import { useState } from 'react'
import { Headphones, Inbox, PhoneForwarded, RefreshCw, Sparkles, User } from 'lucide-react'
import { useQuery, useZino } from '../zino-sdk'
import { fetchCallMessages, fetchMyCalls, type CopilotSession } from '../api'
import { LIVE_CALL_PREFIX } from '../config'

const POLL_MS = 3000

/**
 * What the human colleague sees after a call was transferred to them.
 *
 * Scoped to the signed-in user by the server, not by this component: each call
 * is a co-pilot session OWNED BY the human it was routed to, and every read
 * authorizes on `session.user_id == token.sub`. Someone else's call is a 403.
 */
export default function MyCalls() {
  const { client } = useZino()
  const [selectedId, setSelectedId] = useState<number | null>(null)

  const { data: calls = [], isLoading, isFetching, error, refetch } = useQuery({
    queryKey: ['my-calls'],
    queryFn: () => fetchMyCalls(client),
    refetchInterval: POLL_MS,
  })

  const activeId = selectedId ?? calls[0]?.id ?? null

  return (
    <div>
      <div className="flex items-center gap-3">
        <div>
          <h1 className="text-xl font-semibold">My calls</h1>
          <p className="mt-1 text-sm text-slate-500">
            Calls Meera transferred to you. The conversation streams in live while you talk,
            with quiet suggestions you can relay.
          </p>
        </div>
        <button
          onClick={() => refetch()}
          className="ml-auto inline-flex items-center gap-1.5 rounded-lg border border-slate-300 bg-white px-3 py-1.5 text-xs font-medium text-slate-600 hover:bg-slate-50"
        >
          <RefreshCw size={13} className={isFetching ? 'animate-spin' : ''} />
          Refresh
        </button>
      </div>

      {error && (
        <p className="mt-4 rounded-lg bg-red-50 px-3 py-2 text-sm text-red-700">
          {(error as any)?.message || 'Could not load your calls'}
        </p>
      )}

      {!isLoading && calls.length === 0 && (
        <div className="mt-6 rounded-2xl border border-dashed border-slate-300 bg-white px-6 py-16 text-center">
          <Inbox className="mx-auto text-slate-300" size={28} />
          <p className="mt-3 text-sm font-medium text-slate-600">No calls transferred to you yet</p>
          <p className="mx-auto mt-1 max-w-md text-xs text-slate-400">
            When Meera hands a call to your desk, it appears here — with the brief, the live
            conversation, and the AI's suggestions.
          </p>
        </div>
      )}

      {calls.length > 0 && (
        <div className="mt-5 grid gap-5 lg:grid-cols-[300px_1fr]">
          <ul className="space-y-2">
            {calls.map((c) => (
              <CallRow
                key={c.id}
                call={c}
                active={c.id === activeId}
                onClick={() => setSelectedId(c.id)}
              />
            ))}
          </ul>
          {activeId && <Thread sessionId={activeId} />}
        </div>
      )}
    </div>
  )
}

function CallRow({
  call,
  active,
  onClick,
}: {
  call: CopilotSession
  active: boolean
  onClick: () => void
}) {
  const cd = (call.collected_data ?? {}) as Record<string, unknown>
  const who = String(cd.name ?? cd.lead_name ?? 'Caller')
  const reason = String(cd.handover_reason ?? '')

  return (
    <li>
      <button
        onClick={onClick}
        className={`w-full rounded-xl border px-3.5 py-3 text-left transition-colors ${
          active
            ? 'border-red-200 bg-red-50'
            : 'border-slate-200 bg-white hover:border-slate-300'
        }`}
      >
        <div className="flex items-center gap-2">
          <PhoneForwarded size={13} className="shrink-0 text-red-600" />
          <span className="truncate text-sm font-medium">{who}</span>
        </div>
        {reason && <p className="mt-1 line-clamp-2 text-xs text-slate-500">{reason}</p>}
        <p className="mt-1 text-[11px] text-slate-400">{when(call.updated_at ?? call.created_at)}</p>
      </button>
    </li>
  )
}

function Thread({ sessionId }: { sessionId: number }) {
  const { client } = useZino()
  const { data: messages = [], isLoading, error } = useQuery({
    queryKey: ['call-thread', sessionId],
    queryFn: () => fetchCallMessages(client, sessionId),
    // Polls while the call is live — this is the screen the human works from.
    refetchInterval: POLL_MS,
  })

  if (error) {
    return (
      <div className="rounded-2xl border border-red-200 bg-red-50 p-4 text-sm text-red-700">
        {(error as any)?.status === 403
          ? 'This call was transferred to someone else.'
          : (error as any)?.message || 'Could not load the conversation'}
      </div>
    )
  }

  return (
    <div className="max-h-[70vh] space-y-3 overflow-y-auto rounded-2xl border border-slate-200 bg-white p-5">
      {isLoading && <p className="text-sm text-slate-400">Loading…</p>}
      {messages.map((m) => {
        const overheard = m.content.startsWith(LIVE_CALL_PREFIX)
        if (overheard) {
          return (
            <Bubble
              key={m.id}
              icon={<Headphones size={12} />}
              label="Overheard on the call"
              tone="slate"
              text={m.content.slice(LIVE_CALL_PREFIX.length).trim()}
            />
          )
        }
        if (m.content.startsWith('HANDOVER BRIEF')) {
          return (
            <Bubble
              key={m.id}
              icon={<User size={12} />}
              label="Handover brief"
              tone="amber"
              text={m.content.replace(/^HANDOVER BRIEF\n?/, '')}
            />
          )
        }
        // A lone dash is the co-pilot deliberately staying quiet — rendering it
        // as an empty suggestion box would read as a bug.
        if (m.content.trim() === '—' || m.content.trim() === '-') return null
        return (
          <Bubble
            key={m.id}
            icon={<Sparkles size={12} />}
            label="Suggested — yours to relay"
            tone="indigo"
            text={m.content}
          />
        )
      })}
    </div>
  )
}

function Bubble({
  icon,
  label,
  text,
  tone,
}: {
  icon: React.ReactNode
  label: string
  text: string
  tone: 'slate' | 'indigo' | 'amber'
}) {
  const skin = {
    slate: 'border-slate-200 bg-slate-50 text-slate-700',
    indigo: 'border-indigo-200 bg-indigo-50 text-indigo-900',
    amber: 'border-amber-200 bg-amber-50 text-amber-900',
  }[tone]

  return (
    <div className={`rounded-xl border px-3.5 py-2.5 ${skin}`}>
      <div className="mb-1 flex items-center gap-1.5 text-[11px] font-semibold uppercase tracking-wide opacity-70">
        {icon}
        {label}
      </div>
      <p className="whitespace-pre-wrap text-sm">{text}</p>
    </div>
  )
}

function when(ts?: string): string {
  if (!ts) return ''
  const d = new Date(ts)
  if (Number.isNaN(d.getTime())) return ''
  return d.toLocaleString(undefined, {
    day: 'numeric',
    month: 'short',
    hour: '2-digit',
    minute: '2-digit',
  })
}