import React, { useState } from 'react';
import {
  ShoppingCart,
  TrendingUp,
  AlertCircle,
  Target,
  DollarSign,
  Award,
  Lock,
  BarChart3,
  Package,
  Truck,
  Calendar
} from 'lucide-react';
import {
  LineChart,
  Line,
  XAxis,
  YAxis,
  CartesianGrid,
  Tooltip,
  ResponsiveContainer,
  Legend
} from 'recharts';
import { PageHeader } from '../../../components/layout';
import { Card, StatsGrid, Button, Tabs } from '../../../components/ui';
import { useSubscription } from '../../../api/hooks/subscription';
import { useCurrentTenant } from '../../../stores/tenant.store';
import { useProcurementDashboard, useProcurementTrends } from '../../../api/hooks/procurement';
import { formatters } from '../../../components/ui/Stats/StatsPresets';

const ProcurementAnalyticsPage: React.FC = () => {
  const { canAccessAnalytics, subscriptionInfo } = useSubscription();
  const currentTenant = useCurrentTenant();
  const tenantId = currentTenant?.id || '';

  const [activeTab, setActiveTab] = useState('overview');

  const { data: dashboard, isLoading: dashboardLoading } = useProcurementDashboard(tenantId);
  const { data: trends, isLoading: trendsLoading } = useProcurementTrends(tenantId, 7);

  // Check if user has access to advanced analytics (professional/enterprise)
  const hasAdvancedAccess = canAccessAnalytics('advanced');

  // Show loading state while subscription data is being fetched
  if (subscriptionInfo.loading) {
    return (
      <div className="space-y-6">
        <PageHeader
          title="Analítica de Compras"
          description="Insights avanzados sobre planificación de compras y gestión de proveedores"
        />
        <Card className="p-8 text-center">
          <div className="flex flex-col items-center gap-4">
            <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-[var(--color-primary)]"></div>
            <p className="text-[var(--text-secondary)]">Cargando información de suscripción...</p>
          </div>
        </Card>
      </div>
    );
  }

  // If user doesn't have access to advanced analytics, show upgrade message
  if (!hasAdvancedAccess) {
    return (
      <div className="space-y-6">
        <PageHeader
          title="Analítica de Compras"
          description="Insights avanzados sobre planificación de compras y gestión de proveedores"
        />

        <Card className="p-8 text-center">
          <Lock className="mx-auto h-12 w-12 text-[var(--text-tertiary)] mb-4" />
          <h3 className="text-lg font-medium text-[var(--text-primary)] mb-2">
            Funcionalidad Exclusiva para Profesionales y Empresas
          </h3>
          <p className="text-[var(--text-secondary)] mb-4">
            La analítica avanzada de compras está disponible solo para planes Professional y Enterprise.
            Actualiza tu plan para acceder a análisis detallados de proveedores, optimización de costos y métricas de rendimiento.
          </p>
          <Button
            variant="primary"
            size="md"
            onClick={() => window.location.hash = '#/app/settings/profile'}
          >
            Actualizar Plan
          </Button>
        </Card>
      </div>
    );
  }

  // Tab configuration
  const tabs = [
    {
      id: 'overview',
      label: 'Resumen',
      icon: BarChart3
    },
    {
      id: 'performance',
      label: 'Rendimiento',
      icon: TrendingUp
    },
    {
      id: 'suppliers',
      label: 'Proveedores',
      icon: Truck
    },
    {
      id: 'costs',
      label: 'Costos',
      icon: DollarSign
    },
    {
      id: 'quality',
      label: 'Calidad',
      icon: Award
    }
  ];

  return (
    <div className="space-y-6">
      <PageHeader
        title="Analítica de Compras"
        description="Insights avanzados sobre planificación de compras y gestión de proveedores"
      />

      {/* Summary Stats */}
      <StatsGrid
        stats={[
          {
            label: 'Planes Activos',
            value: dashboard?.summary?.total_plans || 0,
            icon: ShoppingCart,
            formatter: formatters.number
          },
          {
            label: 'Tasa de Cumplimiento',
            value: dashboard?.performance_metrics?.average_fulfillment_rate || 0,
            icon: Target,
            formatter: formatters.percentage,
            change: dashboard?.performance_metrics?.fulfillment_trend
          },
          {
            label: 'Entregas a Tiempo',
            value: dashboard?.performance_metrics?.average_on_time_delivery || 0,
            icon: Calendar,
            formatter: formatters.percentage,
            change: dashboard?.performance_metrics?.on_time_trend
          },
          {
            label: 'Variación de Costos',
            value: dashboard?.performance_metrics?.cost_accuracy || 0,
            icon: DollarSign,
            formatter: formatters.percentage,
            change: dashboard?.performance_metrics?.cost_variance_trend
          }
        ]}
        loading={dashboardLoading}
      />

      {/* Tabs */}
      <Tabs
        items={tabs}
        activeTab={activeTab}
        onTabChange={setActiveTab}
      />

      {/* Tab Content */}
      <div className="space-y-6">
        {activeTab === 'overview' && (
          <>
            {/* Overview Tab */}
            <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
            {/* Plan Status Distribution */}
            <Card>
              <div className="p-6">
                <h3 className="text-lg font-medium text-[var(--text-primary)] mb-4">
                  Distribución de Estados de Planes
                </h3>
                <div className="space-y-3">
                  {dashboard?.plan_status_distribution?.map((status: any) => (
                    <div key={status.status} className="flex items-center justify-between">
                      <span className="text-[var(--text-secondary)]">{status.status}</span>
                      <div className="flex items-center gap-2">
                        <div className="w-32 h-2 bg-[var(--bg-tertiary)] rounded-full overflow-hidden">
                          <div
                            className="h-full bg-[var(--color-primary)]"
                            style={{ width: `${(status.count / (dashboard?.summary?.total_plans || 1)) * 100}%` }}
                          />
                        </div>
                        <span className="text-sm font-medium text-[var(--text-primary)] w-8 text-right">
                          {status.count}
                        </span>
                      </div>
                    </div>
                  ))}
                </div>
              </div>
            </Card>

              {/* Critical Requirements */}
              <Card>
                <div className="p-6">
                  <div className="flex items-center justify-between mb-4">
                    <h3 className="text-lg font-medium text-[var(--text-primary)]">
                      Requerimientos Críticos
                    </h3>
                    <AlertCircle className="h-5 w-5 text-[var(--color-error)]" />
                  </div>
                  <div className="space-y-3">
                    <div className="flex justify-between items-center">
                      <span className="text-[var(--text-secondary)]">Stock Crítico</span>
                      <span className="text-2xl font-bold text-[var(--color-error)]">
                        {dashboard?.critical_requirements?.low_stock || 0}
                      </span>
                    </div>
                    <div className="flex justify-between items-center">
                      <span className="text-[var(--text-secondary)]">Entregas Atrasadas</span>
                      <span className="text-2xl font-bold text-[var(--color-warning)]">
                        {dashboard?.critical_requirements?.overdue || 0}
                      </span>
                    </div>
                    <div className="flex justify-between items-center">
                      <span className="text-[var(--text-secondary)]">Alta Prioridad</span>
                      <span className="text-2xl font-bold text-[var(--color-info)]">
                        {dashboard?.critical_requirements?.high_priority || 0}
                      </span>
                    </div>
                  </div>
                </div>
              </Card>
            </div>

            {/* Recent Plans */}
            <Card>
              <div className="p-6">
                <h3 className="text-lg font-medium text-[var(--text-primary)] mb-4">
                  Planes Recientes
                </h3>
                <div className="overflow-x-auto">
                  <table className="w-full">
                    <thead>
                      <tr className="border-b border-[var(--border-primary)]">
                        <th className="text-left py-3 px-4 text-[var(--text-secondary)] font-medium">Plan</th>
                        <th className="text-left py-3 px-4 text-[var(--text-secondary)] font-medium">Fecha</th>
                        <th className="text-left py-3 px-4 text-[var(--text-secondary)] font-medium">Estado</th>
                        <th className="text-right py-3 px-4 text-[var(--text-secondary)] font-medium">Requerimientos</th>
                        <th className="text-right py-3 px-4 text-[var(--text-secondary)] font-medium">Costo Total</th>
                      </tr>
                    </thead>
                    <tbody>
                      {dashboard?.recent_plans?.map((plan: any) => (
                        <tr key={plan.id} className="border-b border-[var(--border-primary)] hover:bg-[var(--bg-secondary)]">
                          <td className="py-3 px-4 text-[var(--text-primary)]">{plan.plan_number}</td>
                          <td className="py-3 px-4 text-[var(--text-secondary)]">
                            {new Date(plan.plan_date).toLocaleDateString()}
                          </td>
                          <td className="py-3 px-4">
                            <span className={`px-2 py-1 rounded-full text-xs ${getStatusColor(plan.status)}`}>
                              {plan.status}
                            </span>
                          </td>
                          <td className="py-3 px-4 text-right text-[var(--text-primary)]">
                            {plan.total_requirements}
                          </td>
                          <td className="py-3 px-4 text-right text-[var(--text-primary)]">
                            €{formatters.currency(plan.total_estimated_cost)}
                          </td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
              </div>
            </Card>
          </>
        )}

        {activeTab === 'performance' && (
          <>
            {/* Performance Tab */}
            <div className="grid grid-cols-1 md:grid-cols-3 gap-6">
              <Card>
                <div className="p-6 text-center">
                  <Target className="mx-auto h-8 w-8 text-[var(--color-success)] mb-3" />
                  <div className="text-3xl font-bold text-[var(--text-primary)] mb-1">
                    {formatters.percentage(dashboard?.performance_metrics?.average_fulfillment_rate || 0)}
                  </div>
                  <div className="text-sm text-[var(--text-secondary)]">Tasa de Cumplimiento</div>
                </div>
              </Card>

              <Card>
                <div className="p-6 text-center">
                  <Calendar className="mx-auto h-8 w-8 text-[var(--color-info)] mb-3" />
                  <div className="text-3xl font-bold text-[var(--text-primary)] mb-1">
                    {formatters.percentage(dashboard?.performance_metrics?.average_on_time_delivery || 0)}
                  </div>
                  <div className="text-sm text-[var(--text-secondary)]">Entregas a Tiempo</div>
                </div>
              </Card>

              <Card>
                <div className="p-6 text-center">
                  <Award className="mx-auto h-8 w-8 text-[var(--color-warning)] mb-3" />
                  <div className="text-3xl font-bold text-[var(--text-primary)] mb-1">
                    {dashboard?.performance_metrics?.supplier_performance?.toFixed(1) || '0.0'}
                  </div>
                  <div className="text-sm text-[var(--text-secondary)]">Puntuación de Calidad</div>
                </div>
              </Card>
            </div>

            {/* Performance Trend Chart */}
            <Card>
              <div className="p-6">
                <h3 className="text-lg font-medium text-[var(--text-primary)] mb-4">
                  Tendencias de Rendimiento (Últimos 7 días)
                </h3>
                {trendsLoading ? (
                  <div className="h-64 flex items-center justify-center">
                    <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-[var(--color-primary)]"></div>
                  </div>
                ) : trends && trends.performance_trend && trends.performance_trend.length > 0 ? (
                  <ResponsiveContainer width="100%" height={300}>
                    <LineChart data={trends.performance_trend}>
                      <CartesianGrid strokeDasharray="3 3" stroke="var(--border-primary)" />
                      <XAxis
                        dataKey="date"
                        stroke="var(--text-tertiary)"
                        tick={{ fill: 'var(--text-secondary)' }}
                      />
                      <YAxis
                        stroke="var(--text-tertiary)"
                        tick={{ fill: 'var(--text-secondary)' }}
                        tickFormatter={(value) => `${(value * 100).toFixed(0)}%`}
                      />
                      <Tooltip
                        contentStyle={{
                          backgroundColor: 'var(--bg-primary)',
                          border: '1px solid var(--border-primary)',
                          borderRadius: '8px'
                        }}
                        formatter={(value: any) => `${(value * 100).toFixed(1)}%`}
                        labelStyle={{ color: 'var(--text-primary)' }}
                      />
                      <Legend />
                      <Line
                        type="monotone"
                        dataKey="fulfillment_rate"
                        stroke="var(--color-success)"
                        strokeWidth={2}
                        name="Tasa de Cumplimiento"
                        dot={{ fill: 'var(--color-success)' }}
                      />
                      <Line
                        type="monotone"
                        dataKey="on_time_rate"
                        stroke="var(--color-info)"
                        strokeWidth={2}
                        name="Entregas a Tiempo"
                        dot={{ fill: 'var(--color-info)' }}
                      />
                    </LineChart>
                  </ResponsiveContainer>
                ) : (
                  <div className="h-64 flex items-center justify-center text-[var(--text-tertiary)]">
                    No hay datos de tendencias disponibles
                  </div>
                )}
              </div>
            </Card>
          </>
        )}

        {activeTab === 'suppliers' && (
          <>
            {/* Suppliers Tab */}
            <Card>
              <div className="p-6">
                <h3 className="text-lg font-medium text-[var(--text-primary)] mb-4">
                  Rendimiento de Proveedores
                </h3>
                <div className="overflow-x-auto">
                  <table className="w-full">
                    <thead>
                      <tr className="border-b border-[var(--border-primary)]">
                        <th className="text-left py-3 px-4 text-[var(--text-secondary)] font-medium">Proveedor</th>
                        <th className="text-right py-3 px-4 text-[var(--text-secondary)] font-medium">Órdenes</th>
                        <th className="text-right py-3 px-4 text-[var(--text-secondary)] font-medium">Tasa Cumplimiento</th>
                        <th className="text-right py-3 px-4 text-[var(--text-secondary)] font-medium">Entregas a Tiempo</th>
                        <th className="text-right py-3 px-4 text-[var(--text-secondary)] font-medium">Calidad</th>
                      </tr>
                    </thead>
                    <tbody>
                      {dashboard?.supplier_performance?.map((supplier: any) => (
                        <tr key={supplier.id} className="border-b border-[var(--border-primary)] hover:bg-[var(--bg-secondary)]">
                          <td className="py-3 px-4 text-[var(--text-primary)]">{supplier.name}</td>
                          <td className="py-3 px-4 text-right text-[var(--text-primary)]">{supplier.total_orders}</td>
                          <td className="py-3 px-4 text-right text-[var(--text-primary)]">
                            {formatters.percentage(supplier.fulfillment_rate)}
                          </td>
                          <td className="py-3 px-4 text-right text-[var(--text-primary)]">
                            {formatters.percentage(supplier.on_time_rate)}
                          </td>
                          <td className="py-3 px-4 text-right text-[var(--text-primary)]">
                            {supplier.quality_score?.toFixed(1) || 'N/A'}
                          </td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
              </div>
            </Card>
          </>
        )}

        {activeTab === 'costs' && (
          <>
            {/* Costs Tab */}
            <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
              <Card>
                <div className="p-6">
                  <h3 className="text-lg font-medium text-[var(--text-primary)] mb-4">
                    Análisis de Costos
                  </h3>
                  <div className="space-y-4">
                    <div className="flex justify-between items-center">
                      <span className="text-[var(--text-secondary)]">Costo Total Estimado</span>
                      <span className="text-2xl font-bold text-[var(--text-primary)]">
                        €{formatters.currency(dashboard?.summary?.total_estimated_cost || 0)}
                      </span>
                    </div>
                    <div className="flex justify-between items-center">
                      <span className="text-[var(--text-secondary)]">Costo Total Aprobado</span>
                      <span className="text-2xl font-bold text-[var(--text-primary)]">
                        €{formatters.currency(dashboard?.summary?.total_approved_cost || 0)}
                      </span>
                    </div>
                    <div className="flex justify-between items-center">
                      <span className="text-[var(--text-secondary)]">Variación Promedio</span>
                      <span className={`text-2xl font-bold ${
                        (dashboard?.summary?.cost_variance || 0) > 0
                          ? 'text-[var(--color-error)]'
                          : 'text-[var(--color-success)]'
                      }`}>
                        €{formatters.currency(Math.abs(dashboard?.summary?.cost_variance || 0))}
                      </span>
                    </div>
                  </div>
                </div>
              </Card>

              <Card>
                <div className="p-6">
                  <h3 className="text-lg font-medium text-[var(--text-primary)] mb-4">
                    Distribución de Costos por Categoría
                  </h3>
                  <div className="space-y-3">
                    {dashboard?.cost_by_category?.map((category: any) => (
                      <div key={category.name} className="flex items-center justify-between">
                        <span className="text-[var(--text-secondary)]">{category.name}</span>
                        <div className="flex items-center gap-2">
                          <div className="w-32 h-2 bg-[var(--bg-tertiary)] rounded-full overflow-hidden">
                            <div
                              className="h-full bg-[var(--color-primary)]"
                              style={{ width: `${(category.amount / (dashboard?.summary?.total_estimated_cost || 1)) * 100}%` }}
                            />
                          </div>
                          <span className="text-sm font-medium text-[var(--text-primary)] w-20 text-right">
                            €{formatters.currency(category.amount)}
                          </span>
                        </div>
                      </div>
                    ))}
                  </div>
                </div>
              </Card>
            </div>
          </>
        )}

        {activeTab === 'quality' && (
          <>
            {/* Quality Tab */}
            <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
              <Card>
                <div className="p-6">
                  <h3 className="text-lg font-medium text-[var(--text-primary)] mb-4">
                    Métricas de Calidad
                  </h3>
                  <div className="space-y-4">
                    <div className="flex justify-between items-center">
                      <span className="text-[var(--text-secondary)]">Puntuación Promedio</span>
                      <span className="text-3xl font-bold text-[var(--text-primary)]">
                        {dashboard?.quality_metrics?.avg_score?.toFixed(1) || '0.0'} / 10
                      </span>
                    </div>
                    <div className="flex justify-between items-center">
                      <span className="text-[var(--text-secondary)]">Productos con Calidad Alta</span>
                      <span className="text-2xl font-bold text-[var(--color-success)]">
                        {dashboard?.quality_metrics?.high_quality_count || 0}
                      </span>
                    </div>
                    <div className="flex justify-between items-center">
                      <span className="text-[var(--text-secondary)]">Productos con Calidad Baja</span>
                      <span className="text-2xl font-bold text-[var(--color-error)]">
                        {dashboard?.quality_metrics?.low_quality_count || 0}
                      </span>
                    </div>
                  </div>
                </div>
              </Card>

              <Card>
                <div className="p-6">
                  <h3 className="text-lg font-medium text-[var(--text-primary)] mb-4">
                    Tendencia de Calidad (Últimos 7 días)
                  </h3>
                  {trendsLoading ? (
                    <div className="h-48 flex items-center justify-center">
                      <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-[var(--color-primary)]"></div>
                    </div>
                  ) : trends && trends.quality_trend && trends.quality_trend.length > 0 ? (
                    <ResponsiveContainer width="100%" height={200}>
                      <LineChart data={trends.quality_trend}>
                        <CartesianGrid strokeDasharray="3 3" stroke="var(--border-primary)" />
                        <XAxis
                          dataKey="date"
                          stroke="var(--text-tertiary)"
                          tick={{ fill: 'var(--text-secondary)' }}
                        />
                        <YAxis
                          stroke="var(--text-tertiary)"
                          tick={{ fill: 'var(--text-secondary)' }}
                          domain={[0, 10]}
                          ticks={[0, 2, 4, 6, 8, 10]}
                        />
                        <Tooltip
                          contentStyle={{
                            backgroundColor: 'var(--bg-primary)',
                            border: '1px solid var(--border-primary)',
                            borderRadius: '8px'
                          }}
                          formatter={(value: any) => `${value.toFixed(1)} / 10`}
                          labelStyle={{ color: 'var(--text-primary)' }}
                        />
                        <Line
                          type="monotone"
                          dataKey="quality_score"
                          stroke="var(--color-warning)"
                          strokeWidth={2}
                          name="Puntuación de Calidad"
                          dot={{ fill: 'var(--color-warning)' }}
                        />
                      </LineChart>
                    </ResponsiveContainer>
                  ) : (
                    <div className="h-48 flex items-center justify-center text-[var(--text-tertiary)]">
                      No hay datos de calidad disponibles
                    </div>
                  )}
                </div>
              </Card>
            </div>
          </>
        )}
      </div>
    </div>
  );
};

// Helper function for status colors
function getStatusColor(status: string): string {
  const colors: Record<string, string> = {
    draft: 'bg-[var(--bg-tertiary)] text-[var(--text-secondary)]',
    pending_approval: 'bg-yellow-100 text-yellow-800',
    approved: 'bg-green-100 text-green-800',
    in_execution: 'bg-blue-100 text-blue-800',
    completed: 'bg-green-100 text-green-800',
    cancelled: 'bg-red-100 text-red-800'
  };
  return colors[status] || colors.draft;
}

export default ProcurementAnalyticsPage;
