local id

plan/command/add.go

@@ -44,14 +44,14 @@ var AddCmd = &cli.Command{
 	},
 }
 
-func NewAddCmd(repo storage.EventRepo) *cli.Command {
+func NewAddCmd(localRepo storage.LocalID, eventRepo storage.Event) *cli.Command {
 	AddCmd.Action = func(cCtx *cli.Context) error {
-		return Add(cCtx.String("name"), cCtx.String("on"), cCtx.String("at"), cCtx.String("for"), repo)
+		return Add(localRepo, eventRepo, cCtx.String("name"), cCtx.String("on"), cCtx.String("at"), cCtx.String("for"))
 	}
 	return AddCmd
 }
 
-func Add(nameStr, onStr, atStr, frStr string, repo storage.EventRepo) error {
+func Add(localIDRepo storage.LocalID, eventRepo storage.Event, nameStr, onStr, atStr, frStr string) error {
 	if nameStr == "" {
 		return fmt.Errorf("%w: name is required", ErrInvalidArg)
 	}
@@ -91,9 +91,17 @@ func Add(nameStr, onStr, atStr, frStr string, repo storage.EventRepo) error {
 		}
 		e.Duration = fr
 	}
-	if err := repo.Store(e); err != nil {
+	if err := eventRepo.Store(e); err != nil {
 		return fmt.Errorf("could not store event: %v", err)
 	}
 
+	localID, err := localIDRepo.Next()
+	if err != nil {
+		return fmt.Errorf("could not create next local id: %v", err)
+	}
+	if err := localIDRepo.Store(e.ID, localID); err != nil {
+		return fmt.Errorf("could not store local id: %v", err)
+	}
+
 	return nil
 }

plan/command/add_test.go

@@ -7,7 +7,7 @@ import (
 	"github.com/google/go-cmp/cmp"
 	"go-mod.ewintr.nl/planner/item"
 	"go-mod.ewintr.nl/planner/plan/command"
-	"go-mod.ewintr.nl/planner/plan/storage"
+	"go-mod.ewintr.nl/planner/plan/storage/memory"
 )
 
 func TestAdd(t *testing.T) {
@@ -104,21 +104,34 @@ func TestAdd(t *testing.T) {
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			mem := storage.NewMemory()
+			eventRepo := memory.NewEvent()
-			actErr := command.Add(tc.args["name"], tc.args["on"], tc.args["at"], tc.args["for"], mem) != nil
+			localRepo := memory.NewLocalID()
+			actErr := command.Add(localRepo, eventRepo, tc.args["name"], tc.args["on"], tc.args["at"], tc.args["for"]) != nil
 			if tc.expErr != actErr {
 				t.Errorf("exp %v, got %v", tc.expErr, actErr)
 			}
 			if tc.expErr {
 				return
 			}
-			actEvents, err := mem.FindAll()
+			actEvents, err := eventRepo.FindAll()
 			if err != nil {
 				t.Errorf("exp nil, got %v", err)
 			}
 			if len(actEvents) != 1 {
 				t.Errorf("exp 1, got %d", len(actEvents))
 			}
+
+			actLocalIDs, err := localRepo.FindAll()
+			if err != nil {
+				t.Errorf("exp nil, got %v", err)
+			}
+			if len(actLocalIDs) != 1 {
+				t.Errorf("exp 1, got %v", len(actLocalIDs))
+			}
+			if _, ok := actLocalIDs[actEvents[0].ID]; !ok {
+				t.Errorf("exp true, got %v", ok)
+			}
+
 			if actEvents[0].ID == "" {
 				t.Errorf("exp string not te be empty")
 			}

plan/command/list.go

@@ -13,22 +13,29 @@ var ListCmd = &cli.Command{
 	Usage: "List everything",
 }
 
-func NewListCmd(repo storage.EventRepo) *cli.Command {
+func NewListCmd(localRepo storage.LocalID, eventRepo storage.Event) *cli.Command {
-	ListCmd.Action = NewListAction(repo)
+	ListCmd.Action = func(cCtx *cli.Context) error {
+		return List(localRepo, eventRepo)
+	}
 	return ListCmd
 }
 
-func NewListAction(repo storage.EventRepo) func(*cli.Context) error {
+func List(localRepo storage.LocalID, eventRepo storage.Event) error {
-	return func(cCtx *cli.Context) error {
+	localIDs, err := localRepo.FindAll()
-		all, err := repo.FindAll()
+	if err != nil {
-		if err != nil {
+		return fmt.Errorf("could not get local ids: %v", err)
-			return err
+	}
+	all, err := eventRepo.FindAll()
+	if err != nil {
+		return err
+	}
+	for _, e := range all {
+		lid, ok := localIDs[e.ID]
+		if !ok {
+			return fmt.Errorf("could not find local id for %s", e.ID)
 		}
-		for _, e := range all {
+		fmt.Printf("%s\t%d\t%s\t%s\t%s\n", e.ID, lid, e.Title, e.Start.Format(time.DateTime), e.Duration.String())
-			fmt.Printf("%s\t%s\t%s\t%s\n", e.ID, e.Title, e.Start.Format(time.DateTime), e.Duration.String())
-		}
-
-		return nil
 	}
 
+	return nil
 }

plan/main.go

@@ -7,7 +7,7 @@ import (
 
 	"github.com/urfave/cli/v2"
 	"go-mod.ewintr.nl/planner/plan/command"
-	"go-mod.ewintr.nl/planner/plan/storage"
+	"go-mod.ewintr.nl/planner/plan/storage/sqlite"
 	"gopkg.in/yaml.v3"
 )
 
@@ -23,7 +23,7 @@ func main() {
 		os.Exit(1)
 	}
 
-	repo, err := storage.NewSqlite(conf.DBPath)
+	localIDRepo, eventRepo, err := sqlite.NewSqlites(conf.DBPath)
 	if err != nil {
 		fmt.Printf("could not open db file: %s\n", err)
 		os.Exit(1)
@@ -33,8 +33,8 @@ func main() {
 		Name:  "plan",
 		Usage: "Plan your day with events",
 		Commands: []*cli.Command{
-			command.NewAddCmd(repo),
+			command.NewAddCmd(localIDRepo, eventRepo),
-			command.NewListCmd(repo),
+			command.NewListCmd(localIDRepo, eventRepo),
 		},
 	}
 

plan/storage/memory/event.go

@@ -1,4 +1,4 @@
-package storage
+package memory
 
 import (
 	"errors"
@@ -8,18 +8,18 @@ import (
 	"go-mod.ewintr.nl/planner/item"
 )
 
-type Memory struct {
+type Event struct {
 	events map[string]item.Event
 	mutex  sync.RWMutex
 }
 
-func NewMemory() *Memory {
+func NewEvent() *Event {
-	return &Memory{
+	return &Event{
 		events: make(map[string]item.Event),
 	}
 }
 
-func (r *Memory) Find(id string) (item.Event, error) {
+func (r *Event) Find(id string) (item.Event, error) {
 	r.mutex.RLock()
 	defer r.mutex.RUnlock()
 
@@ -30,7 +30,7 @@ func (r *Memory) Find(id string) (item.Event, error) {
 	return event, nil
 }
 
-func (r *Memory) FindAll() ([]item.Event, error) {
+func (r *Event) FindAll() ([]item.Event, error) {
 	r.mutex.RLock()
 	defer r.mutex.RUnlock()
 
@@ -45,15 +45,16 @@ func (r *Memory) FindAll() ([]item.Event, error) {
 	return events, nil
 }
 
-func (r *Memory) Store(e item.Event) error {
+func (r *Event) Store(e item.Event) error {
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
 
 	r.events[e.ID] = e
+
 	return nil
 }
 
-func (r *Memory) Delete(id string) error {
+func (r *Event) Delete(id string) error {
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
 
@@ -61,5 +62,6 @@ func (r *Memory) Delete(id string) error {
 		return errors.New("event not found")
 	}
 	delete(r.events, id)
+
 	return nil
 }

plan/storage/memory/event_test.go

@@ -1,4 +1,4 @@
-package storage
+package memory
 
 import (
 	"testing"
@@ -7,10 +7,10 @@ import (
 	"go-mod.ewintr.nl/planner/item"
 )
 
-func TestMemory(t *testing.T) {
+func TestEvent(t *testing.T) {
 	t.Parallel()
 
-	mem := NewMemory()
+	mem := NewEvent()
 
 	t.Log("empty")
 	actEvents, actErr := mem.FindAll()

plan/storage/memory/localid.go

@@ -0,0 +1,61 @@
+package memory
+
+import (
+	"sync"
+
+	"go-mod.ewintr.nl/planner/plan/storage"
+)
+
+type LocalID struct {
+	ids   map[string]int
+	mutex sync.RWMutex
+}
+
+func NewLocalID() *LocalID {
+	return &LocalID{
+		ids: make(map[string]int),
+	}
+}
+
+func (ml *LocalID) FindAll() (map[string]int, error) {
+	ml.mutex.RLock()
+	defer ml.mutex.RUnlock()
+
+	return ml.ids, nil
+}
+
+func (ml *LocalID) Next() (int, error) {
+	ml.mutex.RLock()
+	defer ml.mutex.RUnlock()
+
+	cur := make([]int, 0, len(ml.ids))
+	for _, i := range ml.ids {
+		cur = append(cur, i)
+	}
+
+	localID := storage.NextLocalID(cur)
+
+	return localID, nil
+}
+
+func (ml *LocalID) Store(id string, localID int) error {
+	ml.mutex.Lock()
+	defer ml.mutex.Unlock()
+
+	ml.ids[id] = localID
+
+	return nil
+}
+
+func (ml *LocalID) Delete(id string) error {
+	ml.mutex.Lock()
+	defer ml.mutex.Unlock()
+
+	if _, ok := ml.ids[id]; !ok {
+		return storage.ErrNotFound
+	}
+
+	delete(ml.ids, id)
+
+	return nil
+}

plan/storage/memory/localid_test.go

@@ -0,0 +1,68 @@
+package memory_test
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"go-mod.ewintr.nl/planner/plan/storage"
+	"go-mod.ewintr.nl/planner/plan/storage/memory"
+)
+
+func TestLocalID(t *testing.T) {
+	t.Parallel()
+
+	repo := memory.NewLocalID()
+
+	t.Log("start empty")
+	actIDs, actErr := repo.FindAll()
+	if actErr != nil {
+		t.Errorf("exp nil, got %v", actErr)
+	}
+	if len(actIDs) != 0 {
+		t.Errorf("exp nil, got %v", actErr)
+	}
+
+	t.Log("next id")
+	actNext, actErr := repo.Next()
+	if actErr != nil {
+		t.Errorf("exp nil, got %v", actErr)
+	}
+	if actNext != 1 {
+		t.Errorf("exp 1, got %v", actNext)
+	}
+
+	t.Log("store")
+	if actErr = repo.Store("test", 1); actErr != nil {
+		t.Errorf("exp nil, got %v", actErr)
+	}
+
+	actIDs, actErr = repo.FindAll()
+	if actErr != nil {
+		t.Errorf("exp nil, got %v", actErr)
+	}
+	expIDs := map[string]int{
+		"test": 1,
+	}
+	if diff := cmp.Diff(expIDs, actIDs); diff != "" {
+		t.Errorf("(exp +, got -)\n%s", diff)
+	}
+
+	t.Log("delete")
+	if actErr = repo.Delete("test"); actErr != nil {
+		t.Errorf("exp nil, got %v", actErr)
+	}
+	actIDs, actErr = repo.FindAll()
+	if actErr != nil {
+		t.Errorf("exp nil, got %v", actErr)
+	}
+	if len(actIDs) != 0 {
+		t.Errorf("exp 0, got %v", actErr)
+	}
+
+	t.Log("delete non-existing")
+	actErr = repo.Delete("non-existing")
+	if !errors.Is(actErr, storage.ErrNotFound) {
+		t.Errorf("exp %v, got %v", storage.ErrNotFound, actErr)
+	}
+}

plan/storage/sqlite.go

@@ -1,206 +0,0 @@
-package storage
-
-import (
-	"database/sql"
-	"errors"
-	"fmt"
-	"time"
-
-	"go-mod.ewintr.nl/planner/item"
-	_ "modernc.org/sqlite"
-)
-
-const (
-	timestampFormat = "2006-01-02 15:04:05"
-)
-
-var migrations = []string{
-	`CREATE TABLE events ("id" TEXT UNIQUE, "title" TEXT, "start" TIMESTAMP, "duration" TEXT)`,
-	`PRAGMA journal_mode=WAL`,
-	`PRAGMA synchronous=NORMAL`,
-	`PRAGMA cache_size=2000`,
-}
-
-var (
-	ErrInvalidConfiguration     = errors.New("invalid configuration")
-	ErrIncompatibleSQLMigration = errors.New("incompatible migration")
-	ErrNotEnoughSQLMigrations   = errors.New("already more migrations than wanted")
-	ErrSqliteFailure            = errors.New("sqlite returned an error")
-)
-
-type Sqlite struct {
-	db *sql.DB
-}
-
-func NewSqlite(dbPath string) (*Sqlite, error) {
-	db, err := sql.Open("sqlite", dbPath)
-	if err != nil {
-		return &Sqlite{}, fmt.Errorf("%w: %v", ErrInvalidConfiguration, err)
-	}
-
-	s := &Sqlite{
-		db: db,
-	}
-
-	if err := s.migrate(migrations); err != nil {
-		return &Sqlite{}, err
-	}
-
-	return s, nil
-}
-
-func (s *Sqlite) Store(event item.Event) error {
-	if _, err := s.db.Exec(`
-INSERT INTO events
-(id, title, start, duration)
-VALUES
-(?, ?, ?, ?)
-ON CONFLICT(id) DO UPDATE
-SET
-title=?,
-start=?,
-duration=?`,
-		event.ID, event.Title, event.Start.Format(timestampFormat), event.Duration.String(),
-		event.Title, event.Start.Format(timestampFormat), event.Duration.String()); err != nil {
-		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-	}
-	return nil
-}
-
-func (s *Sqlite) Find(id string) (item.Event, error) {
-	var event item.Event
-	var durStr string
-	err := s.db.QueryRow(`
-SELECT id, title, start, duration
-FROM events
-WHERE id = ?`, id).Scan(&event.ID, &event.Title, &event.Start, &durStr)
-	switch {
-	case err == sql.ErrNoRows:
-		return item.Event{}, fmt.Errorf("event not found: %w", err)
-	case err != nil:
-		return item.Event{}, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-	}
-	dur, err := time.ParseDuration(durStr)
-	if err != nil {
-		return item.Event{}, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-	}
-	event.Duration = dur
-
-	return event, nil
-}
-
-func (s *Sqlite) FindAll() ([]item.Event, error) {
-	rows, err := s.db.Query(`
-SELECT id, title, start, duration
-FROM events`)
-	if err != nil {
-		return nil, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-	}
-
-	result := make([]item.Event, 0)
-	defer rows.Close()
-	for rows.Next() {
-		var event item.Event
-		var durStr string
-		if err := rows.Scan(&event.ID, &event.Title, &event.Start, &durStr); err != nil {
-			return nil, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-		}
-		dur, err := time.ParseDuration(durStr)
-		if err != nil {
-			return nil, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-		}
-		event.Duration = dur
-		result = append(result, event)
-	}
-
-	return result, nil
-}
-
-func (s *Sqlite) Delete(id string) error {
-	result, err := s.db.Exec(`
-DELETE FROM events
-WHERE id = ?`, id)
-	if err != nil {
-		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-	}
-
-	rowsAffected, err := result.RowsAffected()
-	if err != nil {
-		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-	}
-
-	if rowsAffected == 0 {
-		return fmt.Errorf("event not found: %s", id)
-	}
-
-	return nil
-}
-
-func (s *Sqlite) migrate(wanted []string) error {
-	// admin table
-	if _, err := s.db.Exec(`
-CREATE TABLE IF NOT EXISTS migration
-("id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, "query" TEXT)
-`); err != nil {
-		return err
-	}
-
-	// find existing
-	rows, err := s.db.Query(`SELECT query FROM migration ORDER BY id`)
-	if err != nil {
-		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-	}
-
-	existing := []string{}
-	for rows.Next() {
-		var query string
-		if err := rows.Scan(&query); err != nil {
-			return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-		}
-		existing = append(existing, string(query))
-	}
-	rows.Close()
-
-	// compare
-	missing, err := compareMigrations(wanted, existing)
-	if err != nil {
-		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-	}
-
-	// execute missing
-	for _, query := range missing {
-		if _, err := s.db.Exec(string(query)); err != nil {
-			return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-		}
-
-		// register
-		if _, err := s.db.Exec(`
-INSERT INTO migration
-(query) VALUES (?)
-`, query); err != nil {
-			return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
-		}
-	}
-
-	return nil
-}
-
-func compareMigrations(wanted, existing []string) ([]string, error) {
-	needed := []string{}
-	if len(wanted) < len(existing) {
-		return []string{}, ErrNotEnoughSQLMigrations
-	}
-
-	for i, want := range wanted {
-		switch {
-		case i >= len(existing):
-			needed = append(needed, want)
-		case want == existing[i]:
-			// do nothing
-		case want != existing[i]:
-			return []string{}, fmt.Errorf("%w: %v", ErrIncompatibleSQLMigration, want)
-		}
-	}
-
-	return needed, nil
-}

plan/storage/sqlite/event.go

@@ -0,0 +1,100 @@
+package sqlite
+
+import (
+	"database/sql"
+	"fmt"
+	"time"
+
+	"go-mod.ewintr.nl/planner/item"
+	"go-mod.ewintr.nl/planner/plan/storage"
+)
+
+type SqliteEvent struct {
+	db *sql.DB
+}
+
+func (s *SqliteEvent) Store(event item.Event) error {
+	if _, err := s.db.Exec(`
+INSERT INTO events
+(id, title, start, duration)
+VALUES
+(?, ?, ?, ?)
+ON CONFLICT(id) DO UPDATE
+SET
+title=?,
+start=?,
+duration=?`,
+		event.ID, event.Title, event.Start.Format(timestampFormat), event.Duration.String(),
+		event.Title, event.Start.Format(timestampFormat), event.Duration.String()); err != nil {
+		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+	return nil
+}
+
+func (s *SqliteEvent) Find(id string) (item.Event, error) {
+	var event item.Event
+	var durStr string
+	err := s.db.QueryRow(`
+SELECT id, title, start, duration
+FROM events
+WHERE id = ?`, id).Scan(&event.ID, &event.Title, &event.Start, &durStr)
+	switch {
+	case err == sql.ErrNoRows:
+		return item.Event{}, fmt.Errorf("event not found: %w", err)
+	case err != nil:
+		return item.Event{}, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+	dur, err := time.ParseDuration(durStr)
+	if err != nil {
+		return item.Event{}, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+	event.Duration = dur
+
+	return event, nil
+}
+
+func (s *SqliteEvent) FindAll() ([]item.Event, error) {
+	rows, err := s.db.Query(`
+SELECT id, title, start, duration
+FROM events`)
+	if err != nil {
+		return nil, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+	result := make([]item.Event, 0)
+	defer rows.Close()
+	for rows.Next() {
+		var event item.Event
+		var durStr string
+		if err := rows.Scan(&event.ID, &event.Title, &event.Start, &durStr); err != nil {
+			return nil, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+		}
+		dur, err := time.ParseDuration(durStr)
+		if err != nil {
+			return nil, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+		}
+		event.Duration = dur
+		result = append(result, event)
+	}
+
+	return result, nil
+}
+
+func (s *SqliteEvent) Delete(id string) error {
+	result, err := s.db.Exec(`
+DELETE FROM events
+WHERE id = ?`, id)
+	if err != nil {
+		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+
+	if rowsAffected == 0 {
+		return storage.ErrNotFound
+	}
+
+	return nil
+}

plan/storage/sqlite/localid.go

@@ -0,0 +1,77 @@
+package sqlite
+
+import (
+	"database/sql"
+	"fmt"
+
+	"go-mod.ewintr.nl/planner/plan/storage"
+)
+
+type LocalID struct {
+	db *sql.DB
+}
+
+func (l *LocalID) FindAll() (map[string]int, error) {
+	rows, err := l.db.Query(`
+SELECT id, local_id
+FROM localids
+`)
+	if err != nil {
+		return nil, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+	result := make(map[string]int)
+	defer rows.Close()
+	for rows.Next() {
+		var id string
+		var localID int
+		if err := rows.Scan(&id, &localID); err != nil {
+			return nil, fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+		}
+		result[id] = localID
+	}
+
+	return result, nil
+}
+
+func (l *LocalID) Next() (int, error) {
+	idMap, err := l.FindAll()
+	if err != nil {
+		return 0, err
+	}
+	cur := make([]int, 0, len(idMap))
+	for _, localID := range idMap {
+		cur = append(cur, localID)
+	}
+
+	return storage.NextLocalID(cur), nil
+}
+
+func (l *LocalID) Store(id string, localID int) error {
+	if _, err := l.db.Exec(`
+INSERT INTO localids
+(id, local_id)
+VALUES
+(? ,?)`, id, localID); err != nil {
+		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+
+	return nil
+}
+
+func (l *LocalID) Delete(id string) error {
+	result, err := l.db.Exec(`
+DELETE FROM localids
+WHERE id = ?`, id)
+	if err != nil {
+		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+	if rowsAffected == 0 {
+		return storage.ErrNotFound
+	}
+	return nil
+}

plan/storage/sqlite/sqlite.go

@@ -0,0 +1,117 @@
+package sqlite
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+
+	_ "modernc.org/sqlite"
+)
+
+const (
+	timestampFormat = "2006-01-02 15:04:05"
+)
+
+var migrations = []string{
+	`CREATE TABLE events ("id" TEXT UNIQUE, "title" TEXT, "start" TIMESTAMP, "duration" TEXT)`,
+	`PRAGMA journal_mode=WAL`,
+	`PRAGMA synchronous=NORMAL`,
+	`PRAGMA cache_size=2000`,
+	`CREATE TABLE localids ("id" TEXT UNIQUE, "local_id" INTEGER)`,
+}
+
+var (
+	ErrInvalidConfiguration     = errors.New("invalid configuration")
+	ErrIncompatibleSQLMigration = errors.New("incompatible migration")
+	ErrNotEnoughSQLMigrations   = errors.New("already more migrations than wanted")
+	ErrSqliteFailure            = errors.New("sqlite returned an error")
+)
+
+func NewSqlites(dbPath string) (*LocalID, *SqliteEvent, error) {
+	db, err := sql.Open("sqlite", dbPath)
+	if err != nil {
+		return nil, nil, fmt.Errorf("%w: %v", ErrInvalidConfiguration, err)
+	}
+
+	sl := &LocalID{
+		db: db,
+	}
+	se := &SqliteEvent{
+		db: db,
+	}
+
+	if err := migrate(db, migrations); err != nil {
+		return nil, nil, err
+	}
+
+	return sl, se, nil
+}
+
+func migrate(db *sql.DB, wanted []string) error {
+	// admin table
+	if _, err := db.Exec(`
+CREATE TABLE IF NOT EXISTS migration
+("id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, "query" TEXT)
+`); err != nil {
+		return err
+	}
+
+	// find existing
+	rows, err := db.Query(`SELECT query FROM migration ORDER BY id`)
+	if err != nil {
+		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+
+	existing := []string{}
+	for rows.Next() {
+		var query string
+		if err := rows.Scan(&query); err != nil {
+			return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+		}
+		existing = append(existing, string(query))
+	}
+	rows.Close()
+
+	// compare
+	missing, err := compareMigrations(wanted, existing)
+	if err != nil {
+		return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+	}
+
+	// execute missing
+	for _, query := range missing {
+		if _, err := db.Exec(string(query)); err != nil {
+			return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+		}
+
+		// register
+		if _, err := db.Exec(`
+INSERT INTO migration
+(query) VALUES (?)
+`, query); err != nil {
+			return fmt.Errorf("%w: %v", ErrSqliteFailure, err)
+		}
+	}
+
+	return nil
+}
+
+func compareMigrations(wanted, existing []string) ([]string, error) {
+	needed := []string{}
+	if len(wanted) < len(existing) {
+		return []string{}, ErrNotEnoughSQLMigrations
+	}
+
+	for i, want := range wanted {
+		switch {
+		case i >= len(existing):
+			needed = append(needed, want)
+		case want == existing[i]:
+			// do nothing
+		case want != existing[i]:
+			return []string{}, fmt.Errorf("%w: %v", ErrIncompatibleSQLMigration, want)
+		}
+	}
+
+	return needed, nil
+}

plan/storage/storage.go

@@ -1,10 +1,62 @@
 package storage
 
-import "go-mod.ewintr.nl/planner/item"
+import (
+	"errors"
+	"sort"
 
-type EventRepo interface {
+	"go-mod.ewintr.nl/planner/item"
+)
+
+var (
+	ErrNotFound = errors.New("not found")
+)
+
+type LocalID interface {
+	FindAll() (map[string]int, error)
+	Next() (int, error)
+	Store(id string, localID int) error
+	Delete(id string) error
+}
+
+type Event interface {
 	Store(event item.Event) error
 	Find(id string) (item.Event, error)
 	FindAll() ([]item.Event, error)
 	Delete(id string) error
 }
+
+func NextLocalID(used []int) int {
+	if len(used) == 0 {
+		return 1
+	}
+
+	sort.Ints(used)
+	usedMax := 1
+	for _, u := range used {
+		if u > usedMax {
+			usedMax = u
+		}
+	}
+
+	var limit int
+	for limit = 1; limit <= len(used) || limit < usedMax; limit *= 10 {
+	}
+
+	newId := used[len(used)-1] + 1
+	if newId < limit {
+		return newId
+	}
+
+	usedMap := map[int]bool{}
+	for _, u := range used {
+		usedMap[u] = true
+	}
+
+	for i := 1; i < limit; i++ {
+		if _, ok := usedMap[i]; !ok {
+			return i
+		}
+	}
+
+	return limit
+}

plan/storage/storage_test.go

@@ -0,0 +1,76 @@
+package storage_test
+
+import (
+	"testing"
+
+	"go-mod.ewintr.nl/planner/plan/storage"
+)
+
+func TestNextLocalId(t *testing.T) {
+	for _, tc := range []struct {
+		name string
+		used []int
+		exp  int
+	}{
+		{
+			name: "empty",
+			used: []int{},
+			exp:  1,
+		},
+		{
+			name: "not empty",
+			used: []int{5},
+			exp:  6,
+		},
+		{
+			name: "multiple",
+			used: []int{2, 3, 4},
+			exp:  5,
+		},
+		{
+			name: "holes",
+			used: []int{1, 5, 8},
+			exp:  9,
+		},
+		{
+			name: "expand limit",
+			used: []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10},
+			exp:  11,
+		},
+		{
+			name: "wrap if possible",
+			used: []int{8, 9},
+			exp:  1,
+		},
+		{
+			name: "find hole",
+			used: []int{1, 2, 3, 4, 5, 7, 8, 9},
+			exp:  6,
+		},
+		{
+			name: "dont wrap if expanded before",
+			used: []int{15, 16},
+			exp:  17,
+		},
+		{
+			name: "do wrap if expanded limit is reached",
+			used: []int{99},
+			exp:  1,
+		},
+		{
+			name: "sync bug",
+			used: []int{151, 956, 955, 150, 154, 155, 145, 144,
+				136, 152, 148, 146, 934, 149, 937, 135, 140, 139,
+				143, 137, 153, 939, 138, 953, 147, 141, 938, 142,
+			},
+			exp: 957,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			act := storage.NextLocalID(tc.used)
+			if tc.exp != act {
+				t.Errorf("exp %v, got %v", tc.exp, act)
+			}
+		})
+	}
+}