feat: add new endpoint to retrieve prices from an asset

build.gradle

@@ -27,7 +27,7 @@ dependencies {
 	implementation 'com.fasterxml.jackson.core:jackson-databind'
 	implementation 'org.springframework.integration:spring-integration-core'
 	implementation 'org.springframework.boot:spring-boot-starter-data-mongodb'
-
+	implementation 'com.yahoofinance-api:YahooFinanceAPI:3.17.0'
 
 	testImplementation 'org.springframework.boot:spring-boot-testcontainers'
 	testImplementation 'org.testcontainers:testcontainers'

src/main/java/io/autoinvestor/application/AssetNotFoundException.java

@@ -0,0 +1,9 @@
+package io.autoinvestor.application;
+
+import io.autoinvestor.exceptions.BadRequestException;
+
+public class AssetNotFoundException extends BadRequestException {
+    public AssetNotFoundException(String message) {
+        super(message);
+    }
+}

src/main/java/io/autoinvestor/application/GetAssetPriceCommand.java

@@ -0,0 +1,5 @@
+package io.autoinvestor.application;
+
+import java.util.Date;
+
+public record GetAssetPriceCommand(String assetId, Date date) { }

src/main/java/io/autoinvestor/application/GetAssetPriceCommandHandler.java

@@ -0,0 +1,28 @@
+package io.autoinvestor.application;
+
+import io.autoinvestor.domain.Asset;
+import io.autoinvestor.domain.AssetId;
+import io.autoinvestor.domain.AssetPriceFetcher;
+import io.autoinvestor.domain.AssetRepository;
+import org.springframework.stereotype.Service;
+
+
+@Service
+public class GetAssetPriceCommandHandler {
+
+    private final AssetPriceFetcher fetcher;
+    private final AssetRepository repository;
+
+    public GetAssetPriceCommandHandler(AssetRepository repository, AssetPriceFetcher fetcher) {
+        this.repository = repository;
+        this.fetcher = fetcher;
+    }
+
+    public GetAssetPriceResponse handle(GetAssetPriceCommand command) {
+        Asset asset = repository.findById(AssetId.of(command.assetId()))
+                .orElseThrow(() -> new AssetNotFoundException("Asset not found with id: " + command.assetId()));
+
+        float price = fetcher.priceOn(asset, command.date());
+        return new GetAssetPriceResponse(price, command.date());
+    }
+}

src/main/java/io/autoinvestor/application/GetAssetPriceResponse.java

@@ -0,0 +1,6 @@
+package io.autoinvestor.application;
+
+import java.util.Date;
+
+
+public record GetAssetPriceResponse(float price, Date date) { }

src/main/java/io/autoinvestor/domain/Asset.java

@@ -8,21 +8,25 @@ public class Asset extends AggregateRoot {
     private final Ticker ticker;
     private final CompanyName name;
     private final Date createdAt;
-    private Date updatedAt;
+    private final Date updatedAt;
 
-    private Asset(Mic mic, Ticker ticker, CompanyName name) {
+    private Asset(Mic mic, Ticker ticker, CompanyName name, Date createdAt, Date updatedAt) {
         this.id = AssetId.generate();
         this.mic = mic;
         this.ticker = ticker;
         this.name = name;
-        this.createdAt = new Date();
-        this.updatedAt = new Date();
+        this.createdAt = createdAt;
+        this.updatedAt = updatedAt;
 
         this.recordEvent(AssetWasRegisteredEvent.from(this));
     }
 
     public static Asset create(String mic, String ticker, String name) {
-        return new Asset(Mic.from(mic), Ticker.from(ticker), CompanyName.from(name));
+        return new Asset(Mic.from(mic), Ticker.from(ticker), CompanyName.from(name), new Date(), new Date());
+    }
+
+    public static Asset create(String mic, String ticker, String name, Date createdAt, Date updatedAt) {
+        return new Asset(Mic.from(mic), Ticker.from(ticker), CompanyName.from(name), createdAt, updatedAt);
     }
 
     public String mic() {

src/main/java/io/autoinvestor/domain/AssetId.java

@@ -8,4 +8,8 @@ public class AssetId extends Id {
     public static AssetId generate() {
         return new AssetId(generateId());
     }
+
+    public static AssetId of(String id) {
+        return new AssetId(id);
+    }
 }

src/main/java/io/autoinvestor/domain/AssetPriceFetcher.java

@@ -0,0 +1,7 @@
+package io.autoinvestor.domain;
+
+import java.util.Date;
+
+public interface AssetPriceFetcher {
+    float priceOn(Asset asset, Date date);
+}

src/main/java/io/autoinvestor/domain/AssetRepository.java

@@ -1,6 +1,10 @@
 package io.autoinvestor.domain;
 
+
+import java.util.Optional;
+
 public interface AssetRepository {
     void save(Asset asset);
     boolean exists(String mic, String ticker);
+    Optional<Asset> findById(AssetId assetId);
 }

src/main/java/io/autoinvestor/infrastructure/fetchers/PriceFetchFailedException.java

@@ -0,0 +1,7 @@
+package io.autoinvestor.infrastructure.fetchers;
+
+public class PriceFetchFailedException extends RuntimeException {
+    public PriceFetchFailedException(String message) {
+        super(message);
+    }
+}

src/main/java/io/autoinvestor/infrastructure/fetchers/PriceNotAvailableException.java

@@ -0,0 +1,7 @@
+package io.autoinvestor.infrastructure.fetchers;
+
+public class PriceNotAvailableException extends RuntimeException {
+    public PriceNotAvailableException(String message) {
+        super(message);
+    }
+}

src/main/java/io/autoinvestor/infrastructure/fetchers/YFinanceAssetPriceFetcher.java

@@ -0,0 +1,58 @@
+package io.autoinvestor.infrastructure.fetchers;
+
+import io.autoinvestor.domain.Asset;
+import io.autoinvestor.domain.AssetPriceFetcher;
+import org.springframework.stereotype.Component;
+import yahoofinance.YahooFinance;
+import yahoofinance.Stock;
+import yahoofinance.histquotes.HistoricalQuote;
+import yahoofinance.histquotes.Interval;
+
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.List;
+import java.util.TimeZone;
+
+
+@Component
+public class YFinanceAssetPriceFetcher implements AssetPriceFetcher {
+
+    private static final int DAYS_LOOKBACK_BUFFER = 7;
+
+    @Override
+    public float priceOn(Asset asset, Date date) {
+        Calendar target = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
+        target.setTime(date);
+
+        Calendar from = (Calendar) target.clone();
+        from.add(Calendar.DAY_OF_MONTH, -DAYS_LOOKBACK_BUFFER);
+
+        Calendar to = (Calendar) target.clone();
+        to.add(Calendar.DAY_OF_MONTH, DAYS_LOOKBACK_BUFFER);
+
+        try {
+            Stock stock = YahooFinance.get(asset.ticker(), from, to, Interval.DAILY);
+            List<HistoricalQuote> history = stock.getHistory();
+
+            HistoricalQuote bar = history.stream()
+                    .filter(h -> h.getDate() != null)
+                    .sorted((a, b) -> b.getDate().compareTo(a.getDate()))
+                    .filter(h -> !h.getDate().after(target))
+                    .findFirst()
+                    .orElseThrow(() -> new PriceNotAvailableException(
+                            "No historical bar found for %s on/Before %s".formatted(asset, date)));
+
+            BigDecimal close = bar.getClose() != null ? bar.getClose() : bar.getAdjClose();
+            if (close == null) {
+                throw new PriceNotAvailableException(
+                        "Close price missing for %s on %s".formatted(asset, date));
+            }
+            return close.floatValue();
+        } catch (IOException ex) {
+            throw new PriceFetchFailedException(
+                    "Unable to fetch price for %s from Yahoo Finance".formatted(asset));
+        }
+    }
+}

src/main/java/io/autoinvestor/infrastructure/repositories/AssetMapper.java

@@ -3,6 +3,8 @@
 import io.autoinvestor.domain.Asset;
 import org.springframework.stereotype.Component;
 
+import java.util.Date;
+
 @Component
 class AssetMapper {
 
@@ -15,5 +17,14 @@ AssetDocument toDocument(Asset domain) {
                 domain.getCreatedAt().toInstant(),
                 domain.getUpdatedAt().toInstant());
     }
+
+    public Asset toDomain(AssetDocument assetDocument) {
+        return Asset.create(
+                assetDocument.mic(),
+                assetDocument.ticker(),
+                assetDocument.name(),
+                Date.from(assetDocument.occurredAt()),
+                Date.from(assetDocument.updatedAt()));
+    }
 }
 

src/main/java/io/autoinvestor/infrastructure/repositories/InMemoryAssetRepository.java

@@ -1,12 +1,14 @@
 package io.autoinvestor.infrastructure.repositories;
 
 import io.autoinvestor.domain.Asset;
+import io.autoinvestor.domain.AssetId;
 import io.autoinvestor.domain.AssetRepository;
 import org.springframework.context.annotation.Profile;
 import org.springframework.stereotype.Repository;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Optional;
 
 @Repository
 @Profile("local")
@@ -24,6 +26,11 @@ public boolean exists(String mic, String ticker) {
         return assetStore.containsKey(mic + ":" + ticker);
     }
 
+    @Override
+    public Optional<Asset> findById(AssetId assetId) {
+        return Optional.ofNullable(assetStore.get(assetId.value()));
+    }
+
     public void clear() {
         assetStore.clear();
     }

src/main/java/io/autoinvestor/infrastructure/repositories/MongoAssetRepository.java

@@ -1,13 +1,16 @@
 package io.autoinvestor.infrastructure.repositories;
 
 import io.autoinvestor.domain.Asset;
+import io.autoinvestor.domain.AssetId;
 import io.autoinvestor.domain.AssetRepository;
 import org.springframework.context.annotation.Profile;
 import org.springframework.data.mongodb.core.MongoTemplate;
 import org.springframework.data.mongodb.core.query.Criteria;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.stereotype.Repository;
 
+import java.util.Optional;
+
 
 @Repository
 @Profile("prod")
@@ -33,4 +36,10 @@ public boolean exists(String mic, String ticker) {
                 .and("ticker").is(ticker));
         return template.exists(q, AssetDocument.class);
     }
+
+    @Override
+    public Optional<Asset> findById(AssetId assetId) {
+        return Optional.ofNullable(template.findById(assetId.value(), AssetDocument.class))
+                .map(mapper::toDomain);
+    }
 }

src/main/java/io/autoinvestor/ui/GetAssetPriceController.java

@@ -0,0 +1,38 @@
+package io.autoinvestor.ui;
+
+import io.autoinvestor.application.GetAssetPriceCommand;
+import io.autoinvestor.application.GetAssetPriceCommandHandler;
+import io.autoinvestor.application.GetAssetPriceResponse;
+import org.springframework.format.annotation.DateTimeFormat;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.time.Instant;
+import java.util.Date;
+
+@RestController
+@RequestMapping("/assets")
+public class GetAssetPriceController {
+
+    private final GetAssetPriceCommandHandler handler;
+
+    public GetAssetPriceController(GetAssetPriceCommandHandler handler) {
+        this.handler = handler;
+    }
+
+    @GetMapping("/{assetId}/price")
+    public ResponseEntity<PriceDTO> getPrice(
+            @PathVariable String assetId,
+            @RequestParam(name = "at", required = false)
+            @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) Date at) {
+
+        Date date = at != null ? at : Date.from(Instant.now());
+
+        GetAssetPriceResponse response = handler.handle(new GetAssetPriceCommand(assetId, date));
+        PriceDTO dto = new PriceDTO(
+                response.date(),
+                response.price()
+        );
+        return ResponseEntity.ok(dto);
+    }
+}

src/main/java/io/autoinvestor/ui/GlobalExceptionHandler.java

@@ -1,6 +1,8 @@
 package io.autoinvestor.ui;
 
 import io.autoinvestor.exceptions.*;
+import io.autoinvestor.infrastructure.fetchers.PriceFetchFailedException;
+import io.autoinvestor.infrastructure.fetchers.PriceNotAvailableException;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.ExceptionHandler;
@@ -27,6 +29,22 @@ public ResponseEntity<ErrorResponse> handleBadRequestException(BadRequestExcepti
                 .build();
     }
 
+    @ExceptionHandler(PriceNotAvailableException.class)
+    public ResponseEntity<ErrorResponse> handlePriceNotAvailableException(PriceNotAvailableException ex) {
+        return ErrorResponse.builder()
+                .status(HttpStatus.INTERNAL_SERVER_ERROR)
+                .message(ex.getMessage())
+                .build();
+    }
+
+    @ExceptionHandler(PriceFetchFailedException.class)
+    public ResponseEntity<ErrorResponse> handlePriceFetchFailedException(PriceFetchFailedException ex) {
+        return ErrorResponse.builder()
+                .status(HttpStatus.INTERNAL_SERVER_ERROR)
+                .message(ex.getMessage())
+                .build();
+    }
+
     @ExceptionHandler(InternalErrorException.class)
     public ResponseEntity<ErrorResponse> handleInternalErrorException(InternalErrorException ex) {
         return ErrorResponse.builder()

src/main/java/io/autoinvestor/ui/PriceDTO.java

@@ -0,0 +1,10 @@
+package io.autoinvestor.ui;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+
+import java.util.Date;
+
+public record PriceDTO(
+        @JsonFormat(shape = JsonFormat.Shape.STRING)
+        Date date,
+        float price) { }