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+# Rewards System
+
+This doc provides a comprehensive guide to the rewards system for developers maintaining the codebase.
+
+## Overview
+
+The rewards system manages loyalty benefits for Scandic Hotels members. It combines data from two sources:
+
+1. **Scandic Profile API** - Provides reward availability, states, and coupon codes
+2. **Contentstack CMS** - Provides reward content (labels, descriptions, redeem instructions)
+
+Rewards are tied to **membership levels** (L1-L7, called "Friends") and come in different **types** (Tier, Surprise, Campaign, Member-voucher).
+
+````
+
+### Data Merging Process
+
+Rewards are matched between API and CMS using the `reward_id` field:
+
+```typescript
+// From query.ts - merging API and CMS data
+const rewards: BaseReward[] = cmsRewards.map((cmsReward) => {
+  const apiReward = redeemableRewards.find(
+    ({ rewardId }) => rewardId === cmsReward.reward_id
+  )!
+  return {
+    ...apiReward,  // API data: status, coupon codes, redeem location
+    ...cmsReward,  // CMS data: label, description, redeem_description
+  }
+})
+````
+
+## Reward Types
+
+### 1. Tier Rewards (`rewardType: "Tier"`)
+
+Permanent benefits tied to membership level. These are always available once a member reaches the required tier.
+
+**Characteristics:**
+
+- Linked to `rewardTierLevel` (e.g., "L1", "L2")
+- No coupon codes required for most
+- Examples: 10% food discount, early check-in, late checkout
+
+**Redeem behavior:**
+
+- `On-site`: Show membership number at hotel
+- `Non-redeemable`: Display-only benefits (e.g., earn rate bonuses)
+
+### 2. Surprise Rewards (`rewardType: "Surprise"`)
+
+Special rewards that appear as wrapped gifts and need to be "unwrapped" before use.
+
+**Characteristics:**
+
+- Part of `coupons` array in API response
+- Have `unwrapped: boolean` flag on each coupon
+- Must call `unwrap` mutation before becoming redeemable
+- After unwrapping, appear in regular rewards list
+
+**Flow:**
+
+1. User sees surprise modal with wrapped gift
+2. User clicks to reveal/unwrap
+3. Frontend calls `rewards.unwrap` mutation
+4. Surprise moves to current rewards
+
+### 3. Campaign Rewards (`rewardType: "Campaign"`)
+
+Promotional rewards with promo codes for online use.
+
+**Characteristics:**
+
+- Part of `coupons` array
+- Have `couponCode` for redemption
+- Typically redeemed online
+- May have expiration dates
+
+**Redeem behavior:**
+
+- Display promo code with copy-to-clipboard functionality
+
+### 4. Member Voucher (`rewardType: "Member-voucher"`)
+
+Voucher-based rewards similar to campaigns.
+
+**Characteristics:**
+
+- Part of `coupons` array
+- Have coupon codes
+- Similar flow to Campaign rewards
+
+---
+
+## Coupon States & Redemption
+
+### Coupon States
+
+| State      | Description                                    | Redeemable |
+| ---------- | ---------------------------------------------- | ---------- |
+| `claimed`  | Coupon has been claimed by user                | Yes        |
+| `viewed`   | Coupon has been viewed (schema only, not used) | Yes        |
+| `redeemed` | Coupon has been used                           | No         |
+
+**Note:** Only `redeemed` state is actively filtered out in business logic. Both `claimed` and `viewed` are treated as redeemable.
+
+### Redeem Locations
+
+| Location         | Description                       | UI Behavior                   |
+| ---------------- | --------------------------------- | ----------------------------- |
+| `On-site`        | Redeem at hotel (show to staff)   | Shows membership number badge |
+| `Online`         | Redeem digitally with promo code  | Shows copy-to-clipboard       |
+| `Non-redeemable` | Display-only (automatic benefits) | No redeem button, info only   |