feat(stats): add 5 new user statistics charts

booklore-api/src/main/java/org/booklore/controller/UserStatsController.java

@@ -135,4 +135,40 @@ public ResponseEntity<List<BookCompletionHeatmapResponse>> getBookCompletionHeat
         List<BookCompletionHeatmapResponse> heatmapData = readingSessionService.getBookCompletionHeatmap();
         return ResponseEntity.ok(heatmapData);
     }
+
+    @Operation(summary = "Get page turner scores", description = "Returns engagement/grip scores for completed books based on reading session patterns")
+    @ApiResponses({
+            @ApiResponse(responseCode = "200", description = "Page turner scores retrieved successfully"),
+            @ApiResponse(responseCode = "401", description = "Unauthorized")
+    })
+    @GetMapping("/page-turner-scores")
+    @PreAuthorize("@securityUtil.canAccessUserStats() or @securityUtil.isAdmin()")
+    public ResponseEntity<List<PageTurnerScoreResponse>> getPageTurnerScores() {
+        List<PageTurnerScoreResponse> scores = readingSessionService.getPageTurnerScores();
+        return ResponseEntity.ok(scores);
+    }
+
+    @Operation(summary = "Get completion race data", description = "Returns reading session progress data for completed books in a given year, for visualizing completion races")
+    @ApiResponses({
+            @ApiResponse(responseCode = "200", description = "Completion race data retrieved successfully"),
+            @ApiResponse(responseCode = "401", description = "Unauthorized")
+    })
+    @GetMapping("/completion-race")
+    @PreAuthorize("@securityUtil.canAccessUserStats() or @securityUtil.isAdmin()")
+    public ResponseEntity<List<CompletionRaceResponse>> getCompletionRace(@RequestParam int year) {
+        List<CompletionRaceResponse> data = readingSessionService.getCompletionRace(year);
+        return ResponseEntity.ok(data);
+    }
+
+    @Operation(summary = "Get all reading dates", description = "Returns daily reading session counts across all time for the authenticated user")
+    @ApiResponses({
+            @ApiResponse(responseCode = "200", description = "Reading dates retrieved successfully"),
+            @ApiResponse(responseCode = "401", description = "Unauthorized")
+    })
+    @GetMapping("/reading-dates")
+    @PreAuthorize("@securityUtil.canAccessUserStats() or @securityUtil.isAdmin()")
+    public ResponseEntity<List<ReadingSessionHeatmapResponse>> getReadingDates() {
+        List<ReadingSessionHeatmapResponse> data = readingSessionService.getReadingDates();
+        return ResponseEntity.ok(data);
+    }
 }

booklore-api/src/main/java/org/booklore/model/dto/CompletionRaceSessionDto.java

@@ -0,0 +1,10 @@
+package org.booklore.model.dto;
+
+import java.time.Instant;
+
+public interface CompletionRaceSessionDto {
+    Long getBookId();
+    String getBookTitle();
+    Instant getSessionDate();
+    Float getEndProgress();
+}

booklore-api/src/main/java/org/booklore/model/dto/PageTurnerSessionDto.java

@@ -0,0 +1,14 @@
+package org.booklore.model.dto;
+
+import java.time.Instant;
+
+public interface PageTurnerSessionDto {
+    Long getBookId();
+    String getBookTitle();
+    Integer getPageCount();
+    Integer getPersonalRating();
+    Instant getDateFinished();
+    Instant getStartTime();
+    Instant getEndTime();
+    Integer getDurationSeconds();
+}

booklore-api/src/main/java/org/booklore/model/dto/response/CompletionRaceResponse.java

@@ -0,0 +1,19 @@
+package org.booklore.model.dto.response;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.time.Instant;
+
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class CompletionRaceResponse {
+    private Long bookId;
+    private String bookTitle;
+    private Instant sessionDate;
+    private Float endProgress;
+}

booklore-api/src/main/java/org/booklore/model/dto/response/PageTurnerScoreResponse.java

@@ -0,0 +1,26 @@
+package org.booklore.model.dto.response;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.util.List;
+
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class PageTurnerScoreResponse {
+    private Long bookId;
+    private String bookTitle;
+    private List<String> categories;
+    private Integer pageCount;
+    private Integer personalRating;
+    private Integer gripScore;
+    private Long totalSessions;
+    private Double avgSessionDurationSeconds;
+    private Double sessionAcceleration;
+    private Double gapReduction;
+    private Boolean finishBurst;
+}

booklore-api/src/main/java/org/booklore/repository/ReadingSessionRepository.java

@@ -1,6 +1,9 @@
 package org.booklore.repository;
 
 import org.booklore.model.dto.*;
+import org.booklore.model.dto.CompletionRaceSessionDto;
+import org.booklore.model.dto.PageTurnerSessionDto;
+
 import org.booklore.model.entity.ReadingSessionEntity;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
@@ -136,4 +139,52 @@ Page<ReadingSessionEntity> findByUserIdAndBookId(
             @Param("userId") Long userId,
             @Param("bookId") Long bookId,
             Pageable pageable);
+
+    @Query("""
+            SELECT
+                b.id as bookId,
+                COALESCE(b.metadata.title, 'Unknown Book') as bookTitle,
+                b.metadata.pageCount as pageCount,
+                ubp.personalRating as personalRating,
+                COALESCE(ubp.dateFinished, ubp.readStatusModifiedTime, ubp.lastReadTime) as dateFinished,
+                rs.startTime as startTime,
+                rs.endTime as endTime,
+                rs.durationSeconds as durationSeconds
+            FROM ReadingSessionEntity rs
+            JOIN rs.book b
+            JOIN UserBookProgressEntity ubp ON ubp.book.id = b.id AND ubp.user.id = rs.user.id
+            WHERE rs.user.id = :userId
+            AND ubp.readStatus = org.booklore.model.enums.ReadStatus.READ
+            AND COALESCE(ubp.dateFinished, ubp.readStatusModifiedTime, ubp.lastReadTime) IS NOT NULL
+            ORDER BY b.id, rs.startTime ASC
+            """)
+    List<PageTurnerSessionDto> findPageTurnerSessionsByUser(@Param("userId") Long userId);
+
+    @Query("""
+            SELECT
+                b.id as bookId,
+                COALESCE(b.metadata.title, 'Unknown Book') as bookTitle,
+                rs.startTime as sessionDate,
+                rs.endProgress as endProgress
+            FROM ReadingSessionEntity rs
+            JOIN rs.book b
+            JOIN UserBookProgressEntity ubp ON ubp.book.id = b.id AND ubp.user.id = rs.user.id
+            WHERE rs.user.id = :userId
+            AND ubp.readStatus = org.booklore.model.enums.ReadStatus.READ
+            AND YEAR(COALESCE(ubp.dateFinished, ubp.readStatusModifiedTime, ubp.lastReadTime)) = :year
+            AND rs.endProgress IS NOT NULL
+            ORDER BY b.id, rs.startTime ASC
+            """)
+    List<CompletionRaceSessionDto> findCompletionRaceSessionsByUserAndYear(
+            @Param("userId") Long userId,
+            @Param("year") int year);
+
+    @Query("""
+            SELECT CAST(rs.startTime AS LocalDate) as date, COUNT(rs) as count
+            FROM ReadingSessionEntity rs
+            WHERE rs.user.id = :userId
+            GROUP BY CAST(rs.startTime AS LocalDate)
+            ORDER BY date
+            """)
+    List<ReadingSessionCountDto> findAllSessionCountsByUser(@Param("userId") Long userId);
 }

booklore-api/src/main/java/org/booklore/service/ReadingSessionService.java

@@ -3,18 +3,24 @@
 import org.booklore.config.security.service.AuthenticationService;
 import org.booklore.exception.ApiError;
 import org.booklore.model.dto.BookLoreUser;
+import org.booklore.model.dto.CompletionRaceSessionDto;
 import org.booklore.model.dto.request.ReadingSessionRequest;
+import org.booklore.model.dto.PageTurnerSessionDto;
 import org.booklore.model.dto.response.BookCompletionHeatmapResponse;
+import org.booklore.model.dto.response.CompletionRaceResponse;
 import org.booklore.model.dto.response.CompletionTimelineResponse;
 import org.booklore.model.dto.response.FavoriteReadingDaysResponse;
 import org.booklore.model.dto.response.GenreStatisticsResponse;
+import org.booklore.model.dto.response.PageTurnerScoreResponse;
 import org.booklore.model.dto.response.PeakReadingHoursResponse;
+
 import org.booklore.model.dto.response.ReadingSessionHeatmapResponse;
 import org.booklore.model.dto.response.ReadingSessionResponse;
 import org.booklore.model.dto.response.ReadingSessionTimelineResponse;
 import org.booklore.model.dto.response.ReadingSpeedResponse;
 import org.booklore.model.entity.BookEntity;
 import org.booklore.model.entity.BookLoreUserEntity;
+import org.booklore.model.entity.CategoryEntity;
 import org.booklore.model.entity.ReadingSessionEntity;
 import org.booklore.model.enums.ReadStatus;
 import org.booklore.repository.BookRepository;
@@ -31,15 +37,14 @@
 import org.springframework.transaction.annotation.Transactional;
 
 import java.time.DayOfWeek;
+import java.time.Instant;
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.ZoneId;
+import java.time.temporal.ChronoUnit;
 import java.time.temporal.TemporalAdjusters;
 import java.time.temporal.WeekFields;
-import java.util.EnumMap;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.stream.Collectors;
 
 @Slf4j
@@ -287,4 +292,152 @@ public List<BookCompletionHeatmapResponse> getBookCompletionHeatmap() {
                         .build())
                 .collect(Collectors.toList());
     }
+
+    @Transactional(readOnly = true)
+    public List<PageTurnerScoreResponse> getPageTurnerScores() {
+        BookLoreUser authenticatedUser = authenticationService.getAuthenticatedUser();
+        Long userId = authenticatedUser.getId();
+
+        var sessions = readingSessionRepository.findPageTurnerSessionsByUser(userId);
+
+        Map<Long, List<PageTurnerSessionDto>> sessionsByBook = sessions.stream()
+                .collect(Collectors.groupingBy(PageTurnerSessionDto::getBookId, LinkedHashMap::new, Collectors.toList()));
+
+        Set<Long> bookIds = sessionsByBook.keySet();
+        Map<Long, List<String>> bookCategories = new HashMap<>();
+        if (!bookIds.isEmpty()) {
+            bookRepository.findAllWithMetadataByIds(bookIds).forEach(book -> {
+                List<String> categories = book.getMetadata() != null && book.getMetadata().getCategories() != null
+                        ? book.getMetadata().getCategories().stream()
+                        .map(CategoryEntity::getName)
+                        .sorted()
+                        .collect(Collectors.toList())
+                        : List.of();
+                bookCategories.put(book.getId(), categories);
+            });
+        }
+
+        return sessionsByBook.entrySet().stream()
+                .filter(entry -> entry.getValue().size() >= 2)
+                .map(entry -> {
+                    Long bookId = entry.getKey();
+                    List<PageTurnerSessionDto> bookSessions = entry.getValue();
+                    PageTurnerSessionDto first = bookSessions.getFirst();
+
+                    List<Double> durations = bookSessions.stream()
+                            .map(s -> s.getDurationSeconds() != null ? s.getDurationSeconds().doubleValue() : 0.0)
+                            .collect(Collectors.toList());
+
+                    List<Double> gaps = new ArrayList<>();
+                    for (int i = 1; i < bookSessions.size(); i++) {
+                        Instant prevEnd = bookSessions.get(i - 1).getEndTime();
+                        Instant currStart = bookSessions.get(i).getStartTime();
+                        if (prevEnd != null && currStart != null) {
+                            gaps.add((double) ChronoUnit.HOURS.between(prevEnd, currStart));
+                        }
+                    }
+
+                    double sessionAcceleration = linearRegressionSlope(durations);
+                    double gapReduction = gaps.size() >= 2 ? linearRegressionSlope(gaps) : 0.0;
+
+                    int totalSessions = bookSessions.size();
+                    int lastQuarterStart = (int) Math.floor(totalSessions * 0.75);
+                    double firstThreeQuartersAvg = durations.subList(0, lastQuarterStart).stream()
+                            .mapToDouble(Double::doubleValue).average().orElse(0);
+                    double lastQuarterAvg = durations.subList(lastQuarterStart, totalSessions).stream()
+                            .mapToDouble(Double::doubleValue).average().orElse(0);
+                    boolean finishBurst = lastQuarterAvg > firstThreeQuartersAvg;
+
+                    double accelScore = Math.min(1.0, Math.max(0.0, (sessionAcceleration + 50) / 100.0));
+                    double gapScore = Math.min(1.0, Math.max(0.0, (-gapReduction + 50) / 100.0));
+                    double burstScore = finishBurst ? 1.0 : 0.0;
+
+                    int gripScore = (int) Math.round(
+                            Math.min(100, Math.max(0, accelScore * 35 + gapScore * 35 + burstScore * 30)));
+
+                    double avgDuration = durations.stream().mapToDouble(Double::doubleValue).average().orElse(0);
+
+                    return PageTurnerScoreResponse.builder()
+                            .bookId(bookId)
+                            .bookTitle(first.getBookTitle())
+                            .categories(bookCategories.getOrDefault(bookId, List.of()))
+                            .pageCount(first.getPageCount())
+                            .personalRating(first.getPersonalRating())
+                            .gripScore(gripScore)
+                            .totalSessions((long) totalSessions)
+                            .avgSessionDurationSeconds(Math.round(avgDuration * 100.0) / 100.0)
+                            .sessionAcceleration(Math.round(sessionAcceleration * 100.0) / 100.0)
+                            .gapReduction(Math.round(gapReduction * 100.0) / 100.0)
+                            .finishBurst(finishBurst)
+                            .build();
+                })
+                .sorted(Comparator.comparingInt(PageTurnerScoreResponse::getGripScore).reversed())
+                .collect(Collectors.toList());
+    }
+
+    private static final int COMPLETION_RACE_BOOK_LIMIT = 10;
+
+    @Transactional(readOnly = true)
+    public List<CompletionRaceResponse> getCompletionRace(int year) {
+        BookLoreUser authenticatedUser = authenticationService.getAuthenticatedUser();
+        Long userId = authenticatedUser.getId();
+
+        var allSessions = readingSessionRepository.findCompletionRaceSessionsByUserAndYear(userId, year);
+
+        // Collect unique book IDs in order of appearance, take last N (most recently finished)
+        LinkedHashSet<Long> allBookIds = allSessions.stream()
+                .map(CompletionRaceSessionDto::getBookId)
+                .collect(Collectors.toCollection(LinkedHashSet::new));
+
+        Set<Long> limitedBookIds;
+        if (allBookIds.size() > COMPLETION_RACE_BOOK_LIMIT) {
+            limitedBookIds = allBookIds.stream()
+                    .skip(allBookIds.size() - COMPLETION_RACE_BOOK_LIMIT)
+                    .collect(Collectors.toSet());
+        } else {
+            limitedBookIds = allBookIds;
+        }
+
+        return allSessions.stream()
+                .filter(dto -> limitedBookIds.contains(dto.getBookId()))
+                .map(dto -> CompletionRaceResponse.builder()
+                        .bookId(dto.getBookId())
+                        .bookTitle(dto.getBookTitle())
+                        .sessionDate(dto.getSessionDate())
+                        .endProgress(dto.getEndProgress())
+                        .build())
+                .collect(Collectors.toList());
+    }
+
+    @Transactional(readOnly = true)
+    public List<ReadingSessionHeatmapResponse> getReadingDates() {
+        BookLoreUser authenticatedUser = authenticationService.getAuthenticatedUser();
+        Long userId = authenticatedUser.getId();
+
+        return readingSessionRepository.findAllSessionCountsByUser(userId)
+                .stream()
+                .map(dto -> ReadingSessionHeatmapResponse.builder()
+                        .date(dto.getDate())
+                        .count(dto.getCount())
+                        .build())
+                .collect(Collectors.toList());
+    }
+
+    private double linearRegressionSlope(List<Double> values) {
+        int n = values.size();
+        if (n < 2) return 0.0;
+
+        double sumX = 0, sumY = 0, sumXY = 0, sumX2 = 0;
+        for (int i = 0; i < n; i++) {
+            sumX += i;
+            sumY += values.get(i);
+            sumXY += i * values.get(i);
+            sumX2 += (double) i * i;
+        }
+
+        double denominator = n * sumX2 - sumX * sumX;
+        if (denominator == 0) return 0.0;
+
+        return (n * sumXY - sumX * sumY) / denominator;
+    }
 }