Channels style UUID (#1369)

* server channels style uuids
* webapp channels style uuids

server/utils/utils.go

@@ -1,28 +1,52 @@
 package utils
 
 import (
-	"crypto/rand"
 	"encoding/json"
-	"fmt"
-	"log"
 	"time"
+
+	mm_model "github.com/mattermost/mattermost-server/v6/model"
 )
 
-// CreateGUID returns a random GUID.
-func CreateGUID() string {
-	b := make([]byte, 16)
-	_, err := rand.Read(b)
-	if err != nil {
-		log.Fatal(err)
-	}
-	uuid := fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
+type IDType byte
 
-	return uuid
+const (
+	IDTypeNone      IDType = '7'
+	IDTypeWorkspace IDType = 'w'
+	IDTypeBoard     IDType = 'b'
+	IDTypeCard      IDType = 'c'
+	IDTypeView      IDType = 'v'
+	IDTypeSession   IDType = 's'
+	IDTypeUser      IDType = 'u'
+	IDTypeToken     IDType = 'k'
+	IDTypeBlock     IDType = 'a'
+)
+
+// NewId is a globally unique identifier.  It is a [A-Z0-9] string 27
+// characters long.  It is a UUID version 4 Guid that is zbased32 encoded
+// with the padding stripped off, and a one character alpha prefix indicating the
+// type of entity or a `7` if unknown type.
+func NewID(idType IDType) string {
+	return string(idType) + mm_model.NewId()
 }
 
 // GetMillis is a convenience method to get milliseconds since epoch.
 func GetMillis() int64 {
-	return time.Now().UnixNano() / int64(time.Millisecond)
+	return mm_model.GetMillis()
+}
+
+// GetMillisForTime is a convenience method to get milliseconds since epoch for provided Time.
+func GetMillisForTime(thisTime time.Time) int64 {
+	return mm_model.GetMillisForTime(thisTime)
+}
+
+// GetTimeForMillis is a convenience method to get time.Time for milliseconds since epoch.
+func GetTimeForMillis(millis int64) time.Time {
+	return mm_model.GetTimeForMillis(millis)
+}
+
+// SecondsToMillis is a convenience method to convert seconds to milliseconds.
+func SecondsToMillis(seconds int64) int64 {
+	return seconds * 1000
 }
 
 func StructToMap(v interface{}) (m map[string]interface{}) {