// Package models provides GORM models and business logic.
// Audited models inspired by https://github.com/qor/audited
package models

import (
	"gorm.io/gorm"
)

// AuditedCurrentUserKey is the GORM Set key for the current user.
const AuditedCurrentUserKey = "audited:current_user"

// Audited tracks creator and updater IDs.
type Audited struct {
	CreatorID *int64 `gorm:"type:bigint REFERENCES users(id)" json:"-"`
	Creator   *User  `json:"-"`
	UpdaterID *int64 `gorm:"type:bigint REFERENCES users(id)" json:"-"`
	Updater   *User  `json:"-"`
}

func getCurrentUser(scope *gorm.DB) (int64, bool) {
	var user interface{}
	var hasUser bool

	user, hasUser = scope.Get(AuditedCurrentUserKey)

	// spew.Dump(user, hasUser)
	if hasUser {
		return user.(*User).ID, true
	}

	return 0, false
}

func assignCreatedBy(tx *gorm.DB) {
	name := "CreatorID"
	if field := tx.Statement.Schema.LookUpField(name); field != nil {
		if user, ok := getCurrentUser(tx); ok {
			tx.Statement.SetColumn(name, user)
		}
	}
}

func assignUpdatedBy(tx *gorm.DB) {
	name := "UpdaterID"
	if field := tx.Statement.Schema.LookUpField(name); field != nil {
		if user, ok := getCurrentUser(tx); ok {
			tx.Statement.SetColumn("UpdaterID", user, true)
		}
	}
}

// RegisterCallbacks register callback into GORM DB
func RegisterCallbacks(db *gorm.DB) {
	callback := db.Callback()

	if callback.Create().Get("audited:assign_created_by") == nil {
		_ = callback.Create().After("gorm:before_create").Register("audited:assign_created_by", assignCreatedBy)
	}

	if callback.Update().Get("audited:assign_updated_by") == nil {
		_ = callback.Update().After("gorm:before_update").Register("audited:assign_updated_by", assignUpdatedBy)
	}
}