COUPON CODES INITITIALIZED

backend/src/main/java/com/rit/canteen/sales/controller/CouponController.java

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+package com.rit.canteen.sales.controller;
+
+import com.rit.canteen.sales.model.CouponCode;
+import com.rit.canteen.sales.repository.CouponRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+@RestController
+@RequestMapping("/api/coupons")
+public class CouponController {
+
+    @Autowired
+    private CouponRepository couponRepository;
+
+    @Autowired
+    private com.rit.canteen.sales.repository.CouponRedemptionRepository redemptionRepository;
+
+    @Autowired
+    private com.rit.canteen.sales.service.TokenService tokenService;
+
+    @GetMapping
+    public List<CouponCode> getAllCoupons() {
+        return couponRepository.findAll();
+    }
+
+    @PostMapping("/redeem")
+    @org.springframework.transaction.annotation.Transactional
+    public ResponseEntity<?> redeemCoupon(@RequestBody Map<String, Object> request) {
+        String code = ((String) request.get("code")).toUpperCase().trim();
+        Long userId = Long.valueOf(request.get("userId").toString());
+
+        Optional<CouponCode> couponOpt = couponRepository.findByCode(code);
+        if (couponOpt.isEmpty()) {
+            return ResponseEntity.status(404).body(Map.of("success", false, "message", "Invalid coupon code"));
+        }
+
+        CouponCode coupon = couponOpt.get();
+
+        // 1. Basic Validations
+        if (!coupon.getIsActive()) {
+            return ResponseEntity.status(400).body(Map.of("success", false, "message", "Coupon is currently inactive"));
+        }
+
+        if (java.time.LocalDateTime.now().isAfter(coupon.getExpiryDate())) {
+            return ResponseEntity.status(400).body(Map.of("success", false, "message", "Coupon has expired"));
+        }
+
+        // 2. Global Usage Limit
+        if (coupon.getCurrentClaims() >= coupon.getMaxClaims()) {
+            return ResponseEntity.status(400).body(Map.of("success", false, "message", "Coupon claim limit reached"));
+        }
+
+        // 3. Per-User Limit (Single redemption per code)
+        if (redemptionRepository.existsByUserIdAndCouponId(userId, coupon.getId())) {
+            return ResponseEntity.status(400).body(Map.of("success", false, "message", "You have already redeemed this code"));
+        }
+
+        // 4. Execution
+        try {
+            // Update coupon stats
+            coupon.setCurrentClaims(coupon.getCurrentClaims() + 1);
+            couponRepository.save(coupon);
+
+            // Credit tokens
+            tokenService.topUp(userId, coupon.getRewardAmount(), "COUPON-" + code);
+
+            // Log redemption
+            redemptionRepository.save(new com.rit.canteen.sales.model.CouponRedemption(userId, coupon.getId()));
+
+            return ResponseEntity.ok(Map.of(
+                "success", true, 
+                "message", "Successfully redeemed " + coupon.getRewardAmount() + " Ritz tokens!",
+                "rewardAmount", coupon.getRewardAmount()
+            ));
+        } catch (Exception e) {
+            return ResponseEntity.status(500).body(Map.of("success", false, "message", "Redemption failed: " + e.getMessage()));
+        }
+    }
+
+    @PostMapping
+    public ResponseEntity<?> createCoupon(@RequestBody CouponCode coupon) {
+        if (couponRepository.findByCode(coupon.getCode()).isPresent()) {
+            return ResponseEntity.badRequest().body("Coupon code already exists");
+        }
+        return ResponseEntity.ok(couponRepository.save(coupon));
+    }
+
+    @DeleteMapping("/{id}")
+    public ResponseEntity<?> deleteCoupon(@PathVariable Long id) {
+        couponRepository.deleteById(id);
+        return ResponseEntity.ok().build();
+    }
+
+    @PatchMapping("/{id}/toggle")
+    public ResponseEntity<?> toggleStatus(@PathVariable Long id) {
+        Optional<CouponCode> couponOpt = couponRepository.findById(id);
+        if (couponOpt.isPresent()) {
+            CouponCode coupon = couponOpt.get();
+            coupon.setIsActive(!coupon.getIsActive());
+            return ResponseEntity.ok(couponRepository.save(coupon));
+        }
+        return ResponseEntity.notFound().build();
+    }
+}

backend/src/main/java/com/rit/canteen/sales/model/CouponCode.java

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+package com.rit.canteen.sales.model;
+
+import jakarta.persistence.*;
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import com.fasterxml.jackson.annotation.JsonFormat;
+
+
+@Entity
+@Table(name = "coupon_codes")
+public class CouponCode {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(nullable = false, unique = true)
+    private String code;
+
+    @Column(nullable = false)
+    private BigDecimal rewardAmount;
+
+    @Column(nullable = false)
+    @JsonFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'")
+    private LocalDateTime expiryDate;
+
+
+    @Column(nullable = false)
+    private Integer maxClaims;
+
+    @Column(nullable = false)
+    private Integer currentClaims = 0;
+
+    @Column(nullable = false)
+    private Boolean isActive = true;
+
+    @Column(nullable = true)
+    private String description;
+
+    @Column(nullable = false, updatable = false)
+    @JsonFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'")
+    private LocalDateTime createdAt;
+
+
+    public CouponCode() {}
+
+    @PrePersist
+    protected void onCreate() {
+        if (createdAt == null) createdAt = LocalDateTime.now();
+        if (currentClaims == null) currentClaims = 0;
+        if (isActive == null) isActive = true;
+        if (code != null) code = code.toUpperCase().trim();
+    }
+
+    // Getters and Setters
+    public Long getId() { return id; }
+    public void setId(Long id) { this.id = id; }
+
+    public String getCode() { return code; }
+    public void setCode(String code) { this.code = code; }
+
+    public BigDecimal getRewardAmount() { return rewardAmount; }
+    public void setRewardAmount(BigDecimal rewardAmount) { this.rewardAmount = rewardAmount; }
+
+    public LocalDateTime getExpiryDate() { return expiryDate; }
+    public void setExpiryDate(LocalDateTime expiryDate) { this.expiryDate = expiryDate; }
+
+    public Integer getMaxClaims() { return maxClaims; }
+    public void setMaxClaims(Integer maxClaims) { this.maxClaims = maxClaims; }
+
+    public Integer getCurrentClaims() { return currentClaims; }
+    public void setCurrentClaims(Integer currentClaims) { this.currentClaims = currentClaims; }
+
+    public Boolean getIsActive() { return isActive; }
+    public void setIsActive(Boolean active) { isActive = active; }
+
+    public String getDescription() { return description; }
+    public void setDescription(String description) { this.description = description; }
+
+    public LocalDateTime getCreatedAt() { return createdAt; }
+    public void setCreatedAt(LocalDateTime createdAt) { this.createdAt = createdAt; }
+}

backend/src/main/java/com/rit/canteen/sales/model/CouponRedemption.java

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+package com.rit.canteen.sales.model;
+
+import jakarta.persistence.*;
+import java.time.LocalDateTime;
+
+@Entity
+@Table(name = "coupon_redemptions", uniqueConstraints = {
+    @UniqueConstraint(columnNames = {"user_id", "coupon_id"})
+})
+public class CouponRedemption {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(name = "user_id", nullable = false)
+    private Long userId;
+
+    @Column(name = "coupon_id", nullable = false)
+    private Long couponId;
+
+    @Column(nullable = false)
+    private LocalDateTime redeemedAt;
+
+    public CouponRedemption() {}
+
+    public CouponRedemption(Long userId, Long couponId) {
+        this.userId = userId;
+        this.couponId = couponId;
+        this.redeemedAt = LocalDateTime.now();
+    }
+
+    public Long getId() { return id; }
+    public void setId(Long id) { this.id = id; }
+
+    public Long getUserId() { return userId; }
+    public void setUserId(Long userId) { this.userId = userId; }
+
+    public Long getCouponId() { return couponId; }
+    public void setCouponId(Long couponId) { this.couponId = couponId; }
+
+    public LocalDateTime getRedeemedAt() { return redeemedAt; }
+    public void setRedeemedAt(LocalDateTime redeemedAt) { this.redeemedAt = redeemedAt; }
+}

backend/src/main/java/com/rit/canteen/sales/repository/CouponRedemptionRepository.java

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+package com.rit.canteen.sales.repository;
+
+import com.rit.canteen.sales.model.CouponRedemption;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+import java.util.Optional;
+
+@Repository
+public interface CouponRedemptionRepository extends JpaRepository<CouponRedemption, Long> {
+    Optional<CouponRedemption> findByUserIdAndCouponId(Long userId, Long couponId);
+    boolean existsByUserIdAndCouponId(Long userId, Long couponId);
+}

backend/src/main/java/com/rit/canteen/sales/repository/CouponRepository.java

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+package com.rit.canteen.sales.repository;
+
+import com.rit.canteen.sales.model.CouponCode;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+import java.util.Optional;
+
+@Repository
+public interface CouponRepository extends JpaRepository<CouponCode, Long> {
+    Optional<CouponCode> findByCode(String code);
+}