import React, { useState, useEffect, useCallback } from 'react';
import { Link } from 'react-router-dom';
import { PublicLayout } from '../../components/layout';
import { Button } from '../../components/ui';
import { getDemoAccounts, createDemoSession, DemoAccount, demoSessionAPI } from '../../api/services/demo';
import { apiClient } from '../../api/client';
import { Check, Clock, Shield, Play, Zap, ArrowRight, Store, Factory, Loader2 } from 'lucide-react';
import { markTourAsStartPending } from '../../features/demo-onboarding';

const POLL_INTERVAL_MS = 1500; // Poll every 1.5 seconds

export const DemoPage: React.FC = () => {
  const [demoAccounts, setDemoAccounts] = useState<DemoAccount[]>([]);
  const [loading, setLoading] = useState(true);
  const [creatingSession, setCreatingSession] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [progressPercentage, setProgressPercentage] = useState(0);
  const [estimatedTime, setEstimatedTime] = useState(5);

  useEffect(() => {
    const fetchDemoAccounts = async () => {
      try {
        const accounts = await getDemoAccounts();
        setDemoAccounts(accounts);
      } catch (err) {
        setError('Error al cargar las cuentas demo');
        console.error('Error fetching demo accounts:', err);
      } finally {
        setLoading(false);
      }
    };

    fetchDemoAccounts();
  }, []);

  const pollStatus = useCallback(async (sessionId: string) => {
    try {
      const statusData = await demoSessionAPI.getSessionStatus(sessionId);

      // Calculate progress - ALWAYS update, even if no progress data yet
      if (statusData.progress && Object.keys(statusData.progress).length > 0) {
        const services = Object.values(statusData.progress);
        const totalServices = services.length;

        if (totalServices > 0) {
          const completedServices = services.filter(
            (s) => s.status === 'completed' || s.status === 'failed'
          ).length;
          const percentage = Math.round((completedServices / totalServices) * 100);
          setProgressPercentage(percentage);

          // Estimate remaining time
          const remainingServices = totalServices - completedServices;
          setEstimatedTime(Math.max(remainingServices * 2, 1));
        } else {
          // No services yet, show minimal progress
          setProgressPercentage(5);
        }
      } else {
        // No progress data yet, show initial state
        setProgressPercentage(10);
      }

      // Check if ready to redirect
      const hasUsableData = statusData.total_records_cloned > 100;
      const shouldRedirect =
        statusData.status === 'ready' ||
        (statusData.status === 'partial' && hasUsableData) ||
        (statusData.status === 'failed' && hasUsableData);

      if (shouldRedirect) {
        // Show 100% before redirect
        setProgressPercentage(100);
        // Small delay for smooth transition
        setTimeout(() => {
          window.location.href = `/app/dashboard?session=${sessionId}`;
        }, 300);
        return true; // Stop polling
      }

      return false; // Continue polling
    } catch (err) {
      console.error('Error polling session status:', err);
      return false;
    }
  }, []);

  const handleStartDemo = async (accountType: string) => {
    setCreatingSession(true);
    setError(null);
    setProgressPercentage(0);
    setEstimatedTime(6);

    try {
      const session = await createDemoSession({
        demo_account_type: accountType as 'individual_bakery' | 'central_baker',
      });

      console.log('✅ Demo session created:', session);

      // Store session ID in API client
      apiClient.setDemoSessionId(session.session_id);

      // Set the virtual tenant ID in API client
      apiClient.setTenantId(session.virtual_tenant_id);
      console.log('✅ Set API client tenant ID:', session.virtual_tenant_id);

      // Store session info in localStorage for UI
      localStorage.setItem('demo_mode', 'true');
      localStorage.setItem('demo_session_id', session.session_id);
      localStorage.setItem('demo_account_type', accountType);
      localStorage.setItem('demo_expires_at', session.expires_at);
      localStorage.setItem('demo_tenant_id', session.virtual_tenant_id);

      // Start polling IMMEDIATELY in parallel with other setup
      const pollInterval = setInterval(async () => {
        const shouldStop = await pollStatus(session.session_id);
        if (shouldStop) {
          clearInterval(pollInterval);
        }
      }, POLL_INTERVAL_MS);

      // Initialize tenant store and other setup in parallel (non-blocking)
      Promise.all([
        import('../../stores/tenant.store').then(({ useTenantStore }) => {
          const demoTenant = {
            id: session.virtual_tenant_id,
            name: session.demo_config?.name || `Demo ${accountType}`,
            business_type: accountType === 'individual_bakery' ? 'bakery' : 'central_baker',
            business_model: accountType,
            address: session.demo_config?.address || 'Demo Address',
            city: session.demo_config?.city || 'Madrid',
            postal_code: '28001',
            phone: null,
            is_active: true,
            subscription_tier: 'demo',
            ml_model_trained: false,
            last_training_date: null,
            owner_id: 'demo-user',
            created_at: new Date().toISOString(),
          };
          useTenantStore.getState().setCurrentTenant(demoTenant);
          console.log('✅ Initialized tenant store with demo tenant:', demoTenant);
        }),
        // Mark tour to start automatically
        Promise.resolve(markTourAsStartPending()),
      ]).catch(err => console.error('Error initializing tenant store:', err));

      // Initial poll (don't wait for tenant store)
      const shouldStop = await pollStatus(session.session_id);
      if (shouldStop) {
        clearInterval(pollInterval);
      }
    } catch (err: any) {
      setError(err?.message || 'Error al crear sesión demo');
      console.error('Error creating demo session:', err);
      setCreatingSession(false);
    }
  };

  const getAccountIcon = (accountType: string) => {
    return accountType === 'individual_bakery' ? Store : Factory;
  };

  if (loading) {
    return (
      <PublicLayout
        variant="full-width"
        contentPadding="none"
        headerProps={{
          showThemeToggle: true,
          showAuthButtons: true,
          showLanguageSelector: true,
        }}
      >
        <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-[var(--bg-primary)] via-[var(--bg-secondary)] to-[var(--color-primary)]/5">
          <div className="text-center">
            <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-[var(--color-primary)] mx-auto"></div>
            <p className="mt-4 text-[var(--text-secondary)]">Cargando cuentas demo...</p>
          </div>
        </div>
      </PublicLayout>
    );
  }

  return (
    <PublicLayout
      variant="full-width"
      contentPadding="none"
      headerProps={{
        showThemeToggle: true,
        showAuthButtons: true,
        showLanguageSelector: true,
      }}
    >
      {/* Hero Section */}
      <section className="relative py-20 lg:py-32 bg-gradient-to-br from-[var(--bg-primary)] via-[var(--bg-secondary)] to-[var(--color-primary)]/5">
        <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8">
          <div className="text-center mb-16">
            <div className="mb-6">
              <span className="inline-flex items-center px-3 py-1 rounded-full text-sm font-medium bg-[var(--color-primary)]/10 text-[var(--color-primary)]">
                <Play className="w-4 h-4 mr-2" />
                Demo Interactiva
              </span>
            </div>

            <h1 className="text-4xl tracking-tight font-extrabold text-[var(--text-primary)] sm:text-5xl lg:text-6xl">
              <span className="block">Prueba BakeryIA</span>
              <span className="block text-[var(--color-primary)]">sin compromiso</span>
            </h1>

            <p className="mt-6 max-w-3xl mx-auto text-lg text-[var(--text-secondary)] sm:text-xl">
              Explora nuestro sistema con datos reales de panaderías españolas.
              Elige el tipo de negocio que mejor se adapte a tu caso.
            </p>

            <div className="mt-8 flex items-center justify-center space-x-6 text-sm text-[var(--text-tertiary)]">
              <div className="flex items-center">
                <Check className="w-4 h-4 text-green-500 mr-2" />
                Sin tarjeta de crédito
              </div>
              <div className="flex items-center">
                <Clock className="w-4 h-4 text-green-500 mr-2" />
                30 minutos de acceso
              </div>
              <div className="flex items-center">
                <Shield className="w-4 h-4 text-green-500 mr-2" />
                Datos aislados y seguros
              </div>
            </div>
          </div>

          {error && (
            <div className="mb-8 bg-red-50 dark:bg-red-900/20 border border-red-200 dark:border-red-800 text-red-700 dark:text-red-400 px-4 py-3 rounded-lg max-w-2xl mx-auto">
              {error}
            </div>
          )}

          {/* Demo Account Cards */}
          <div className="grid md:grid-cols-2 gap-8 max-w-6xl mx-auto">
            {demoAccounts.map((account) => {
              const Icon = getAccountIcon(account.account_type);

              return (
                <div
                  key={account.account_type}
                  className="relative bg-[var(--bg-primary)] rounded-2xl shadow-xl hover:shadow-2xl transition-all duration-300 overflow-hidden border border-[var(--border-default)] group"
                >
                  {/* Gradient overlay */}
                  <div className="absolute inset-0 bg-gradient-to-br from-[var(--color-primary)]/5 to-transparent opacity-0 group-hover:opacity-100 transition-opacity duration-300"></div>

                  <div className="relative p-8">
                    {/* Header */}
                    <div className="flex items-start justify-between mb-6">
                      <div className="flex items-center">
                        <div className="p-3 rounded-xl bg-[var(--color-primary)]/10 text-[var(--color-primary)]">
                          <Icon className="w-6 h-6" />
                        </div>
                        <div className="ml-4">
                          <h2 className="text-2xl font-bold text-[var(--text-primary)]">
                            {account.name}
                          </h2>
                          <p className="text-sm text-[var(--text-tertiary)] mt-1">
                            {account.business_model}
                          </p>
                        </div>
                      </div>
                      <span className="px-3 py-1 bg-[var(--color-primary)]/10 text-[var(--color-primary)] rounded-full text-xs font-semibold">
                        DEMO
                      </span>
                    </div>

                    {/* Description */}
                    <p className="text-[var(--text-secondary)] mb-6">
                      {account.description}
                    </p>

                    {/* Features */}
                    {account.features && account.features.length > 0 && (
                      <div className="mb-6 space-y-2">
                        <p className="text-sm font-semibold text-[var(--text-primary)] mb-3">
                          Funcionalidades incluidas:
                        </p>
                        {account.features.map((feature, idx) => (
                          <div key={idx} className="flex items-center text-sm text-[var(--text-secondary)]">
                            <Zap className="w-4 h-4 mr-2 text-[var(--color-primary)]" />
                            {feature}
                          </div>
                        ))}
                      </div>
                    )}

                    {/* Demo Benefits */}
                    <div className="space-y-2 mb-8 pt-6 border-t border-[var(--border-default)]">
                      <div className="flex items-center text-sm text-[var(--text-secondary)]">
                        <Check className="w-4 h-4 mr-2 text-green-500" />
                        Datos reales en español
                      </div>
                      <div className="flex items-center text-sm text-[var(--text-secondary)]">
                        <Check className="w-4 h-4 mr-2 text-green-500" />
                        Sesión aislada de 30 minutos
                      </div>
                      <div className="flex items-center text-sm text-[var(--text-secondary)]">
                        <Check className="w-4 h-4 mr-2 text-green-500" />
                        Sin necesidad de registro
                      </div>
                    </div>

                    {/* CTA Button */}
                    <Button
                      onClick={() => handleStartDemo(account.account_type)}
                      disabled={creatingSession}
                      size="lg"
                      className="w-full bg-[var(--color-primary)] hover:bg-[var(--color-primary-dark)] text-white shadow-lg hover:shadow-xl transform hover:scale-105 transition-all duration-200"
                    >
                      <Play className="mr-2 w-5 h-5" />
                      Probar Demo Ahora
                    </Button>
                  </div>
                </div>
              );
            })}
          </div>

          {/* Footer CTA */}
          <div className="mt-16 text-center">
            <p className="text-[var(--text-secondary)] mb-4">
              ¿Ya tienes una cuenta?
            </p>
            <Link
              to="/login"
              className="inline-flex items-center text-[var(--color-primary)] hover:text-[var(--color-primary-dark)] font-semibold transition-colors"
            >
              Inicia sesión aquí
              <ArrowRight className="ml-2 w-4 h-4" />
            </Link>
          </div>
        </div>
      </section>

      {/* Loading Modal Overlay */}
      {creatingSession && (
        <div className="fixed inset-0 bg-black/50 backdrop-blur-sm flex items-center justify-center z-50">
          <div className="bg-[var(--bg-primary)] rounded-2xl shadow-2xl p-8 max-w-md w-full mx-4 border border-[var(--border-default)]">
            <div className="text-center">
              {/* Animated loader */}
              <div className="mb-6 flex justify-center">
                <div className="relative w-20 h-20">
                  <Loader2 className="w-20 h-20 text-[var(--color-primary)] animate-spin" />
                  <div className="absolute inset-0 flex items-center justify-center">
                    <span className="text-xl font-bold text-[var(--color-primary)]">
                      {Math.min(progressPercentage, 100)}%
                    </span>
                  </div>
                </div>
              </div>

              <h2 className="text-2xl font-bold text-[var(--text-primary)] mb-2">
                {progressPercentage >= 100 ? '¡Listo! Redirigiendo...' : 'Preparando tu Demo'}
              </h2>
              <p className="text-[var(--text-secondary)] mb-6">
                {progressPercentage >= 100
                  ? 'Tu entorno está listo. Accediendo al dashboard...'
                  : 'Configurando tu entorno personalizado con datos de muestra...'}
              </p>

              {/* Progress bar */}
              <div className="w-full bg-[var(--bg-secondary)] rounded-full h-3 mb-4 overflow-hidden">
                <div
                  className="bg-gradient-to-r from-[var(--color-primary)] to-[var(--color-primary-dark)] h-full rounded-full transition-all duration-500 ease-out"
                  style={{ width: `${Math.min(progressPercentage, 100)}%` }}
                />
              </div>

              {/* Estimated time - Only show if not complete */}
              {progressPercentage < 100 && (
                <div className="flex items-center justify-center text-sm text-[var(--text-tertiary)] mb-4">
                  <Clock className="w-4 h-4 mr-2" />
                  <span>Tiempo estimado: ~{estimatedTime}s</span>
                </div>
              )}

              {/* Tips while loading */}
              {progressPercentage < 100 && (
                <div className="mt-2 p-4 bg-[var(--color-primary)]/5 rounded-lg border border-[var(--color-primary)]/20">
                  <p className="text-xs text-[var(--text-secondary)] italic">
                    💡 Tip: La demo incluye datos reales de panaderías españolas para que puedas explorar todas las funcionalidades
                  </p>
                </div>
              )}

              {/* Error message if any */}
              {error && (
                <div className="mt-4 p-3 bg-red-50 dark:bg-red-900/20 border border-red-200 dark:border-red-800 text-red-700 dark:text-red-400 rounded-lg text-sm">
                  {error}
                </div>
              )}
            </div>
          </div>
        </div>
      )}
    </PublicLayout>
  );
};

export default DemoPage;