Gamifying Daily Habit Tracking with a Stock Market Engine

I built a mobile app that turns daily habit completion into a live stock market-like experience. The core is a Moving Average Model — instead of simple streak counting, your “performance index” fluctuates up or down based on whether today’s output beats or misses your 7-day rolling average. This creates authentic volatility: good days pump your index, bad days cause drawdowns, just like a real ticker. I’ll walk through the architecture - how the index is calculated, how chart scrubbing and real-time data point rendering works, how I structured persistent storage for historical navigation, and the glassmorphism UI system built on top of React Native. No pitch. Just the messy, interesting engineering decisions.