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name: project-context description: OpenCivilizations project architecture, patterns, and conventions. Auto-applies for implementation tasks to ensure consistency. allowed-tools: Read, Grep, Glob

Project Context Skill

Architecture and conventions for OpenCivilizations (web-based MMORTS).

Quick Reference

Key Documentation

• docs/architecture.md - System design
• shared/constants.ts - Game balance data
• shared/types.ts - Type definitions

Domain Model

Project Structure

Copyclient/src/
  assets/         # Sprites, tiles, audio
  game/
    scenes/       # Phaser scenes (MainMap, Battle, Loading)
    entities/     # Buildings, Units, Projectiles
    systems/      # Pathfinding, Grid, Input
  ui/             # React/Vue overlays (HUD, Menus)

server/src/
  rooms/          # Colyseus game rooms
  models/         # MongoDB schemas (User, Base, Clan)
  mechanics/      # Authoritative game logic

shared/
  constants.ts    # Building costs, Unit stats
  types.ts        # Shared interfaces

Code Patterns

Isometric Projection

Copy// Grid to Screen
function cartesianToIsometric(x: number, y: number) {
  return {
    x: (x - y) * TILE_WIDTH_HALF,
    y: (x + y) * TILE_HEIGHT_HALF
  };
}

// Screen to Grid
function isometricToCartesian(isoX: number, isoY: number) {
  return {
    x: (isoX / TILE_WIDTH_HALF + isoY / TILE_HEIGHT_HALF) / 2,
    y: (isoY / TILE_HEIGHT_HALF - isoX / TILE_WIDTH_HALF) / 2
  };
}

Server Authority

Copy// Server calculates resources based on time
const elapsed = Date.now() - player.lastUpdate;
const produced = Math.floor(elapsed / 3600000) * farm.productionRate;
player.gold += produced;

State Synchronization

Copy// Colyseus schema for synced state
class GameState extends Schema {
  @type([Building]) buildings = new ArraySchema<Building>();
  @type({ map: Player }) players = new MapSchema<Player>();
}

Code Standards

1. TypeScript strict - No any without justification
2. Server authoritative - Never trust client input
3. Client predicts - Show optimistic updates, reconcile with server
4. Colyseus for sync - Use schemas for multiplayer state
5. MongoDB for persistence - Save base layouts, user data
6. Redis for sessions - Leaderboards, active sessions