_upgrade)}</div><div className="sub">from {st.manager} history</div></div>
        <div className="tile"><div className="label">Unattended</div><div className="value">{st.auto_upgrades ? 'on' : 'off'}</div><div className="sub">automatic upgrades</div></div>
      </div>

      <div className="svc-actions">
        <Btn className="btn" disabled={!canAct} onClick={() => start(api.refreshUpdates)}>Refresh index</Btn>
        <Btn className="btn on" disabled={!canAct || st.packages.length === 0} confirm={`Upgrade all ${st.packages.length} packages?`} onClick={() => start(() => api.upgrade([]))}>Upgrade all</Btn>
        <Btn className="btn" disabled={!canAct || sel.size === 0 || !st.selective} title={st.selective ? undefined : `${st.manager} upgrades everything or nothing`} onClick={() => start(() => api.upgrade([...sel]))}>Upgrade selected ({sel.size})</Btn>
        <span className="spacer" />
        {st.packages.length > 0 && <button className="btn" onClick={() => setSel(sel.size === st.packages.length ? new Set() : new Set(st.packages.map((p) => p.name)))}>{sel.size === st.packages.length ? 'None' : 'All'}</button>}
        <button className="btn" title="reload" disabled={reloading} onClick={load}>{reloading ? <Spinner /> : '↻'}</button>
      </div>

      <div ref={taskBox}>{task && <TaskOutput id={task} onDone={done} />}</div>

      <div className="card pkgs">
        {st.packages.length === 0 && <div className="empty">Everything is up to date.</div>}
        {st.packages.map((p) => (
          <div key={p.name}>
            <div className={'pkg' + (sel.has(p.name) ? ' sel' : '')}>
              <input type="checkbox" checked={sel.has(p.name)} onChange={() => toggle(p.name)} />
              <span className="pkg-name" onClick={() => showChangelog(p)}>
                <span className="n">{p.name}{p.security && <span className="badge bad">security</span>}</span>
                <span className="d">{p.description}</span>
              </span>
              <span className="pkg-ver"><span className="muted">{p.current}</span> → {p.candidate}<span className="muted"> · {p.suite}</span></span>
            </div>
            {open === p.name && <pre className="run-out changelog">{changelog[p.name] ?? <span className="muted"><Spinner /> fetching changelog…</span>}</pre>}
          </div>
        ))}
      </div>
    </div>
  )
}