import { loadGA4 } from "./ga4-loader";

type GA4Event =
  | "session_start"
  | "page_view"
  | "scroll"
  | "click"
  | "user_signup"
  | "user_login"
  | "user_logout"
  | "project_create"
  | "project_update"
  | "project_delete"
  | "screenplay_create"
  | "screenplay_update"
  | "screenplay_export"
  | "begin_checkout"
  | "add_to_cart"
  | "add_to_wishlist"
  | "view_item"
  | "view_item_list"
  | "select_item"
  | "purchase"
  | "refund"
  | "sign_up"
  | "lead"
  | "search";

export interface GA4Config {
  measurementId: string;
  apiSecret?: string;
  streamId?: string;
  options?: {
    debug?: boolean;
    autoTrackPageViews?: boolean;
    autoTrackScrolls?: boolean;
    autoTrackOutboundLinks?: boolean;
  };
}

export interface GA4EcommerceItem {
  item_id: string;
  item_name: string;
  item_category?: string;
  price: number;
  quantity: number;
  currency?: string;
}

export interface GA4PurchaseEvent {
  transaction_id: string;
  value: number;
  currency: string;
  tax?: number;
  shipping?: number;
  items: GA4EcommerceItem[];
}

export class GA4Service {
  private measurementId: string;
  private config: GA4Config;
  private initialized: boolean = false;

  constructor(config: GA4Config) {
    this.measurementId = config.measurementId;
    this.config = config;
  }

  async initialize(): Promise<void> {
    await loadGA4(this.measurementId, this.config.options);
    this.initialized = true;
  }

  track(event: GA4Event, params?: Record<string, unknown>): void {
    if (!this.initialized) {
      console.warn("GA4 not initialized");
      return;
    }
    (window as any).gtag?.("event", event, params);
  }

  trackPageView(pageLocation?: string, pagePath?: string): void {
    this.track("page_view", {
      page_location: pageLocation || window.location.href,
      page_path: pagePath || window.location.pathname,
      page_title: document.title,
    });
  }

  trackEcommerce(event: "purchase" | "refund", data: GA4PurchaseEvent): void {
    this.track(event, {
      transaction_id: data.transaction_id,
      value: data.value,
      currency: data.currency,
      tax: data.tax,
      shipping: data.shipping,
      items: data.items,
    });
  }

  trackAddToCart(item: GA4EcommerceItem): void {
    this.track("add_to_cart", {
      items: [item],
    });
  }

  trackBeginCheckout(items: GA4EcommerceItem[], value: number): void {
    this.track("begin_checkout", {
      items,
      value,
      currency: items[0]?.currency || "USD",
    });
  }

  trackViewItemList(items: GA4EcommerceItem[], itemListName: string): void {
    this.track("view_item_list", {
      items,
      item_list_name: itemListName,
    });
  }

  trackSelectItem(item: GA4EcommerceItem, itemListName: string): void {
    this.track("select_item", {
      items: [item],
      item_list_name: itemListName,
    });
  }

  setUserProperty(userId: string, userProperties?: Record<string, string>): void {
    (window as any).gtag?.("set", "user_properties", {
      user_id: userId,
      ...userProperties,
    });
  }
}

export const createGA4Service = (config: GA4Config): GA4Service => {
  return new GA4Service(config);
};