import React, { useState } from 'react';
import { Plus, Search, Download, ShoppingCart, Truck, DollarSign, Calendar, Clock, CheckCircle, AlertCircle, Package, Eye, Loader } from 'lucide-react';
import { Button, Input, Card, StatsGrid, StatusCard, getStatusColor, StatusModal } from '../../../../components/ui';
import { formatters } from '../../../../components/ui/Stats/StatsPresets';
import { PageHeader } from '../../../../components/layout';
import {
  useProcurementDashboard,
  useProcurementPlans,
  useCurrentProcurementPlan,
  useCriticalRequirements,
  useGenerateProcurementPlan,
  useUpdateProcurementPlanStatus,
  useTriggerDailyScheduler
} from '../../../../api';
import { useTenantStore } from '../../../../stores/tenant.store';

const ProcurementPage: React.FC = () => {
  const [activeTab, setActiveTab] = useState('plans');
  const [searchTerm, setSearchTerm] = useState('');
  const [showForm, setShowForm] = useState(false);
  const [modalMode, setModalMode] = useState<'view' | 'edit'>('view');
  const [selectedPlan, setSelectedPlan] = useState<any>(null);
  
  const { currentTenant } = useTenantStore();
  const tenantId = currentTenant?.id || '';

  // Real API data hooks
  const { data: dashboardData, isLoading: isDashboardLoading } = useProcurementDashboard(tenantId);
  const { data: procurementPlans, isLoading: isPlansLoading } = useProcurementPlans({
    tenant_id: tenantId,
    limit: 50,
    offset: 0
  });
  const { data: currentPlan, isLoading: isCurrentPlanLoading } = useCurrentProcurementPlan(tenantId);
  const { data: criticalRequirements, isLoading: isCriticalLoading } = useCriticalRequirements(tenantId);
  
  const generatePlanMutation = useGenerateProcurementPlan();
  const updatePlanStatusMutation = useUpdateProcurementPlanStatus();
  const triggerSchedulerMutation = useTriggerDailyScheduler();

  if (!tenantId) {
    return (
      <div className="flex justify-center items-center h-64">
        <div className="text-center">
          <h3 className="text-lg font-medium text-[var(--text-primary)] mb-2">
            No hay tenant seleccionado
          </h3>
          <p className="text-[var(--text-secondary)]">
            Selecciona un tenant para ver los datos de procurement
          </p>
        </div>
      </div>
    );
  }


  const getPlanStatusConfig = (status: string) => {
    const statusConfig = {
      draft: { text: 'Borrador', icon: Clock },
      pending_approval: { text: 'Pendiente Aprobación', icon: Clock },
      approved: { text: 'Aprobado', icon: CheckCircle },
      in_execution: { text: 'En Ejecución', icon: Truck },
      completed: { text: 'Completado', icon: CheckCircle },
      cancelled: { text: 'Cancelado', icon: AlertCircle },
    };
    
    const config = statusConfig[status as keyof typeof statusConfig];
    const Icon = config?.icon;
    
    return {
      color: getStatusColor(status === 'in_execution' ? 'inTransit' : status === 'pending_approval' ? 'pending' : status),
      text: config?.text || status,
      icon: Icon,
      isCritical: status === 'cancelled',
      isHighlight: status === 'pending_approval'
    };
  };

  const filteredPlans = procurementPlans?.plans?.filter(plan => {
    const matchesSearch = plan.plan_number.toLowerCase().includes(searchTerm.toLowerCase()) ||
      plan.status.toLowerCase().includes(searchTerm.toLowerCase()) ||
      (plan.special_requirements && plan.special_requirements.toLowerCase().includes(searchTerm.toLowerCase()));
    
    return matchesSearch;
  }) || [];

  const stats = {
    totalPlans: dashboardData?.summary?.total_plans || 0,
    activePlans: dashboardData?.summary?.active_plans || 0,
    pendingRequirements: dashboardData?.summary?.pending_requirements || 0,
    criticalRequirements: dashboardData?.summary?.critical_requirements || 0,
    totalEstimatedCost: dashboardData?.summary?.total_estimated_cost || 0,
    totalApprovedCost: dashboardData?.summary?.total_approved_cost || 0,
  };

  const procurementStats = [
    {
      title: 'Planes Totales',
      value: stats.totalPlans,
      variant: 'default' as const,
      icon: Package,
    },
    {
      title: 'Planes Activos',
      value: stats.activePlans,
      variant: 'success' as const,
      icon: CheckCircle,
    },
    {
      title: 'Requerimientos Pendientes',
      value: stats.pendingRequirements,
      variant: 'warning' as const,
      icon: Clock,
    },
    {
      title: 'Críticos',
      value: stats.criticalRequirements,
      variant: 'warning' as const,
      icon: AlertCircle,
    },
    {
      title: 'Costo Estimado',
      value: formatters.currency(stats.totalEstimatedCost),
      variant: 'info' as const,
      icon: DollarSign,
    },
    {
      title: 'Costo Aprobado',
      value: formatters.currency(stats.totalApprovedCost),
      variant: 'success' as const,
      icon: DollarSign,
    },
  ];

  return (
    <div className="space-y-6">
      <PageHeader
        title="Planificación de Compras"
        description="Administra planes de compras, requerimientos y análisis de procurement"
        actions={[
          {
            id: "export",
            label: "Exportar",
            variant: "outline" as const,
            icon: Download,
            onClick: () => console.log('Export procurement data')
          },
          {
            id: "generate",
            label: "Generar Plan",
            variant: "primary" as const,
            icon: Plus,
            onClick: () => generatePlanMutation.mutate({
              tenantId,
              request: {
                force_regenerate: false,
                planning_horizon_days: 14,
                include_safety_stock: true,
                safety_stock_percentage: 20
              }
            })
          },
          {
            id: "trigger",
            label: "Ejecutar Programador",
            variant: "outline" as const,
            icon: Calendar,
            onClick: () => triggerSchedulerMutation.mutate(tenantId)
          }
        ]}
      />

      {/* Stats Grid */}
      {isDashboardLoading ? (
        <div className="flex justify-center items-center h-32">
          <Loader className="w-8 h-8 animate-spin text-[var(--color-primary)]" />
        </div>
      ) : (
        <StatsGrid 
          stats={procurementStats}
          columns={3}
        />
      )}

      {/* Tabs Navigation */}
      <div className="border-b border-[var(--border-primary)]">
        <nav className="-mb-px flex space-x-8">
          <button
            onClick={() => setActiveTab('plans')}
            className={`py-2 px-1 border-b-2 font-medium text-sm ${
              activeTab === 'plans'
                ? 'border-orange-500 text-[var(--color-primary)]'
                : 'border-transparent text-[var(--text-tertiary)] hover:text-[var(--text-secondary)] hover:border-[var(--border-secondary)]'
            }`}
          >
            Planes de Compra
          </button>
          <button
            onClick={() => setActiveTab('requirements')}
            className={`py-2 px-1 border-b-2 font-medium text-sm ${
              activeTab === 'requirements'
                ? 'border-orange-500 text-[var(--color-primary)]'
                : 'border-transparent text-[var(--text-tertiary)] hover:text-[var(--text-secondary)] hover:border-[var(--border-secondary)]'
            }`}
          >
            Requerimientos Críticos
          </button>
          <button
            onClick={() => setActiveTab('analytics')}
            className={`py-2 px-1 border-b-2 font-medium text-sm ${
              activeTab === 'analytics'
                ? 'border-orange-500 text-[var(--color-primary)]'
                : 'border-transparent text-[var(--text-tertiary)] hover:text-[var(--text-secondary)] hover:border-[var(--border-secondary)]'
            }`}
          >
            Análisis
          </button>
        </nav>
      </div>

      {activeTab === 'plans' && (
        <Card className="p-4">
          <div className="flex flex-col sm:flex-row gap-4">
            <div className="flex-1">
              <Input
                placeholder="Buscar planes por número, estado o notas..."
                value={searchTerm}
                onChange={(e) => setSearchTerm(e.target.value)}
                className="w-full"
              />
            </div>
            <Button variant="outline" onClick={() => console.log('Export filtered')}>
              <Download className="w-4 h-4 mr-2" />
              Exportar
            </Button>
          </div>
        </Card>
      )}

      {/* Procurement Plans Grid */}
      {activeTab === 'plans' && (
        <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
          {isPlansLoading ? (
            <div className="col-span-full flex justify-center items-center h-32">
              <Loader className="w-8 h-8 animate-spin text-[var(--color-primary)]" />
            </div>
          ) : (
            filteredPlans.map((plan) => {
              const statusConfig = getPlanStatusConfig(plan.status);
              
              return (
                <StatusCard
                  key={plan.id}
                  id={plan.plan_number}
                  statusIndicator={statusConfig}
                  title={`Plan ${plan.plan_number}`}
                  subtitle={new Date(plan.plan_date).toLocaleDateString('es-ES')}
                  primaryValue={formatters.currency(plan.total_estimated_cost)}
                  primaryValueLabel={`${plan.total_requirements} requerimientos`}
                  secondaryInfo={{
                    label: 'Período',
                    value: `${new Date(plan.plan_period_start).toLocaleDateString('es-ES')} - ${new Date(plan.plan_period_end).toLocaleDateString('es-ES')}`
                  }}
                  metadata={[
                    `${plan.planning_horizon_days} días de horizonte`,
                    `Estrategia: ${plan.procurement_strategy}`,
                    ...(plan.special_requirements ? [`"${plan.special_requirements}"`] : [])
                  ]}
                  actions={[
                    {
                      label: 'Ver',
                      icon: Eye,
                      variant: 'outline',
                      onClick: () => {
                        setSelectedPlan(plan);
                        setModalMode('view');
                        setShowForm(true);
                      }
                    },
                    ...(plan.status === 'pending_approval' ? [{
                      label: 'Aprobar',
                      icon: CheckCircle,
                      variant: 'outline' as const,
                      onClick: () => {
                        updatePlanStatusMutation.mutate({
                          tenant_id: tenantId,
                          plan_id: plan.id,
                          status: 'approved'
                        });
                      }
                    }] : [])
                  ]}
                />
              );
            })
          )}
        </div>
      )}

      {/* Empty State for Procurement Plans */}
      {activeTab === 'plans' && !isPlansLoading && filteredPlans.length === 0 && (
        <div className="text-center py-12">
          <Package 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">
            No se encontraron planes de compra
          </h3>
          <p className="text-[var(--text-secondary)] mb-4">
            Intenta ajustar la búsqueda o generar un nuevo plan de compra
          </p>
          <Button 
            onClick={() => generatePlanMutation.mutate({
              tenantId,
              request: {
                force_regenerate: false,
                planning_horizon_days: 14,
                include_safety_stock: true,
                safety_stock_percentage: 20
              }
            })}
            disabled={generatePlanMutation.isPending}
          >
            {generatePlanMutation.isPending ? (
              <Loader className="w-4 h-4 mr-2 animate-spin" />
            ) : (
              <Plus className="w-4 h-4 mr-2" />
            )}
            Generar Plan de Compra
          </Button>
        </div>
      )}

      {activeTab === 'requirements' && (
        <div className="space-y-4">
          {isCriticalLoading ? (
            <div className="flex justify-center items-center h-32">
              <Loader className="w-8 h-8 animate-spin text-[var(--color-primary)]" />
            </div>
          ) : criticalRequirements && criticalRequirements.length > 0 ? (
            <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
              {criticalRequirements.map((requirement) => (
                <StatusCard
                  key={requirement.id}
                  id={requirement.requirement_number}
                  statusIndicator={{
                    color: getStatusColor('danger'),
                    text: 'Crítico',
                    icon: AlertCircle,
                    isCritical: true
                  }}
                  title={requirement.product_name}
                  subtitle={requirement.requirement_number}
                  primaryValue={`${requirement.required_quantity} ${requirement.unit_of_measure}`}
                  primaryValueLabel="Cantidad requerida"
                  secondaryInfo={{
                    label: 'Fecha límite',
                    value: new Date(requirement.required_by_date).toLocaleDateString('es-ES')
                  }}
                  metadata={[
                    `Stock actual: ${requirement.current_stock_level} ${requirement.unit_of_measure}`,
                    `Proveedor: ${requirement.supplier_name || 'No asignado'}`,
                    `Costo estimado: ${formatters.currency(requirement.estimated_total_cost || 0)}`
                  ]}
                  actions={[
                    {
                      label: 'Ver Detalles',
                      icon: Eye,
                      variant: 'outline',
                      onClick: () => console.log('View requirement details')
                    }
                  ]}
                />
              ))}
            </div>
          ) : (
            <div className="text-center py-12">
              <CheckCircle className="mx-auto h-12 w-12 text-green-500 mb-4" />
              <h3 className="text-lg font-medium text-[var(--text-primary)] mb-2">
                No hay requerimientos críticos
              </h3>
              <p className="text-[var(--text-secondary)]">
                Todos los requerimientos están bajo control
              </p>
            </div>
          )}
        </div>
      )}

      {activeTab === 'analytics' && (
        <div className="space-y-6">
          <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
            <Card className="p-6">
              <h3 className="text-lg font-semibold text-[var(--text-primary)] mb-4">Costos de Procurement</h3>
              <div className="space-y-4">
                <div className="flex justify-between items-center">
                  <span className="text-sm text-[var(--text-secondary)]">Costo Estimado Total</span>
                  <span className="text-lg font-semibold text-[var(--text-primary)]">
                    {formatters.currency(stats.totalEstimatedCost)}
                  </span>
                </div>
                <div className="flex justify-between items-center">
                  <span className="text-sm text-[var(--text-secondary)]">Costo Aprobado</span>
                  <span className="text-lg font-semibold text-green-600">
                    {formatters.currency(stats.totalApprovedCost)}
                  </span>
                </div>
                <div className="flex justify-between items-center">
                  <span className="text-sm text-[var(--text-secondary)]">Varianza</span>
                  <span className="text-lg font-semibold text-[var(--text-primary)]">
                    {formatters.currency(stats.totalEstimatedCost - stats.totalApprovedCost)}
                  </span>
                </div>
              </div>
            </Card>

            <Card className="p-6">
              <h3 className="text-lg font-semibold text-[var(--text-primary)] mb-4">Alertas Críticas</h3>
              <div className="space-y-3">
                {dashboardData?.low_stock_alerts?.slice(0, 5).map((alert: any, index: number) => (
                  <div key={index} className="flex items-center justify-between p-3 bg-red-50 rounded-lg">
                    <div className="flex items-center">
                      <AlertCircle className="w-4 h-4 text-red-500 mr-2" />
                      <span className="text-sm text-[var(--text-primary)]">{alert.product_name || `Alerta ${index + 1}`}</span>
                    </div>
                    <span className="text-xs text-red-600 font-medium">
                      Stock Bajo
                    </span>
                  </div>
                )) || (
                  <div className="text-center py-8">
                    <CheckCircle className="mx-auto h-8 w-8 text-green-500 mb-2" />
                    <p className="text-sm text-[var(--text-secondary)]">No hay alertas críticas</p>
                  </div>
                )}
              </div>
            </Card>
          </div>

          <Card className="p-6">
            <h3 className="text-lg font-semibold text-[var(--text-primary)] mb-4">Resumen de Performance</h3>
            <div className="grid grid-cols-2 md:grid-cols-4 gap-4">
              <div className="text-center p-4 bg-[var(--bg-secondary)] rounded-lg">
                <p className="text-2xl font-bold text-[var(--color-primary)]">{stats.totalPlans}</p>
                <p className="text-sm text-[var(--text-secondary)] mt-1">Planes Totales</p>
              </div>
              <div className="text-center p-4 bg-[var(--bg-secondary)] rounded-lg">
                <p className="text-2xl font-bold text-green-600">{stats.activePlans}</p>
                <p className="text-sm text-[var(--text-secondary)] mt-1">Planes Activos</p>
              </div>
              <div className="text-center p-4 bg-[var(--bg-secondary)] rounded-lg">
                <p className="text-2xl font-bold text-yellow-600">{stats.pendingRequirements}</p>
                <p className="text-sm text-[var(--text-secondary)] mt-1">Pendientes</p>
              </div>
              <div className="text-center p-4 bg-[var(--bg-secondary)] rounded-lg">
                <p className="text-2xl font-bold text-red-600">{stats.criticalRequirements}</p>
                <p className="text-sm text-[var(--text-secondary)] mt-1">Críticos</p>
              </div>
            </div>
          </Card>
        </div>
      )}

      {/* Procurement Plan Modal */}
      {showForm && selectedPlan && (
        <StatusModal
          isOpen={showForm}
          onClose={() => {
            setShowForm(false);
            setSelectedPlan(null);
            setModalMode('view');
          }}
          mode={modalMode}
          onModeChange={setModalMode}
          title={`Plan de Compra ${selectedPlan.plan_number}`}
          subtitle={new Date(selectedPlan.plan_date).toLocaleDateString('es-ES')}
          statusIndicator={getPlanStatusConfig(selectedPlan.status)}
          size="lg"
          sections={[
            {
              title: 'Información del Plan',
              icon: Package,
              fields: [
                {
                  label: 'Número de Plan',
                  value: selectedPlan.plan_number,
                  highlight: true
                },
                {
                  label: 'Tipo de Plan',
                  value: selectedPlan.plan_type
                },
                {
                  label: 'Estrategia',
                  value: selectedPlan.procurement_strategy
                },
                {
                  label: 'Prioridad',
                  value: selectedPlan.priority,
                  type: 'status'
                }
              ]
            },
            {
              title: 'Fechas y Períodos',
              icon: Calendar,
              fields: [
                {
                  label: 'Fecha del Plan',
                  value: selectedPlan.plan_date,
                  type: 'date'
                },
                {
                  label: 'Período de Inicio',
                  value: selectedPlan.plan_period_start,
                  type: 'date'
                },
                {
                  label: 'Período de Fin',
                  value: selectedPlan.plan_period_end,
                  type: 'date',
                  highlight: true
                },
                {
                  label: 'Horizonte de Planificación',
                  value: `${selectedPlan.planning_horizon_days} días`
                }
              ]
            },
            {
              title: 'Información Financiera',
              icon: DollarSign,
              fields: [
                {
                  label: 'Costo Estimado Total',
                  value: selectedPlan.total_estimated_cost,
                  type: 'currency',
                  highlight: true
                },
                {
                  label: 'Costo Aprobado Total',
                  value: selectedPlan.total_approved_cost,
                  type: 'currency'
                },
                {
                  label: 'Varianza de Costo',
                  value: selectedPlan.cost_variance,
                  type: 'currency'
                }
              ]
            },
            {
              title: 'Estadísticas',
              icon: ShoppingCart,
              fields: [
                {
                  label: 'Total de Requerimientos',
                  value: `${selectedPlan.total_requirements} requerimientos`
                },
                {
                  label: 'Demanda Total (Cantidad)',
                  value: `${selectedPlan.total_demand_quantity} unidades`
                },
                {
                  label: 'Proveedores Primarios',
                  value: `${selectedPlan.primary_suppliers_count} proveedores`
                },
                {
                  label: 'Proveedores de Respaldo',
                  value: `${selectedPlan.backup_suppliers_count} proveedores`
                }
              ]
            },
            ...(selectedPlan.special_requirements ? [{
              title: 'Requerimientos Especiales',
              fields: [
                {
                  label: 'Observaciones',
                  value: selectedPlan.special_requirements,
                  span: 2 as const,
                  editable: true,
                  placeholder: 'Añadir requerimientos especiales para el plan...'
                }
              ]
            }] : [])
          ]}
          onEdit={() => {
            console.log('Editing procurement plan:', selectedPlan.id);
          }}
        />
      )}
    </div>
  );
};

export default ProcurementPage;