Add comprehensive code review and technical feedback

[Copilot]

Requested feedback on codebase quality, security, and architecture.

Deliverables

Three technical documents (1,200+ lines):

• CODE_FEEDBACK.md - Detailed analysis with file/line references, code examples, and solutions
• FEEDBACK_SUMMARY.md - Prioritized issues and quick wins
• HOW_TO_USE_FEEDBACK.md - Implementation guide with time estimates

Key Findings

Security (5 critical)

• Authentication stores userId as principal but controllers expect username
• No rate limiting on /api/v1/auth/** endpoints
• Missing CORS configuration
• DBHandler.checkIfLeaderboardExists() queries wrong table (checks metadata not records)
• JWT secret strength not validated

Code Quality (6 major)

• Parameter named role actually contains username (JWTHandler.getJWTToken)
• Controllers return Map<String, Object> instead of typed DTOs
• Magic strings ("leaderboard:", "userID", "role") need constants
• Static PasswordEncoder instead of Spring bean
• DBHandler handles both users and leaderboards (split needed)

Performance (3)

• Missing index on user.username
• No TTL on Redis keys
• N-tuple potential in score queries

Testing

• No integration tests
• No Redis operation tests
• Only JWTHandler has unit tests

Assessment

⭐⭐⭐⭐ (4/5) - Well-architected Spring Boot app with clean separation of concerns, proper DI, and good security fundamentals. Needs hardening and test coverage.

Strengths: Modern stack, PreparedStatements prevent SQL injection, BCrypt password hashing, comprehensive logging, proper Redis Sorted Set usage.

Estimated remediation: 32-56 hours (4-8h critical, 8-16h quality, 16-24h testing, 4-8h docs)

Example Issue

// Current - misleading
public String getJWTToken(int userID, String role) {
    claims.put("role", role);  // Actually stores username!
}

// Fix
public String getJWTToken(int userID, String username) {
    claims.put("username", username);
    claims.put("userID", userID);
}

Each finding includes location, current code, fix, and priority. No code changes made - documentation only.

Original prompt

give me feedback on the code

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