export type SkuGroup = {

  masterSku: string;

  masterStock: number;

  variantIds: string[];

  updatedAt: string;

};



const STORAGE_KEY = 'pazaryonetimi-sku-groups';



function loadFromStorage(tenantId: string): SkuGroup[] {

  if (typeof window === 'undefined') return [];

  try {

    const raw = localStorage.getItem(`${STORAGE_KEY}:${tenantId}`);

    if (!raw) return [];

    const parsed = JSON.parse(raw) as SkuGroup[];

    return Array.isArray(parsed) ? parsed : [];

  } catch {

    return [];

  }

}



function saveToStorage(tenantId: string, groups: SkuGroup[]): void {

  if (typeof window === 'undefined') return;

  localStorage.setItem(`${STORAGE_KEY}:${tenantId}`, JSON.stringify(groups));

}



export async function loadSkuGroups(tenantId: string): Promise<SkuGroup[]> {

  try {

    const res = await fetch('/api/inventory/sku-groups', { cache: 'no-store' });

    if (res.ok) {

      const data = (await res.json()) as SkuGroup[];

      if (Array.isArray(data)) {

        saveToStorage(tenantId, data);

        return data;

      }

    }

  } catch {

    // fallback to local cache

  }

  return loadFromStorage(tenantId);

}



export async function saveSkuGroups(tenantId: string, groups: SkuGroup[]): Promise<SkuGroup[]> {

  saveToStorage(tenantId, groups);

  try {

    const res = await fetch('/api/inventory/sku-groups', {

      method: 'PUT',

      headers: { 'content-type': 'application/json' },

      body: JSON.stringify({ groups }),

    });

    if (res.ok) {

      const data = (await res.json()) as SkuGroup[];

      if (Array.isArray(data)) {

        saveToStorage(tenantId, data);

        return data;

      }

    }

  } catch {

    // keep local copy

  }

  return groups;

}