// backend\main.go

package main

import (
	"context"
	"encoding/json"
	"log"
	"net/http"
	"os"
	"strings"

	"github.com/jackc/pgx/v5/pgxpool"
	"github.com/joho/godotenv"
)

func main() {
	if err := godotenv.Load(); err != nil {
		log.Println("Keine .env Datei gefunden, nutze System-Environment oder Fallbacks")
	}

	port := env("PORT", "8080")
	databaseURL := env("DATABASE_URL", "postgres://postgres:postgres@localhost:5432/teg?sslmode=disable")
	jwtSecret := env("JWT_SECRET", "dev-secret-change-me")
	frontendOrigin := env("FRONTEND_ORIGIN", "http://localhost:5173")

	ctx := context.Background()

	db, err := pgxpool.New(ctx, databaseURL)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	if err := db.Ping(ctx); err != nil {
		log.Fatal(err)
	}

	if err := ensureRuntimeDeviceSchema(ctx, db); err != nil {
		log.Fatal(err)
	}

	server := NewServer(db, jwtSecret, frontendOrigin)
	server.startPresenceMonitor(ctx)
	server.startDisappearingMessagesMonitor(ctx)
	if !server.webPushConfigured() {
		log.Println("Web Push ist nicht konfiguriert. VAPID_PUBLIC_KEY und VAPID_PRIVATE_KEY sowie eine Absenderadresse fehlen.")
	}

	log.Printf("Backend läuft auf http://localhost:%s", port)

	if err := http.ListenAndServe(":"+port, server.Routes()); err != nil {
		log.Fatal(err)
	}
}

func readJSON(r *http.Request, target any) error {
	return json.NewDecoder(r.Body).Decode(target)
}

func writeJSON(w http.ResponseWriter, status int, payload any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(payload)
}

func writeError(w http.ResponseWriter, status int, message string) {
	writeJSON(w, status, map[string]string{
		"error": message,
	})
}

func normalizeEmail(email string) string {
	return strings.ToLower(strings.TrimSpace(email))
}

func env(key string, fallback string) string {
	value := os.Getenv(key)

	if value == "" {
		return fallback
	}

	return value
}