// Alerts: rules over sensors, watched by this hub for itself and every machine it manages.
import { useCallback, useEffect, useState } from 'react'
import { api, AlertChannel, AlertEvent, AlertRule, AlertsInfo } from './api'
import { accentFor } from './accents'
import { Btn, Loading, askYes, toast, useEscape } from './ui'

const OPS = ['>', '>=', '<', '<=', '==', '!=']
const ago = (ms: number) => { const s = Math.max(0, (Date.now() - ms) / 1000); return s < 90 ? `${Math.round(s)} s` : s < 5400 ? `${Math.round(s / 60)} min` : s < 129600 ? `${Math.round(s / 3600)} h` : `${Math.round(s / 86400)} d` }
const patience = (s: number) => (s === 0 ? 'at once' : s < 120 ? `for ${s} s` : `for ${Math.round(s / 60)} min`)
const show = (v: unknown) => (typeof v === 'number' ? String(Math.round(v * 10) / 10) : String(v))
const parse = (raw: string): number | boolean | string => (raw === 'true' ? true : raw === 'false' ? false : raw.trim() !== '' && !isNaN(Number(raw)) ? Number(raw) : raw)

// A rule names the machines it watches by the name the hub knows them by; on screen each is
// titled by its own hostname, like everywhere else.
function RuleDialog({ rule, machines, title, onSave, onClose }: { rule: AlertRule; machines: string[]; title: (n: string) => string; onSave: (r: AlertRule) => void; onClose: () => void }) {
  const [r, setR] = useState({ ...rule, value: String(rule.value) })
  const [hits, setHits] = useState<string>('')
  useEscape(onClose)
  useEffect(() => { // what the selector matches right now, across the fleet
    if (!r.sensor.trim()) { setHits(''); return }
    const t = window.setTimeout(async () => {
      try {
        const res = await fetch('/api/fleet/sensors/query', { method: 'POST', credentials: 'same-origin', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ machines: '*', query: { x: r.sensor.trim() } }) })
        if (!res.ok) { setHits((await res.json().catch(() => ({}))).error ?? 'not a valid pattern'); return }
        const by = await res.json() as Record<string, { x?: unknown; error?: string }>
        const n = Object.entries(by).map(([m, v]) => [m, v.error ? 0 : v.x && typeof v.x === 'object' ? Object.keys(v.x).length : v.x === null || v.x === undefined ? 0 : 1] as const)
        setHits(r.sensor.trim() === 'hamlab.reachable' ? 'every machine: whether it answers the hub' : n.every(([, c]) => c === 0) ? 'matches nothing right now' : 'matches ' + n.filter(([, c]) => c).map(([m, c]) => `${c} on ${m}`).join(', '))
      } catch { setHits('') }
    }, 350)
    return () => clearTimeout(t)
  }, [r.sensor])
  const all = !r.machines || r.machines === '*'
  const picked = all ? [] : r.machines.split(',').map((x) => x.trim()).filter(Boolean)
  return (
    <div className="modal-back" onClick={onClose}>
      <form className="modal picker" onClick={(e) => e.stopPropagation()} onSubmit={(e) => { e.preventDefault(); onSave({ ...r, name: r.name.trim(), sensor: r.sensor.trim(), value: parse(r.value) }) }}>
        <h3>{rule.name ? 'Edit rule' : 'New rule'}</h3>
        <label className="muted">Name<input autoFocus value={r.name} maxLength={64} onChange={(e) => setR({ ...r, name: e.target.value })} placeholder="Tank nearly full" /></label>
        <label className="muted">Sensor — an ID or a pattern; the Widgets tab lists them all
          <input className="mono" value={r.sensor} onChange={(e) => setR({ ...r, sensor: e.target.value })} placeholder="zfs.tank.used_pct" spellCheck={false} autoCapitalize="off" />
        </label>
        {hits && <div className="muted small">{hits}</div>}
        <div className="rule-cond">
          <select value={r.op} onChange={(e) => setR({ ...r, op: e.target.value })}>{OPS.map((o) => <option key={o}>{o}</option>)}</select>
          <input className="mono" value={r.value} onChange={(e) => setR({ ...r, value: e.target.value })} placeholder="90 · true · unhealthy" spellCheck={false} autoCapitalize="off" />
          <span className="muted">for</span>
          <input className="mono" type="number" min={0} max={86400} value={r.for_sec} onChange={(e) => setR({ ...r, for_sec: Math.max(0, Number(e.target.value) || 0) })} style={{ width: 90 }} /><span className="muted">s</span>
        </div>
        <div className="chips">{(['info', 'warn', 'crit'] as const).map((s) => <button type="button" key={s} className={'chip' + (r.severity === s ? ' on' : '')} onClick={() => setR({ ...r, severity: s })}>{s === 'crit' ? 'critical' : s === 'warn' ? 'warning' : 'info'}</button>)}</div>
        <div className="chips">
          <button type="button" className={'chip' + (all ? ' on' : '')} onClick={() => setR({ ...r, machines: '*' })}>every machine</button>
          {machines.map((m) => <button type="button" key={m} className={'chip' + (picked.includes(m) ? ' on' : '')} onClick={() => { const next = picked.includes(m) ? picked.filter((x) => x !== m) : [...picked, m]; setR({ ...r, machines: next.length ? next.join(',') : '*' }) }}>{title(m)}</button>)}
        </div>
        <div className="svc-actions"><button type="submit" className="btn on" disabled={!r.name.trim() || !r.sensor.trim()}>Save</button><span className="spacer" /><button type="button" className="btn" onClick={onClose}>Cancel</button></div>
      </form>
    </div>
  )
}

export default function Alerts({ machines, titleOf: title }: { machines: string[]; titleOf: (n: string) => string }) {
  const [a, setA] = useState<AlertsInfo | null>(null)
  const [err, setErr] = useState('')
  const [editing, setEditing] = useState<AlertRule | null>(null)
  const [chan, setChan] = useState<AlertChannel>({ type: 'ntfy', url: '' })
  const load = useCallback(async () => { try { const r = await api.alerts(); setA({ ...r, rules: r.rules ?? [], channels: r.channels ?? [], events: r.events ?? [], firing: r.firing ?? [] }); setErr('') } catch (e) { setErr(e instanceof Error ? e.message : 'failed') } }, [])
  useEffect(() => { load(); const t = setInterval(() => { if (document.visibilityState === 'visible') load() }, 5000); return () => clearInterval(t) }, [load])
  if (!a) return <div className="dash">{err ? <div className="error">{err}</div> : <Loading label="Loading alerts…" />}</div>

  const save = async (patch: { rules?: AlertRule[]; channels?: AlertChannel[] }, done: string) => {
    try { await api.saveAlerts(patch); toast(done); window.dispatchEvent(new Event('hamlab:alerts')); await load() } catch (e) { toast(e instanceof Error ? e.message : 'failed', 'err') }
  }
  const saveRule = (r: AlertRule) => { const exists = a.rules.some((x) => x.id === r.id); save({ rules: exists ? a.rules.map((x) => (x.id === r.id ? r : x)) : [...a.rules, r] }, exists ? 'rule saved' : 'rule added'); setEditing(null) }
  const sevClass = (s: string) => (s === 'crit' ? 'bad' : s === 'warn' ? 'warn' : '')

  return (
    <div className="dash alerts">
      <div className="dash-bar"><h2 className="section">Now</h2><span className="spacer" /><span className="muted small">checked {a.checked > 0 ? `${ago(a.checked)} ago` : 'not yet'} · every {a.every_sec} s · all machines</span></div>
      {a.firing.length === 0 ? <section className="card all-clear"><span className="good">✓ All clear</span><span className="muted small"> — {a.rules.filter((r) => r.enabled).length} rules watching {machines.length + 1} machine{machines.length ? 's' : ''}</span></section> : (
        <div className="cards">
          {a.firing.map((f) => (
            <section className={'card firing ' + sevClass(f.severity)} key={f.rule_id + f.machine + f.sensor}>
              <div className="sub-head"><span className={'sdot ' + (f.severity === 'crit' ? 'bad' : 'warn')} /><span className="dname">{f.rule}</span><span className="spacer" /><span className="badge" style={{ color: accentFor(f.machine), borderColor: accentFor(f.machine) }}>{title(f.machine)}</span></div>
              <div className="mono small">{f.sensor} = {show(f.value)}</div>
              <div className="muted small">for {ago(f.since)}</div>
            </section>
          ))}
        </div>
      )}

      <div className="dash-bar"><h2 className="section">Rules</h2><span className="spacer" />
        <button className="btn" onClick={() => setEditing({ id: 'r' + Date.now().toString(36), name: '', sensor: '', op: '>=', value: 90, for_sec: 300, severity: 'warn', enabled: true, machines: '*' })}>+ Rule</button>
      </div>
      <section className="card rules">
        {a.rules.length === 0 && <div className="empty">No rules. Nothing is being watched.</div>}
        {a.rules.map((r) => (
          <div className={'rule' + (r.enabled ? '' : ' off')} key={r.id}>
            <button className={'toggle' + (r.enabled ? ' on' : '')} title={r.enabled ? 'watching — tap to pause' : 'paused — tap to watch'} onClick={() => save({ rules: a.rules.map((x) => (x.id === r.id ? { ...x, enabled: !x.enabled } : x)) }, r.enabled ? `${r.name}: paused` : `${r.name}: watching`)}><i /></button>
            <div className="rule-body" onClick={() => setEditing(r)}>
              <div className="rule-name"><span className={'sdot ' + (r.severity === 'crit' ? 'bad' : r.severity === 'warn' ? 'warn' : 'ok')} />{r.name}{a.firing.some((f) => f.rule_id === r.id) && <span className="badge bad">firing</span>}</div>
              <div className="mono small muted">{r.sensor} {r.op} {show(r.value)} · {patience(r.for_sec)}{r.machines && r.machines !== '*' ? ` · ${r.machines}` : ''}</div>
            </div>
            <button className="icon-btn" title="delete" onClick={async () => { if (await askYes(`Delete the rule "${r.name}"?`)) save({ rules: a.rules.filter((x) => x.id !== r.id) }, 'rule deleted') }}>✕</button>
          </div>
        ))}
      </section>

      <div className="dash-bar"><h2 className="section">Where alerts go</h2><span className="spacer" />{a.channels.length > 0 && <Btn className="btn" onClick={async () => { try { await api.testAlerts(); toast('test sent') } catch (e) { toast(e instanceof Error ? e.message : 'failed', 'err') } }}>Send a test</Btn>}</div>
      <section className="card">
        <div className="muted small" style={{ marginBottom: 8 }}>Always here, and on the rail. To reach your phone: an <b>ntfy</b> topic URL (the ntfy app, from ntfy.sh or your own server), or a <b>webhook</b> — Home Assistant, Slack, anything that takes a POST. Sent when an alert fires and again when it clears.</div>
        {a.channels.map((c, i) => <div className="row" key={i}><span className="badge" style={{ marginLeft: 0 }}>{c.type}</span><span className="k mono small">{c.url}</span><Btn className="btn danger" confirm={`Remove this ${c.type} channel?`} onClick={() => save({ channels: a.channels.filter((_, j) => j !== i) }, 'channel removed')}>Remove</Btn></div>)}
        <form className="chan-add" onSubmit={(e) => { e.preventDefault(); if (!/^https?:\/\/./.test(chan.url.trim())) { toast('a channel needs an http(s) URL', 'err'); return } save({ channels: [...a.channels, { type: chan.type, url: chan.url.trim() }] }, 'channel added'); setChan({ ...chan, url: '' }) }}>
          <select value={chan.type} onChange={(e) => setChan({ ...chan, type: e.target.value as AlertChannel['type'] })}><option value="ntfy">ntfy</option><option value="webhook">webhook</option></select>
          <input className="mono" value={chan.url} onChange={(e) => setChan({ ...chan, url: e.target.value })} placeholder={chan.type === 'ntfy' ? 'https://ntfy.sh/your-secret-topic' : 'https://…/api/webhook/…'} spellCheck={false} autoCapitalize="off" />
          <button className="btn on" disabled={!chan.url.trim()}>Add</button>
        </form>
      </section>

      <div className="dash-bar"><h2 className="section">History</h2><span className="spacer" /><span className="muted small">the last {a.events.length}</span></div>
      <section className="card">
        {a.events.length === 0 && <div className="empty">Nothing has fired yet.</div>}
        {a.events.map((e: AlertEvent, i) => (
          <div className="ev" key={i}>
            <span className={e.kind === 'firing' ? (e.severity === 'crit' ? 'warn-text bad-text' : 'warn-text') : 'good'}>{e.kind === 'firing' ? '▲' : '✓'}</span>
            <span className="ev-main">{e.rule} <span className="muted">· {title(e.machine)} · </span><span className="mono small muted">{e.sensor} = {show(e.value)}</span></span>
            <span className="muted small num" title={new Date(e.t).toLocaleString()}>{ago(e.t)} ago</span>
          </div>
        ))}
      </section>
      {editing && <RuleDialog rule={editing} machines={machines} title={title} onSave={saveRule} onClose={() => setEditing(null)} />}
    </div>
  )
}