stocks-be/src/main/java/com/danielbohry/stocks/service/StockInfoService.java

package com.danielbohry.stocks.service;

import com.danielbohry.stocks.client.FinanceClient;
import com.danielbohry.stocks.domain.Quote;
import com.danielbohry.stocks.domain.StockInfo;
import com.danielbohry.stocks.exception.NotFoundException;
import com.danielbohry.stocks.repository.StockInfoRepository;
import com.danielbohry.stocks.repository.StockRepository;
import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Set;

import static java.util.stream.Collectors.toSet;

@Slf4j
@Service
@AllArgsConstructor
public class StockInfoService {

    private FinanceClient client;
    private StockRepository stockRepository;
    private StockInfoRepository infoRepository;

    @Cacheable(value = "stockInfo", key = "#code")
    public StockInfo get(String code) {
        return infoRepository.findById(code)
            .orElseThrow(() -> new NotFoundException("No stock found with id: " + code));
    }

    @Async("stockInfoExecutor")
    public void generate() {
        List<Quote> stocks = stockRepository.findAll();

        Set<String> existingIds = infoRepository.findAllById(
                stocks.stream()
                    .map(Quote::getCode)
                    .collect(toSet())
            ).stream()
            .map(StockInfo::getCode)
            .collect(toSet());

        List<Quote> request = stocks.stream()
            .filter(stock -> !existingIds.contains(stock.getCode()))
            .filter(stock -> !stock.getCode().contains(":"))
            .toList();

        int batchSize = 20;
        for (int i = 0; i < request.size(); i += batchSize) {
            int end = Math.min(i + batchSize, request.size());
            List<Quote> batch = request.subList(i, end);
            List<StockInfo> stockInfos = client.fetchStockInfo(batch);
            infoRepository.saveAll(stockInfos);
        }
    }

}