// Package app1svc 是小程序 app1 的业务逻辑。
// 其余小程序（app2..app10）按相同目录结构各自建包，互不耦合。
package app1svc

import (
	"context"
	"crypto/rand"
	"encoding/hex"
	"time"

	"portal-mini-go/internal/model"
	"portal-mini-go/internal/pkg/errors"
	"portal-mini-go/internal/pkg/session"
	"portal-mini-go/internal/pkg/wechat"
	"portal-mini-go/internal/repository/miniapp"
	"portal-mini-go/internal/repository/user"
)

const sessionKeyPrefix = "ma:session:"

// Service app1 业务服务，依赖用户仓储、小程序仓储、微信客户端与会话存储。
type Service struct {
	userRepo *user.Repository
	miniRepo *miniapp.Repository
	wx       *wechat.Client
	store    session.Store
}

func New(userRepo *user.Repository, miniRepo *miniapp.Repository, wx *wechat.Client, store session.Store) *Service {
	return &Service{userRepo: userRepo, miniRepo: miniRepo, wx: wx, store: store}
}

// Login 完成小程序登录：按 app_id 取凭证 -> code2session -> 落库用户 -> 签发会话 token。
// app_id 由接入层（MiniAppAuth 中间件）校验过为已启用小程序，此处用于查出 secret 与小程序主键。
func (s *Service) Login(ctx context.Context, appID, code string) (string, *model.User, error) {
	mp, err := s.miniRepo.GetActiveByAppID(ctx, appID)
	if err != nil {
		return "", nil, err
	}
	info, err := s.wx.Code2Session(ctx, appID, mp.AppSecret, code)
	if err != nil {
		return "", nil, err
	}
	u, err := s.userRepo.UpsertByOpenID(ctx, mp.ID, info.OpenID, info.UnionID, "", "")
	if err != nil {
		return "", nil, err
	}
	token, err := newSessionToken()
	if err != nil {
		return "", nil, err
	}
	if err := s.store.Set(ctx, sessionKeyPrefix+token, u.ID, 7*24*time.Hour); err != nil {
		return "", nil, errors.Wrap(50000, "save session", err)
	}
	return token, u, nil
}

func newSessionToken() (string, error) {
	b := make([]byte, 24)
	if _, err := rand.Read(b); err != nil {
		return "", errors.Wrap(50000, "gen token", err)
	}
	return hex.EncodeToString(b), nil
}