package main

import (
	"crypto"
	"fmt"
	"net"
	"net/http"
	"os"
	"strconv"
	"time"

	"github.com/chipaca/progress"
	_ "golang.org/x/crypto/sha3"
)

func die(msg interface{}) {
	fmt.Fprintln(os.Stderr, msg)
	os.Exit(1)
}

func main() {
	if len(os.Args) != 3 {
		die("usage: schmurl <URL> <SHA3-384>")
	}

	tr := &http.Transport{
		Proxy: http.ProxyFromEnvironment,
		Dial: (&net.Dialer{
			Timeout:   30 * time.Second,
			KeepAlive: 10 * time.Millisecond,
		}).Dial,
		TLSHandshakeTimeout:   10 * time.Second,
		ExpectContinueTimeout: 1 * time.Second,
	}

	client := &http.Client{Transport: tr}

	rsp, err := client.Get(os.Args[1])
	if err != nil {
		die(err)
	}

	toRead, err := strconv.ParseInt(rsp.Header.Get("content-length"), 10, 64)
	if err != nil {
		die(err)
	}

	bar := progress.Bar{
		ToRead: toRead,
	}

	h := crypto.SHA3_384.New()

	if _, err := bar.Copy(h, rsp.Body); err != nil {
		die(err)
	}
	sha := fmt.Sprintf("%x", h.Sum(nil))
	fmt.Println("\ngot sha:", sha)
	if os.Args[2] != sha {
		die("bad SHA")
	}
	fmt.Println("OK")
}