import { useState, useEffect } from 'react'
import { Link, useNavigate } from 'react-router-dom'
import { AlertTriangle, ChevronDown, ChevronRight, Hash } from 'lucide-react'
import { aiSessionsApi } from '@/api/aiSessions'
import type { AISessionSummary } from '@/types/ai-session'
import { timeAgo } from '@/lib/timeAgo'
import { cn } from '@/lib/utils'

export function PendingEscalations() {
  const [escalations, setEscalations] = useState<AISessionSummary[]>([])
  // Single expansion at a time — keeps the dashboard compact even when
  // multiple escalations are pending. Click a row again to collapse.
  const [expandedId, setExpandedId] = useState<string | null>(null)
  const navigate = useNavigate()

  useEffect(() => {
    aiSessionsApi.getEscalationQueue()
      .then(setEscalations)
      .catch(() => {})
  }, [])

  if (escalations.length === 0) return null

  return (
    <div
      className="card-flat overflow-hidden"
      style={{ borderColor: 'rgba(234, 179, 8, 0.2)' }}
    >
      <div
        className="flex items-center justify-between px-5 py-3"
        style={{ borderBottom: '1px solid var(--color-border-default)' }}
      >
        <div className="flex items-center gap-2">
          <AlertTriangle size={14} className="text-amber-400" />
          <h3 className="font-heading text-sm font-bold text-foreground">
            Pending Escalations
            <span className="ml-2 inline-flex h-5 min-w-5 items-center justify-center rounded-full bg-amber-400/10 px-1.5 text-[0.625rem] font-bold text-amber-400">
              {escalations.length}
            </span>
          </h3>
        </div>
        <Link
          to="/escalations"
          className="text-[0.6875rem] text-muted-foreground hover:text-foreground transition-colors"
        >
          View all
        </Link>
      </div>
      <div>
        {escalations.slice(0, 3).map((esc, i) => {
          const isExpanded = expandedId === esc.id
          const isLast = i >= Math.min(escalations.length, 3) - 1
          return (
            <div
              key={esc.id}
              style={{
                borderBottom: !isLast
                  ? '1px solid var(--color-border-default)'
                  : undefined,
              }}
            >
              <button
                type="button"
                onClick={() => setExpandedId(isExpanded ? null : esc.id)}
                aria-expanded={isExpanded}
                className="w-full flex items-center gap-3 px-5 py-3 text-left hover:bg-elevated/30 transition-colors"
              >
                <span className="h-2 w-2 shrink-0 rounded-full bg-amber-400 animate-pulse" />
                {isExpanded ? (
                  <ChevronDown size={12} className="shrink-0 text-muted-foreground" />
                ) : (
                  <ChevronRight size={12} className="shrink-0 text-muted-foreground" />
                )}
                <div className="flex-1 min-w-0">
                  <div className="text-sm text-foreground truncate">
                    {esc.problem_summary || 'Escalated session'}
                  </div>
                  <div className="text-[0.6875rem] text-muted-foreground">
                    {esc.problem_domain || 'General'}
                    <span className="mx-1.5 text-[var(--text-dimmed)]">&middot;</span>
                    <span className="font-sans text-xs">{timeAgo(esc.created_at)}</span>
                    {esc.psa_ticket_id && (
                      <>
                        <span className="mx-1.5 text-[var(--text-dimmed)]">&middot;</span>
                        <span className="inline-flex items-center gap-0.5 font-mono text-[0.625rem] text-accent-text">
                          <Hash size={9} />
                          {esc.psa_ticket_id}
                        </span>
                      </>
                    )}
                  </div>
                </div>
                <span
                  onClick={(e) => {
                    e.stopPropagation()
                    navigate(`/pilot/${esc.id}?pickup=true`)
                  }}
                  role="button"
                  tabIndex={0}
                  onKeyDown={(e) => {
                    if (e.key === 'Enter' || e.key === ' ') {
                      e.preventDefault()
                      e.stopPropagation()
                      navigate(`/pilot/${esc.id}?pickup=true`)
                    }
                  }}
                  className="shrink-0 rounded-lg border border-amber-400/30 bg-amber-400/10 px-3 py-1 text-[0.6875rem] font-medium text-amber-400 hover:bg-amber-400/20 transition-colors cursor-pointer"
                >
                  Pick up
                </span>
              </button>

              {isExpanded && (
                <div
                  className={cn(
                    'px-5 pb-3 pl-12 space-y-2 text-xs animate-fade-in'
                  )}
                >
                  {esc.escalation_reason && (
                    <div>
                      <p className="font-sans text-[0.5625rem] uppercase tracking-wider text-muted-foreground mb-0.5">
                        Why escalated
                      </p>
                      <p className="text-foreground whitespace-pre-wrap leading-snug">
                        {esc.escalation_reason}
                      </p>
                    </div>
                  )}
                  <div className="flex flex-wrap gap-x-3 gap-y-1 text-muted-foreground">
                    <span>
                      <span className="font-medium text-foreground">{esc.step_count}</span>{' '}
                      diagnostic {esc.step_count === 1 ? 'step' : 'steps'} on record
                    </span>
                    {esc.confidence_tier && (
                      <span className="font-sans uppercase tracking-wider text-[0.5625rem]">
                        Confidence: {esc.confidence_tier}
                      </span>
                    )}
                  </div>
                  {!esc.escalation_reason && (
                    <p className="italic text-muted-foreground">
                      No reason note from the original engineer. Pick up to see the full session
                      context and AI assessment.
                    </p>
                  )}
                </div>
              )}
            </div>
          )
        })}
      </div>
    </div>
  )
}