FitCore - AI-Powered Fitness App (Backend )

📌 Project Overview

FitCore is a cross-platform fitness app that offers AI-generated personalised meal plans and premium workout videos. The backend will be built using Django & Django REST Framework to serve as a robust API-driven system for both Android and ios clients.

Users will be able to:

• Watch categorised workout videos
• Receive AI-based meal plans
• Track health data via smart devices or manual input
• Subscribe or make one-time purchases for content

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🏋️ FitCore System Architecture Overview

The FitCore app will follow a client-server architecture with several key components:

🧩 Key Components

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📱 Client Applications

• iOS and Android Apps: Built with React Native for cross-platform support.
• Admin Web Dashboard: Used for managing content, users, and analytics.

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🚪 API Gateway / Load Balancer

• Routes requests to appropriate backend services.
• Handles authentication, rate limiting, and request validation.
• Ensures scalability and load distribution.

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🧠 Backend Services

Service Name	Description
Authentication Service	Manages user sign-up, login, tokens, and OAuth.
User Profile Service	Stores and manages user data, goals, preferences, etc.
Content Management Service	Allows admins to manage workout videos, meal plans, articles, etc.
Payment Processing Service	Handles subscription billing and in-app purchases.
Health Data Integration	Syncs with devices like Google Fit and Apple HealthKit.
AI Meal Plan Generator	Uses Openai API to generate personalised meal plans.
Notification Service	Sends push, email, and in-app notifications.
Analytics Service	Tracks user engagement, health trends, and admin reports.

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☁️ External Services & Storage

Component	Purpose
PostgreSQL Database	Relational data storage for core app data.
AWS S3 / Cloudinary	Stores media files like images, videos, and documents.
OpenAI API	Generates AI-driven meal plans and suggestions.
Payment Gateways	Integrates Stripe, PayPal, etc. for handling payments.
Health Data Providers	Syncs data from Google Fit, Apple HealthKit, etc.

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FitCore - Relational Database Design & Architecture

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📐 Entity Relationship Diagram Overview

🧱 Database Models

• User: Stores basic user credentials and serves as the central entity linked to almost all other components.
• users_profiles: Contains extended user information like age, weight, height, gender, and fitness goals.
• HealthData: Tracks users' health metrics such as heart rate and other measurable health indicators over time.
• MealPlan: Stores a user’s daily or AI-generated nutritional plan, including calories, macros (protein, carbs, fats), and date.
• meal: Details individual meals within a meal plan, including ingredients, macros, description, recipe, and mealtime.
• workout: Defines high-level workout goals, difficulty level, categories, and whether it's a premium plan.
• WorkoutVideo: Each workout can include multiple videos with order index, duration, thumbnails, and access settings (free/premium).
• Subscription: Stores data about users’ active or past subscription plans, including plan type and validity.
• Payments: Logs payment transactions related to subscriptions or other purchases, along with plan details and transaction status.
• Purchases: Stores non-subscription purchases like premium workout plans or meal packages.
• Notification: Contains app notifications specific to users, such as messages, alerts, or updates.
• UserWorkoutProgress: Tracks a user's progress for each workout, including completion timestamp and progress percentage.

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🔄 Database Relationships

• Users ↔ UsersProfile, HealthData, Subscriptions, Payments, Notifications, MealPlan, UserWorkoutProgress, Purchases
• MealPlan ↔ Meal (One-to-Many)
• Workout ↔ WorkoutVideo (One-to-Many)
• Users ↔ UserWorkoutProgress (One-to-Many)
• Workout ↔ UserWorkoutProgress (Many-to-Many through tracking)
• Workout ↔ Purchases (for purchasing premium content)
• Users ↔ Workout (via Progress and Purchases)

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📌 API Endpoints

All endpoints are categorised by service, along with HTTP methods, descriptions, and estimated implementation times.

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🔐 Authentication Service

Endpoint	Method	Description	Time Estimate
/api/auth/register	POST	Register a new user	1 day
/api/auth/login	POST	Login with email/password	1 day
/api/auth/social/google	POST	Google OAuth login	1.5 days
/api/auth/social/apple	POST	Apple OAuth login	1.5 days
/api/auth/refresh-token	POST	Refresh JWT token	0.5 day
/api/auth/password-reset	POST	Request password reset	1 day
/api/auth/password-reset/confirm	POST	Confirm password reset	1 day

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👤 User Service

Endpoint	Method	Description	Time Estimate
/api/users/profile	GET	Get user profile	0.5 day
/api/users/profile	PUT	Update user profile	0.5 day
/api/users/settings	GET	Get user settings	0.5 day
/api/users/settings	PUT	Update user settings	0.5 day
/api/users/progress	GET	Get user fitness progress	1 day
/api/users/favorites	GET	Get user favorite workouts/meals	0.5 day
/api/users/favorites	POST	Add to favorites	0.5 day
/api/users/favorites/:id	DELETE	Remove from favorites	0.5 day
/api/users/dashboard	GET	Get user dashboard summary	undefine

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🧬 Health Data Service

Endpoint	Method	Description	Time Estimate
/api/health/data	GET	Get user health data	1 day
/api/health/data	POST	Add manual health data	1 day
/api/health/sync/google-fit	POST	Sync with Google Fit	undefine
/api/health/sync/apple-health	POST	Sync with Apple HealthKit	undefine
/api/health/metrics	GET	Get user health metrics	1 day
/api/health/goals	GET	Get fitness goals	0.5 day
/api/health/goals	PUT	Update fitness goals	0.5 day

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🏋️‍♂️ Workouts

Endpoint	Method	Description	Time Estimate
/api/workouts	GET	List workouts with filters	1 day
/api/workouts/:id	GET	Get workout details	0.5 day
/api/workouts/categories	GET	Get workout categories	0.5 day
/api/workouts/featured	GET	Get featured workouts	0.5 day
/api/workouts/:id/videos	GET	Get workout videos	1 day
/api/workouts/:id/progress	POST	Update workout progress	2 day
/api/workouts/:id/rate	POST	Rate a workout	0.5 day
/api/workouts/search	GET	Search workouts	1 day

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⚙️ Admin Endpoints

Endpoint	Method	Description	Time Estimate
/api/admin/workouts	GET	List all workouts (admin)	0.5 day
/api/admin/workouts	POST	Create workout (admin)	1 day
/api/admin/workouts/:id	PUT	Update workout (admin)	1 day
/api/admin/workouts/:id	DELETE	Delete workout (admin)	0.5 day
/api/admin/videos	POST	Upload workout video (admin)	1.5 days
/api/admin/videos/:id	PUT	Update video (admin)	1 day
/api/admin/videos/:id	DELETE	Delete video (admin)	0.5 day
/api/admin/users	GET	List users (admin)	1 day
/api/admin/analytics	GET	Get platform analytics (admin)	undefine

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🥗 Meal Plan Service - Manual Endpoints

Endpoint	Method	Description	Time Estimate
/api/meals/plans	POST	Create a manual meal plan	1 days
/api/meals/plans/:id	PUT	Update meal plan	1 day
/api/meals/plans/:id	DELETE	Cancel user meal plan	0.5 day

🧠 AI Meal Plan Service

Endpoint	Method	Description	Time Estimate
/api/meals/plans	GET	Get user meal plans	.5 day
/api/meals/plans/generate	POST	Generate AI meal plan	undefine
/api/meals/plans/:id	GET	Get specific meal plan	.5 day
/api/meals/plans/:id	DELETE	Delete meal plan	undefine
/api/meals/templates	GET	Get meal plan templates	undefine
/api/meals/foods	GET	Search foods database	.5 day

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💳 Payment Service

Endpoint	Method	Description	Time Estimate
/api/payments/subscriptions	GET	Get user subscriptions	0.5 day
/api/payments/subscriptions	POST	Create subscription	2 days
/api/payments/subscriptions/:id	PUT	Update subscription	1 day
/api/payments/subscriptions/:id/cancel	POST	Cancel subscription	1 day
/api/payments/purchases	GET	Get user purchases	0.5 day
/api/payments/purchases	POST	Make one-time purchase	2 days
/api/payments/methods	GET	Get payment methods	0.5 day
/api/payments/methods	POST	Add payment method	1 day
/api/payments/methods/:id	DELETE	Remove payment method	0.5 day
/api/payments/webhooks	POST	Payment provider webhooks	1.5 days

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🔔 Notification Service

Endpoint	Method	Description	Time Estimate
/api/notifications	GET	Get user notifications	0.5 day
/api/notifications/:id/read	PUT	Mark notification as read	0.5 day
/api/notifications/settings	GET	Get notification settings	0.5 day
/api/notifications/settings	PUT	Update notification settings	1 day
/api/notifications/subscribe	POST	Subscribe to push notifications	1 day
/api/notifications/unsubscribe	POST	Unsubscribe from push notifications	0.5 day

🛒 Monetization

• Monthly/Yearly Subscription: Unlock full access
• One-time Purchase: Buy specific videos or plans
• Free Tier: Access limited features and samples

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🗂️ Tech Stack

• Backend: Django, Django REST Framework
• Database: PostgreSQL
• Authentication: JWT, OAuth2
• AI Integration: OpenAI API / Custom ML
• Media: AWS S3 or Cloudinary
• Payments: Google Play Billing, Apple IAP, Stripe (for web)

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