package trusttunnel

import (
	"context"
	"net"

	"github.com/sagernet/sing-box/adapter"
	"github.com/sagernet/sing-box/adapter/outbound"
	"github.com/sagernet/sing-box/common/dialer"
	"github.com/sagernet/sing-box/common/tls"
	C "github.com/sagernet/sing-box/constant"
	"github.com/sagernet/sing-box/log"
	"github.com/sagernet/sing-box/option"
	"github.com/sagernet/sing-box/transport/trusttunnel"
	"github.com/sagernet/sing/common"
	"github.com/sagernet/sing/common/bufio"
	E "github.com/sagernet/sing/common/exceptions"
	"github.com/sagernet/sing/common/logger"
	M "github.com/sagernet/sing/common/metadata"
	N "github.com/sagernet/sing/common/network"

	"golang.org/x/net/http2"
)

func RegisterOutbound(registry *outbound.Registry) {
	outbound.Register[option.TrustTunnelOutboundOptions](registry, C.TypeTrustTunnel, NewOutbound)
}

type Outbound struct {
	outbound.Adapter
	logger logger.ContextLogger
	client trusttunnel.Dialer
}

func NewOutbound(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.TrustTunnelOutboundOptions) (adapter.Outbound, error) {
	if options.TLS == nil || !options.TLS.Enabled {
		return nil, C.ErrTLSRequired
	}
	outboundDialer, err := dialer.New(ctx, options.DialerOptions, options.ServerIsDomain())
	if err != nil {
		return nil, err
	}
	serverAddr := options.ServerOptions.Build()
	networkList := options.Network.Build()
	clientOpts := trusttunnel.ClientOptions{
		Server:            serverAddr,
		Username:          options.Username,
		Password:          options.Password,
		QUIC:              options.QUIC,
		CongestionControl: options.CongestionController,
		CWND:              options.CWND,
		BBRProfile:        options.BBRProfile,
		HealthCheck:       options.HealthCheck,
	}
	if options.QUIC {
		tlsConfig, err := tls.NewClient(ctx, logger, options.Server, common.PtrValueOrDefault(options.TLS))
		if err != nil {
			return nil, err
		}
		if len(tlsConfig.NextProtos()) == 0 {
			tlsConfig.SetNextProtos([]string{"h3"})
		}
		clientOpts.QUICDialer = outboundDialer
		clientOpts.QUICTLSConfig = tlsConfig
	} else {
		tlsConfig, err := tls.NewClient(ctx, logger, options.Server, common.PtrValueOrDefault(options.TLS))
		if err != nil {
			return nil, err
		}
		if len(tlsConfig.NextProtos()) == 0 {
			tlsConfig.SetNextProtos([]string{http2.NextProtoTLS})
		}
		clientOpts.TLSDialer = tls.NewDialer(outboundDialer, tlsConfig)
	}
	var client trusttunnel.Dialer
	if options.Multiplex != nil && options.Multiplex.Enabled {
		clientOpts.MaxConnections = options.Multiplex.MaxConnections
		clientOpts.MinStreams = options.Multiplex.MinStreams
		clientOpts.MaxStreams = options.Multiplex.MaxStreams
		client, err = trusttunnel.NewMultiplexClient(ctx, clientOpts)
	} else {
		client, err = trusttunnel.NewClient(ctx, clientOpts)
	}
	if err != nil {
		return nil, err
	}
	return &Outbound{
		Adapter: outbound.NewAdapterWithDialerOptions(C.TypeTrustTunnel, tag, networkList, options.DialerOptions),
		logger:  logger,
		client:  client,
	}, nil
}

func (h *Outbound) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
	switch N.NetworkName(network) {
	case N.NetworkTCP:
		h.logger.InfoContext(ctx, "outbound connection to ", destination)
		return h.client.Dial(ctx, destination.String())
	case N.NetworkUDP:
		h.logger.InfoContext(ctx, "outbound packet connection to ", destination)
		conn, err := h.client.ListenPacket(ctx)
		if err != nil {
			return nil, err
		}
		return bufio.NewBindPacketConn(conn, destination), nil
	default:
		return nil, E.New("unsupported network: ", network)
	}
}

func (h *Outbound) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
	h.logger.InfoContext(ctx, "outbound packet connection to ", destination)
	return h.client.ListenPacket(ctx)
}

func (h *Outbound) Close() error {
	return h.client.Close()
}