'use client';

import { useState } from 'react';
import { useRouter } from 'next/navigation';
import Link from 'next/link';
import { Button, Input, Label, Card, CardContent, CardHeader, CardTitle, cn } from '@horux/shared-ui';
import { useAuthStore } from '@/stores/auth-store';
import { apiClient } from '@/lib/api/client';
import { CheckCircle2, Server, Cloud, ArrowLeft, Clock, Building, Sparkles } from 'lucide-react';

type VerticalProfile = 'CONTABLE' | 'JURIDICO' | 'ARQUITECTURA';
type PlanType = 'trial' | 'mi_empresa' | 'mi_empresa_plus' | 'business_control' | 'business_cloud';

export default function RegisterDespachoPage() {
  const router = useRouter();
  const { setUser, setTokens } = useAuthStore();
  const [step, setStep] = useState(1);
  const [verticalProfile, setVerticalProfile] = useState<VerticalProfile | null>(null);
  const [selectedPlan, setSelectedPlan] = useState<PlanType | null>(null);
  // Default 'annual' — sesgo intencional al cash-flow del negocio (10 meses
  // = 17% descuento para el cliente, año completo cobrado upfront para nosotros).
  const [billingFrequency, setBillingFrequency] = useState<'monthly' | 'annual'>('annual');
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState('');
  const [form, setForm] = useState({
    despachoNombre: '',
    ownerNombre: '',
    ownerEmail: '',
    ownerPassword: '',
    acceptedTerms: false,
  });

  const handleChange = (field: string) => (e: React.ChangeEvent<HTMLInputElement>) => {
    setForm((prev) => ({ ...prev, [field]: e.target.value }));
    setError('');
  };

  const handleSubmit = async () => {
    if (!form.acceptedTerms) { setError('Debes aceptar los términos y condiciones'); return; }
    if (!verticalProfile || !selectedPlan) { setError('Completa todos los pasos'); return; }
    setLoading(true);
    setError('');
    try {
      const { data } = await apiClient.post('/despachos/signup', {
        despacho: {
          nombre: form.despachoNombre,
          verticalProfile,
          plan: selectedPlan,
          // Solo mi_empresa(+) acepta monthly; el backend ignora frequency
          // para los demás planes. Mandamos siempre el state para coherencia.
          frequency: billingFrequency,
        },
        owner: {
          nombre: form.ownerNombre,
          email: form.ownerEmail,
          password: form.ownerPassword,
        },
      });
      setTokens(data.accessToken, data.refreshToken);
      setUser(data.user);

      // If paid plan with payment URL, redirect to MercadoPago
      if (data.paymentUrl) {
        window.location.href = data.paymentUrl;
      } else {
        router.push('/onboarding');
      }
    } catch (err: any) {
      setError(err.response?.data?.message || 'Error al registrar el despacho');
      setStep(1);
    } finally {
      setLoading(false);
    }
  };

  // =================== STEP 1: Registration Form ===================
  if (step === 1) {
    const canProceed = form.despachoNombre && form.ownerNombre && form.ownerEmail && form.ownerPassword.length >= 10 && form.acceptedTerms;

    return (
      <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-blue-50 to-purple-50 dark:from-gray-900 dark:to-gray-800 p-4">
        <Card className="w-full max-w-lg">
          <CardHeader className="text-center">
            <div className="flex items-center justify-center gap-2 text-xs text-muted-foreground mb-4">
              <span className="bg-primary text-primary-foreground rounded-full w-6 h-6 flex items-center justify-center font-bold">1</span>
              <span className="w-8 h-px bg-muted" />
              <span className="bg-muted text-muted-foreground rounded-full w-6 h-6 flex items-center justify-center">2</span>
              <span className="w-8 h-px bg-muted" />
              <span className="bg-muted text-muted-foreground rounded-full w-6 h-6 flex items-center justify-center">3</span>
            </div>
            <CardTitle className="text-2xl font-bold">Crea tu cuenta</CardTitle>
            <p className="text-sm text-muted-foreground mt-1">Plataforma para despachos profesionales</p>
          </CardHeader>
          <CardContent className="space-y-6">
            <div className="space-y-3">
              <div><Label htmlFor="dn">Nombre del despacho</Label><Input id="dn" value={form.despachoNombre} onChange={handleChange('despachoNombre')} placeholder="Despacho Pérez y Asociados" required /></div>
            </div>
            <div className="space-y-3">
              <div><Label htmlFor="on">Tu nombre completo</Label><Input id="on" value={form.ownerNombre} onChange={handleChange('ownerNombre')} placeholder="Juan Pérez" required /></div>
              <div><Label htmlFor="oe">Email</Label><Input id="oe" type="email" value={form.ownerEmail} onChange={handleChange('ownerEmail')} placeholder="juan@despacho.com" required /></div>
              <div><Label htmlFor="op">Contraseña</Label><Input id="op" type="password" value={form.ownerPassword} onChange={handleChange('ownerPassword')} placeholder="Mínimo 10 caracteres" minLength={10} required /></div>
            </div>
            <div className="flex items-start gap-2">
              <input type="checkbox" id="terms" checked={form.acceptedTerms} onChange={(e) => setForm((p) => ({ ...p, acceptedTerms: e.target.checked }))} className="mt-1" />
              <label htmlFor="terms" className="text-sm text-muted-foreground">Acepto los <Link href="/terminos" target="_blank" className="underline text-primary">términos y condiciones</Link></label>
            </div>
            {error && <p className="text-sm text-destructive bg-destructive/10 p-3 rounded-md">{error}</p>}
            <Button onClick={() => canProceed && setStep(2)} className="w-full" disabled={!canProceed}>
              Continuar
            </Button>
            <p className="text-center text-sm text-muted-foreground">
              ¿Ya tienes cuenta? <Link href="/login" className="text-primary underline">Inicia sesión</Link>
            </p>
          </CardContent>
        </Card>
      </div>
    );
  }

  // =================== STEP 2: Vertical Selection ===================
  if (step === 2) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-blue-50 to-purple-50 dark:from-gray-900 dark:to-gray-800 p-4">
        <div className="w-full max-w-3xl space-y-8 text-center">
          <div>
            <div className="flex items-center justify-center gap-2 text-xs text-muted-foreground mb-4">
              <span className="bg-green-500 text-white rounded-full w-6 h-6 flex items-center justify-center"><CheckCircle2 className="h-4 w-4" /></span>
              <span className="w-8 h-px bg-primary" />
              <span className="bg-primary text-primary-foreground rounded-full w-6 h-6 flex items-center justify-center font-bold">2</span>
              <span className="w-8 h-px bg-muted" />
              <span className="bg-muted text-muted-foreground rounded-full w-6 h-6 flex items-center justify-center">3</span>
            </div>
            <h1 className="text-3xl font-bold">¿Qué tipo de despacho eres?</h1>
            <p className="text-muted-foreground mt-2">Selecciona tu área profesional</p>
          </div>
          <div className="grid md:grid-cols-3 gap-4">
            <button
              onClick={() => { setVerticalProfile('CONTABLE'); setStep(3); }}
              className="p-8 rounded-xl border-2 border-primary bg-card hover:bg-accent transition-all text-center space-y-3"
            >
              <div className="text-4xl">📊</div>
              <h3 className="text-lg font-semibold">Contable</h3>
              <p className="text-sm text-muted-foreground">Gestión fiscal, CFDI, IVA/ISR, SAT sync</p>
            </button>
            <div className="p-8 rounded-xl border-2 border-dashed border-muted bg-muted/30 text-center space-y-3 opacity-50 cursor-not-allowed">
              <div className="text-4xl">⚖️</div>
              <h3 className="text-lg font-semibold">Jurídico</h3>
              <p className="text-sm text-muted-foreground">Próximamente</p>
            </div>
            <div className="p-8 rounded-xl border-2 border-dashed border-muted bg-muted/30 text-center space-y-3 opacity-50 cursor-not-allowed">
              <div className="text-4xl">🏗️</div>
              <h3 className="text-lg font-semibold">Arquitectura</h3>
              <p className="text-sm text-muted-foreground">Próximamente</p>
            </div>
          </div>
          <button onClick={() => setStep(1)} className="text-sm text-muted-foreground underline">
            <ArrowLeft className="h-3 w-3 inline mr-1" />Volver al formulario
          </button>
        </div>
      </div>
    );
  }

  // =================== STEP 3: Subscription Selection ===================
  return (
    <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-blue-50 to-purple-50 dark:from-gray-900 dark:to-gray-800 py-8 px-4">
      <div className="w-full max-w-7xl space-y-8">
        <div className="text-center">
          <div className="flex items-center justify-center gap-2 text-xs text-muted-foreground mb-4">
            <span className="bg-green-500 text-white rounded-full w-6 h-6 flex items-center justify-center"><CheckCircle2 className="h-4 w-4" /></span>
            <span className="w-8 h-px bg-green-500" />
            <span className="bg-green-500 text-white rounded-full w-6 h-6 flex items-center justify-center"><CheckCircle2 className="h-4 w-4" /></span>
            <span className="w-8 h-px bg-primary" />
            <span className="bg-primary text-primary-foreground rounded-full w-6 h-6 flex items-center justify-center font-bold">3</span>
          </div>
          <h1 className="text-3xl font-bold">Elige tu plan</h1>
          <p className="text-muted-foreground mt-2">Empieza con el trial gratuito de 30 días o contrata un plan directo.</p>
        </div>

        {/* Toggle facturación mensual / anual (afecta solo Mi Empresa y Mi Empresa+) */}
        <div className="flex justify-center">
          <div className="inline-flex items-center gap-1 rounded-full border bg-muted/30 p-1">
            <button
              type="button"
              onClick={() => setBillingFrequency('monthly')}
              className={cn(
                'px-4 py-1.5 rounded-full text-sm font-medium transition-colors',
                billingFrequency === 'monthly'
                  ? 'bg-background shadow-sm'
                  : 'text-muted-foreground hover:text-foreground'
              )}
            >
              Mensual
            </button>
            <button
              type="button"
              onClick={() => setBillingFrequency('annual')}
              className={cn(
                'px-4 py-1.5 rounded-full text-sm font-medium transition-colors flex items-center gap-2',
                billingFrequency === 'annual'
                  ? 'bg-background shadow-sm'
                  : 'text-muted-foreground hover:text-foreground'
              )}
            >
              Anual
              <span className={cn(
                'text-[10px] px-1.5 py-0.5 rounded-full',
                billingFrequency === 'annual'
                  ? 'bg-green-100 text-green-700 dark:bg-green-900/40 dark:text-green-400'
                  : 'bg-muted text-muted-foreground'
              )}>
                Ahorra 17%
              </span>
            </button>
          </div>
        </div>

        <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-5 gap-4">
          {/* Trial Gratuito */}
          <Card
            className={cn(
              'cursor-pointer transition-all hover:shadow-lg',
              selectedPlan === 'trial' && 'border-primary ring-2 ring-primary/20'
            )}
            onClick={() => setSelectedPlan('trial')}
          >
            <CardHeader className="text-center pb-2">
              <div className="mx-auto bg-green-100 dark:bg-green-900 rounded-full p-3 w-fit mb-2">
                <Clock className="h-6 w-6 text-green-600 dark:text-green-400" />
              </div>
              <CardTitle className="text-lg">Trial Gratuito</CardTitle>
              <p className="text-xs text-muted-foreground">Prueba sin compromiso</p>
            </CardHeader>
            <CardContent className="space-y-3">
              <div className="text-center">
                <div className="text-2xl font-bold">$0</div>
                <p className="text-xs text-muted-foreground">30 días</p>
                <p className="text-xs text-muted-foreground mt-1">Sin tarjeta</p>
              </div>
              <div className="space-y-1.5 text-xs">
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>Hasta 3 RFCs</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>1 usuario</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>Todas las funcionalidades</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>BD en la nube</span></div>
              </div>
            </CardContent>
          </Card>

          {/* Mi Empresa */}
          <Card
            className={cn(
              'cursor-pointer transition-all hover:shadow-lg',
              selectedPlan === 'mi_empresa' && 'border-primary ring-2 ring-primary/20'
            )}
            onClick={() => setSelectedPlan('mi_empresa')}
          >
            <CardHeader className="text-center pb-2">
              <div className="mx-auto bg-orange-100 dark:bg-orange-900 rounded-full p-3 w-fit mb-2">
                <Building className="h-6 w-6 text-orange-600 dark:text-orange-400" />
              </div>
              <CardTitle className="text-lg">Mi Empresa</CardTitle>
              <p className="text-xs text-muted-foreground">Para 1 contribuyente</p>
            </CardHeader>
            <CardContent className="space-y-3">
              <div className="text-center">
                {billingFrequency === 'annual' ? (
                  <>
                    <div className="text-2xl font-bold">$5,800</div>
                    <p className="text-xs text-muted-foreground">por año</p>
                    <p className="text-xs text-green-600 dark:text-green-400 mt-1 font-medium">Equivale a 10 meses</p>
                  </>
                ) : (
                  <>
                    <div className="text-2xl font-bold">$580</div>
                    <p className="text-xs text-muted-foreground">mensual</p>
                    <p className="text-xs text-muted-foreground mt-1">o $5,800/año (10 meses)</p>
                  </>
                )}
              </div>
              <div className="space-y-1.5 text-xs">
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>1 RFC</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>3 usuarios</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>50 timbres/mes</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>BD en la nube</span></div>
              </div>
            </CardContent>
          </Card>

          {/* Mi Empresa + */}
          <Card
            className={cn(
              'cursor-pointer transition-all hover:shadow-lg',
              selectedPlan === 'mi_empresa_plus' && 'border-primary ring-2 ring-primary/20'
            )}
            onClick={() => setSelectedPlan('mi_empresa_plus')}
          >
            <CardHeader className="text-center pb-2">
              <div className="mx-auto bg-purple-100 dark:bg-purple-900 rounded-full p-3 w-fit mb-2">
                <Sparkles className="h-6 w-6 text-purple-600 dark:text-purple-400" />
              </div>
              <CardTitle className="text-lg">Mi Empresa +</CardTitle>
              <p className="text-xs text-muted-foreground">Con IA + API</p>
            </CardHeader>
            <CardContent className="space-y-3">
              <div className="text-center">
                {billingFrequency === 'annual' ? (
                  <>
                    <div className="text-2xl font-bold">$9,000</div>
                    <p className="text-xs text-muted-foreground">por año</p>
                    <p className="text-xs text-green-600 dark:text-green-400 mt-1 font-medium">Equivale a 10 meses</p>
                  </>
                ) : (
                  <>
                    <div className="text-2xl font-bold">$900</div>
                    <p className="text-xs text-muted-foreground">mensual</p>
                    <p className="text-xs text-muted-foreground mt-1">o $9,000/año (10 meses)</p>
                  </>
                )}
              </div>
              <div className="space-y-1.5 text-xs">
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>Todo Mi Empresa</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>Lolita IA Fiscal</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>API de integración</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>SAT incremental</span></div>
              </div>
            </CardContent>
          </Card>

          {/* Business Control */}
          <Card
            className={cn(
              'cursor-pointer transition-all hover:shadow-lg relative',
              selectedPlan === 'business_control' && 'border-primary ring-2 ring-primary/20'
            )}
            onClick={() => setSelectedPlan('business_control')}
          >
            <div className="absolute -top-3 left-1/2 -translate-x-1/2 bg-primary text-primary-foreground text-xs px-3 py-1 rounded-full">
              Más popular
            </div>
            <CardHeader className="text-center pb-2">
              <div className="mx-auto bg-blue-100 dark:bg-blue-900 rounded-full p-3 w-fit mb-2">
                <Server className="h-6 w-6 text-blue-600 dark:text-blue-400" />
              </div>
              <CardTitle className="text-lg">Business Control</CardTitle>
              <p className="text-xs text-muted-foreground">Despachos contables</p>
            </CardHeader>
            <CardContent className="space-y-3">
              <div className="text-center">
                <div className="text-2xl font-bold">$25,850</div>
                <p className="text-xs text-muted-foreground">por año (IVA inc.)</p>
                <p className="text-xs text-muted-foreground mt-1">+ $45/mes por RFC extra</p>
              </div>
              <div className="space-y-1.5 text-xs">
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>100 RFCs incluidos</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>Usuarios ilimitados</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>BD en tu servidor</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>Servidor backup</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>API de integración</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>SAT incremental</span></div>
              </div>
            </CardContent>
          </Card>

          {/* Enterprise (business_cloud) */}
          <Card
            className={cn(
              'cursor-pointer transition-all hover:shadow-lg',
              selectedPlan === 'business_cloud' && 'border-primary ring-2 ring-primary/20'
            )}
            onClick={() => setSelectedPlan('business_cloud')}
          >
            <CardHeader className="text-center pb-2">
              <div className="mx-auto bg-amber-100 dark:bg-amber-900 rounded-full p-3 w-fit mb-2">
                <Cloud className="h-6 w-6 text-amber-600 dark:text-amber-400" />
              </div>
              <CardTitle className="text-lg">Enterprise</CardTitle>
              <p className="text-xs text-muted-foreground">Despachos de alto volumen</p>
            </CardHeader>
            <CardContent className="space-y-3">
              <div className="text-center">
                <div className="text-2xl font-bold">$43,000</div>
                <p className="text-xs text-muted-foreground">por año (IVA inc.)</p>
                <p className="text-xs text-muted-foreground mt-1">+ $45/mes por RFC extra</p>
              </div>
              <div className="space-y-1.5 text-xs">
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>100 RFCs incluidos</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>3M CFDIs por contribuyente</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>Usuarios ilimitados</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>BD en tu servidor</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>Servidor backup</span></div>
                <div className="flex items-start gap-1.5"><CheckCircle2 className="h-3.5 w-3.5 text-green-500 flex-shrink-0 mt-0.5" /><span>SAT incremental + API</span></div>
              </div>
            </CardContent>
          </Card>
        </div>

        {error && <p className="text-sm text-destructive bg-destructive/10 p-3 rounded-md text-center max-w-lg mx-auto">{error}</p>}

        <div className="flex flex-col items-center gap-3">
          <Button
            onClick={handleSubmit}
            disabled={!selectedPlan || loading}
            size="lg"
            className="px-12"
          >
            {loading ? 'Creando tu despacho...' : selectedPlan === 'trial' ? 'Comenzar trial gratuito' : 'Continuar al pago'}
          </Button>
          <button onClick={() => setStep(2)} className="text-sm text-muted-foreground underline">
            <ArrowLeft className="h-3 w-3 inline mr-1" />Volver
          </button>
        </div>
      </div>
    </div>
  );
}