refactor: loader package

client/loader/loader.go

@@ -0,0 +1,112 @@
+package loader
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"galaxy/connector"
+	mc "galaxy/model/client"
+	"galaxy/storage"
+	"plugin"
+	"time"
+
+	"fyne.io/fyne/v2"
+)
+
+type ClientInit func(context.Context, storage.UIStorage, connector.UIConnector, fyne.App) (mc.Client, error)
+
+type loader struct {
+	s    storage.Storage
+	conn connector.Connector
+	cli  mc.Client
+}
+
+const (
+	clientLibraryFile = "client"
+)
+
+var (
+	checkConnectionTimeout = time.Second * 5
+	checkVersionTimeout    = time.Minute * 60
+)
+
+func NewLoader(ctx context.Context, s storage.Storage, conn connector.Connector, app fyne.App) (*loader, error) {
+	cli, err := loadClientPlugin(ctx, s, conn, app, "./client.so", "Factory")
+	if err != nil {
+		return nil, err
+	}
+	l := &loader{
+		conn: conn,
+		cli:  cli,
+		s:    s,
+	}
+	return l, nil
+}
+
+func (l *loader) Run(ctx context.Context) error {
+	final := make(chan struct{}, 1)
+	if l.conn != nil {
+		go l.backgroundLoop(ctx, final)
+		defer func() { final <- struct{}{} }()
+	}
+	if err := l.cli.Run(); err != nil {
+		return err
+	}
+	final <- struct{}{}
+	return nil
+}
+
+func (l *loader) backgroundLoop(ctx context.Context, final <-chan struct{}) {
+	checkConnTimer := time.NewTimer(checkConnectionTimeout)
+	checkVersionTimer := time.NewTimer(checkVersionTimeout)
+	defer func() {
+		checkConnTimer.Stop()
+		checkVersionTimer.Stop()
+	}()
+	for {
+		select {
+		case <-ctx.Done():
+			l.cli.Shutdown()
+			return
+		case <-final:
+			return
+		case <-checkConnTimer.C:
+			isGood := l.conn.CheckConnection()
+			l.cli.OnConnection(isGood)
+			checkConnTimer.Reset(checkConnectionTimeout)
+		case <-checkVersionTimer.C:
+			versions, err := l.conn.CheckVersion()
+			if err != nil {
+				// propagate error to the UI
+			} else if latest, ok := latestVersion(versions); ok {
+				l.downloadVersion(latest)
+			}
+			checkVersionTimer.Reset(checkVersionTimeout)
+		}
+	}
+}
+
+// loadClientPlugin loads a Client implementation from a shared object (.so) file at the specified path.
+// It calls the constructor function by name, passing the necessary dependencies, and returns the initialized Client.
+func loadClientPlugin(ctx context.Context, s storage.UIStorage, conn connector.UIConnector, app fyne.App, path, name string) (mc.Client, error) {
+	if path == "" {
+		return nil, errors.New("no plugin path given")
+	}
+
+	plug, err := plugin.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("open plugin %q: %w", path, err)
+	}
+
+	sym, err := plug.Lookup(name)
+	if err != nil {
+		return nil, fmt.Errorf("lookup symbol %q: %w", name, err)
+	}
+
+	initializerPtr, ok := sym.(*ClientInit)
+	if !ok {
+		return nil, fmt.Errorf("unexpected type %T; want %T", sym, initializerPtr)
+	}
+
+	return (*initializerPtr)(ctx, s, conn, app)
+}