fix: prevent migration from breaking new installs

migrations/v3_v4.go

@@ -2,6 +2,8 @@ package migrations
 
 import (
 	"encoding/json"
+	"errors"
+	"fmt"
 	"log/slog"
 
 	"git.sr.ht/~ashkeel/strimertul/twitch/eventsub"
@@ -23,7 +25,7 @@ func migrateToV4(db database.Database, logger *slog.Logger) error {
 		"twitch/bot-custom-commands":       chat.CustomCommandsKey,
 	} {
 		if err := renameKey(db, oldKey, newKey, true); err != nil {
-			return err
+			return fmt.Errorf("failed to rename key '%s' to '%s': %w", oldKey, newKey, err)
 		}
 	}
 
@@ -37,7 +39,7 @@ func migrateToV4(db database.Database, logger *slog.Logger) error {
 		"twitch/ev/eventsub-event",
 	} {
 		if err := db.RemoveKey(key); err != nil {
-			return err
+			return fmt.Errorf("failed to remove key '%s': %w", key, err)
 		}
 	}
 
@@ -46,12 +48,16 @@ func migrateToV4(db database.Database, logger *slog.Logger) error {
 		CommandCooldown int `json:"command_cooldown"`
 	}
 	if err := db.GetJSON("twitch/bot-config", &botConfig); err != nil {
-		return err
+		if errors.Is(err, database.ErrEmptyKey) {
+			botConfig.CommandCooldown = 0
+		} else {
+			return fmt.Errorf("failed to get bot config: %w", err)
+		}
 	}
 	if err := db.PutJSON(chat.ConfigKey, chat.Config{
 		CommandCooldown: botConfig.CommandCooldown,
 	}); err != nil {
-		return err
+		return fmt.Errorf("failed to put chat config to new key: %w", err)
 	}
 
 	// Migrate eventsub history to their new keys
@@ -61,7 +67,10 @@ func migrateToV4(db database.Database, logger *slog.Logger) error {
 	}
 	var eventsubHistory []eventSubNotification
 	if err := db.GetJSON("twitch/eventsub-history", &eventsubHistory); err != nil {
-		return err
+		if !errors.Is(err, database.ErrEmptyKey) {
+			return fmt.Errorf("failed to get eventsub history: %w", err)
+		}
+		eventsubHistory = []eventSubNotification{}
 	}
 	eventsubHistoryMap := make(map[string][]eventSubNotification)
 	for _, notification := range eventsubHistory {
@@ -70,12 +79,12 @@ func migrateToV4(db database.Database, logger *slog.Logger) error {
 	}
 	for key, notifications := range eventsubHistoryMap {
 		if err := db.PutJSON(key, notifications); err != nil {
-			return err
+			return fmt.Errorf("failed to put eventsub history to new key '%s': %w", key, err)
 		}
 	}
 	// Clear old eventsub history key
 	if err := db.RemoveKey("twitch/eventsub-history"); err != nil {
-		return err
+		return fmt.Errorf("failed to remove key 'twitch/eventsub-history': %w", err)
 	}
 
 	return nil