main.go

package main

import (
	"fmt"
	"net/http"
	"net/http/httputil"
	"net/url"

	"snowy_viewer/internal/cache"
	"snowy_viewer/internal/config"
	"snowy_viewer/internal/handlers"
	"snowy_viewer/internal/masterdata"
	"snowy_viewer/internal/middleware"
)

func main() {
	// Load configuration
	cfg := config.Load()

	// Initialize cache (Redis with memory fallback)
	appCache := cache.New(cfg.RedisURL)
	defer appCache.Close()

	// Initialize and load master data
	store := masterdata.NewStore(cfg.MasterDataPath)
	if err := store.Fetch(); err != nil {
		fmt.Printf("Initial fetch error: %v\n", err)
	}

	// Create router and register handlers
	mux := http.NewServeMux()
	handler := handlers.New(store)
	handler.RegisterRoutes(mux)

	// Prevent unknown /api/* paths from bouncing between Go and Next.js.
	mux.HandleFunc("/api/", func(w http.ResponseWriter, r *http.Request) {
		http.NotFound(w, r)
	})

	// Set up frontend proxy or default to API-only mode
	if cfg.FrontendProxyURL != "" && cfg.FrontendProxyURL != "none" {
		nextjsURL, err := url.Parse(cfg.FrontendProxyURL)
		if err != nil {
			fmt.Printf("Invalid FRONTEND_PROXY_URL %q: %v\n", cfg.FrontendProxyURL, err)
			setupAPIOnlyMode(mux)
		} else {
			nextjsProxy := httputil.NewSingleHostReverseProxy(nextjsURL)
			nextjsProxy.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
				fmt.Printf("Next.js proxy error for %s: %v\n", r.URL.Path, err)
				http.Error(w, "frontend upstream unavailable", http.StatusBadGateway)
			}
			fmt.Printf("Proxying frontend requests to Next.js server on %s\n", cfg.FrontendProxyURL)
			mux.Handle("/", nextjsProxy)
		}
	} else {
		setupAPIOnlyMode(mux)
	}

	// Apply middlewares and start server
	finalHandler := middleware.Chain(mux, middleware.CORS, middleware.Gzip)

	fmt.Printf("Server starting on :%s...\n", cfg.Port)
	if err := http.ListenAndServe(":"+cfg.Port, finalHandler); err != nil {
		fmt.Printf("Error starting server: %s\n", err)
	}
}

func setupAPIOnlyMode(mux *http.ServeMux) {
	fmt.Println("Frontend proxy is disabled. API-only mode active.")
	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/" {
			w.Header().Set("Content-Type", "application/json")
			w.WriteHeader(http.StatusOK)
			w.Write([]byte(`{"status":"ok","message":"PJSK Moe API Server"}`))
			return
		}
		http.NotFound(w, r)
	})
}