// ================================================================
// frontend/src/components/dashboard/PurchaseOrderDetailsModal.tsx
// ================================================================
/**
 * Purchase Order Details Modal
 * Unified view/edit modal for PO details from the Action Queue
 * Now using EditViewModal with proper API response structure
 */

import React, { useState, useMemo } from 'react';
import {
  Package,
  Building2,
  Calendar,
  Euro,
  FileText,
  CheckCircle,
  Edit,
} from 'lucide-react';
import { useTranslation } from 'react-i18next';
import { usePurchaseOrder, useUpdatePurchaseOrder } from '../../api/hooks/purchase-orders';
import { useUserById } from '../../api/hooks/user';
import { EditViewModal, EditViewModalSection } from '../ui/EditViewModal/EditViewModal';
import type { PurchaseOrderItem } from '../../api/services/purchase_orders';

interface PurchaseOrderDetailsModalProps {
  poId: string;
  tenantId: string;
  isOpen: boolean;
  onClose: () => void;
  onApprove?: (poId: string) => void;
  initialMode?: 'view' | 'edit';
}

export const PurchaseOrderDetailsModal: React.FC<PurchaseOrderDetailsModalProps> = ({
  poId,
  tenantId,
  isOpen,
  onClose,
  onApprove,
  initialMode = 'view',
}) => {
  const { t, i18n } = useTranslation(['purchase_orders', 'common']);
  const { data: po, isLoading, refetch } = usePurchaseOrder(tenantId, poId);
  const [mode, setMode] = useState<'view' | 'edit'>(initialMode);
  const updatePurchaseOrderMutation = useUpdatePurchaseOrder();

  // Component to display user name with data fetching
  const UserName: React.FC<{ userId: string | undefined | null }> = ({ userId }) => {
    if (!userId) return <>{t('common:not_available')}</>;

    if (userId === '00000000-0000-0000-0000-000000000001' || userId === '00000000-0000-0000-0000-000000000000') {
      return <>{t('common:system')}</>;
    }

    const { data: user, isLoading } = useUserById(userId, {
      retry: 1,
      staleTime: 10 * 60 * 1000,
    });

    if (isLoading) return <>{t('common:loading')}</>;
    if (!user) return <>{t('common:unknown_user')}</>;

    return <>{user.full_name || user.email || t('common:user')}</>;
  };

  // Component to display PO items
  const PurchaseOrderItemsTable: React.FC<{ items: PurchaseOrderItem[] }> = ({ items }) => {
    if (!items || items.length === 0) {
      return (
        <div className="text-center py-8 text-[var(--text-secondary)] border-2 border-dashed border-[var(--border-secondary)] rounded-lg">
          <Package className="h-12 w-12 mx-auto mb-2 opacity-50" />
          <p>{t('no_items')}</p>
        </div>
      );
    }

    const totalAmount = items.reduce((sum, item) => {
      const price = parseFloat(item.unit_price) || 0;
      const quantity = item.ordered_quantity || 0;
      return sum + (price * quantity);
    }, 0);

    return (
      <div className="space-y-3">
        {items.map((item: PurchaseOrderItem, index: number) => {
          const unitPrice = parseFloat(item.unit_price) || 0;
          const quantity = item.ordered_quantity || 0;
          const itemTotal = unitPrice * quantity;
          const productName = item.product_name || `${t('product')} ${index + 1}`;

          return (
            <div
              key={item.id || index}
              className="p-4 border border-[var(--border-secondary)] rounded-lg bg-[var(--bg-secondary)]/50 space-y-3"
            >
              <div className="flex justify-between items-start">
                <div className="flex-1">
                  <h4 className="font-semibold text-[var(--text-primary)]">{productName}</h4>
                  {item.product_code && (
                    <p className="text-sm text-[var(--text-secondary)]">
                      {t('sku')}: {item.product_code}
                    </p>
                  )}
                </div>
                <div className="text-right">
                  <p className="font-bold text-lg text-[var(--color-primary-600)]">
                    €{itemTotal.toFixed(2)}
                  </p>
                </div>
              </div>
              <div className="grid grid-cols-2 gap-4 text-sm">
                <div>
                  <p className="text-[var(--text-secondary)]">{t('quantity')}</p>
                  <p className="font-medium text-[var(--text-primary)]">
                    {quantity} {item.unit_of_measure}
                  </p>
                </div>
                <div>
                  <p className="text-[var(--text-secondary)]">{t('unit_price')}</p>
                  <p className="font-medium text-[var(--text-primary)]">€{unitPrice.toFixed(2)}</p>
                </div>
              </div>
              {item.quality_requirements && (
                <div className="pt-2 border-t border-[var(--border-secondary)]">
                  <p className="text-xs text-[var(--text-secondary)]">{t('quality_requirements')}</p>
                  <p className="text-sm text-[var(--text-primary)]">{item.quality_requirements}</p>
                </div>
              )}
              {item.item_notes && (
                <div className="pt-2 border-t border-[var(--border-secondary)]">
                  <p className="text-xs text-[var(--text-secondary)]">{t('common:notes')}</p>
                  <p className="text-sm text-[var(--text-primary)]">{item.item_notes}</p>
                </div>
              )}
            </div>
          );
        })}
        <div className="flex justify-between items-center pt-4 border-t-2 border-[var(--border-primary)]">
          <span className="font-semibold text-lg text-[var(--text-primary)]">{t('total')}</span>
          <span className="font-bold text-2xl text-[var(--color-primary-600)]">€{totalAmount.toFixed(2)}</span>
        </div>
      </div>
    );
  };

  // Priority and unit options for edit mode
  const priorityOptions = [
    { value: 'urgent', label: t('priority_urgent') },
    { value: 'high', label: t('priority_high') },
    { value: 'normal', label: t('priority_normal') },
    { value: 'low', label: t('priority_low') }
  ];

  const unitOptions = [
    { value: 'kg', label: t('unit_kg') },
    { value: 'g', label: t('unit_g') },
    { value: 'l', label: t('unit_l') },
    { value: 'ml', label: t('unit_ml') },
    { value: 'units', label: t('unit_units') },
    { value: 'boxes', label: t('unit_boxes') },
    { value: 'bags', label: t('unit_bags') }
  ];

  // Build sections for EditViewModal
  const buildViewSections = (): EditViewModalSection[] => {
    if (!po) return [];

    const formatCurrency = (value: any) => {
      const num = Number(value);
      return isNaN(num) ? '0.00' : num.toFixed(2);
    };

    const sections: EditViewModalSection[] = [
      {
        title: t('general_information'),
        icon: FileText,
        fields: [
          {
            label: t('po_number'),
            value: po.po_number,
            type: 'text' as const
          },
          {
            label: t('status_label'),
            value: t(`status.${po.status}`),
            type: 'status' as const
          },
          {
            label: t('priority'),
            value: t(`priority_${po.priority}` as any) || po.priority,
            type: 'text' as const
          },
          {
            label: t('created'),
            value: new Date(po.created_at).toLocaleDateString(i18n.language, {
              year: 'numeric',
              month: 'long',
              day: 'numeric',
              hour: '2-digit',
              minute: '2-digit'
            }),
            type: 'text' as const
          }
        ]
      },
      {
        title: t('supplier_info'),
        icon: Building2,
        fields: [
          {
            label: t('supplier_name'),
            value: po.supplier?.name || t('common:unknown'),
            type: 'text' as const
          }
        ]
      },
      {
        title: t('financial_summary'),
        icon: Euro,
        fields: [
          {
            label: t('total_amount'),
            value: `€${formatCurrency(po.total_amount)}`,
            type: 'text' as const,
            highlight: true
          }
        ]
      },
      {
        title: t('items'),
        icon: Package,
        fields: [
          {
            label: '',
            value: <PurchaseOrderItemsTable items={po.items || []} />,
            type: 'component' as const,
            span: 2
          }
        ]
      },
      {
        title: t('dates'),
        icon: Calendar,
        fields: [
          {
            label: t('order_date'),
            value: new Date(po.order_date).toLocaleDateString(i18n.language, {
              year: 'numeric',
              month: 'short',
              day: 'numeric'
            }),
            type: 'text' as const
          },
          ...(po.required_delivery_date ? [{
            label: t('required_delivery_date'),
            value: new Date(po.required_delivery_date).toLocaleDateString(i18n.language, {
              year: 'numeric',
              month: 'short',
              day: 'numeric'
            }),
            type: 'text' as const
          }] : []),
          ...(po.estimated_delivery_date ? [{
            label: t('expected_delivery'),
            value: new Date(po.estimated_delivery_date).toLocaleDateString(i18n.language, {
              year: 'numeric',
              month: 'short',
              day: 'numeric'
            }),
            type: 'text' as const
          }] : [])
        ]
      }
    ];

    // Add notes section if present
    if (po.notes) {
      sections.push({
        title: t('notes'),
        icon: FileText,
        fields: [
          {
            label: t('order_notes'),
            value: po.notes,
            type: 'text' as const
          }
        ]
      });
    }

    return sections;
  };

  // Build sections for edit mode
  const buildEditSections = (): EditViewModalSection[] => {
    if (!po) return [];

    return [
      {
        title: t('supplier_info'),
        icon: Building2,
        fields: [
          {
            label: t('supplier'),
            value: po.supplier?.name || t('common:unknown'),
            type: 'text' as const,
            editable: false,
            helpText: t('supplier_cannot_modify')
          }
        ]
      },
      {
        title: t('order_details'),
        icon: Calendar,
        fields: [
          {
            label: t('priority'),
            value: po.priority,
            type: 'select' as const,
            editable: true,
            options: priorityOptions,
            helpText: t('adjust_priority')
          },
          {
            label: t('required_delivery_date'),
            value: po.required_delivery_date || '',
            type: 'date' as const,
            editable: true,
            helpText: t('delivery_deadline')
          },
          {
            label: t('notes'),
            value: po.notes || '',
            type: 'textarea' as const,
            editable: true,
            placeholder: t('special_instructions'),
            span: 2,
            helpText: t('additional_info')
          }
        ]
      },
      {
        title: t('products'),
        icon: Package,
        fields: [
          {
            label: t('products'),
            value: (po.items || []).map((item: PurchaseOrderItem) => ({
              id: item.id,
              inventory_product_id: item.inventory_product_id,
              product_code: item.product_code || '',
              product_name: item.product_name || '',
              ordered_quantity: item.ordered_quantity,
              unit_of_measure: item.unit_of_measure,
              unit_price: parseFloat(item.unit_price),
            })),
            type: 'list' as const,
            editable: true,
            span: 2,
            helpText: t('modify_quantities')
          }
        ]
      }
    ];
  };

  // Save handler for edit mode
  const handleSave = async (formData: Record<string, any>) => {
    try {
      const items = formData.items || [];

      if (items.length === 0) {
        throw new Error(t('at_least_one_product'));
      }

      // Validate quantities
      const invalidQuantities = items.some((item: any) => item.ordered_quantity <= 0);
      if (invalidQuantities) {
        throw new Error(t('quantities_greater_zero'));
      }

      // Validate required fields
      const invalidProducts = items.some((item: any) => !item.product_name);
      if (invalidProducts) {
        throw new Error(t('products_need_names'));
      }

      // Prepare the update data
      const updateData: any = {
        notes: formData.notes || undefined,
        priority: formData.priority || undefined,
      };

      // Add delivery date if changed
      if (formData.required_delivery_date) {
        updateData.required_delivery_date = formData.required_delivery_date;
      }

      // Update purchase order
      await updatePurchaseOrderMutation.mutateAsync({
        tenantId,
        poId,
        data: updateData
      });

      // Refetch data and switch back to view mode
      await refetch();
      setMode('view');
    } catch (error) {
      console.error('Error modifying purchase order:', error);
      throw error;
    }
  };

  // Build actions for modal footer - only Approve button for pending approval POs
  const buildActions = () => {
    if (!po) return undefined;

    // Only show Approve button in view mode for pending approval POs
    if (mode === 'view' && po.status === 'pending_approval') {
      return [
        {
          label: t('actions.approve'),
          icon: CheckCircle,
          onClick: () => {
            onApprove?.(poId);
            onClose();
          },
          variant: 'primary' as const
        }
      ];
    }

    return undefined;
  };

  const sections = mode === 'view' ? buildViewSections() : buildEditSections();

  return (
    <EditViewModal
      isOpen={isOpen}
      onClose={() => {
        setMode('view');
        onClose();
      }}
      mode={mode}
      onModeChange={setMode}
      title={po?.po_number || t('purchase_order')}
      subtitle={po ? new Date(po.created_at).toLocaleDateString(i18n.language, {
        year: 'numeric',
        month: 'long',
        day: 'numeric'
      }) : undefined}
      sections={sections}
      actions={buildActions()}
      isLoading={isLoading}
      size="lg"
      // Enable edit mode via standard Edit button (only for pending approval)
      onEdit={po?.status === 'pending_approval' ? () => setMode('edit') : undefined}
      onSave={mode === 'edit' ? handleSave : undefined}
      onCancel={mode === 'edit' ? () => setMode('view') : undefined}
      saveLabel={t('actions.save')}
      cancelLabel={t('actions.cancel')}
    />
  );
};
