feat: integrate points with lottery participation

backend/src/main/java/com/openisle/controller/PostController.java

@@ -41,7 +41,8 @@ public class PostController {
         Post post = postService.createPost(auth.getName(), req.getCategoryId(),
                 req.getTitle(), req.getContent(), req.getTagIds(),
                 req.getType(), req.getPrizeDescription(), req.getPrizeIcon(),
-                req.getPrizeCount(), req.getStartTime(), req.getEndTime());
+                req.getPrizeCount(), req.getPointCost(),
+                req.getStartTime(), req.getEndTime());
         draftService.deleteDraft(auth.getName());
         PostDetailDto dto = postMapper.toDetailDto(post, auth.getName());
         dto.setReward(levelService.awardForPost(auth.getName()));

backend/src/main/java/com/openisle/dto/LotteryDto.java

@@ -10,6 +10,7 @@ public class LotteryDto {
     private String prizeDescription;
     private String prizeIcon;
     private int prizeCount;
+    private int pointCost;
     private LocalDateTime startTime;
     private LocalDateTime endTime;
     private List<AuthorDto> participants;

backend/src/main/java/com/openisle/dto/PostRequest.java

@@ -23,6 +23,7 @@ public class PostRequest {
     private String prizeDescription;
     private String prizeIcon;
     private Integer prizeCount;
+    private Integer pointCost;
     private LocalDateTime startTime;
     private LocalDateTime endTime;
 }

backend/src/main/java/com/openisle/mapper/PostMapper.java

@@ -86,6 +86,7 @@ public class PostMapper {
             l.setPrizeDescription(lp.getPrizeDescription());
             l.setPrizeIcon(lp.getPrizeIcon());
             l.setPrizeCount(lp.getPrizeCount());
+            l.setPointCost(lp.getPointCost());
             l.setStartTime(lp.getStartTime());
             l.setEndTime(lp.getEndTime());
             l.setParticipants(lp.getParticipants().stream().map(userMapper::toAuthorDto).collect(Collectors.toList()));

backend/src/main/java/com/openisle/model/LotteryPost.java

@@ -26,6 +26,9 @@ public class LotteryPost extends Post {
     @Column(nullable = false)
     private int prizeCount;
 
+    @Column(nullable = false)
+    private int pointCost;
+
     @Column
     private LocalDateTime startTime;
 

backend/src/main/java/com/openisle/model/PointHistoryType.java

@@ -8,5 +8,7 @@ public enum PointHistoryType {
     INVITE,
     FEATURE,
     SYSTEM_ONLINE,
-    REDEEM
+    REDEEM,
+    LOTTERY_JOIN,
+    LOTTERY_REWARD
 }

backend/src/main/java/com/openisle/service/PointService.java

@@ -2,6 +2,7 @@ package com.openisle.service;
 
 import com.openisle.model.*;
 import com.openisle.repository.*;
+import com.openisle.exception.FieldException;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
@@ -39,6 +40,17 @@ public class PointService {
         return addPoint(user, 500, PointHistoryType.FEATURE, post, null, null);
     }
 
+    public void processLotteryJoin(User participant, LotteryPost post) {
+        int cost = post.getPointCost();
+        if (cost > 0) {
+            if (participant.getPoint() < cost) {
+                throw new FieldException("point", "积分不足");
+            }
+            addPoint(participant, -cost, PointHistoryType.LOTTERY_JOIN, post, null, post.getAuthor());
+            addPoint(post.getAuthor(), cost, PointHistoryType.LOTTERY_REWARD, post, null, participant);
+        }
+    }
+
     private PointLog getTodayLog(User user) {
         LocalDate today = LocalDate.now();
         return pointLogRepository.findByUserAndLogDate(user, today)

backend/src/main/java/com/openisle/service/PostService.java

@@ -164,6 +164,7 @@ public class PostService {
                            String prizeDescription,
                            String prizeIcon,
                            Integer prizeCount,
+                           Integer pointCost,
                            LocalDateTime startTime,
                            LocalDateTime endTime) {
         long recent = postRepository.countByAuthorAfter(username,
@@ -188,10 +189,14 @@ public class PostService {
         PostType actualType = type != null ? type : PostType.NORMAL;
         Post post;
         if (actualType == PostType.LOTTERY) {
+            if (pointCost != null && (pointCost < 0 || pointCost > 100)) {
+                throw new IllegalArgumentException("pointCost must be between 0 and 100");
+            }
             LotteryPost lp = new LotteryPost();
             lp.setPrizeDescription(prizeDescription);
             lp.setPrizeIcon(prizeIcon);
             lp.setPrizeCount(prizeCount != null ? prizeCount : 0);
+            lp.setPointCost(pointCost != null ? pointCost : 0);
             lp.setStartTime(startTime);
             lp.setEndTime(endTime);
             post = lp;
@@ -250,8 +255,10 @@ public class PostService {
                 .orElseThrow(() -> new com.openisle.exception.NotFoundException("Post not found"));
         User user = userRepository.findByUsername(username)
                 .orElseThrow(() -> new com.openisle.exception.NotFoundException("User not found"));
-        post.getParticipants().add(user);
-        lotteryPostRepository.save(post);
+        if (post.getParticipants().add(user)) {
+            pointService.processLotteryJoin(user, post);
+            lotteryPostRepository.save(post);
+        }
     }
 
     @Transactional