package linknorm

import (
	"fmt"
	"net/url"
	"strings"

	"vpnclient/internal/config"
	"vpnclient/internal/protocols/awg"
	"vpnclient/internal/protocols/hysteria2"
	"vpnclient/internal/protocols/naive"
	"vpnclient/internal/protocols/xray"
)

// LooksLikeSubscriptionURL reports whether raw is a plain http(s) URL without
// userinfo — i.e. a subscription URL rather than a naive proxy share link
// (which always carries user:pass@). Callers should route such input into the
// subscription import flow instead of the proxy-URI parser.
func LooksLikeSubscriptionURL(raw string) bool {
	raw = strings.TrimSpace(raw)
	lower := strings.ToLower(raw)
	if !strings.HasPrefix(lower, "http://") && !strings.HasPrefix(lower, "https://") {
		return false
	}
	u, err := url.Parse(raw)
	if err != nil || u.Host == "" {
		return false
	}
	return u.User == nil
}

// Normalize normalizes a share/proxy URI for the given protocol (or auto-detect).
func Normalize(proto config.Protocol, raw string) (normalized string, detected config.Protocol, remark string, err error) {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return "", proto, "", fmt.Errorf("пустая ссылка")
	}
	if proto == "" {
		proto = config.DetectProtocol(raw)
	}
	switch proto {
	case config.ProtocolHysteria2:
		u, rem, err := hysteria2.NormalizeShareLink(raw)
		return u, config.ProtocolHysteria2, rem, err
	case config.ProtocolAWG:
		u, rem, err := awg.NormalizeShareLink(raw)
		return u, config.ProtocolAWG, rem, err
	case config.ProtocolVLESS, config.ProtocolVMess, config.ProtocolTrojan:
		u, rem, err := xray.NormalizeShareLink(raw)
		if err != nil {
			return "", proto, "", err
		}
		detected = xray.DetectProtocol(u)
		if detected == "" {
			detected = proto
		}
		return u, detected, rem, nil
	case config.ProtocolNaive, "":
		if awg.Detect(raw) {
			u, rem, err := awg.NormalizeShareLink(raw)
			return u, config.ProtocolAWG, rem, err
		}
		// Safety net: a bare http(s) URL without user:pass@ is a subscription
		// URL, not a naive proxy link — callers should have routed it to the
		// subscription import flow (see LooksLikeSubscriptionURL).
		if LooksLikeSubscriptionURL(raw) {
			return "", config.ProtocolNaive, "", fmt.Errorf("это ссылка подписки (нет логина и пароля) — вставьте её в поле «URL подписки» или сохраните ещё раз: импорт запустится автоматически")
		}
		if xray.Detect(raw) {
			u, rem, err := xray.NormalizeShareLink(raw)
			return u, xray.DetectProtocol(raw), rem, err
		}
		u, rem, err := naive.ParseShareLink(raw)
		if err != nil {
			if hysteria2.Detect(raw) {
				u2, rem2, err2 := hysteria2.NormalizeShareLink(raw)
				return u2, config.ProtocolHysteria2, rem2, err2
			}
			return "", config.ProtocolNaive, "", err
		}
		return u, config.ProtocolNaive, rem, nil
	default:
		return "", proto, "", fmt.Errorf("unsupported protocol %q", proto)
	}
}