package parseurl

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

// Target is host, port, secret string from tg://proxy or explicit flags.
type Target struct {
	Host   string
	Port   int
	Secret string
}

// ParseTGProxy parses tg://proxy?server=&port=&secret= or t.me/proxy style query.
func ParseTGProxy(raw string) (*Target, error) {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return nil, fmt.Errorf("empty proxy url")
	}

	u, err := url.Parse(raw)
	if err != nil {
		return nil, err
	}

	if u.Scheme != "tg" {
		return nil, fmt.Errorf("expected tg:// scheme, got %q", u.Scheme)
	}

	host := u.Hostname()
	if host != "" && host != "proxy" {
		return nil, fmt.Errorf("unexpected tg host %q", host)
	}

	q := u.Query()
	server := strings.TrimSpace(q.Get("server"))
	if server == "" {
		return nil, fmt.Errorf("missing server parameter")
	}
	portStr := strings.TrimSpace(q.Get("port"))
	if portStr == "" {
		return nil, fmt.Errorf("missing port parameter")
	}
	port, err := strconv.Atoi(portStr)
	if err != nil || port < 1 || port > 65535 {
		return nil, fmt.Errorf("invalid port %q", portStr)
	}
	sec := strings.TrimSpace(q.Get("secret"))
	if sec == "" {
		return nil, fmt.Errorf("missing secret parameter")
	}

	return &Target{Host: server, Port: port, Secret: sec}, nil
}