TrainStudent

A production-ready Android + Go backend application for finding student train discounts across UK train operators.

Project Structure

trainstudent/
├── android/                          # Android app (Kotlin + Jetpack Compose)
│   ├── app/
│   │   ├── build.gradle.kts          # Dependencies: Compose, Hilt, Room, Retrofit
│   │   └── src/main/
│   │       ├── AndroidManifest.xml   # Permissions, activities
│   │       └── java/com/trainstudent/
│   │           ├── TrainStudentApp.kt        # @HiltAndroidApp
│   │           ├── di/
│   │           │   ├── AppModule.kt          # Room, Voice handlers
│   │           │   └── NetworkModule.kt      # Retrofit, OkHttp
│   │           ├── model/
│   │           │   ├── BookingPlan.kt        # NetCost, BookingAction
│   │           │   ├── TrainService.kt       # Live train data
│   │           │   ├── TravelIntent.kt       # ParsedStation, ParsedDateTime
│   │           │   └── UserProfile.kt        # Railcard, verification
│   │           ├── network/
│   │           │   └── TrainStudentApi.kt    # Retrofit interface
│   │           ├── repository/
│   │           │   └── TrainStudentRepository.kt
│   │           ├── data/
│   │           │   └── VoiceMetricsDatabase.kt # Room DB for metrics
│   │           ├── voice/
│   │           │   ├── VoiceInputHandler.kt  # Interface
│   │           │   ├── SpeechRecognizerHandler.kt  # Android STT
│   │           │   ├── CactusLlmHandler.kt   # Cactus 7B/13B
│   │           │   ├── CactusModelDownloader.kt    # DownloadManager
│   │           │   ├── DownloadCompleteReceiver.kt
│   │           │   ├── StationMatcher.kt     # Fuzzy + Soundex
│   │           │   ├── TimeParser.kt         # NLU time parsing
│   │           │   └── VoiceMetricsCollector.kt
│   │           └── ui/
│   │               ├── MainActivity.kt       # Navigation host
│   │               ├── theme/
│   │               │   ├── Theme.kt
│   │               │   └── Type.kt
│   │               ├── save/
│   │               │   ├── SaveMoneyScreen.kt
│   │               │   └── SaveMoneyViewModel.kt
│   │               ├── live/
│   │               │   ├── LiveTrainsScreen.kt
│   │               │   └── LiveTrainsViewModel.kt
│   │               ├── offers/
│   │               │   ├── OffersScreen.kt
│   │               │   └── OffersViewModel.kt
│   │               └── components/
│   │                   ├── AnimatedInputChip.kt
│   │                   ├── BookingPlanCard.kt
│   │                   ├── TimePickerBottomSheet.kt
│   │                   ├── StationPickerDialog.kt
│   │                   └── SettingsBottomSheet.kt
│   ├── build.gradle.kts              # Root project config
│   ├── settings.gradle.kts
│   └── gradle/wrapper/
│       └── gradle-wrapper.properties
│
├── backend/                          # Go backend (Fiber)
│   ├── main.go                       # Server entry, routes
│   ├── go.mod                        # Module definition
│   ├── handlers/
│   │   ├── discount.go               # POST /api/search
│   │   ├── codes.go                  # POST /api/codes/northern
│   │   ├── grandcentral.go           # POST /api/codes/grandcentral
│   │   ├── offers.go                 # GET /api/offers
│   │   ├── avanti.go                 # POST /api/avanti/search
│   │   └── live_trains.go            # GET /api/trains/live
│   ├── services/
│   │   ├── northern/
│   │   │   └── code_generator.go     # Salesforce Aura flow
│   │   ├── avanti/
│   │   │   └── avanti_client.go      # Token scraper + UNiDAYS search
│   │   ├── grandcentral/
│   │   │   └── student_discount.go   # .ac.uk email verification
│   │   └── gmail/
│   │       └── oauth_poller.go       # Gmail API code extraction
│   └── convex/
│       ├── schema.ts                 # Convex tables
│       └── queries.ts                # Convex functions
│
└── README.md                         # This file

Features

Voice Input

• Dual Provider Support: Switch between Android SpeechRecognizer and Cactus LLM (7B/13B models)
• Live Correction: Tappable chips for accent tolerance with 300ms debounce
• Metrics Collection: Room DB tracks latency, correction count, battery drain

Operator Integrations

1. Northern Railway (50% Discount)

   • Salesforce Aura flow submission
   • Gmail API polling for code extraction
   • Code expires at 23:59 same day

2. Avanti West Coast (UNiDAYS)

   • Server-rendered token extraction (clientstamp/noncestamp)
   • /TravelSolution/NewSearch with PromotionCode: "UNIDAYS"

3. Grand Central (Student Discount)

   • .ac.uk email validation
   • Multipart form submission to atreemosurvey.com

UI Components

• 96dp Mic Button with pulsing animation ring
• AnimatedInputChip with infinite transition (1→1.05 scale)
• Material 3 TimePicker/DatePicker bottom sheet with quick select chips
• BookingPlanCard with CHEAPEST badge and proof chips

Getting Started

Android

cd android
./gradlew assembleDebug

Backend

cd backend
go mod tidy
go run main.go

The server runs on http://localhost:8080

API Endpoints

Method	Endpoint	Description
POST	/api/search	Search discounts for route
POST	/api/codes/northern	Generate Northern 50% code
POST	/api/codes/grandcentral	Submit Grand Central student form
POST	/api/avanti/search	Search Avanti with UNiDAYS
GET	/api/offers	List available offers
GET	/api/trains/live	Get live departures

Tech Stack

Android

• Kotlin 1.9.22
• Jetpack Compose (BOM 2024.01.00)
• Hilt 2.50 (DI)
• Room 2.6.1 (Local DB)
• Retrofit 2.9 + OkHttp 4.12
• kotlinx-serialization 1.6.3
• kotlinx-datetime 0.5.0
• Cactus LLM SDK

Backend

• Go 1.21
• Fiber v2.52.0
• Google Gmail API
• Convex (optional persistence)

License

MIT