
CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL UNIQUE,
    email VARCHAR(100) NOT NULL UNIQUE,
    password VARCHAR(255) NOT NULL,          -- hashed
    referral_code VARCHAR(10) UNIQUE,        -- e.g. random 6-8 chars
    referred_by VARCHAR(10) DEFAULT NULL,    -- referral code of referrer
    balance DECIMAL(10,2) DEFAULT 0.00,
    lifetime_earned DECIMAL(10,2) DEFAULT 0.00,
    level VARCHAR(20) DEFAULT 'L1: Pearl',
    streak_days INT DEFAULT 0,
    last_active DATE DEFAULT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Optional: index for faster lookups
CREATE INDEX idx_referral ON users(referral_code);