package main

import (
	"encoding/json"
	"fmt"
	"github.com/gorilla/sessions"
	"log"
	"math/rand"
	"net/http"
	"strconv"
)

type prob struct {
	Operation string
	First     int
	Second    int
	Score     int
}

type solution struct {
	Status bool
	Score  int
}

type JsonHandler func(http.ResponseWriter, *http.Request)

func (h JsonHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	h(w, req)
}

func getScore(session *sessions.Session) int {
	score := session.Values["Score"]
	var parsed_score int
	if score == nil {
		parsed_score = 0
	} else {
		parsed_score = score.(int)
	}
	return parsed_score
}

func problem(w http.ResponseWriter, req *http.Request) {
	operation := "+"
	if r := rand.Intn(2); r == 0 {
		operation = "-"
	}

	first := rand.Intn(MAX)
	var second int
	if operation == "-" {
		if first == 0 {
			second = 0
		} else {
			second = rand.Intn(first)
		}
	} else {
		second = rand.Intn(MAX)
	}

	session, _ := store.Get(req, "Score")
	score := getScore(session)

	r := prob{operation, first, second, score}

	b, err := json.Marshal(r)
	if err != nil {
		log.Fatal("issue with json marshalling", err)
	}
	j := string(b)
	fmt.Println("problem", j)
	fmt.Fprintf(w, j)
}

func attempt(w http.ResponseWriter, req *http.Request) {
	first, err := strconv.Atoi(req.FormValue("first"))
	if err != nil {
		log.Fatal("cannot parse first", err)
	}

	operation := req.FormValue("operation")

	second, err := strconv.Atoi(req.FormValue("second"))
	if err != nil {
		log.Fatal("cannot parse second", err)
	}

	var guess int
	answer := req.FormValue("answer")
	if answer == "" {
		guess = 0
	} else {
		guess, err = strconv.Atoi(answer)
		if err != nil {
			log.Fatal("cannot parser answer", err)
		}
	}

	var result bool
	if operation == "+" {
		result = first+second == guess
	} else if operation == "-" {
		result = first-second == guess
	}

	session, _ := store.Get(req, "Score")
	score := getScore(session)
	if result {
		score += 1
	} else {
		score -= 1
	}
	session.Values["Score"] = score
	session.Save(req, w)

	b, err := json.Marshal(solution{result, score})
	if err != nil {
		log.Fatal("cannot marshal solution", err)
	}
	j := string(b)
	fmt.Println("attempt", j)
	fmt.Fprintf(w, j)
}