R. Yusup

postify/pom.xml

@@ -45,11 +45,21 @@
 			<artifactId>lombok</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<!-- RestClient.Builder auto-configuration (used by RestClientConfig) -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-restclient</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-webmvc-test</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<!-- Spring JDBC — includes JdbcTemplate -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-jdbc</artifactId>
+		</dependency>
 	</dependencies>
 
 	<build>

postify/src/main/java/net/hackyourfuture/backend/week6/postify/DatabaseConnectionCheck.java

@@ -0,0 +1,21 @@
+package net.hackyourfuture.backend.week6.postify;
+
+import org.springframework.boot.context.event.ApplicationReadyEvent;
+import org.springframework.context.event.EventListener;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.stereotype.Component;
+
+@Component
+public class DatabaseConnectionCheck {
+     private final JdbcTemplate jdbcTemplate;
+
+    public DatabaseConnectionCheck(JdbcTemplate jdbcTemplate) {
+        this.jdbcTemplate = jdbcTemplate;
+    }
+
+    @EventListener(ApplicationReadyEvent.class)
+    public void checkConnection() {
+        String result = this.jdbcTemplate.queryForObject("SELECT 'connected'", String.class);
+        System.out.println("Database status: " + result);
+    }
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/client/LyricsApiClient.java

@@ -0,0 +1,40 @@
+package net.hackyourfuture.backend.week6.postify.client;
+
+import java.util.Optional;
+
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.HttpClientErrorException;
+import org.springframework.web.client.RestClient;
+
+/**
+ * Wraps the external lyrics.ovh API call.
+ * Returns Optional.empty() when the API has no lyrics for the song.
+ */
+@Component
+public class LyricsApiClient {
+    private final RestClient lyricsRestClient;
+
+    public LyricsApiClient(RestClient lyricsRestClient) {
+        this.lyricsRestClient = lyricsRestClient;
+    }
+
+    public Optional<String> fetchLyrics(String artistName, String trackTitle) {
+        try {
+            LyricsResponse response = lyricsRestClient.get()
+                    .uri("/{artist}/{title}", artistName, trackTitle)
+                    .retrieve()
+                    .body(LyricsResponse.class);
+
+            if (response == null || response.lyrics() == null || response.lyrics().isBlank()) {
+                return Optional.empty();
+            }
+            return Optional.of(response.lyrics());
+        } catch (HttpClientErrorException.NotFound e) {
+            return Optional.empty();
+        }
+    }
+
+    // Shape of the lyrics.ovh response: {"lyrics": "..."}
+    private record LyricsResponse(String lyrics) {
+    }
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/config/RestClientConfig.java

@@ -0,0 +1,18 @@
+package net.hackyourfuture.backend.week6.postify.config;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.client.RestClient;
+
+@Configuration
+public class RestClientConfig {
+
+    @Bean
+    public RestClient lyricsRestClient(RestClient.Builder builder,
+                                       @Value("${lyrics.api.base-url}") String baseUrl) {
+        return builder
+                .baseUrl(baseUrl)
+                .build();
+    }
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/controller/TrackLyricsController.java

@@ -0,0 +1,23 @@
+package net.hackyourfuture.backend.week6.postify.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RestController;
+
+import net.hackyourfuture.backend.week6.postify.dto.TrackLyrics;
+import net.hackyourfuture.backend.week6.postify.service.TrackLyricsService;
+
+@RestController
+public class TrackLyricsController {
+    private final TrackLyricsService service;
+
+    public TrackLyricsController(TrackLyricsService service) {
+        this.service = service;
+    }
+
+    @GetMapping("/tracks/{id}/lyrics")
+    public TrackLyrics getLyrics(@PathVariable Long id) {
+        return service.getLyrics(id);
+    }
+
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/controller/UserStatisticsController.java

@@ -0,0 +1,22 @@
+package net.hackyourfuture.backend.week6.postify.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RestController;
+
+import net.hackyourfuture.backend.week6.postify.dto.UserStatistics;
+import net.hackyourfuture.backend.week6.postify.service.UserStatisticsService;
+
+@RestController
+public class UserStatisticsController {
+    private final UserStatisticsService service;
+
+    public UserStatisticsController(UserStatisticsService service){
+        this.service = service;
+    }
+    @GetMapping("/users/{id}/stats")
+    public UserStatistics getStats(@PathVariable Long id) {
+        return service.getStats(id); 
+    }
+
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/dto/TrackLyrics.java

@@ -0,0 +1,13 @@
+package net.hackyourfuture.backend.week6.postify.dto;
+
+import lombok.Builder;
+import lombok.Data;
+
+@Data
+@Builder
+public class TrackLyrics {
+    private long trackId;
+    private String trackTitle;
+    private String artistName;
+    private String lyrics;
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/dto/UserStatistics.java

@@ -0,0 +1,18 @@
+package net.hackyourfuture.backend.week6.postify.dto;
+
+import lombok.Builder;
+import lombok.Data;
+
+@Data
+@Builder
+public class UserStatistics {
+    private long userId;
+    private String userName;
+    private String userCountry;
+    private long totalStreams;
+    private long uniqueTracksStreamed;
+    private long uniqueArtistsStreamed;
+    private String favoriteGenre;
+    private long totalListeningTimeSeconds;
+
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/exception/LyricsNotFoundException.java

@@ -0,0 +1,11 @@
+package net.hackyourfuture.backend.week6.postify.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(HttpStatus.NOT_FOUND)
+public class LyricsNotFoundException extends RuntimeException {
+    public LyricsNotFoundException(String artistName, String trackTitle) {
+        super("No lyrics found for \"" + trackTitle + "\" by " + artistName + ".");
+    }
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/exception/TrackNotFoundException.java

@@ -0,0 +1,11 @@
+package net.hackyourfuture.backend.week6.postify.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(HttpStatus.NOT_FOUND)
+public class TrackNotFoundException extends RuntimeException {
+    public TrackNotFoundException(Long id) {
+        super("Track not found: " + id);
+    }
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/exception/UserNotFoundException.java

@@ -0,0 +1,11 @@
+package net.hackyourfuture.backend.week6.postify.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(HttpStatus.NOT_FOUND)
+public class UserNotFoundException extends RuntimeException {
+    public UserNotFoundException(Long id) {
+        super("User not found: " + id);
+    }
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/repository/StreamRepository.java

@@ -0,0 +1,63 @@
+package net.hackyourfuture.backend.week6.postify.repository;
+
+import java.util.Optional;
+
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.stereotype.Repository;
+
+import net.hackyourfuture.backend.week6.postify.dto.UserStatistics;
+
+@Repository
+public class StreamRepository {
+    private final JdbcTemplate jdbcTemplate;
+
+    public StreamRepository(JdbcTemplate jdbcTemplate) {
+        this.jdbcTemplate = jdbcTemplate;
+    }
+
+    public Optional<UserStatistics> findStats(Long userId) {
+        String sql = """
+            SELECT users.user_id, users.user_name, users.user_country,
+                   COUNT(streams.stream_id)                    AS total_streams,
+                   COUNT(DISTINCT streams.track_id)            AS unique_tracks,
+                   COUNT(DISTINCT albums.artist_id)            AS unique_artists,
+                   COALESCE(SUM(tracks.track_duration_s), 0)   AS total_listening_seconds
+            FROM users
+            LEFT JOIN streams ON streams.user_id  = users.user_id
+            LEFT JOIN tracks  ON tracks.track_id  = streams.track_id
+            LEFT JOIN albums  ON albums.album_id  = tracks.album_id
+            WHERE users.user_id = ?
+            GROUP BY users.user_id, users.user_name, users.user_country
+            """;
+
+        return jdbcTemplate.query(sql, (rs, rowNum) -> UserStatistics.builder()
+                        .userId(rs.getLong("user_id"))
+                        .userName(rs.getString("user_name"))
+                        .userCountry(rs.getString("user_country"))
+                        .totalStreams(rs.getLong("total_streams"))
+                        .uniqueTracksStreamed(rs.getLong("unique_tracks"))
+                        .uniqueArtistsStreamed(rs.getLong("unique_artists"))
+                        .totalListeningTimeSeconds(rs.getLong("total_listening_seconds"))
+                        .build(),
+                userId)
+                .stream()
+                .findFirst();
+    }
+
+
+    public Optional<String> findFavoriteGenre(Long userId) {
+        String sql = """
+            SELECT tracks.genre
+            FROM streams
+            JOIN tracks ON tracks.track_id = streams.track_id
+            WHERE streams.user_id = ? AND tracks.genre IS NOT NULL
+            GROUP BY tracks.genre
+            ORDER BY COUNT(*) DESC
+            LIMIT 1
+            """;
+
+        return jdbcTemplate.query(sql, (rs, rowNum) -> rs.getString("genre"), userId)
+                .stream()
+                .findFirst();
+    }
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/repository/TrackRepository.java

@@ -0,0 +1,37 @@
+package net.hackyourfuture.backend.week6.postify.repository;
+
+import java.util.Optional;
+
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.stereotype.Repository;
+
+import net.hackyourfuture.backend.week6.postify.dto.TrackLyrics;
+
+@Repository
+public class TrackRepository {
+    private final JdbcTemplate jdbcTemplate;
+
+    public TrackRepository(JdbcTemplate jdbcTemplate) {
+        this.jdbcTemplate = jdbcTemplate;
+    }
+
+
+    public Optional<TrackLyrics> findTrackWithArtist(Long trackId) {
+        String sql = """
+            SELECT tracks.track_id, tracks.track_title, artists.artist_name
+            FROM tracks
+            JOIN albums  ON albums.album_id   = tracks.album_id
+            JOIN artists ON artists.artist_id = albums.artist_id
+            WHERE tracks.track_id = ?
+            """;
+
+        return jdbcTemplate.query(sql, (rs, rowNum) -> TrackLyrics.builder()
+                        .trackId(rs.getLong("track_id"))
+                        .trackTitle(rs.getString("track_title"))
+                        .artistName(rs.getString("artist_name"))
+                        .build(),
+                trackId)
+                .stream()
+                .findFirst();
+    }
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/service/TrackLyricsService.java

@@ -0,0 +1,31 @@
+package net.hackyourfuture.backend.week6.postify.service;
+
+import org.springframework.stereotype.Service;
+
+import net.hackyourfuture.backend.week6.postify.client.LyricsApiClient;
+import net.hackyourfuture.backend.week6.postify.dto.TrackLyrics;
+import net.hackyourfuture.backend.week6.postify.exception.LyricsNotFoundException;
+import net.hackyourfuture.backend.week6.postify.exception.TrackNotFoundException;
+import net.hackyourfuture.backend.week6.postify.repository.TrackRepository;
+
+@Service
+public class TrackLyricsService {
+    private final TrackRepository trackRepository;
+    private final LyricsApiClient lyricsApiClient;
+
+    public TrackLyricsService(TrackRepository trackRepository, LyricsApiClient lyricsApiClient) {
+        this.trackRepository = trackRepository;
+        this.lyricsApiClient = lyricsApiClient;
+    }
+
+    public TrackLyrics getLyrics(Long trackId) {
+        TrackLyrics track = trackRepository.findTrackWithArtist(trackId)
+                .orElseThrow(() -> new TrackNotFoundException(trackId));
+
+        String lyrics = lyricsApiClient.fetchLyrics(track.getArtistName(), track.getTrackTitle())
+                .orElseThrow(() -> new LyricsNotFoundException(track.getArtistName(), track.getTrackTitle()));
+
+        track.setLyrics(lyrics);
+        return track;
+    }
+}

postify/src/main/java/net/hackyourfuture/backend/week6/postify/service/UserStatisticsService.java

@@ -0,0 +1,27 @@
+package net.hackyourfuture.backend.week6.postify.service;
+
+import org.springframework.stereotype.Service;
+
+import net.hackyourfuture.backend.week6.postify.dto.UserStatistics;
+import net.hackyourfuture.backend.week6.postify.exception.UserNotFoundException;
+import net.hackyourfuture.backend.week6.postify.repository.StreamRepository;
+
+@Service
+public class UserStatisticsService {
+    private final StreamRepository streamRepository;
+
+    public UserStatisticsService(StreamRepository streamRepository) {
+        this.streamRepository = streamRepository;
+    }
+
+    public UserStatistics getStats(Long id) {
+        // Fetch the aggregate row. Empty means the user id does not exist -> 404.
+        UserStatistics stats = streamRepository.findStats(id)
+                .orElseThrow(() -> new UserNotFoundException(id));
+
+        // Favorite genre is a separate query; absent when the user has no streams.
+        streamRepository.findFavoriteGenre(id).ifPresent(stats::setFavoriteGenre);
+
+        return stats;
+    }
+}

postify/src/main/resources/application.properties

@@ -1 +1,7 @@
-spring.application.name=postify
+spring.datasource.url=jdbc:postgresql://localhost:5432/POSTIFY
+spring.datasource.username=hyfuser
+spring.datasource.password=hyfpassword
+spring.datasource.driver-class-name=org.postgresql.Driver
+
+# External lyrics API (https://lyricsovh.docs.apiary.io)
+lyrics.api.base-url=https://api.lyrics.ovh/v1