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

package com.danielbohry.stocks.service;

import com.danielbohry.stocks.context.UserContextHolder;
import com.danielbohry.stocks.domain.Portfolio;
import com.danielbohry.stocks.domain.Quote;
import com.danielbohry.stocks.domain.Stock;
import com.danielbohry.stocks.exception.BadRequestException;
import com.danielbohry.stocks.exception.NotFoundException;
import com.danielbohry.stocks.exception.UnauthorizedException;
import com.danielbohry.stocks.repository.portfolio.PortfolioEntity;
import com.danielbohry.stocks.repository.portfolio.PortfolioEntity.PortfolioStock;
import com.danielbohry.stocks.repository.portfolio.PortfolioRepository;
import com.danielbohry.stocks.service.ExchangeService.ExchangeRateResponse;
import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.ObjectUtils;
import org.springframework.stereotype.Service;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.UUID;

import static com.danielbohry.stocks.domain.Portfolio.convert;
import static java.time.LocalDateTime.now;
import static java.util.Collections.emptyList;

@Slf4j
@Service
@AllArgsConstructor
public class PortfolioService {

    private final PortfolioRepository repository;
    private final StockService stockService;
    private final ExchangeService exchangeService;
    private final PortfolioEncryptService encryptService;

    public List<String> getAllIds() {
        return repository.findAllPortfolioIds();
    }

    public List<Portfolio> getByUser(String userId, String currency) {
        return repository.findAllByUser(userId).stream()
            .map(entity -> get(entity.getId(), currency))
            .toList();
    }

    public Portfolio get(String id, String currency) {
        PortfolioEntity entity = repository.findById(id)
            .orElseThrow(() -> new NotFoundException("No portfolio found with id: " + id));

        String encrypted = entity.getEncryptedStocks();
        if (encrypted != null) {
            entity.setStocks(encryptService.decryptStocks(encrypted));
        }

        Portfolio portfolio = convert(entity);
        ExchangeRateResponse exchangeRate = exchangeService.getCurrentRate(currency);
        Map<String, BigDecimal> rates = exchangeRate.getConversionRates();
        BigDecimal targetRate = rates.getOrDefault(currency, BigDecimal.ONE);

        log.info("Getting portfolio [{}] and converting to [{}]", id, currency);
        List<Stock> updatedStocks = portfolio.getStocks().stream()
            .peek(stock -> {
                Quote quote = stockService.getStockQuote(stock.getCode());
                stock.setName(quote.getName());

                BigDecimal quoteRate = rates.getOrDefault(quote.getCurrency(), BigDecimal.ONE);

                BigDecimal convertedPrice = quote.getPrice()
                    .divide(quoteRate, 2, RoundingMode.HALF_UP)
                    .multiply(targetRate);

                stock.setPrice(convertedPrice);
                stock.setTotal(convertedPrice.multiply(new BigDecimal(stock.getQuantity())));
            }).toList();

        portfolio.setStocks(updatedStocks);

        return portfolio;
    }

    public Portfolio create() {
        String id = UUID.randomUUID().toString();

        PortfolioEntity toSave = PortfolioEntity.builder()
            .id(id)
            .stocks(emptyList())
            .user(UserContextHolder.get().getId())
            .createdAt(now())
            .updatedAt(now())
            .build();

        return convert(repository.save(toSave));
    }

    public Portfolio update(String id, List<Stock> stocks) {
        log.info("Updating portfolio [{}]", id);
        PortfolioEntity toUpdate = repository.findById(id).orElseThrow(() -> new NotFoundException("Failed to update portfolio with id: " + id));

        if (!Objects.equals(toUpdate.getUser(), UserContextHolder.get().getId()) || UserContextHolder.isAdmin()) {
            throw new UnauthorizedException("You do not have permission to update portfolio");
        }

        validate(stocks);

        toUpdate.setUpdatedAt(now());
        toUpdate.setEncryptedStocks(encryptService.encryptStocks(stocks.stream()
            .map(stock -> new PortfolioStock(stock.getCode(), stock.getQuantity()))
            .toList()));
        toUpdate.setStocks(null);

        PortfolioEntity updated = repository.save(toUpdate);

        List<PortfolioStock> decryptStocks = encryptService.decryptStocks(updated.getEncryptedStocks());
        updated.setStocks(decryptStocks);

        return convert(updated);
    }

    public void delete(String id) {
        log.info("Deleting portfolio [{}]", id);
        repository.deleteById(id);
    }

    public void cleanup() {
        repository.findAll().forEach(portfolio -> {
            if ((ObjectUtils.isEmpty(portfolio.getEncryptedStocks()))) {
                log.info("Removing empty portfolio [{}]", portfolio.getId());
                repository.deleteById(portfolio.getId());
            }
        });
    }

    private void validate(List<Stock> stocks) {
        boolean anyInvalid = stocks.stream()
            .anyMatch(stock -> !stockService.isValid(stock.getCode()));

        if (anyInvalid) {
            throw new BadRequestException("Invalid stock found");
        }
    }

}