DropIn

Casual micro-plans for friends.
Share what you're already up to, and let friends drop in if they're free.

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Note: This is just a fun personal project; it's not actually a real/published app :)

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About

Making plans with busy friends usually means group chats, calendars, and a lot of "maybe next week." DropIn skips all that. Instead of planning an event, you post what you're already doing, like "Grabbing coffee at Starbucks" or "Studying at the library". Friends see it in a live feed and can tap I'm Coming! if they're free.

No pressure to reply and no awkward "no." Plans disappear on their own once they expire.

Screenshots

Features

Plans

• Live feed of friends' plans, updated in real time with Firestore
• Right now or plan ahead. Post something that's happening now, or schedule it to start later. Upcoming plans show in a separate "Starting Soon" section
• Auto-expiring. Each plan has a timer and disappears when it ends
• Categories (coffee, study, walk, food), each with its own icon and card color
• Search through what friends are up to

Friends

• Every account gets a short friend code (like K7Q-2MX) with a QR code to scan in person
• Add friends by typing a code, scanning their QR (VisionKit), or sharing your code by text
• Friend requests with accept, decline, cancel, and remove
• The feed and the "Choose friends" picker only include your friends

Safety & account control

• Block anyone from their plan, nudge, friend request, or your friends list. Blocking unfriends you, hides you from each other both ways, and stops new requests. Unblock anytime.
• Report a person, plan, or nudge with a reason. Reports go to a private, write-only collection for review.
• Delete account (required by the App Store): confirms your password, then removes your profile, plans, friendships, nudges, and blocks before deleting the login.
• All of this is also enforced by Firestore security rules, not just the app.

Who's Down? nudges

Not ready to post to everyone? Privately ping up to 4 friends to see if anyone's nearby. They tap I'm down or Not nearby, you see who's in, and the nudge disappears after 30 minutes.

Vibes

Every plan says how you want company, not just where you are:

• Open Door: drop in anytime
• Quiet: sit nearby and bring a laptop, but mostly silent
• Limited Seats: "only 2 open seats at my table!" The plan locks automatically once it's full, and reopens if someone gives up their seat

Seats are claimed with a Firestore transaction, so if two friends tap the last seat at the same moment, only one gets it.

✨ AI autofill (on-device)

Type one casual sentence and DropIn fills in the whole plan:

You type	DropIn fills in
dinner at chipotle, only have room for 2	Food · Limited Seats (2) · starts now
library grind till 6, quiet pls	Study · Quiet · lasts until 6:00
walk in 30 min for an hour	Walk · starts in 30 min · lasts 1 hour

• Runs on Apple Intelligence with Apple's Foundation Models framework: free, works offline, and nothing you type leaves your phone
• Uses guided generation (@Generable), so the model returns a typed Swift struct with limited choices instead of free text
• A rule-based parser double-checks exact times ("till 6") and seat counts ("room for 2"), since small models can be off with clock math
• On iPhones without Apple Intelligence, the same parser fills in the plan on its own, so autofill works everywhere

Dropping in

• The button matches the vibe: I'm Coming!, I'll Sit Nearby, or Grab a Seat (and Plan's Full once it locks). Friends can undo with Can't Make It or Give Up Seat
• The person who made the plan can't drop in on their own plan. They get a "who's dropping in" list instead

Privacy

• Choose friends. Share a plan with everyone, or only with selected friends
• Pause. Hide your plan from everyone without deleting it and without notifying anyone

Avatars

• Build-your-own avatar with skin tone, face shape, build, hair, facial hair, eyes, brows, mouth, outfit, hats, glasses, earrings, and background
• Every option is open to everyone, with no gender step
• Avatars are drawn in code with SwiftUI Canvas, so there are no image assets and they stay sharp at any size
• Includes shuffle, reset, and quick-start looks

Tech Stack

Language	Swift
UI	SwiftUI (@Observable, Canvas)
Architecture	MVVM
Backend	Firebase Authentication (email/password) and Cloud Firestore
Dependencies	Firebase iOS SDK via Swift Package Manager
On-device AI	Foundation Models framework (Apple Intelligence), guided generation with @Generable
Security	Firestore security rules (firestore.rules)
Camera	VisionKit DataScannerViewController for QR scanning, Core Image for QR generation
Testing	Swift Testing (unit tests), GitHub Actions (runs on every push)
Notifications	UserNotifications (local notifications for now)
Fonts	Raleway (logo) and Open Sans (everything else)

Project Structure

DropIn/
├── App/
│   └── DropInApp.swift # entry point, switches between Login and Home
├── Models/
│   ├── User.swift # user profile (Firestore "users")
│   ├── Status.swift # A plan (Firestore "statuses")
│   ├── PlanRules.swift # vibes + who can join (tested)
│   ├── PlanTextParser.swift # rule-based autofill (tested)
│   ├── Friendship.swift # friend requests + friend codes (tested)
│   ├── Nudge.swift # Who's Down? nudges (tested)
│   ├── Safety.swift # blocks + reports (tested)
│   ├── AvatarConfig.swift # every avatar choice + save format
│   └── MockData.swift # sample data for Xcode Previews
├── ViewModels/
│   ├── AuthViewModel.swift # log in, sign up, password reset, session
│   └── HomeViewModel.swift # feed, RSVP transactions, friends, nudges
├── Views/
│   ├── Auth/LoginView.swift
│   ├── Home/
│   │   ├── HomeFeedView.swift # live feed + search
│   │   └── StatusRowView.swift # plan card + "who's dropping in" sheet
│   ├── Component/
│   │   ├── CreateStatusSheet.swift # "What are you up to?"
│   │   └── AvatarView.swift
│   ├── Avatar/
│   │   ├── AvatarBuilderView.swift # avatar customization screen
│   │   └── AvatarRenderer.swift # draws avatars w/ Canvas
│   ├── Friends/
│   │   ├── FriendsView.swift # your code + QR, requests, friends list
│   │   └── QRScannerView.swift # camera QR scanner
│   ├── Nudges/
│   │   ├── NudgeSheet.swift # send a Who's Down? nudge
│   │   └── NudgeCardView.swift # nudge card in the feed
│   ├── Safety/ReportSheet.swift # report a person, plan, or nudge
│   └── Profile/
│       ├── ProfileView.swift
│       └── DeleteAccountView.swift
├── Services/
│   ├── PlanAssistant.swift # on-device AI autofill
│   ├── FirebaseBootstrap.swift
│   ├── FirestoreService.swift
│   └── NotificationService.swift
├── Theme/
│   ├── Theme.swift # Colors, fonts, spacing, shared styles
│   └── AppBackground.swift
└── Resources/Fonts/
DropInTests/ # Swift Testing unit tests
.github/workflows/tests.yml # runs the tests on every push
firestore.rules # server-side security rules

Getting Started

Requirements

• A Mac with a recent version of Xcode
• A free Firebase account

1. Clone the repo

git clone https://github.com/<your-username>/DropIn.git
cd DropIn
open DropIn.xcodeproj

Xcode downloads the Firebase packages automatically the first time you open the project.

2. Set up Firebase

1. Create a new project in the Firebase console.
2. Add an iOS app using the same bundle identifier as the Xcode project.
3. Download GoogleService-Info.plist and put it in the DropIn/ app folder (next to Assets.xcassets). It's in .gitignore, so it won't be committed.
4. Under Authentication → Sign-in method, turn on Email/Password.
5. Under Firestore Database, create a database.

3. Add the security rules

In the Firebase console, open Firestore Database → Rules, paste the contents of firestore.rules, and tap Publish.

4. Run

Choose an iPhone simulator and press ⌘R.

On the login screen, enter a username, email, and password, then tap Get Started. If there's no account for that email yet, one is created for you.

AI autofill needs a device or simulator with Apple Intelligence turned on (iPhone 15 Pro or newer, or a Mac with Apple silicon running the simulator). Everywhere else, autofill uses the rule-based parser.

Running Tests

The unit tests cover RSVP rules (seat limits, expired plans, hosts can't join), plan visibility, the autofill parser, avatar saving, friend codes and requests, nudge limits, and blocking. They don't need Firebase.

• In Xcode: press ⌘U
• From Terminal:

  xcodebuild test -project DropIn.xcodeproj -scheme DropIn \
    -destination 'platform=iOS Simulator,name=iPhone 17' \
    -only-testing:DropInTests CODE_SIGNING_ALLOWED=NO

GitHub Actions runs the same tests on every push and pull request. See the Actions tab.

Design

Color	Hex	Used for
Warm Coral	#E2735A	Main buttons and highlights
Indigo Blue	#23345C	Headings and text
Cream	#FFFCFA	Backgrounds
Soft Sage Green	#AFC2A5	Cards and accents
Pale Pink	#F2C9CE	Cards and accents

Colors, fonts, and spacing all live in Theme/Theme.swift, so every screen uses the same values.

Roadmap

• Push notifications for new plans, friend requests, and nudges (needs Firebase Cloud Functions + Apple Push Notification service)
• Server-side plan privacy: query only friends' plans so private plans are never downloaded by others
• Home screen widgets
• Haptic feedback on "I'm Coming!"

Credits

• Fonts: Raleway and Open Sans, both under the SIL Open Font License. License files are in Resources/Fonts.
• Built with Firebase.