package main

import (
	"fmt"
	"log"
	"net"
	"net/http"
	"net/http/pprof"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
)

var (
	grainSpawns = promauto.NewCounter(prometheus.CounterOpts{
		Name: "cart_grain_spawned_total",
		Help: "The total number of spawned grains",
	})
	grainMutations = promauto.NewCounter(prometheus.CounterOpts{
		Name: "cart_grain_mutations_total",
		Help: "The total number of mutations",
	})
	grainLookups = promauto.NewCounter(prometheus.CounterOpts{
		Name: "cart_grain_lookups_total",
		Help: "The total number of lookups",
	})
)

func spawn(id CartId) (*CartGrain, error) {
	grainSpawns.Inc()
	ret := &CartGrain{
		lastItemId:      0,
		lastDeliveryId:  0,
		Deliveries:      []*CartDelivery{},
		Id:              id,
		Items:           []*CartItem{},
		storageMessages: []Message{},
		TotalPrice:      0,
	}
	err := loadMessages(ret, id)
	return ret, err
}

func init() {
	os.Mkdir("data", 0755)
}

type App struct {
	pool    *GrainLocalPool
	storage *DiskStorage
}

func (a *App) Save() error {
	hasChanges := false
	a.pool.mu.RLock()
	defer a.pool.mu.RUnlock()
	for id, grain := range a.pool.GetGrains() {
		if grain == nil {
			continue
		}
		if grain.GetLastChange() > a.storage.LastSaves[id] {
			hasChanges = true
			err := a.storage.Store(id, grain)
			if err != nil {
				log.Printf("Error saving grain %s: %v\n", id, err)
			}
		}
	}

	if !hasChanges {
		return nil
	}
	return a.storage.saveState()
}

func (a *App) HandleSave(w http.ResponseWriter, r *http.Request) {
	err := a.Save()
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte(err.Error()))
	} else {
		w.WriteHeader(http.StatusCreated)
	}
}

var podIp = os.Getenv("POD_IP")
var name = os.Getenv("POD_NAME")

func GetDiscovery() Discovery {
	if podIp == "" {
		return nil
	}

	config, kerr := rest.InClusterConfig()

	if kerr != nil {
		log.Fatalf("Error creating kubernetes client: %v\n", kerr)
	}
	client, err := kubernetes.NewForConfig(config)
	if err != nil {
		log.Fatalf("Error creating client: %v\n", err)
	}
	return NewK8sDiscovery(client)
}

func main() {
	// Create a new instance of the server
	storage, err := NewDiskStorage(fmt.Sprintf("data/%s_state.gob", name))
	if err != nil {
		log.Printf("Error loading state: %v\n", err)
	}
	app := &App{
		pool:    NewGrainLocalPool(65535, 5*time.Minute, spawn),
		storage: storage,
	}

	syncedPool, err := NewSyncedPool(app.pool, podIp, GetDiscovery())
	if err != nil {
		log.Fatalf("Error creating synced pool: %v\n", err)
	}

	hg, err := NewGrainHandler(app.pool, ":1337")
	if err != nil {
		log.Fatalf("Error creating handler: %v\n", err)
	}

	go func() {
		for range time.Tick(time.Minute * 10) {

			err := app.Save()
			if err != nil {
				log.Printf("Error saving: %v\n", err)
			}
		}
	}()

	syncedServer := NewPoolServer(syncedPool, fmt.Sprintf("%s, %s", name, podIp))
	mux := http.NewServeMux()
	mux.Handle("/cart/", http.StripPrefix("/cart", syncedServer.Serve()))
	// only for local
	// mux.HandleFunc("GET /add/remote/{host}", func(w http.ResponseWriter, r *http.Request) {
	// 	syncedPool.AddRemote(r.PathValue("host"))
	// })
	// mux.HandleFunc("GET /save", app.HandleSave)
	//mux.HandleFunc("/", app.RewritePath)
	mux.HandleFunc("/debug/pprof/", pprof.Index)
	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
	mux.Handle("/metrics", promhttp.Handler())
	mux.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
		if !hg.IsHealthy() {
			w.WriteHeader(http.StatusInternalServerError)
			w.Write([]byte("handler not healthy"))
			return
		}
		if !syncedPool.IsHealthy() {
			w.WriteHeader(http.StatusInternalServerError)
			w.Write([]byte("pool not healthy"))
			return
		}

		w.WriteHeader(http.StatusOK)
		w.Write([]byte("ok"))
	})
	mux.HandleFunc("/readyz", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("ok"))
	})
	mux.HandleFunc("/livez", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("ok"))
	})
	mux.HandleFunc("/push", func(w http.ResponseWriter, r *http.Request) {
		log.Print(r.Body)
	})
	mux.HandleFunc("/version", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("1.0.0"))
	})

	l, err := net.Listen("tcp", ":1234")
	if err == nil {

		go func(listener net.Listener) {
			conn, err := l.Accept()
			log.Printf("Accepted connection from %s\n", conn.RemoteAddr())
			if err != nil {
				log.Fatalf("Error accepting echo connection: %v\n", err)
			}
			go func(c net.Conn) {
				defer c.Close()
				buf := make([]byte, 1024)
				for {
					n, err := c.Read(buf)
					if err != nil {
						log.Fatalf("Error reading from connection: %v\n", err)
					}
					log.Println("Echoing", string(buf[:n]))
					_, err = c.Write(buf[:n])
					if err != nil {
						log.Fatalf("Error writing to connection: %v\n", err)
					}
				}
			}(conn)
		}(l)
	} else {
		log.Println("Error creating echo server: %v\n", err)
	}

	sigs := make(chan os.Signal, 1)
	done := make(chan bool, 1)
	signal.Notify(sigs, syscall.SIGTERM)

	go func() {
		sig := <-sigs
		fmt.Println("Shutting down due to signal:", sig)
		app.Save()
		done <- true
	}()

	go http.ListenAndServe(":8080", mux)
	<-done

}