package link

import (
	"net/url"
	"strings"

	"github.com/sagernet/sing-box/common"
	C "github.com/sagernet/sing-box/constant"
	"github.com/sagernet/sing-box/option"
	E "github.com/sagernet/sing/common/exceptions"
	"github.com/sagernet/sing/common/json/badoption"
)

func parseVLESSLink(link string) (option.Outbound, error) {
	linkURL, err := url.Parse(link)
	if err != nil {
		return option.Outbound{}, err
	}
	if linkURL.User == nil || linkURL.User.Username() == "" {
		return option.Outbound{}, E.New("missing uuid")
	}
	var options option.VLESSOutboundOptions
	TLSOptions := option.OutboundTLSOptions{
		ECH:     &option.OutboundECHOptions{},
		UTLS:    &option.OutboundUTLSOptions{},
		Reality: &option.OutboundRealityOptions{},
	}
	options.UUID = linkURL.User.Username()
	options.Server = linkURL.Hostname()
	TLSOptions.ServerName = linkURL.Hostname()
	options.ServerPort = common.StringToType[uint16](linkURL.Port())
	proxy := map[string]string{}
	for key, values := range linkURL.Query() {
		value := values[0]
		switch key {
		case "key", "alpn", "seed", "path", "host":
			proxy[key] = value
		default:
			proxy[key] = value
		}
	}
	for key, value := range proxy {
		switch key {
		case "type":
			Transport := option.V2RayTransportOptions{
				HTTPOptions: option.V2RayHTTPOptions{
					Host:    badoption.Listable[string]{},
					Headers: badoption.HTTPHeader{},
				},
				GRPCOptions: option.V2RayGRPCOptions{},
			}
			switch value {
			case "ws":
				Transport.Type = C.V2RayTransportTypeWebsocket
				Transport.WebsocketOptions = v2rayTransportWs(proxy["host"], proxy["path"])
			case "http":
				Transport.Type = C.V2RayTransportTypeHTTP
				if host, exists := proxy["host"]; exists && host != "" {
					Transport.HTTPOptions.Host = strings.Split(host, ",")
				}
				if path, exists := proxy["path"]; exists && path != "" {
					Transport.HTTPOptions.Path = path
				}
			case "grpc":
				Transport.Type = C.V2RayTransportTypeGRPC
				if serviceName, exists := proxy["serviceName"]; exists && serviceName != "" {
					Transport.GRPCOptions.ServiceName = serviceName
				}
			default:
				continue
			}
			options.Transport = &Transport
		case "security":
			if value == "tls" {
				TLSOptions.Enabled = true
			} else if value == "reality" {
				TLSOptions.Enabled = true
				TLSOptions.Reality.Enabled = true
			}
		case "insecure", "skip-cert-verify":
			if value == "1" || value == "true" {
				TLSOptions.Insecure = true
			}
		case "serviceName", "sni", "peer":
			TLSOptions.ServerName = value
		case "alpn":
			TLSOptions.ALPN = strings.Split(value, ",")
		case "fp":
			TLSOptions.UTLS.Enabled = true
			TLSOptions.UTLS.Fingerprint = value
		case "flow":
			if value == "xtls-rprx-vision" {
				options.Flow = "xtls-rprx-vision"
			}
		case "pbk":
			TLSOptions.Reality.PublicKey = value
		case "sid":
			TLSOptions.Reality.ShortID = value
		case "tfo", "tcp-fast-open", "tcp_fast_open":
			if value == "1" || value == "true" {
				options.TCPFastOpen = true
			}
		}
	}
	outbound := option.Outbound{
		Type: C.TypeVLESS,
		Tag:  linkURL.Fragment,
	}
	if TLSOptions.Enabled {
		options.TLS = &TLSOptions
	}
	outbound.Options = &options
	return outbound, nil
}