package main

import (
	"encoding/gob"
	"encoding/json"
	"log"
	"net/http"
	"os"
	"time"
)

func spawn(id string) Grain {

	ret := &CartGrain{
		Id:              id,
		Items:           []CartItem{},
		storageMessages: []Message{},
		TotalPrice:      0,
	}
	err := loadMessages(ret, id)
	if err != nil {
		log.Printf("Error loading messages for grain %s: %v\n", id, err)
	}
	return ret
}

func init() {
	os.Mkdir("data", 0755)
	gob.Register(CartItem{})
	gob.Register(Message{})
}

type App struct {
	pool    *GrainLocalPool
	storage *DiskStorage
}

func (a *App) HandleGet(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	grain, err := a.pool.GetOrSpawn(id, spawn)
	if err != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(grain)
}

func (a *App) HandleAddSku(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	sku := r.PathValue("sku")
	grain, err := a.pool.GetOrSpawn(id, spawn)
	if err != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}
	message := &Message{
		Type:    "add",
		Content: sku,
	}
	var reply CartGrain
	err = grain.HandleMessage(message, false, &reply)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte(err.Error()))
		return
	}
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(reply)
}

func (a *App) Save() error {
	for id, grain := range a.pool.GetGrains() {
		err := a.storage.Store(id, grain)
		if err != nil {
			log.Printf("Error saving grain %s: %v\n", id, err)
		}
	}
	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)
	}
}

func main() {
	// Create a new instance of the server
	storage, err := NewDiskStorage("data/state.json")
	if err != nil {
		log.Printf("Error loading state: %v\n", err)
	}
	app := &App{
		pool:    NewGrainLocalPool(1000, 5*time.Minute),
		storage: storage,
	}

	mux := http.NewServeMux()
	mux.HandleFunc("GET /{id}", app.HandleGet)
	mux.HandleFunc("GET /{id}/add/{sku}", app.HandleAddSku)
	mux.HandleFunc("GET /save", app.HandleSave)
	http.ListenAndServe(":8080", mux)

}