package xgorm

import (
	"errors"
	"fmt"
	"gorm.io/gorm"
	"strings"
)

type Callback struct {
	Name     string
	Action   string
	Before   string
	After    string
	Callback func(db *gorm.DB)
}

func (c Callback) Valid() error {
	if c.Name == "" {
		return errors.New("db callback name is nil")
	}

	if c.Callback == nil {
		return errors.New("db callback is nil")
	}

	if c.Action == "" {
		return errors.New("db action is nil")
	}

	return nil
}

func RegisterCallBack(db *gorm.DB, callbacks ...Callback) error {
	if db == nil || len(callbacks) == 0 {
		return nil
	}
	errs := make([]error, 0)
	for _, callback := range callbacks {
		if err := callback.Valid(); err != nil {
			errs = append(errs, fmt.Errorf("callback: %s, err: %v", callback.Name, err))
			continue
		}

		var processor = db.Callback().Create()

		if strings.ToLower(callback.Action) == "update" {
			processor = db.Callback().Update()
		}

		if strings.ToLower(callback.Action) == "delete" {
			processor = db.Callback().Delete()
		}
		if strings.ToLower(callback.Action) == "query" {
			processor = db.Callback().Query()
		}
		if strings.ToLower(callback.Action) == "row" {
			processor = db.Callback().Row()
		}
		if strings.ToLower(callback.Action) == "raw" {
			processor = db.Callback().Raw()
		}

		if processor == db.Callback().Create() && strings.ToLower(callback.Action) != "create" {
			errs = append(errs, fmt.Errorf("callback: %s, db action invalid", callback.Name))
			continue
		}

		if processor.Get(callback.Name) != nil {
			//errs = append(errs, fmt.Errorf("callback: %s, already registered", callback.Name))
			continue
		}
		if callback.Before != "" {
			if err := processor.Before(callback.Before).Register(callback.Name, callback.Callback); err != nil {
				errs = append(errs, err)
			}
		}

		if callback.After != "" {
			if err := processor.After(callback.After).Register(callback.Name, callback.Callback); err != nil {
				errs = append(errs, err)
			}
		}

		if callback.Before == "" && callback.After == "" {
			if err := processor.Register(callback.Name, callback.Callback); err != nil {
				errs = append(errs, err)
			}
		}
	}

	if len(errs) > 0 {
		return fmt.Errorf("db register callback errs: %v", errs)
	}

	return nil
}