-- Create audit log table for tracking all user actions
CREATE TABLE IF NOT EXISTS audit_log (
  audit_id BIGINT AUTO_INCREMENT PRIMARY KEY,
  user_id INT,
  action_type VARCHAR(50) NOT NULL,
  entity_type VARCHAR(50) NOT NULL,
  entity_id VARCHAR(50),
  details JSON,
  ip_address VARCHAR(45),
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  FOREIGN KEY (user_id) REFERENCES users(user_id) ON DELETE SET NULL,
  INDEX idx_user_id (user_id),
  INDEX idx_created_at (created_at),
  INDEX idx_entity (entity_type, entity_id),
  INDEX idx_action_type (action_type)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;