import type { IPaywall, NamiProductDetails } from '@namiml/sdk-core';
import { NamiPaywallManager, logger } from '@namiml/sdk-core';
import { expoPurchaseAdapter } from '../adapters';

// Accumulated store product details, keyed by product_ref_id (== sku_ref_id).
const productsById = new Map<string, NamiProductDetails>();

// Serializes backfill runs so concurrent launches/prefetches don't double-fetch
// or race the map (parity with the Apple SDK's backfillTaskLock).
let pending: Promise<boolean> = Promise.resolve(false);

/** Collect unique store product ids (sku_ref_id) from the given paywalls' sku menus. */
export function collectSkuRefIds(paywalls: IPaywall[]): string[] {
  const ids = new Set<string>();
  for (const paywall of paywalls ?? []) {
    for (const menu of paywall?.sku_menus ?? []) {
      for (const sku of menu?.products ?? []) {
        if (sku?.sku_ref_id) ids.add(sku.sku_ref_id);
      }
    }
  }
  return [...ids];
}

/**
 * Fetch store product details for any of `skuRefIds` not already loaded, merge them into
 * the accumulated set, and push the union to core via NamiPaywallManager.setProductDetails.
 * Serialized; returns whether new products were added. Never throws.
 */
export function backfill(skuRefIds: string[]): Promise<boolean> {
  pending = pending.then(() => backfillOnce(skuRefIds));
  return pending;
}

async function backfillOnce(skuRefIds: string[]): Promise<boolean> {
  const missing = [...new Set(skuRefIds)].filter((id) => id && !productsById.has(id));
  if (!missing.length) return false;
  try {
    const products = await expoPurchaseAdapter.getProducts(missing);
    let added = false;
    for (const product of products ?? []) {
      if (product?.product_ref_id) {
        productsById.set(product.product_ref_id, product);
        added = true;
      }
    }
    if (added) {
      NamiPaywallManager.setProductDetails([...productsById.values()]);
    }
    return added;
  } catch (error) {
    logger.warn('[NamiExpo] Failed to load store products.', error);
    return false;
  }
}

/** Clear accumulated products. Called on Nami.reset so reconfigure doesn't serve stale data. */
export function reset(): void {
  pending = pending.then(() => {
    productsById.clear();
    return false;
  });
}