EVA Balancer 2.0

The ultimate team balancing tool for EVA (Esports Virtual Arenas)

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What is this?

EVA Balancer pulls real player statistics from EVA's API and uses a brute-force algorithm to split players into two teams with the minimum possible KDA difference — creating the fairest matches possible.

Built for the Bahrain EVA community by the community.

Features

• Booking Import — Paste an EVA booking link, automatically imports all players with live stats and balances them instantly
• Live Stats — Fetches KDA, level, games played, and win rate directly from EVA's GraphQL API
• Smart Balancing — Brute-force combinatorial optimization finds the mathematically optimal team split
• Weighted Mode — Balance by KDA alone, or use a composite score (60% KDA + 25% Win Rate + 15% Level)
• Season Selector — Switch between Season 6, 7, and 8 stats on the fly
• Private Profile Detection — Flags players with private stats and prompts for manual entry
• Balance History — Past results saved locally, browse and reload previous matchups
• Share Links — Generate a URL to share balanced team results with your squad
• Refresh All — One-click refresh of every player's stats from the API
• Manual Editing — Override any player's KDA, level, or game count
• Mobile Friendly — Responsive design with sticky action bar for mobile use

Quick Start

Prerequisites

• Node.js 18+
• PostgreSQL database (or use SQLite locally — see below)

Setup

# Clone
git clone https://github.com/Meowkai123/EVA-BALANCER.git
cd EVA-BALANCER

# Install
npm install

# Configure
cp .env.example .env
# Edit .env with your DATABASE_URL

# Database
npx prisma migrate dev --name init

# Run
npm run dev

Open http://localhost:3000.

Environment Variables

Variable	Description	Example
DATABASE_URL	PostgreSQL connection string	postgresql://user:pass@host:5432/db

Using SQLite Locally

If you don't have PostgreSQL, change prisma/schema.prisma:

datasource db {
  provider = "sqlite"
  url      = "file:./dev.db"
}

Then run npx prisma migrate dev --name init.

Usage

1. Add players individually by username (e.g. PLAYER#1234), or
2. Import a booking — paste an EVA booking URL to pull in everyone at once
3. Select players (up to 10) and hit Balance Squad
4. Share the result with your squad via the Copy or Share button

Tech Stack

Layer	Technology
Framework	Next.js 16 (App Router)
Language	TypeScript 5
Database	PostgreSQL via Prisma ORM
Styling	Tailwind CSS 4
Data Source	EVA GraphQL API
Hosting	Render (Docker)

Architecture

app/
  page.tsx              # Main UI (single-page client component)
  api/
    players/            # CRUD for players (GET, POST, DELETE)
    players/[id]/       # Update/delete individual player (PATCH, DELETE)
    balance/            # Team balancing endpoint (POST)
    import-booking/     # Extract players from EVA booking URL (POST)
    fetch-stats/        # Re-fetch stats for a player (POST)
lib/
    evaClient.ts        # EVA GraphQL API client with caching & retry
    balancer.ts         # Brute-force team balancing algorithm
    prisma.ts           # Database client singleton
    scheduler.ts        # Weekly stat refresh cron job
prisma/
    schema.prisma       # Database schema (Player, PlayerStats, StatsSnapshot)

Deployment

The app ships with a Dockerfile for easy deployment on Render, Railway, Fly.io, or any Docker host.

On Render:

1. Create a free PostgreSQL database
2. Create a Web Service pointing to this repo (Runtime: Docker)
3. Set DATABASE_URL to the internal database URL
4. Deploy — migrations run automatically on startup

Known Limitations

• Region: Hardcoded for Bahrain region (en-BH)
• Rate Limiting: EVA's API throttles requests — the app uses 1.5s delays and retries to handle this
• Max 10 Players: The brute-force algorithm enumerates all combinations, so 10 is the practical limit
• No Map Data: EVA's public API only exposes aggregate season stats, not per-map breakdowns

License

MIT

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Built for the EVA Bahrain community

Made for the community