import { createSyncStoragePersister } from "@tanstack/query-sync-storage-persister";
import { QueryClient, QueryKey, onlineManager } from "@tanstack/react-query";
import * as Network from 'expo-network';

import { MMKVStorage } from "../storages";
import { useNetworkStore } from "../storages/network";

export const BASE_URL = 'https://api.getwemap.com/v3.0';

export const persister = createSyncStoragePersister({
    storage: MMKVStorage,
})

export const queryClient = new QueryClient({
    defaultOptions: {
        queries: {
            networkMode: 'always',
            refetchOnWindowFocus: false,
            gcTime: Infinity,
            staleTime: Infinity,
            retry: 0,
        },
    }
});

onlineManager.setEventListener((setOnline) => {
    return () => {
        Network.addNetworkStateListener((state) => {
            setOnline(state.isConnected ?? false)
        })
    }
})

export const queryAll = async <T>(baseURL: URL, options: { slice: number, queryKey: QueryKey } = { slice: 100, queryKey: [] }) => {
    const totalResults: T[] = [];

    let count = 0;
    let offset = 0;

    baseURL.searchParams.set('limit', options.slice.toString());

    do {
        baseURL.searchParams.set('offset', offset.toString());
        const queryKey = ['queryAll', ...options.queryKey, offset];
        
        const data: SearchResponse<T> = await queryClient.fetchQuery({
            queryKey: queryKey,
            queryFn: async () => {
                if (useNetworkStore.getState().isOnline) {
                    const response = await fetch(baseURL).then((response) => response.json());
                    MMKVStorage.setItem(queryKey.toString(), JSON.stringify(response));
    
                    return response;
                }

                const cachedData = JSON.parse(MMKVStorage.getItem(queryKey.toString()) ?? 'null');
                if (cachedData) return cachedData;

                throw new Error('Offline - cannot fetch data and cache is empty');
            }
        });

        count = count || data.count;

        totalResults.push(...data.results);

        offset += options.slice;
    } while (totalResults.length < count);

    return {
        count: count,
        next: null,
        previous: null,
        results: totalResults
    };
}

export type SearchResponse<T> = {
    count: number
    next: string | null;
    previous: string | null;
    results: T[];
}