package http

import (
	"errors"
	"fmt"
	"net/url"
	"slices"
	"strings"
)

var ErrOrigin = errors.New("http: the origin is not scheme://host[:port] of a served host")

func ParseOrigin(raw, scheme string, hosts ...string) (string, error) {
	refuse := fmt.Errorf("%w: %q", ErrOrigin, raw)
	if strings.Contains(raw, "#") {
		return "", refuse
	}
	u, err := url.Parse(raw)
	if err != nil || u.Scheme != scheme || u.Opaque != "" || u.User != nil || u.Host == "" || u.Path != "" || u.RawPath != "" || u.RawQuery != "" || u.ForceQuery || u.Fragment != "" {
		return "", refuse
	}
	host := CanonicalHost(u.Host)
	if host != u.Hostname() || !slices.Contains(hosts, host) {
		return "", refuse
	}
	return host, nil
}