package dialer

import (
	"context"
	"net"
	"time"

	"github.com/sagernet/sing-box/adapter"
	"github.com/sagernet/sing-box/common/warning"
	C "github.com/sagernet/sing-box/constant"
	"github.com/sagernet/sing-box/option"
	"github.com/sagernet/sing/common"
	"github.com/sagernet/sing/common/control"
	M "github.com/sagernet/sing/common/metadata"

	"github.com/database64128/tfo-go"
)

var warnBindInterfaceOnUnsupportedPlatform = warning.New(
	func() bool {
		return !(C.IsLinux || C.IsWindows)
	},
	"outbound option `bind_interface` is only supported on Linux and Windows",
)

var warnRoutingMarkOnUnsupportedPlatform = warning.New(
	func() bool {
		return !C.IsLinux
	},
	"outbound option `routing_mark` is only supported on Linux",
)

var warnReuseAdderOnUnsupportedPlatform = warning.New(
	func() bool {
		return !(C.IsDarwin || C.IsDragonfly || C.IsFreebsd || C.IsLinux || C.IsNetbsd || C.IsOpenbsd || C.IsSolaris || C.IsWindows)
	},
	"outbound option `reuse_addr` is unsupported on current platform",
)

var warnProtectPathOnNonAndroid = warning.New(
	func() bool {
		return !C.IsAndroid
	},
	"outbound option `protect_path` is only supported on Android",
)

var warnTFOOnUnsupportedPlatform = warning.New(
	func() bool {
		return !(C.IsDarwin || C.IsFreebsd || C.IsLinux || C.IsWindows)
	},
	"outbound option `tcp_fast_open` is unsupported on current platform",
)

type DefaultDialer struct {
	tfo.Dialer
	net.ListenConfig
}

func NewDefault(router adapter.Router, options option.DialerOptions) *DefaultDialer {
	var dialer net.Dialer
	var listener net.ListenConfig
	if options.BindInterface != "" {
		warnBindInterfaceOnUnsupportedPlatform.Check()
		dialer.Control = control.Append(dialer.Control, control.BindToInterface(router.InterfaceBindManager(), options.BindInterface))
		listener.Control = control.Append(listener.Control, control.BindToInterface(router.InterfaceBindManager(), options.BindInterface))
	} else if router.AutoDetectInterface() {
		if C.IsWindows {
			dialer.Control = control.Append(dialer.Control, control.BindToInterfaceIndexFunc(func() int {
				return router.AutoDetectInterfaceIndex()
			}))
			listener.Control = control.Append(listener.Control, control.BindToInterfaceIndexFunc(func() int {
				return router.AutoDetectInterfaceIndex()
			}))
		} else {
			dialer.Control = control.Append(dialer.Control, control.BindToInterfaceFunc(router.InterfaceBindManager(), func() string {
				return router.AutoDetectInterfaceName()
			}))
			listener.Control = control.Append(listener.Control, control.BindToInterfaceFunc(router.InterfaceBindManager(), func() string {
				return router.AutoDetectInterfaceName()
			}))
		}
	} else if router.DefaultInterface() != "" {
		dialer.Control = control.Append(dialer.Control, control.BindToInterface(router.InterfaceBindManager(), router.DefaultInterface()))
		listener.Control = control.Append(listener.Control, control.BindToInterface(router.InterfaceBindManager(), router.DefaultInterface()))
	}
	if options.RoutingMark != 0 {
		warnRoutingMarkOnUnsupportedPlatform.Check()
		dialer.Control = control.Append(dialer.Control, control.RoutingMark(options.RoutingMark))
		listener.Control = control.Append(listener.Control, control.RoutingMark(options.RoutingMark))
	} else if router.DefaultMark() != 0 {
		dialer.Control = control.Append(dialer.Control, control.RoutingMark(router.DefaultMark()))
		listener.Control = control.Append(listener.Control, control.RoutingMark(router.DefaultMark()))
	}
	if options.ReuseAddr {
		warnReuseAdderOnUnsupportedPlatform.Check()
		listener.Control = control.Append(listener.Control, control.ReuseAddr())
	}
	if options.ProtectPath != "" {
		warnProtectPathOnNonAndroid.Check()
		dialer.Control = control.Append(dialer.Control, control.ProtectPath(options.ProtectPath))
		listener.Control = control.Append(listener.Control, control.ProtectPath(options.ProtectPath))
	}
	if options.ConnectTimeout != 0 {
		dialer.Timeout = time.Duration(options.ConnectTimeout)
	} else {
		dialer.Timeout = C.TCPTimeout
	}
	if options.TCPFastOpen {
		warnTFOOnUnsupportedPlatform.Check()
	}
	return &DefaultDialer{tfo.Dialer{Dialer: dialer, DisableTFO: !options.TCPFastOpen}, listener}
}

func (d *DefaultDialer) DialContext(ctx context.Context, network string, address M.Socksaddr) (net.Conn, error) {
	conn, err := d.Dialer.DialContext(ctx, network, address.Unwrap().String())
	if err != nil {
		return nil, err
	}
	if tcpConn, isTCP := common.Cast[*net.TCPConn](conn); isTCP {
		tcpConn.SetKeepAlive(true)
		tcpConn.SetKeepAlivePeriod(C.TCPKeepAlivePeriod)
	}
	return conn, nil
}

func (d *DefaultDialer) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
	return d.ListenConfig.ListenPacket(ctx, C.NetworkUDP, "")
}

func (d *DefaultDialer) Upstream() any {
	return &d.Dialer
}