Remove migration dependency to models

pkg/migration/20200516123847.go

@@ -17,28 +17,77 @@
 package migration
 
 import (
-	"code.vikunja.io/api/pkg/models"
+	"code.vikunja.io/api/pkg/timeutil"
 	"src.techknowlogick.com/xormigrate"
+	"strings"
 	"xorm.io/xorm"
 )
 
+type list20200516123847 struct {
+	ID          int64              `xorm:"int(11) autoincr not null unique pk" json:"id" param:"list"`
+	Title       string             `xorm:"varchar(250) not null" json:"title" valid:"required,runelength(3|250)" minLength:"3" maxLength:"250"`
+	Description string             `xorm:"longtext null" json:"description"`
+	Identifier  string             `xorm:"varchar(10) null" json:"identifier" valid:"runelength(0|10)" minLength:"0" maxLength:"10"`
+	HexColor    string             `xorm:"varchar(6) null" json:"hex_color" valid:"runelength(0|6)" maxLength:"6"`
+	OwnerID     int64              `xorm:"int(11) INDEX not null" json:"-"`
+	NamespaceID int64              `xorm:"int(11) INDEX not null" json:"-" param:"namespace"`
+	IsArchived  bool               `xorm:"not null default false" json:"is_archived" query:"is_archived"`
+	Created     timeutil.TimeStamp `xorm:"created not null" json:"created"`
+	Updated     timeutil.TimeStamp `xorm:"updated not null" json:"updated"`
+}
+
 func init() {
 	migrations = append(migrations, &xormigrate.Migration{
 		ID:          "20200516123847",
 		Description: "Generate a list identifier for each list",
 		Migrate: func(tx *xorm.Engine) error {
-			lists := []*models.List{}
+			lists := []*list20200516123847{}
 			err := tx.Find(&lists)
 			if err != nil {
 				return err
 			}
 
+			// Copied and adopted from pkg/models/list.go:374
+			generateListIdentifier := func(l *list20200516123847, sess *xorm.Engine) (err error) {
+				// The general idea here is to take the title and slice it into pieces, until we found a unique piece.
+
+				var exists = true
+				titleSlug := strings.Replace(strings.ToUpper(l.Title), " ", "", -1)
+
+				// We can save at most 10 characters in the db, so we need to ensure it has at most 10 characters
+				if len(titleSlug) > 10 {
+					titleSlug = titleSlug[0:9]
+				}
+
+				var i = 0
+
+				for exists {
+
+					// Prevent endless looping
+					if i == len(titleSlug) {
+						break
+					}
+
+					// Take a random part of the title slug, starting at the beginning
+					l.Identifier = titleSlug[i:]
+					exists, err = sess.
+						Where("identifier = ?", l.Identifier).
+						And("id != ?", l.ID).
+						Exist(&list20200516123847{})
+					if err != nil {
+						return
+					}
+					i++
+				}
+				return nil
+			}
+
 			for _, l := range lists {
 				if l.Identifier != "" {
 					continue
 				}
 
-				err := models.GenerateListIdentifier(l, tx)
+				err := generateListIdentifier(l, tx)
 				if err != nil {
 					return err
 				}