#!/bin/sh

urlencode() {
    ENCODEDURL="$(curl -Gs -w %{url_effective} --data-urlencode @- ./ ||: )"
    printf '%s' "$ENCODEDURL" | sed 's/%0[aA]$//;s/^.*[?]//'
}

get_asp_var() {
    i=0
    for VAR in __VIEWSTATE __VIEWSTATEGENERATOR __EVENTVALIDATION ; do
        VAL="$(printf '%s' "$RESPONSE" | grep "id=\"$VAR\"" | cut -d '"' -f 8 | urlencode)"
        [ "$i" != 0 ] && printf '&'
        printf '%s=%s' "$VAR" "$VAL"
        i=+1
    done
}

download_iso() {
    hiddenISO="$1" SN="$2"
    URL="https://soportefirmadigital.com/sfdj/dl.aspx"
    RESPONSE="$(curl -s --compressed "$URL" -o -)"
    ASP_VARS="$(get_asp_var)"

    curl -s --compressed "$URL" --data-raw "$ASP_VARS" \
        --data-raw "__EVENTTARGET=ctl00%24certContents%24LinkButton3" \
        --data-raw "ctl00%24certContents%24hiddenISO=$hiddenISO" \
        --data-raw "ctl00%24certContents%24txtSerialNumber=$SN" \
        --data-raw "ctl00%24certContents%24chkConfirmo=on" \
        -o -
}