package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"
	"strings"

	"github.com/PuerkitoBio/goquery"
)

type (
	// Meal contains the info about a meals
	Meal struct {
		Category string `json:"category"`
		Price    string `json:"price"`
		Title    string `json:"title"`
	}
	// Menu contains all info to menues in a mensa on one day
	Menu struct {
		Day   int    `json:"day"`
		Mensa string `json:"mensa"`
		Meals []Meal `json:"meals"`
	}
)

var (
	mensen = []string{
		"Zentralmensa",
		"Nordmensa",
	}
)

func main() {
	path := "./"
	if len(os.Args) == 2 {
		path = os.Args[1] + "/"
	}

	for _, mensa := range mensen {
		for day := 1; day < 8; day = day + 1 {
			menu, err := operate(mensa, day)
			if err != nil {
				fmt.Println(err.Error())
				return
			}

			content, err := json.Marshal(menu)
			if err != nil {
				fmt.Println(err.Error())
				return
			}

			err = ioutil.WriteFile(fmt.Sprintf("%s/%s.%v.json", path, strings.ToLower(mensa), day), content, 0644)
			if err != nil {
				fmt.Println(err.Error())
				return
			}
		}
	}
}

func writeToFile(content []byte) error {
	err := ioutil.WriteFile(os.Args[1], content, 0644)
	if err != nil {
		return err
	}
	return nil
}

func operate(mensa string, day int) (Menu, error) {
	meals, err := parseHTML(fmt.Sprintf("http://www.studentenwerk-goettingen.de/speiseplan.html?no_cache=1&day=%vpush=0&selectmensa=%s", day, mensa))
	if err != nil {
		return Menu{}, err
	}

	return Menu{Day: day, Mensa: mensa, Meals: meals}, nil
}

func parseHTML(url string) ([]Meal, error) {
	doc, err := goquery.NewDocument(url)
	if err != nil {
		return nil, err
	}

	meals := []Meal{}
	doc.Find("table.speise-tblmain tbody tr").Each(func(i int, s *goquery.Selection) {
		meal := Meal{
			Category: s.Find(".ext_sits_preis").Text(), // yes, really preis
			Title:    s.Find(".ext_sits_essen").Text(),
		}
		meals = append(meals, meal)
	})
	return meals, nil
}