[PHASE-8] Add config load

cmd/server/main.go

@@ -2,32 +2,48 @@ package main
 
 import (
 	"context"
+	"flag"
 	"log/slog"
+	"net/http"
 	"os"
 	"os/signal"
 	"syscall"
 	"time"
 
+	"hash-of-wisdom/internal/config"
 	"hash-of-wisdom/internal/lib/sl"
 	"hash-of-wisdom/internal/pow/challenge"
 	"hash-of-wisdom/internal/quotes"
 	"hash-of-wisdom/internal/server"
 	"hash-of-wisdom/internal/service"
+
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	_ "net/http/pprof"
 )
 
 func main() {
-	addr := ":8080"
-	if len(os.Args) > 1 {
-		addr = os.Args[1]
+	configPath := flag.String("config", "", "path to configuration file")
+	flag.Parse()
+
+	// Load configuration
+	cfg, err := config.Load(*configPath)
+	if err != nil {
+		slog.Error("failed to load config", sl.Err(err))
+		os.Exit(1)
 	}
 
 	logger := slog.Default()
-	logger.Info("starting word of wisdom server", "address", addr)
+	logger.Info("starting word of wisdom server", "address", cfg.Server.Address)
 
-	// Create components
-	challengeConfig, err := challenge.NewConfig()
+	// Create components using config
+	challengeConfig, err := challenge.NewConfig(
+		challenge.WithDefaultDifficulty(cfg.PoW.Difficulty),
+		challenge.WithMaxDifficulty(cfg.PoW.MaxDifficulty),
+		challenge.WithChallengeTTL(cfg.PoW.TTL),
+		challenge.WithHMACSecret([]byte(cfg.PoW.HMACSecret)),
+	)
 	if err != nil {
-		logger.Error("failed to create config", sl.Err(err))
+		logger.Error("failed to create challenge config", sl.Err(err))
 		os.Exit(1)
 	}
 	generator := challenge.NewGenerator(challengeConfig)