From 85dd10640324dc7682d397d6c35e89383dba488a Mon Sep 17 00:00:00 2001
From: Cho Young-Hwi <cyh76507707@gmail.com>
Date: Tue, 21 Apr 2026 19:00:53 +0900
Subject: [PATCH] [#916] Fix streak tier drop logic to drop to previous tier
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dropOneTier was snapping to the current tier threshold instead of dropping
to the one below. E.g. streak 50 stayed at 50 instead of dropping to 30.

Fixed: streak now drops to previous tier (100→50, 50→30, 30→14, 14→7, 7→0).

Fixes #916

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 lib/airdrop/streak.ts                | 8 ++++----
 package.json                         | 2 +-
 src/app/api/airdrop/checkin/route.ts | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/airdrop/streak.ts b/lib/airdrop/streak.ts
index 87202c84..506a23a4 100644
--- a/lib/airdrop/streak.ts
+++ b/lib/airdrop/streak.ts
@@ -25,14 +25,14 @@ export function getStreakBoost(currentStreak: number): number {
 
 /**
  * Drop one tier after a missed day. Returns the new streak value.
- * Per spec: streak snaps down to the current tier's threshold.
- *   100+ → 100, 50-99 → 50, 30-49 → 30, 14-29 → 14, 7-13 → 7, 1-6 → 0
+ * Per spec: streak drops to the previous tier's threshold.
+ *   100+ → 50, 50-99 → 30, 30-49 → 14, 14-29 → 7, 7-13 → 0, 1-6 → 0
  */
 export function dropOneTier(streak: number): number {
-  // Find the current tier and snap to its threshold
+  // Find the current tier and drop to the one below it
   for (let i = TIER_THRESHOLDS.length - 1; i >= 0; i--) {
     if (streak >= TIER_THRESHOLDS[i]) {
-      return TIER_THRESHOLDS[i];
+      return i > 0 ? TIER_THRESHOLDS[i - 1] : 0;
     }
   }
   return 0;
diff --git a/package.json b/package.json
index d69bab56..00464f7f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "plotlink",
-  "version": "0.1.29",
+  "version": "0.1.30",
   "private": true,
   "workspaces": [
     "packages/*"
diff --git a/src/app/api/airdrop/checkin/route.ts b/src/app/api/airdrop/checkin/route.ts
index 53825bec..5d7d8a80 100644
--- a/src/app/api/airdrop/checkin/route.ts
+++ b/src/app/api/airdrop/checkin/route.ts
@@ -102,7 +102,7 @@ export async function POST(req: Request) {
         // Consecutive day — increment streak
         newStreak = existing.current_streak + 1;
       } else {
-        // Missed 2+ days — snap to current tier threshold
+        // Missed 2+ days — drop to previous tier threshold
         newStreak = dropOneTier(existing.current_streak);
       }
     } else {