package main

import (
	"context"
	"errors"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/julienschmidt/httprouter"
)

func newRouter() *httprouter.Router {
	apiKey := os.Getenv("YOUTUBE_API_KEY")
	channelID := os.Getenv("YOUTUBE_CHANNEL_ID")

	if apiKey == "" {
		log.Fatalln("YOUTUBE_API_KEY is required")
	}

	if channelID == "" {
		log.Fatalln("YOUTUBE_CHANNEL_ID is required")
	}

	router := httprouter.New()
	router.GET("/stats", getChannelStats(apiKey, channelID))
	return router
}

func main() {
	srv := &http.Server{
		Addr:    ":8080",
		Handler: newRouter(),
	}

	idleConnsClosed := make(chan struct{})
	go func() {

		sigint := make(chan os.Signal, 1)
		signal.Notify(sigint, os.Interrupt)
		signal.Notify(sigint, syscall.SIGTERM)
		<-sigint

		log.Println("Shutting down server...")
		ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
		defer cancel()

		if err := srv.Shutdown(ctx); err != nil {
			log.Printf("error shutting down server: %v", err)
		}

		log.Println("Server shut down")
		close(idleConnsClosed)

	}()

	log.Println("Server is running at :8080")
	if err := srv.ListenAndServe(); err != nil {
		if !errors.Is(err, http.ErrServerClosed) {
			log.Fatalf("fatal http server error: %v", err)
		}
	}

	<-idleConnsClosed
	log.Println("Exiting...")
}