The Big Mac Index (BMI)

An iOS app inspired by The Economist's Big Mac Index — a crowdsourced tracker where users report the cost, quality, and context of McDonald's Big Mac meals around the world.

Website: https://bmi.bysam.fun
Mac setup checklist: docs/SETUP_CHECKLIST.md
App Store copy templates: docs/APP_STORE.md

Features

• Sign in with Apple with unique username registration
• CloudKit public index — reports, photos, profiles, and friend links sync globally
• Live exchange rates — Frankfurter API (current + historical per report date)
• Today's dollars — US CPI-U inflation adjustment (live via FRED when API key configured)
• Friend linking — search by username, accept requests, push notifications for incoming requests
• Activity notifications — push + in-app inbox when friends post, tag you, or react to your reports
• Reactions — emoji reactions on public reports (❤️ 👍 🔥 😋 🍔)
• Public profiles — tap any author or friend to view their reports; share profile/report links
• Universal links — https://bmi.bysam.fun/report/… and /u/username open in the app
• Account deletion — remove CloudKit data from Settings
• Meal reporting — price, rating, review, photos, location type, GPS, friend tags
• Feed, map, stats — normalized global comparisons

Requirements

• Xcode 15+, iOS 17+
• Apple Developer account (Sign in with Apple, CloudKit, Push Notifications, Associated Domains)
• iCloud signed in on device/simulator

Getting Started

1. Open BMI/BMI.xcodeproj
2. Set your Development Team in Signing & Capabilities
3. Enable capabilities: Sign in with Apple, iCloud (CloudKit), Push Notifications, Associated Domains (applinks:bmi.bysam.fun)
4. CloudKit container: iCloud.com.bigmacindex.bmi
5. Deploy CloudKit schema record types in CloudKit Dashboard:
   • PublicUser (includes normalizedUsername)
   • PublicReport (includes photoCount, authorAppleUserID queryable)
   • PublicReportPhoto (includes imageAsset CKAsset)
   • FriendConnection
   • UserNotification (activity inbox records)
   • ReportReaction
6. Replace TEAMID in docs/.well-known/apple-app-site-association with your Apple Team ID
7. Enable GitHub Pages from /docs and point DNS bmi.bysam.fun → svickars.github.io (see checklist)
8. Optional: add your FRED API key to Info.plist as FRED_API_KEY
9. Build and run on a physical iPhone for best CloudKit/push results

Full step-by-step: docs/SETUP_CHECKLIST.md

Architecture

Layer	Technology
Local cache	SwiftData
Global sync	CloudKit Public Database
Photos	CKAsset on PublicReportPhoto records (JPEG compressed)
FX	Frankfurter API
Inflation	FRED CPI-U (live) + bundled fallback
Friend push	CloudKit subscriptions + APNs
Activity push	UserNotification records + per-user CloudKit subscriptions
Reactions	ReportReaction records synced via CloudKit public database
Deep links	Universal links via bmi.bysam.fun + in-app AppNavigationRouter
Auth	Sign in with Apple + unique username

Key flows

Photo sync

Reports upload metadata to PublicReport. Each photo becomes a PublicReportPhoto with a compressed JPEG CKAsset. Other users download photos during public sync.

Username uniqueness

After Sign in with Apple, users choose a username checked against CloudKit normalizedUsername before joining the public index.

Friend request notifications

CloudKit query subscriptions notify recipients when a pending friend request arrives. The app syncs connections and posts a local notification.

Activity notifications

When a friend publishes a public report, tags you, or reacts to your report, the app writes a UserNotification record in CloudKit for each recipient. A per-user CloudKit subscription triggers a silent push; the app fetches the record, caches it in SwiftData, and shows a local alert (respecting Settings toggles). Profile → Notifications shows the full inbox with links to each report.

Reactions

On any public report detail screen, signed-in users can react with emoji. Reactions sync globally via ReportReaction records; reacting to someone else's report notifies the author.

Public profiles & sharing

Tap a reporter on any card or report detail to open their public profile. Share buttons copy universal links:

• Report: https://bmi.bysam.fun/report/{uuid}
• Profile: https://bmi.bysam.fun/u/{username}

Today's dollars

1. Historical FX converts local price → USD at report date (usdAtReportDate)
2. CPI inflation adjusts USD to today's purchasing power
3. Live FX converts to viewer's comparison currency

Settings

Profile → Currency & Sync Settings:

• Device locale vs custom comparison currency
• Today's dollars toggle
• CloudKit sync toggle + manual sync
• Activity notification toggles (friend posts, tags, reactions)
• Delete account
• Data source info (Frankfurter, FRED/bundled CPI)

Profile → Notifications:

• In-app inbox with unread badge
• Tap through to the related report

Privacy

• Location, Photo Library, Sign in with Apple, iCloud/CloudKit, Push Notifications
• Privacy policy: https://bmi.bysam.fun/privacy.html

License

MIT