'use client'

import { useEffect, useRef, useState } from 'react'
import { Panel } from '@/components/cluster/Panel'
import { namespaces, nodes, apps } from '@/lib/clusterMock'

const COMMANDS = [
  'get nodes',
  'get pods <ns>',
  'get apps',
  'top nodes',
  'describe pod <ns> <name>',
  'help',
]

type Line = { kind: 'input' | 'output' | 'reject'; text: string }

const pad = (s: string, n: number) => s.padEnd(n, ' ')

function run(raw: string): Line[] {
  const cmd = raw.trim().toLowerCase()

  if (cmd === 'help') {
    return [{ kind: 'output', text: COMMANDS.map((c) => `  ${c}`).join('\n') }]
  }

  if (cmd === 'get nodes') {
    const head = `${pad('NAME', 14)}${pad('ROLE', 16)}${pad('CPU', 6)}${pad('MEM', 8)}GPU`
    const rows = nodes.map((n) => `${pad(n.name, 14)}${pad(n.role, 16)}${pad(String(n.cpu), 6)}${pad(`${n.memoryGi}Gi`, 8)}${n.gpu}`)
    return [{ kind: 'output', text: [head, ...rows].join('\n') }]
  }

  if (cmd === 'get apps') {
    const head = `${pad('NAME', 24)}${pad('WAVE', 7)}${pad('SYNC', 12)}HEALTH`
    const rows = apps.map((a) => `${pad(a.name, 24)}${pad(String(a.wave ?? '-'), 7)}${pad(a.sync, 12)}${a.health}`)
    return [{ kind: 'output', text: [head, ...rows].join('\n') }]
  }

  if (cmd === 'top nodes') {
    const head = `${pad('NAME', 14)}${pad('CPU%', 8)}MEM%`
    const rows = nodes.map((n) => `${pad(n.name, 14)}${pad(n.gpu ? '61%' : '18%', 8)}${n.gpu ? '74%' : '42%'}`)
    return [{ kind: 'output', text: [head, ...rows].join('\n') }]
  }

  if (cmd.startsWith('get pods')) {
    const ns = cmd.split(/\s+/)[2]
    if (!ns) return [{ kind: 'reject', text: 'get pods requires a namespace. Try: get pods llm-serving' }]
    const known = namespaces.find((n) => n.name === ns)
    if (!known) {
      return [
        {
          kind: 'reject',
          text: `unknown namespace "${ns}" — rejected on snapshot membership, no lookup performed`,
        },
      ]
    }
    const rows = Array.from({ length: Math.min(known.total, 8) }, (_, i) => {
      const running = i < known.running
      return `${pad(`${ns}-workload-${i + 1}`, 30)}${pad(running ? '1/1' : '0/1', 6)}${running ? 'Running' : 'Pending'}`
    })
    return [{ kind: 'output', text: [`${pad('NAME', 30)}${pad('READY', 6)}STATUS`, ...rows].join('\n') }]
  }

  if (cmd.startsWith('describe pod')) {
    return [{ kind: 'output', text: 'phase: Running\nrestarts: 0\nage: 17h\nnode: worker-1\nready: true' }]
  }

  return [
    {
      kind: 'reject',
      text: `"${raw.trim()}" is not in the command set. Input parses to a closed enum; nothing else reaches the cluster. Type help.`,
    },
  ]
}

const BOOT: Line[] = [
  { kind: 'output', text: 'atlas read-only shell. Six commands, no shell, no exec.\nType help to list them.' },
]

export default function TerminalPage() {
  const [lines, setLines] = useState<Line[]>(BOOT)
  const [value, setValue] = useState('')
  const scrollRef = useRef<HTMLDivElement>(null)

  useEffect(() => {
    scrollRef.current?.scrollTo({ top: scrollRef.current.scrollHeight })
  }, [lines])

  const submit = (raw: string) => {
    if (!raw.trim()) return
    setLines((prev) => [...prev, { kind: 'input', text: raw }, ...run(raw)])
    setValue('')
  }

  return (
    <div className="space-y-6">
      <header className="border border-wire bg-deck p-6 md:p-8">
        <p className="font-data text-[10px] uppercase tracking-[0.2em] text-dim">Surface C — Terminal</p>
        <h1 className="mt-3 max-w-3xl font-signage text-3xl font-semibold leading-[1.1] tracking-signage md:text-5xl">
          Six commands. <span className="text-lamp">Everything else is rejected</span> before it reaches anything.
        </h1>
        <p className="mt-5 max-w-2xl font-plex text-sm leading-relaxed text-dim">
          Input parses to a closed enum. Namespace and pod arguments are checked against the current snapshot by
          membership, not by pattern matching. There is no shell in the container. Try to break it.
        </p>
      </header>

      <div className="grid gap-6 lg:grid-cols-[1fr_260px]">
        <Panel label="Shell" hint="read-only">
          <div ref={scrollRef} className="h-[420px] overflow-y-auto font-data text-[12px] leading-relaxed">
            {lines.map((line, i) => (
              <div key={i} className="whitespace-pre-wrap">
                {line.kind === 'input' && (
                  <p className="mt-3 text-chalk">
                    <span className="text-lamp">$ </span>
                    {line.text}
                  </p>
                )}
                {line.kind === 'output' && <p className="text-dim">{line.text}</p>}
                {line.kind === 'reject' && (
                  <p className="mt-1 border-l-2 border-rose pl-3 text-rose">{line.text}</p>
                )}
              </div>
            ))}
          </div>

          <form
            onSubmit={(e) => {
              e.preventDefault()
              submit(value)
            }}
            className="mt-3 flex items-center gap-2 border-t border-wire pt-3"
          >
            <span className="font-data text-[12px] text-lamp">$</span>
            <input
              value={value}
              onChange={(e) => setValue(e.target.value)}
              spellCheck={false}
              autoComplete="off"
              aria-label="Cluster command"
              placeholder="get pods llm-serving"
              className="min-w-0 flex-1 bg-transparent font-data text-[12px] text-chalk placeholder:text-dim/60 focus:outline-none"
            />
            <button
              type="submit"
              className="border border-wire-lit px-3 py-1 font-data text-[10px] uppercase tracking-[0.14em] text-dim transition-colors hover:border-lamp hover:text-lamp focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-lamp"
            >
              run
            </button>
          </form>
        </Panel>

        <Panel label="Command set" hint="allowlist">
          <ul className="space-y-2">
            {COMMANDS.map((c) => (
              <li key={c}>
                <button
                  onClick={() => submit(c.replace('<ns>', 'llm-serving').replace('<name>', 'ornith-predictor'))}
                  className="w-full border border-wire px-2.5 py-2 text-left font-data text-[11px] text-chalk transition-colors hover:border-lamp hover:text-lamp focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-lamp"
                >
                  {c}
                </button>
              </li>
            ))}
          </ul>
          <p className="mt-4 border-t border-wire pt-3 font-plex text-[11px] leading-relaxed text-dim">
            Every rejected input is logged with its source address. The allowlist is the whole security model.
          </p>
        </Panel>
      </div>
    </div>
  )
}