local function escape(s)
    return string.gsub(s, "([^A-Za-z0-9_])", function(c)
        return string.format("%%%02x", string.byte(c))
    end)
end

local function geturl(str, to, from)
    from = from or "en"
    assert(str)
    assert(to)
    return ("http://translate.google.com/translate_a/t?client=t&text=%s&sl=%s&tl=%s&ie=UTF-8&oe=UTF-8"):format(escape(str), from, to)
end

local function translate(str, from, to, callback)
    http.Fetch(geturl(str, to, from), function(data)
        local res = data:match("%[%[%[\"(.-)\"")
        callback(res)
    end)
end

google_translate = translate