'use client';

import { clientFetch } from '../api-client';

// Analytics Types
export interface AnalyticsOverview {
  orders: {
    total: number;
    completed: number;
    pending: number;
    completionRate: string;
  };
  revenue: {
    total: number;
    monthly: number;
    weekly: number;
    averageOrderValue: number;
  };
  products: {
    total: number;
  };
  customers: {
    unique: number;
  };
  userType?: 'vendor' | 'staff';
}

export interface RevenueData {
  _id: {
    year: number;
    month: number;
    day: number;
  };
  revenue: number;
  orders: number;
}

export interface ProductPerformance {
  productId: string;
  name: string;
  image: string;
  unitType: string;
  currentStock: number;
  stockStatus: string;
  totalSold: number;
  totalRevenue: number;
  orderCount: number;
  averagePrice: number;
}

export interface CustomerInsights {
  totalCustomers: number;
  segments: {
    new: number;
    returning: number;
    loyal: number;
    vip: number;
  };
  topCustomers: Array<{
    _id: string;
    orderCount: number;
    totalSpent: number;
    averageOrderValue: number;
    firstOrder: string;
    lastOrder: string;
  }>;
  averageOrdersPerCustomer: string;
}

export interface OrderAnalytics {
  statusDistribution: Array<{
    _id: string;
    count: number;
  }>;
  dailyOrders: Array<{
    _id: {
      year: number;
      month: number;
      day: number;
    };
    orders: number;
    revenue: number;
  }>;
  averageProcessingDays: number;
}

// Analytics Service Functions

/**
 * Get analytics overview data
 * @param storeId Optional storeId for staff users
 */
export const getAnalyticsOverview = async (storeId?: string): Promise<AnalyticsOverview> => {
  const url = storeId ? `/analytics/overview?storeId=${storeId}` : '/analytics/overview';
  return clientFetch<AnalyticsOverview>(url);
};

/**
 * Get revenue trends data
 * @param period Time period in days (7, 30, 90)
 * @param storeId Optional storeId for staff users
 */
export const getRevenueTrends = async (period: string = '30', storeId?: string): Promise<RevenueData[]> => {
  const params = new URLSearchParams({ period });
  if (storeId) params.append('storeId', storeId);
  
  const url = `/analytics/revenue-trends?${params.toString()}`;
  return clientFetch<RevenueData[]>(url);
};

/**
 * Get product performance data
 * @param storeId Optional storeId for staff users
 */
export const getProductPerformance = async (storeId?: string): Promise<ProductPerformance[]> => {
  const url = storeId ? `/analytics/product-performance?storeId=${storeId}` : '/analytics/product-performance';
  return clientFetch<ProductPerformance[]>(url);
};

/**
 * Get customer insights data
 * @param storeId Optional storeId for staff users
 */
export const getCustomerInsights = async (storeId?: string): Promise<CustomerInsights> => {
  const url = storeId ? `/analytics/customer-insights?storeId=${storeId}` : '/analytics/customer-insights';
  return clientFetch<CustomerInsights>(url);
};

/**
 * Get order analytics data
 * @param period Time period in days (7, 30, 90)
 * @param storeId Optional storeId for staff users
 */
export const getOrderAnalytics = async (period: string = '30', storeId?: string): Promise<OrderAnalytics> => {
  const params = new URLSearchParams({ period });
  if (storeId) params.append('storeId', storeId);
  
  const url = `/analytics/order-analytics?${params.toString()}`;
  return clientFetch<OrderAnalytics>(url);
};

// Helper function to determine if user is staff and get storeId
export const getStoreIdForUser = (): string | undefined => {
  if (typeof window === 'undefined') return undefined;
  
  // Check if user is staff (you might need to adjust this based on your auth system)
  const userType = localStorage.getItem('userType');
  const storeId = localStorage.getItem('storeId');
  
  if (userType === 'staff' && storeId) {
    return storeId;
  }
  
  return undefined;
};

// Enhanced analytics functions that automatically handle storeId for staff users
export const getAnalyticsOverviewWithStore = async (): Promise<AnalyticsOverview> => {
  const storeId = getStoreIdForUser();
  return getAnalyticsOverview(storeId);
};

export const getRevenueTrendsWithStore = async (period: string = '30'): Promise<RevenueData[]> => {
  const storeId = getStoreIdForUser();
  return getRevenueTrends(period, storeId);
};

export const getProductPerformanceWithStore = async (): Promise<ProductPerformance[]> => {
  const storeId = getStoreIdForUser();
  return getProductPerformance(storeId);
};

export const getCustomerInsightsWithStore = async (): Promise<CustomerInsights> => {
  const storeId = getStoreIdForUser();
  return getCustomerInsights(storeId);
};

export const getOrderAnalyticsWithStore = async (period: string = '30'): Promise<OrderAnalytics> => {
  const storeId = getStoreIdForUser();
  return getOrderAnalytics(period, storeId);
};

export function formatGBP(value: number) {
  return value.toLocaleString('en-GB', {
    style: 'currency',
    currency: 'GBP',
    minimumFractionDigits: 2,
    maximumFractionDigits: 2,
  });
}