-- =====================================================================================
-- Trigger Function: handle_new_user
-- Version: v2
-- Purpose: auth.users 新用户创建后，同步写入 public.ak_users（权威用户表）并保持 user_roles 兼容写入
-- Security: SECURITY DEFINER + 固定 search_path
-- Depends:
--   - public.ak_users(auth_id,email,username,role)
--   - public.user_roles(user_id,role,created_by) (如存在)
-- Notes:
--   - 角色权威口径为 public.ak_users.role
--   - user_roles 为历史/兼容表：存在则写入，不存在则跳过
-- =====================================================================================

CREATE OR REPLACE FUNCTION public.handle_new_user()
RETURNS trigger
LANGUAGE plpgsql
SECURITY DEFINER
SET search_path = public
AS $$
DECLARE
  user_role TEXT := 'customer';
  user_email TEXT := NEW.email;
  user_name TEXT;
  has_user_roles BOOLEAN := FALSE;
BEGIN
  -- 1) 基于邮箱规则分配默认角色（可按需调整）
  IF user_email ILIKE '%@teacher.%' OR user_email ILIKE '%@edu.%' THEN
    user_role := 'teacher';
  ELSIF user_email ILIKE '%@admin.%' THEN
    user_role := 'admin';
  END IF;

  -- 2) 默认 username：取邮箱 @ 前缀
  IF user_email IS NOT NULL AND POSITION('@' IN user_email) > 1 THEN
    user_name := SPLIT_PART(user_email, '@', 1);
  ELSE
    user_name := 'user';
  END IF;

  -- 3) 写入 ak_users（权威）
  -- 使用 ON CONFLICT 确保幂等：同一 auth_id 只会有一条记录
  INSERT INTO public.ak_users (auth_id, email, username, role)
  VALUES (NEW.id, user_email, user_name, user_role)
  ON CONFLICT (auth_id)
  DO UPDATE SET
    email = COALESCE(EXCLUDED.email, public.ak_users.email),
    username = COALESCE(EXCLUDED.username, public.ak_users.username),
    role = COALESCE(public.ak_users.role, EXCLUDED.role),
    updated_at = now();

  -- 4) 兼容写入 user_roles（如果表存在）
  SELECT EXISTS (
    SELECT 1
    FROM information_schema.tables
    WHERE table_schema='public'
      AND table_name='user_roles'
  ) INTO has_user_roles;

  IF has_user_roles THEN
    BEGIN
      INSERT INTO public.user_roles (user_id, role, created_by)
      VALUES (NEW.id, user_role, NEW.id);
    EXCEPTION WHEN unique_violation THEN
      -- 忽略重复
      NULL;
    END;
  END IF;

  -- 5) 更新 auth.users 元数据（可选保留）
  UPDATE auth.users
  SET raw_user_meta_data = COALESCE(raw_user_meta_data, '{}'::jsonb) || jsonb_build_object('user_role', user_role)
  WHERE id = NEW.id;

  RETURN NEW;
END;
$$;