package system

import (
	"wpw-common/internal"

	"go.uber.org/zap"

	"gorm.io/gorm"
)

type SystemKV struct {
	gorm.Model
	Key   string
	Value string
}

type system struct {
	logger *zap.SugaredLogger
	db     *gorm.DB
}

var Default system

func (s *system) init(appCtx *internal.AppContext) {
	logger := appCtx.Logger.Sugar().Named("system")
	db, exist := appCtx.Data["db"]
	if !exist {
		logger.Fatal("system requires `db` in application context")
	}
	s.logger = logger
	s.db = db.(*gorm.DB)
	s.db.AutoMigrate(&SystemKV{})
}

func (s *system) DoOnce(key string, fn func() error) (err error) {
	var kv SystemKV
	kv.Key = key
	tx := s.db.First(&kv)
	if err = tx.Error; err == gorm.ErrRecordNotFound {
		s.logger.Info("doOnce call",
			"key", key)
		if err = fn(); err != nil {

			return
		}
		tx = s.db.Create(&kv)
		if err = tx.Error; err != nil {
			return
		}
	} else if err == nil {
		s.logger.Infow("doOnce done",
			"key", key,
			"at", kv.CreatedAt)
		return
	}
	return
}

func Init(appCtx *internal.AppContext) {
	Default.init(appCtx)
}