package main

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

	messages "git.tornberg.me/go-cart-actor/proto"
	"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"
	"k8s.io/client-go/tools/clientcmd"
)

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{
		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
	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)
	}
}

type PoolServer struct {
	pod_name string
	pool     GrainPool
}

func NewPoolServer(pool GrainPool, pod_name string) *PoolServer {
	return &PoolServer{
		pod_name: pod_name,
		pool:     pool,
	}
}

func (s *PoolServer) HandleGet(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	data, err := s.pool.Get(ToCartId(id))
	if err != nil {
		w.WriteHeader(http.StatusNotFound)
		w.Write([]byte(err.Error()))
		return
	}
	w.Header().Set("Content-Type", "application/json")
	w.Header().Set("X-Pod-Name", s.pod_name)
	w.WriteHeader(http.StatusOK)
	w.Write(data)
}

func (s *PoolServer) HandleAddSku(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	sku := r.PathValue("sku")
	data, err := s.pool.Process(ToCartId(id), Message{
		Type:    AddRequestType,
		Content: &messages.AddRequest{Sku: sku},
	})
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte(err.Error()))
		return
	}
	w.Header().Set("Content-Type", "application/json")
	w.Header().Set("X-Pod-Name", s.pod_name)
	w.WriteHeader(http.StatusOK)
	w.Write(data)
}

func (s *PoolServer) Serve() *http.ServeMux {
	mux := http.NewServeMux()
	mux.HandleFunc("GET /{id}", s.HandleGet)
	mux.HandleFunc("GET /{id}/add/{sku}", s.HandleAddSku)
	return mux
}

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

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(1000, 5*time.Minute, spawn),
		storage: storage,
	}

	var config *rest.Config
	var kerr error
	if podIp == "" {
		config, kerr = clientcmd.BuildConfigFromFlags("", "/Users/mats/.kube/config")
	} else {
		config, kerr = rest.InClusterConfig()
	}
	if kerr != nil {
		log.Fatalf("Error creating kubernetes client: %v\n", err)
	}
	client, err := kubernetes.NewForConfig(config)
	if err != nil {
		log.Fatalf("Error creating client: %v\n", err)
	}
	d := NewK8sDiscovery(client)

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

	// if local
	//syncedPool.AddRemote("localhost")

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

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

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

	syncedServer := NewPoolServer(syncedPool, name)
	mux := http.NewServeMux()
	mux.Handle("/api/", http.StripPrefix("/api", 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.Handle("/metrics", promhttp.Handler())

	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, syscall.SIGTERM)
	done := make(chan bool, 1)
	go func() {
		sig := <-sigs
		fmt.Println("Shutting down due to signal:", sig)
		app.Save()
		done <- true
	}()

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

}