"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;
    displayName?: string;
    username?: string;
  }>;
  averageOrdersPerCustomer: string;
  pagination?: {
    currentPage: number;
    totalPages: number;
    totalCustomers: number;
    limit: number;
    hasNextPage: boolean;
    hasPrevPage: boolean;
    startIndex: number;
    endIndex: number;
  };
}

export interface OrderAnalytics {
  statusDistribution: Array<{
    _id: string;
    count: number;
  }>;
}

export interface GrowthAnalytics {
  period: {
    start: string;
    end: string;
    days: number;
    granularity: "daily" | "weekly" | "monthly";
  };
  summary: {
    currentPeriod: {
      revenue: number;
      orders: number;
      avgOrderValue: number;
      customers: number;
    };
    previousPeriod: {
      revenue: number;
      orders: number;
      avgOrderValue: number;
      customers: number;
    };
    growthRates: {
      revenue: number;
      orders: number;
      avgOrderValue: number;
      customers: number;
    };
  };
  customerInsights: {
    newCustomers: number;
    returningCustomers: number;
    totalCustomers: number;
    newCustomerRate: number;
    avgOrdersPerCustomer: number;
    avgSpentPerCustomer: number;
  };
  timeSeries: Array<{
    date: string;
    revenue: number;
    orders: number;
    avgOrderValue: number;
    uniqueCustomers: number;
    cumulativeRevenue: number;
    cumulativeOrders: number;
  }>;
  topGrowingProducts: Array<{
    productId: string;
    productName: string;
    currentPeriodRevenue: number;
    previousPeriodRevenue: number;
    revenueGrowth: number;
    currentPeriodQuantity: number;
    previousPeriodQuantity: 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
 * @param page Page number (default: 1)
 * @param limit Number of customers per page (default: 10)
 */
export const getCustomerInsights = async (
  storeId?: string,
  page: number = 1,
  limit: number = 10,
): Promise<CustomerInsights> => {
  const params = new URLSearchParams({
    page: page.toString(),
    limit: limit.toString(),
  });
  if (storeId) params.append("storeId", storeId);

  const url = `/analytics/customer-insights?${params.toString()}`;
  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);
};

/**
 * Get growth analytics data
 * @param period Time period: "7", "30", "90", "365", or "all" (default: "30")
 * @param granularity Data granularity: "daily", "weekly", "monthly" (auto-selected if not specified)
 * @param storeId Optional storeId for staff users
 */
export const getGrowthAnalytics = async (
  period: string = "30",
  granularity?: string,
  storeId?: string,
): Promise<GrowthAnalytics> => {
  const params = new URLSearchParams({ period });
  if (granularity) params.append("granularity", granularity);
  if (storeId) params.append("storeId", storeId);

  const url = `/analytics/growth?${params.toString()}`;
  return clientFetch<GrowthAnalytics>(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 (
  page: number = 1,
  limit: number = 10,
): Promise<CustomerInsights> => {
  const storeId = getStoreIdForUser();
  return getCustomerInsights(storeId, page, limit);
};

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

export const getGrowthAnalyticsWithStore = async (
  period: string = "30",
  granularity?: string,
): Promise<GrowthAnalytics> => {
  const storeId = getStoreIdForUser();
  return getGrowthAnalytics(period, granularity, storeId);
};

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