package main

import (
	"encoding/json"
	"log"
	"net/http"
	"strings"
)

type Restaurant struct {
	RestaurantId int64
	Name         string
}

type RestaurantList struct {
	Restaurants *[]*Restaurant `json:"restaurants"`
}

func (r *Restaurant) Write(w http.ResponseWriter) error {
	enc := json.NewEncoder(w)
	return enc.Encode(r)
}

func (r *Restaurant) Read(json_str string) error {
	dec := json.NewDecoder(strings.NewReader(json_str))
	return dec.Decode(r)
}

func (rl *RestaurantList) Write(w http.ResponseWriter) error {
	enc := json.NewEncoder(w)
	return enc.Encode(rl)
}

type RestaurantExistsError struct{}

func (aeu RestaurantExistsError) Error() string {
	return "Restaurant exists"
}

func GetRestaurants() (*[]*Restaurant, error) {
	var restaurants []*Restaurant

	_, err := DB.Select(&restaurants, "SELECT * from restaurants")
	if err != nil {
		return nil, err
	}
	return &restaurants, nil
}

func InsertRestaurant(r *Restaurant) error {
	transaction, err := DB.Begin()
	if err != nil {
		return err
	}

	existing, err := transaction.SelectInt("SELECT count(*) from users where Name=?", r.Name)
	if err != nil {
		transaction.Rollback()
		return err
	}
	if existing > 0 {
		transaction.Rollback()
		return RestaurantExistsError{}
	}

	err = transaction.Insert(r)
	if err != nil {
		transaction.Rollback()
		return err
	}

	err = transaction.Commit()
	if err != nil {
		transaction.Rollback()
		return err
	}

	return nil
}

func RestaurantHandler(w http.ResponseWriter, r *http.Request) {
	_, err := GetUserFromSession(r)
	if err != nil {
		WriteError(w, 1 /*Not Signed In*/)
		return
	}

	if r.Method == "POST" {
		restaurant_json := r.PostFormValue("restaurant")
		if restaurant_json == "" {
			WriteError(w, 3 /*Invalid Request*/)
			return
		}

		var restaurant Restaurant
		err := restaurant.Read(restaurant_json)
		if err != nil {
			WriteError(w, 3 /*Invalid Request*/)
			return
		}
		restaurant.RestaurantId = -1

		err = InsertRestaurant(&restaurant)
		if err != nil {
			if _, ok := err.(RestaurantExistsError); ok {
				WriteError(w, 6 /*Restaurant Exists*/)
			} else {
				WriteError(w, 999 /*Internal Error*/)
				log.Print(err)
			}
			return
		}

		w.WriteHeader(201 /*Created*/)
		err = restaurant.Write(w)
		if err != nil {
			WriteError(w, 999 /*Internal Error*/)
			log.Print(err)
			return
		}
	} else if r.Method == "GET" {
		var rl RestaurantList

		restaurants, err := GetRestaurants()
		if err != nil {
			WriteError(w, 999 /*Internal Error*/)
			log.Print(err)
			return
		}

		rl.Restaurants = restaurants
		err = (&rl).Write(w)
		if err != nil {
			WriteError(w, 999 /*Internal Error*/)
			log.Print(err)
			return
		}
	} else {
		/* No PUT or DELETE */
		WriteError(w, 3 /*Invalid Request*/)
		return
	}
}