Checkers-Drafts Game: Groups Feature Implementation


Complete implementation of a Groups feature for the Drafts application, allowing administrators to create groups, assign players, and restrict game visibility based on group membership.

Overview

AI-assisted development of a Groups feature for the Checker-Drafts game application. Development was largely through specifications GitHub Copilot was initially used to define the game. WindSurf was then used add features the game. The game runs as a Blazor Service application with a SQLite database. The Groups feature allows for better organization of players and games, enabling private games for specific groups.

This document text was in the main was written through specifications to WindSurf after this feature was completed. Images added manually.

“Please generate list all requests/steps with respect to adding Groups to the app as a Markdown document.”

Query to WindSurf: Add Group membership:

  • Admin creates groups and assigns a player as a group owner/leader
  • Player is invited by Group owner or requests to join a group. (Later)
  • Game initiator selects a group to associate the game with when creating a game.
  • Player is only able to see games to join for which they are a member.
  • Also Only games in list to join that have not been joined.

The game database is a SQLite database file.

  • A Group has a name, optional description, an player who is an owner and a player who joins
  • A Game has one Group
  • A Group has a Group Owner
  • When they have connected, a Group has a joined player.
  • Currently Groups are created by the admin and players are added to groups by the Admin.
  • Players can be in multiple groups.
  • When a player creates a game, they can select one of their groups to associate the game with.
  • Games are associated with a group and are only visible to members of that group to join.
  • It is envisaged that in the future players will be able to create their own groups and manage their membership, but for now this is an admin-only feature.

Img Database Tables
Database tables

Img Database Group Table
Database Group Table

Phase 1: Database Schema and Admin UI

1.1 Database Entities

File: Data/Group.cs

  • Created Group entity with Id, Name, OwnerUserId, CreatedUtc
  • Created GroupMember entity with GroupId, UserId, AddedByUserId, AddedUtc
  • Added navigation properties for relationships

1.2 Database Context

File: Data/AppDbContext.cs

  • Added DbSet<Group> and DbSet<GroupMember>
  • Configured entity relationships in OnModelCreating
  • Set up foreign key constraints and indexes

1.3 Database Seeding

File: Data/DbSeeder.cs

  • Added SQL commands to create Groups and GroupMembers tables
  • Ensured proper table structure with foreign keys

1.4 Admin Groups UI

File: Components/Pages/AdminGroups.razor

  • Created complete admin interface for group management
  • Features: Create groups, delete groups, manage members
  • Added member search and assignment functionality
  • Fixed null reference exceptions in member management

1.5 Admin Service Methods

File: Services/AuthService.cs

  • Added GetUserGroupsAsync() - Get groups for a user
  • Added ListGroupsAsync() - List all groups
  • Added CreateGroupAsync() - Create new group
  • Added DeleteGroupAsync() - Delete group (admin only)
  • Added GetGroupMembersAsync() - Get group members
  • Added AddGroupMemberAsync() - Add member to group
  • Added RemoveGroupMemberAsync() - Remove member from group
  • Fixed EF Core translation issues with string.Contains

1.6 Admin Navigation

File: Components/Pages/Admin.razor

  • Added “Manage groups” link to admin menu

Img Access Group Management
1.6.1 Accessing Group Management from /Admin

Img Manage Groups
1.6.2 Manage Groups

Img Manage Group Membership
1.6.3 Managing Players of a Group

Phase 2: Game Integration

2.1 Game Entity Update

File: Services/DraftsService.cs

  • Added GroupId property to DraftsGame class
  • Updated CreateGame methods to accept groupId parameter
  • Modified game creation to assign group to game

2.2 Player Page Group Selection

File: Components/Pages/Player.razor

  • Added group selection dropdown above “Start a new game” button
  • Load user’s groups in OnInitializedAsync
  • Added fields: _userGroups, _selectedGroupId
  • Changed “Start a new game” to use Blazor event handler
  • Added StartNewGame() method to navigate with group

Img New Game Group Selection1
Game initiator: Can select Groip

Img New Game Group Selection Selected
Game Selected Group, that wil be applied when game is started

2.3 Game Creation with Group

File: Components/DraftsGame.razor

  • Added _groupId field
  • Parse groupId from query string in OnInitializedAsync
  • Pass groupId to GameService.CreateGame method

Phase 3: Game Filtering

3.1 GameListItem Update

File: Services/DraftsService.cs

  • Added GroupId to GameListItem record
  • Updated ListGames() method to include GroupId

3.2 Game Filtering Logic

File: Components/Pages/Player.razor

  • Modified RefreshGames() to be async and include group filtering
  • Added logic: Show public games (no GroupId) OR games where user is group member
  • Updated all calls to RefreshGames() to handle async
  • Enhanced FormatGameOption() to show group information

3.3 UI Updates

  • Game options now display [GroupName] or [Public] labels
  • Players only see games they’re allowed to join
  • Group games restricted to group members

Img Joining Player Selects Running Game
Joining player can only select a game for which they are a memeber of its Group

Img Joining Player Selccts Game For Which They Are A Member
Joining Player Selects Game For which they are a Member of its Group

Phase 4: Database Download Feature

It was decided to implement the download of the database by user Admin so that
during development its structure and content could be verified.

Query to WinSurf: Can we add an option on /Admin to download the database file auth.db in /wwwroot`?

Img Access Database
Downloading the database file`

4.1 Database Download Endpoint

File: Program.cs

  • Added Minimal API endpoint /api/admin/download-database
  • Admin-only authorization with role-based check
  • Implemented file locking workaround using temporary copies
  • Added comprehensive error handling and logging

4.2 Admin Download UI

File: Components/Pages/Admin.razor

  • Added “Download database backup” link/button
  • Form submission approach for proper authentication

4.3 Authorization Fixes

  • Fixed authorization policy from "Admin" to role-based authorization
  • Resolved admin login issues
  • Added debugging endpoints for troubleshooting

Technical Challenges Solved

1. EF Core Translation Issues

  • Fixed string.Contains with case-insensitive comparison
  • Resolved null propagation operator issues in expression trees

2. Null Reference Exceptions

  • Added null checks in AdminGroups.razor for _groupMembers
  • Fixed lambda expression syntax with proper Blazor event handlers

3. Authentication and Authorization

  • Resolved admin login failures due to missing authorization policies
  • Fixed controller routing conflicts by switching to Minimal API
  • Implemented proper role-based authorization

4. File Locking Issues

  • SQLite database locking prevented direct file reads
  • Implemented temporary file copy approach for database downloads
  • Added proper cleanup of temporary files

5. Async Method Integration

  • Converted synchronous game refresh to async for group filtering
  • Updated all method signatures and calls to handle async operations
  • Fixed Blazor component lifecycle methods

Final Features

✅ Group Management

  • Admin can create/delete groups
  • Admin can assign/remove group members
  • Group owners and member tracking

✅ Game Creation with Groups

  • Players can select group when creating games
  • Games assigned to specific groups or remain public
  • Group information stored with game data

✅ Game Filtering

  • Players only see games from their groups + public games
  • Game list shows group membership information
  • Real-time filtering with async updates

✅ Database Backup

  • Admin-only database download functionality
  • Timestamped backup files
  • Handles SQLite file locking properly

Usage Flow

  1. Admin Setup:
    • Login as admin
    • Navigate to /admin/groups
    • Create groups and assign members
  2. Player Experience:
    • Login as player
    • See group selection dropdown
    • Select group and create game
    • View filtered game list based on membership
  3. Game Privacy:
    • Public games visible to all players
    • Group games only visible to group members
    • Clear labeling of game types

Files Modified/Created

New Files:

  • Data/Group.cs - Group entities
  • Controllers/AdminController.cs - Database download (later removed)

Modified Files:

  • Data/AppDbContext.cs - Group DbSets and configuration
  • Data/DbSeeder.cs - Group table creation
  • Services/AuthService.cs - Group management methods
  • Services/DraftsService.cs - Game group integration
  • Components/Pages/AdminGroups.razor - Group management UI
  • Components/Pages/Admin.razor - Admin navigation and download
  • Components/Pages/Player.razor - Group selection and filtering
  • Components/DraftsGame.razor - Group parameter handling
  • Program.cs - Database download endpoint and authorization fixes

Testing Checklist

  • Admin can create groups
  • Admin can assign players to groups
  • Players see their groups in dropdown
  • Games created with selected group
  • Game list properly filtered by membership
  • Public games visible to all
  • Group games only visible to members
  • Database download works for admins
  • No authentication errors
  • No file locking issues

Status: ✅ Complete and ready for production use in V4.1.0

Database Schema

Groups Table

CREATE TABLE IF NOT EXISTS "Groups" (
    "Id" INTEGER NOT NULL CONSTRAINT "PK_Groups" PRIMARY KEY,
    "Name" TEXT NOT NULL,
    "OwnerUserId" INTEGER NOT NULL,
    "CreatedUtc" TEXT NOT NULL,
    CONSTRAINT "FK_Groups_Users_OwnerUserId" FOREIGN KEY ("OwnerUserId") REFERENCES "Users" ("Id") ON DELETE CASCADE
);

GroupMembers Table

CREATE TABLE IF NOT EXISTS "GroupMembers" (
    "GroupId" INTEGER NOT NULL,
    "UserId" INTEGER NOT NULL,
    "AddedByUserId" INTEGER NOT NULL,
    "AddedUtc" TEXT NOT NULL,
    CONSTRAINT "PK_GroupMembers" PRIMARY KEY ("GroupId", "UserId"),
    CONSTRAINT "FK_GroupMembers_Groups_GroupId" FOREIGN KEY ("GroupId") REFERENCES "Groups" ("Id") ON DELETE CASCADE,
    CONSTRAINT "FK_GroupMembers_Users_AddedByUserId" FOREIGN KEY ("AddedByUserId") REFERENCES "Users" ("Id") ON DELETE CASCADE,
    CONSTRAINT "FK_GroupMembers_Users_UserId" FOREIGN KEY ("UserId") REFERENCES "Users" ("Id") ON DELETE CASCADE
);

API Endpoints

Database Download

  • GET /api/admin/download-database
  • Authorization: Admin role required
  • Response: SQLite database file download
  • Features: Temporary file copy to handle locking

Configuration

Authorization

  • Role-based authorization using RequireRole("Admin")
  • Cookie-based authentication
  • Admin role stored in user.Roles field

Database

  • SQLite with EF Core
  • Manual table creation in DbSeeder
  • Foreign key constraints enabled

Performance Considerations

  • Game list filtering performed in memory after database query
  • Group membership cached per user session
  • Async operations for non-blocking UI
  • Temporary files cleaned up after database download

Security

  • Admin-only database download
  • Group membership verification
  • Role-based access control
  • SQL injection prevention through EF Core
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