Implement session creation

pkg/model/ent/schema/codesSequence.go

@@ -0,0 +1,10 @@
+package schema
+
+import (
+	"entgo.io/ent"
+)
+
+// Provides a DBMS independent way of obtaining unique values
+type CodesSequence struct {
+	ent.Schema
+}

pkg/model/ent/schema/game.go

@@ -17,6 +17,7 @@ func (Game) Fields() []ent.Field {
 		field.Text("name").MaxLen(64),
 		field.Time("created").Immutable(),
 		field.Text("author").MaxLen(64),
+		field.Text("code").MinLen(1).Unique(),
 	}
 }
 

pkg/model/ent/schema/session.go

@@ -16,7 +16,7 @@ func (Session) Fields() []ent.Field {
 		field.UUID("id", uuid.Nil).Immutable(),
 		field.Time("created").Immutable(),
 		field.Time("started").Nillable().Optional(),
-		field.String("code").MinLen(6).MaxLen(6).Immutable().Unique(),
+		field.String("code").MinLen(1).Immutable().Unique(),
 	}
 }
 

pkg/model/model.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"github.com/google/uuid"
 	"time"
+	"vkane.cz/tinyquiz/pkg/codeGenerator"
 	"vkane.cz/tinyquiz/pkg/model/ent"
 	"vkane.cz/tinyquiz/pkg/model/ent/answer"
 	"vkane.cz/tinyquiz/pkg/model/ent/askedquestion"
@@ -84,6 +85,41 @@ func (m *Model) RegisterPlayer(playerName string, sessionCode string, now time.T
 	}
 }
 
+func (m *Model) CreateSession(organiserName string, gameCode string, now time.Time, c context.Context) (*ent.Session, *ent.Player, error) {
+	tx, err := m.c.BeginTx(c, &sql.TxOptions{
+		Isolation: sql.LevelReadCommitted,
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+	defer tx.Rollback()
+
+	if gameId, err := tx.Game.Query().Where(game.Code(gameCode)).OnlyID(c); err == nil {
+		if incremental, err := m.getCodeIncremental(c); err == nil {
+			if code, err := codeGenerator.GenerateRandomCode(incremental, codeRandomPartLength); err == nil {
+				if s, err := tx.Session.Create().SetID(uuid.New()).SetCreated(now).SetCode(string(code)).SetGameID(gameId).Save(c); err == nil {
+					if p, err := tx.Player.Create().SetID(uuid.New()).SetJoined(now).SetName(organiserName).SetSession(s).SetOrganiser(true).Save(c); err == nil {
+						err := tx.Commit()
+						return s, p, err
+					} else {
+						return nil, nil, err
+					}
+				} else {
+					return nil, nil, err
+				}
+			} else {
+				return nil, nil, err
+			}
+		} else {
+			return nil, nil, err
+		}
+	} else if ent.IsNotFound(err) {
+		return nil, nil, NoSuchEntity
+	} else {
+		return nil, nil, err
+	}
+}
+
 func (m *Model) GetPlayerWithSessionAndGame(uid uuid.UUID, c context.Context) (*ent.Player, error) {
 	tx, err := m.c.BeginTx(c, &sql.TxOptions{
 		Isolation: sql.LevelRepeatableRead,
@@ -268,3 +304,13 @@ func (m *Model) SaveAnswer(playerId uuid.UUID, choiceId uuid.UUID, now time.Time
 		return nil, err
 	}
 }
+
+const codeRandomPartLength uint8 = 3
+
+func (m *Model) getCodeIncremental(c context.Context) (uint64, error) {
+	if c, err := m.c.CodesSequence.Create().Save(c); err == nil {
+		return uint64(c.ID), nil
+	} else {
+		return 0, nil
+	}
+}

pkg/model/model_test.go

@@ -43,7 +43,7 @@ func newTestModelWithData(t *testing.T) *Model {
 	defer tx.Rollback()
 
 	var gamesC = []*ent.GameCreate{
-		tx.Game.Create().SetID(uuid.MustParse("cab48de7-bba3-4873-9335-eec4aaaae1e9")).SetName("5th grade knowledge test").SetCreated(time.Unix(1613387448, 0)).SetAuthor("Adam Smith PhD."),
+		tx.Game.Create().SetID(uuid.MustParse("cab48de7-bba3-4873-9335-eec4aaaae1e9")).SetName("5th grade knowledge test").SetCode("abcdef").SetCreated(time.Unix(1613387448, 0)).SetAuthor("Adam Smith PhD."),
 	}
 
 	games := tx.Game.CreateBulk(gamesC...).SaveX(c)