import { useQuery } from '@tanstack/react-query'
import { useNavigate } from '@tanstack/react-router'
import { CalendarClock, Loader2, Plus, UserCheck, Users, Wallet, type LucideIcon } from 'lucide-react'
import type { HomeSummaryDto, NextClassDto, PaymentDto, UpcomingPaymentDto } from '@gruperly/shared'
import { Badge, Button } from '../components/ui'
import { getHomeSummary } from '../lib/api'
import {
  formatPrice,
  formatRelativeDateTime,
  formatSchedule,
  PAYMENT_STATUS_LABELS,
} from '../lib/format'
import { cn } from '../lib/utils'

const PAYMENT_BADGE_VARIANT: Record<
  PaymentDto['status'],
  'success' | 'warning' | 'danger' | 'neutral'
> = {
  PENDING: 'warning',
  OVERDUE: 'danger',
  PAID: 'success',
  CANCELLED: 'neutral',
}

function NextClassHero({ nextClass }: { nextClass: NextClassDto }) {
  const navigate = useNavigate()
  const hasSchedule = (nextClass.days?.length ?? 0) > 0

  return (
    <article className="relative overflow-hidden rounded-xl border border-accent/30 bg-surface p-5">
      <div className="flex flex-col gap-3 sm:flex-row sm:items-start sm:justify-between sm:gap-4">
        <div className="min-w-0">
          <p className="text-xs font-medium uppercase tracking-wide text-foreground/50">
            {nextClass.isNow ? 'Clase en curso' : 'Próxima clase'}
          </p>
          <h2 className="mt-1 truncate text-xl font-bold text-primary">{nextClass.name}</h2>
          {hasSchedule ? (
            <div className="mt-2 flex items-center gap-2 text-sm text-foreground/70">
              <CalendarClock className="size-4 shrink-0 text-accent" />
              <span>{formatSchedule(nextClass.days ?? [], nextClass.time)}</span>
            </div>
          ) : null}
        </div>
        <div className="flex shrink-0 items-center gap-2">
          <Badge variant={nextClass.isNow ? 'success' : 'neutral'}>
            {nextClass.isNow ? 'En curso ahora' : formatRelativeDateTime(nextClass.occurrenceAt)}
          </Badge>
        </div>
      </div>
      <div className="mt-4 flex justify-end border-t border-border pt-3">
        <Button
          variant="outline"
          size="sm"
          onClick={() => void navigate({ to: `/groups/${nextClass.groupId}` })}
        >
          Ver grupo
        </Button>
      </div>
    </article>
  )
}

function UpcomingPaymentRow({ payment }: { payment: UpcomingPaymentDto }) {
  return (
    <li className="flex items-center justify-between gap-3 rounded-xl border border-border bg-surface px-4 py-3">
      <div className="min-w-0">
        <p className="truncate text-sm font-semibold text-primary">{payment.attendeeName}</p>
        <p className="mt-0.5 truncate text-xs text-foreground/60">
          {payment.groupName} · {formatRelativeDateTime(payment.dueDate)}
        </p>
      </div>
      <div className="flex shrink-0 items-center gap-2">
        <span className="text-sm font-semibold text-primary">{formatPrice(payment.amount)}</span>
        <Badge variant={PAYMENT_BADGE_VARIANT[payment.status]}>
          {PAYMENT_STATUS_LABELS[payment.status]}
        </Badge>
      </div>
    </li>
  )
}

function SummaryStats({ summary }: { summary: HomeSummaryDto }) {
  const navigate = useNavigate()
  const stats: {
    label: string
    value: string
    sub?: string
    icon: LucideIcon
    to: '/groups' | '/payments'
  }[] = [
    {
      label: 'Grupos activos',
      value: String(summary.stats.groups),
      icon: Users,
      to: '/groups',
    },
    {
      label: 'Cobros pendientes',
      value: summary.stats.pendingAmount > 0 ? formatPrice(summary.stats.pendingAmount) : '0',
      sub: `${summary.stats.pendingPayments} por cobrar`,
      icon: Wallet,
      to: '/payments',
    },
    {
      label: 'Asistentes',
      value: String(summary.stats.attendees),
      icon: UserCheck,
      to: '/groups',
    },
  ]

  return (
    <div className="grid grid-cols-1 gap-4 sm:grid-cols-3">
      {stats.map((stat) => {
        const Icon = stat.icon
        return (
          <button
            key={stat.label}
            type="button"
            onClick={() => void navigate({ to: stat.to })}
            className={cn(
              'flex items-center gap-3 rounded-xl border border-border bg-surface p-4 text-left transition-all',
              'hover:border-accent/40',
            )}
          >
            <span className="flex size-10 shrink-0 items-center justify-center rounded-lg bg-accent-soft text-accent">
              <Icon className="size-5" />
            </span>
            <span className="min-w-0">
              <span className="block text-xl font-bold leading-tight text-primary">{stat.value}</span>
              <span className="block truncate text-xs text-foreground/60">
                {stat.sub ?? stat.label}
              </span>
            </span>
          </button>
        )
      })}
    </div>
  )
}

export function HomeView() {
  const navigate = useNavigate()
  const summaryQuery = useQuery({
    queryKey: ['home-summary'],
    queryFn: getHomeSummary,
  })

  return (
    <section>
      <div>
        <h1 className="text-2xl font-bold text-primary">Inicio</h1>
        <p className="mt-2 text-sm text-foreground/60">Tu actividad de cobros de un vistazo.</p>
      </div>

      {summaryQuery.isPending ? (
        <div className="mt-8 flex items-center justify-center py-16">
          <Loader2 className="size-6 animate-spin text-foreground/40" />
        </div>
      ) : null}

      {summaryQuery.isError ? (
        <div className="mt-8 space-y-3 rounded-xl bg-danger-soft px-4 py-3 text-sm text-danger">
          <p>No pudimos cargar tu resumen.</p>
          <Button variant="outline" size="sm" onClick={() => void summaryQuery.refetch()}>
            Reintentar
          </Button>
        </div>
      ) : null}

      {summaryQuery.isSuccess && summaryQuery.data.stats.groups === 0 ? (
        <div className="mt-8 rounded-xl border border-dashed border-border bg-surface px-4 py-12 text-center">
          <p className="font-medium text-primary">Todavía no tenés grupos</p>
          <p className="mt-1 text-sm text-foreground/60">
            Crea tu primer grupo para empezar a cobrar.
          </p>
          <Button
            variant="primary"
            className="mt-5"
            onClick={() => void navigate({ to: '/groups/new' })}
          >
            <Plus className="size-4" />
            Crear tu primer grupo
          </Button>
        </div>
      ) : null}

      {summaryQuery.isSuccess && summaryQuery.data.stats.groups > 0 ? (
        <div className="mt-6 space-y-6">
          {summaryQuery.data.nextClass ? (
            <NextClassHero nextClass={summaryQuery.data.nextClass} />
          ) : (
            <div className="rounded-xl border border-dashed border-border bg-surface px-4 py-8 text-center">
              <p className="text-sm font-medium text-primary">Sin clases programadas</p>
              <p className="mt-1 text-sm text-foreground/60">
                Agregá días y horario a tus grupos para ver tu próxima clase acá.
              </p>
            </div>
          )}

          <SummaryStats summary={summaryQuery.data} />

          <div>
            <div className="flex items-center justify-between gap-3">
              <h2 className="text-lg font-bold text-primary">Próximos cobros</h2>
              <Button
                variant="ghost"
                size="sm"
                onClick={() => void navigate({ to: '/payments' })}
              >
                Ver todos
              </Button>
            </div>

            {summaryQuery.data.upcomingPayments.length > 0 ? (
              <ul className="mt-3 space-y-3">
                {summaryQuery.data.upcomingPayments.map((payment) => (
                  <UpcomingPaymentRow key={payment.id} payment={payment} />
                ))}
              </ul>
            ) : (
              <p className="mt-3 rounded-xl border border-dashed border-border bg-surface px-4 py-6 text-center text-sm text-foreground/60">
                Sin cobros pendientes por ahora.
              </p>
            )}
          </div>
        </div>
      ) : null}
    </section>
  )
}