package main

import (
	"fmt"
	"github.com/antchfx/xpath"
	"github.com/antchfx/xquery/html"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strings"

	cli "github.com/urfave/cli/v2"
)

func main() {
	app := &cli.App{
		Name:  "GFS MOS",
		Usage: "Parse NOAA's GFS MOS for a given airport",
		Action: func(c *cli.Context) error {
			airport := strings.ToUpper(c.Args().First())
			if airport == "" {
				return cli.NewExitError("please pass the airport's ICAO as an argument", 1)
			}
			pre := getDataFromPre(airport)
			fmt.Println(pre)
			return nil
		},
	}

	err := app.Run(os.Args)
	if err != nil {
		log.Fatal(err)
	}
}

func getDataFromPre(airport string) string {
	url := fmt.Sprintf("https://www.nws.noaa.gov/cgi-bin/mos/getmav.pl?sta=%s", airport)

	response, err := http.Get(url)
	defer response.Body.Close()
	if err != nil {
		log.Fatal(err)
	}

	bytes, err := ioutil.ReadAll(response.Body)
	if err != nil {
		log.Fatal(err)
	}
	doc, err := htmlquery.Parse(string(bytes))
	if err != nil{
		panic(err)
	}
	for _, n := range htmlquery.Find(doc, "//a/@href") {
		fmt.Printf("%s \n", htmlquery.SelectAttr(n, "href")) // output href
	}

	return string(bytes)
}