Add HTTP API server for file downloads from Telegram links

Co-authored-by: krau <71133316+krau@users.noreply.github.com>

api/server.go

@@ -0,0 +1,72 @@
+package api
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/charmbracelet/log"
+	"github.com/krau/SaveAny-Bot/config"
+)
+
+var server *http.Server
+
+// Init initializes and starts the HTTP API server
+func Init(ctx context.Context) error {
+	cfg := config.C()
+	if !cfg.API.Enable {
+		return nil
+	}
+
+	logger := log.FromContext(ctx).WithPrefix("api")
+	
+	mux := http.NewServeMux()
+	
+	// Register API routes
+	registerRoutes(mux)
+	
+	// Wrap with middleware
+	handler := loggingMiddleware(logger)(authMiddleware(mux))
+	
+	server = &http.Server{
+		Addr:         fmt.Sprintf(":%d", cfg.API.Port),
+		Handler:      handler,
+		ReadTimeout:  15 * time.Second,
+		WriteTimeout: 15 * time.Second,
+		IdleTimeout:  60 * time.Second,
+	}
+	
+	go func() {
+		logger.Infof("Starting API server on port %d", cfg.API.Port)
+		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			logger.Errorf("API server error: %v", err)
+		}
+	}()
+	
+	// Graceful shutdown on context cancellation
+	go func() {
+		<-ctx.Done()
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		
+		if err := server.Shutdown(shutdownCtx); err != nil {
+			logger.Errorf("Failed to shutdown API server: %v", err)
+		} else {
+			logger.Info("API server stopped")
+		}
+	}()
+	
+	return nil
+}
+
+func registerRoutes(mux *http.ServeMux) {
+	// Health check endpoint (no auth required)
+	mux.HandleFunc("/health", handleHealth)
+	
+	// API v1 endpoints
+	mux.HandleFunc("POST /api/v1/tasks", handleCreateTask)
+	mux.HandleFunc("GET /api/v1/tasks/{id}", handleGetTask)
+	mux.HandleFunc("GET /api/v1/tasks", handleListTasks)
+	mux.HandleFunc("DELETE /api/v1/tasks/{id}", handleCancelTask)
+}