import type {
  AnalyticsAdapter,
  AnalyticsEvent,
  IdentifyPayload,
  ScreenEvent,
} from '../types';

export interface FirebaseAdapterOptions {
  /**
   * Pass the analytics instance from `@react-native-firebase/analytics`.
   *
   * Install peer dependency:
   *   npm install @react-native-firebase/app @react-native-firebase/analytics
   *
   * Usage:
   *   import analytics from '@react-native-firebase/analytics';
   *   createAnalytics({ adapters: [createFirebaseAdapter({ instance: analytics() })] });
   */
  instance: any;
  /**
   * Firebase event names must be ≤40 chars and snake_case.
   * Set to true to auto-sanitize event names (default: true).
   */
  sanitizeEventNames?: boolean;
}

function sanitizeName(name: string): string {
  return name
    .toLowerCase()
    .replace(/[^a-z0-9_]/g, '_')
    .slice(0, 40);
}

function sanitizeProperties(
  properties?: Record<string, any>
): Record<string, string | number> | undefined {
  if (!properties) return undefined;

  const result: Record<string, string | number> = {};
  for (const [key, value] of Object.entries(properties)) {
    const cleanKey = sanitizeName(key);
    if (typeof value === 'string' || typeof value === 'number') {
      result[cleanKey] = value;
    } else {
      result[cleanKey] = JSON.stringify(value);
    }
  }
  return result;
}

export function createFirebaseAdapter(options: FirebaseAdapterOptions): AnalyticsAdapter {
  const { instance, sanitizeEventNames = true } = options;

  return {
    name: 'firebase',

    async initialize() {
      // Firebase initializes via native modules
    },

    async track(event: AnalyticsEvent) {
      const name = sanitizeEventNames ? sanitizeName(event.name) : event.name;
      await instance.logEvent(name, sanitizeProperties(event.properties) ?? {});
    },

    async screen(event: ScreenEvent) {
      await instance.logScreenView({
        screen_name: event.name,
        screen_class: event.name,
      });
    },

    async identify(payload: IdentifyPayload) {
      await instance.setUserId(payload.userId);

      if (payload.traits) {
        await Promise.all(
          Object.entries(payload.traits).map(([key, value]) =>
            instance.setUserProperty(sanitizeName(key), String(value))
          )
        );
      }
    },

    async reset() {
      await instance.setUserId(null);
    },
  };
}