package libp2p

// This file contains all libp2p configuration options (except the defaults,
// those are in defaults.go).

import (
	"errors"
	"fmt"
	"time"

	"github.com/libp2p/go-libp2p-core/connmgr"
	"github.com/libp2p/go-libp2p-core/crypto"
	"github.com/libp2p/go-libp2p-core/metrics"
	"github.com/libp2p/go-libp2p-core/network"
	"github.com/libp2p/go-libp2p-core/peer"
	"github.com/libp2p/go-libp2p-core/peerstore"
	"github.com/libp2p/go-libp2p-core/pnet"

	"github.com/libp2p/go-libp2p/config"
	"github.com/libp2p/go-libp2p/p2p/host/autorelay"
	bhost "github.com/libp2p/go-libp2p/p2p/host/basic"
	relayv2 "github.com/libp2p/go-libp2p/p2p/protocol/circuitv2/relay"
	"github.com/libp2p/go-libp2p/p2p/protocol/holepunch"

	ma "github.com/multiformats/go-multiaddr"
	madns "github.com/multiformats/go-multiaddr-dns"
)

// ListenAddrStrings configures libp2p to listen on the given (unparsed)
// addresses.
func ListenAddrStrings(s ...string) Option {
	return func(cfg *Config) error {
		for _, addrstr := range s {
			a, err := ma.NewMultiaddr(addrstr)
			if err != nil {
				return err
			}
			cfg.ListenAddrs = append(cfg.ListenAddrs, a)
		}
		return nil
	}
}

// ListenAddrs configures libp2p to listen on the given addresses.
func ListenAddrs(addrs ...ma.Multiaddr) Option {
	return func(cfg *Config) error {
		cfg.ListenAddrs = append(cfg.ListenAddrs, addrs...)
		return nil
	}
}

// Security configures libp2p to use the given security transport (or transport
// constructor).
//
// Name is the protocol name.
//
// The transport can be a constructed security.Transport or a function taking
// any subset of this libp2p node's:
// * Public key
// * Private key
// * Peer ID
// * Host
// * Network
// * Peerstore
func Security(name string, tpt interface{}) Option {
	stpt, err := config.SecurityConstructor(tpt)
	err = traceError(err, 1)
	return func(cfg *Config) error {
		if err != nil {
			return err
		}
		if cfg.Insecure {
			return fmt.Errorf("cannot use security transports with an insecure libp2p configuration")
		}
		cfg.SecurityTransports = append(cfg.SecurityTransports, config.MsSecC{SecC: stpt, ID: name})
		return nil
	}
}

// NoSecurity is an option that completely disables all transport security.
// It's incompatible with all other transport security protocols.
var NoSecurity Option = func(cfg *Config) error {
	if len(cfg.SecurityTransports) > 0 {
		return fmt.Errorf("cannot use security transports with an insecure libp2p configuration")
	}
	cfg.Insecure = true
	return nil
}

// Muxer configures libp2p to use the given stream multiplexer (or stream
// multiplexer constructor).
//
// Name is the protocol name.
//
// The transport can be a constructed mux.Transport or a function taking any
// subset of this libp2p node's:
// * Peer ID
// * Host
// * Network
// * Peerstore
func Muxer(name string, tpt interface{}) Option {
	mtpt, err := config.MuxerConstructor(tpt)
	err = traceError(err, 1)
	return func(cfg *Config) error {
		if err != nil {
			return err
		}
		cfg.Muxers = append(cfg.Muxers, config.MsMuxC{MuxC: mtpt, ID: name})
		return nil
	}
}

// Transport configures libp2p to use the given transport (or transport
// constructor).
//
// The transport can be a constructed transport.Transport or a function taking
// any subset of this libp2p node's:
// * Transport Upgrader (*tptu.Upgrader)
// * Host
// * Stream muxer (muxer.Transport)
// * Security transport (security.Transport)
// * Private network protector (pnet.Protector)
// * Peer ID
// * Private Key
// * Public Key
// * Address filter (filter.Filter)
// * Peerstore
func Transport(tpt interface{}, opts ...interface{}) Option {
	tptc, err := config.TransportConstructor(tpt, opts...)
	err = traceError(err, 1)
	return func(cfg *Config) error {
		if err != nil {
			return err
		}
		cfg.Transports = append(cfg.Transports, tptc)
		return nil
	}
}

// Peerstore configures libp2p to use the given peerstore.
func Peerstore(ps peerstore.Peerstore) Option {
	return func(cfg *Config) error {
		if cfg.Peerstore != nil {
			return fmt.Errorf("cannot specify multiple peerstore options")
		}

		cfg.Peerstore = ps
		return nil
	}
}

// PrivateNetwork configures libp2p to use the given private network protector.
func PrivateNetwork(psk pnet.PSK) Option {
	return func(cfg *Config) error {
		if cfg.PSK != nil {
			return fmt.Errorf("cannot specify multiple private network options")
		}

		cfg.PSK = psk
		return nil
	}
}

// BandwidthReporter configures libp2p to use the given bandwidth reporter.
func BandwidthReporter(rep metrics.Reporter) Option {
	return func(cfg *Config) error {
		if cfg.Reporter != nil {
			return fmt.Errorf("cannot specify multiple bandwidth reporter options")
		}

		cfg.Reporter = rep
		return nil
	}
}

// Identity configures libp2p to use the given private key to identify itself.
func Identity(sk crypto.PrivKey) Option {
	return func(cfg *Config) error {
		if cfg.PeerKey != nil {
			return fmt.Errorf("cannot specify multiple identities")
		}

		cfg.PeerKey = sk
		return nil
	}
}

// ConnectionManager configures libp2p to use the given connection manager.
//
// The current "standard" connection manager lives in github.com/libp2p/go-libp2p-connmgr. See
// https://pkg.go.dev/github.com/libp2p/go-libp2p-connmgr?utm_source=godoc#NewConnManager.
func ConnectionManager(connman connmgr.ConnManager) Option {
	return func(cfg *Config) error {
		if cfg.ConnManager != nil {
			return fmt.Errorf("cannot specify multiple connection managers")
		}
		cfg.ConnManager = connman
		return nil
	}
}

// AddrsFactory configures libp2p to use the given address factory.
func AddrsFactory(factory config.AddrsFactory) Option {
	return func(cfg *Config) error {
		if cfg.AddrsFactory != nil {
			return fmt.Errorf("cannot specify multiple address factories")
		}
		cfg.AddrsFactory = factory
		return nil
	}
}

// EnableRelay configures libp2p to enable the relay transport.
// This option only configures libp2p to accept inbound connections from relays
// and make outbound connections_through_ relays when requested by the remote peer.
// This option supports both circuit v1 and v2 connections.
// (default: enabled)
func EnableRelay() Option {
	return func(cfg *Config) error {
		cfg.RelayCustom = true
		cfg.Relay = true
		return nil
	}
}

// DisableRelay configures libp2p to disable the relay transport.
func DisableRelay() Option {
	return func(cfg *Config) error {
		cfg.RelayCustom = true
		cfg.Relay = false
		return nil
	}
}

// EnableRelayService configures libp2p to run a circuit v2 relay,
// if we detect that we're publicly reachable.
func EnableRelayService(opts ...relayv2.Option) Option {
	return func(cfg *Config) error {
		cfg.EnableRelayService = true
		cfg.RelayServiceOpts = opts
		return nil
	}
}

// EnableAutoRelay configures libp2p to enable the AutoRelay subsystem.
//
// Dependencies:
//  * Relay (enabled by default)
//  * Routing (to find relays), or StaticRelays/DefaultStaticRelays.
//
// This subsystem performs automatic address rewriting to advertise relay addresses when it
// detects that the node is publicly unreachable (e.g. behind a NAT).
func EnableAutoRelay(opts ...autorelay.StaticRelayOption) Option {
	return func(cfg *Config) error {
		if len(opts) > 0 {
			if len(opts) > 1 {
				return errors.New("only expected a single static relay configuration option")
			}
			cfg.StaticRelayOpt = opts[0]
		}
		cfg.EnableAutoRelay = true
		return nil
	}
}

// StaticRelays configures known relays for autorelay; when this option is enabled
// then the system will use the configured relays instead of querying the DHT to
// discover relays.
// Deprecated: pass an autorelay.WithStaticRelays option to EnableAutoRelay.
func StaticRelays(relays []peer.AddrInfo) Option {
	return func(cfg *Config) error {
		cfg.StaticRelayOpt = autorelay.WithStaticRelays(relays)
		return nil
	}
}

// DefaultStaticRelays configures the static relays to use the known PL-operated relays.
// Deprecated: pass autorelay.WithDefaultStaticRelays to EnableAutoRelay.
func DefaultStaticRelays() Option {
	relays := make([]peer.AddrInfo, 0, len(autorelay.DefaultRelays))
	for _, addr := range autorelay.DefaultRelays {
		pi, err := peer.AddrInfoFromString(addr)
		if err != nil {
			panic(fmt.Sprintf("failed to initialize default static relays: %s", err))
		}
		relays = append(relays, *pi)
	}
	return StaticRelays(relays)
}

// ForceReachabilityPublic overrides automatic reachability detection in the AutoNAT subsystem,
// forcing the local node to believe it is reachable externally.
func ForceReachabilityPublic() Option {
	return func(cfg *Config) error {
		public := network.Reachability(network.ReachabilityPublic)
		cfg.AutoNATConfig.ForceReachability = &public
		return nil
	}
}

// ForceReachabilityPrivate overrides automatic reachability detection in the AutoNAT subsystem,
// forceing the local node to believe it is behind a NAT and not reachable externally.
func ForceReachabilityPrivate() Option {
	return func(cfg *Config) error {
		private := network.Reachability(network.ReachabilityPrivate)
		cfg.AutoNATConfig.ForceReachability = &private
		return nil
	}
}

// EnableNATService configures libp2p to provide a service to peers for determining
// their reachability status. When enabled, the host will attempt to dial back
// to peers, and then tell them if it was successful in making such connections.
func EnableNATService() Option {
	return func(cfg *Config) error {
		cfg.AutoNATConfig.EnableService = true
		return nil
	}
}

// AutoNATServiceRateLimit changes the default rate limiting configured in helping
// other peers determine their reachability status. When set, the host will limit
// the number of requests it responds to in each 60 second period to the set
// numbers. A value of '0' disables throttling.
func AutoNATServiceRateLimit(global, perPeer int, interval time.Duration) Option {
	return func(cfg *Config) error {
		cfg.AutoNATConfig.ThrottleGlobalLimit = global
		cfg.AutoNATConfig.ThrottlePeerLimit = perPeer
		cfg.AutoNATConfig.ThrottleInterval = interval
		return nil
	}
}

// ConnectionGater configures libp2p to use the given ConnectionGater
// to actively reject inbound/outbound connections based on the lifecycle stage
// of the connection.
//
// For more information, refer to go-libp2p-core.ConnectionGater.
func ConnectionGater(cg connmgr.ConnectionGater) Option {
	return func(cfg *Config) error {
		if cfg.ConnectionGater != nil {
			return errors.New("cannot configure multiple connection gaters, or cannot configure both Filters and ConnectionGater")
		}
		cfg.ConnectionGater = cg
		return nil
	}
}

// ResourceManager configures libp2p to use the given ResourceManager.
func ResourceManager(rcmgr network.ResourceManager) Option {
	return func(cfg *Config) error {
		if cfg.ResourceManager != nil {
			return errors.New("cannot configure multiple resource managers")
		}
		cfg.ResourceManager = rcmgr
		return nil
	}
}

// NATPortMap configures libp2p to use the default NATManager. The default
// NATManager will attempt to open a port in your network's firewall using UPnP.
func NATPortMap() Option {
	return NATManager(bhost.NewNATManager)
}

// NATManager will configure libp2p to use the requested NATManager. This
// function should be passed a NATManager *constructor* that takes a libp2p Network.
func NATManager(nm config.NATManagerC) Option {
	return func(cfg *Config) error {
		if cfg.NATManager != nil {
			return fmt.Errorf("cannot specify multiple NATManagers")
		}
		cfg.NATManager = nm
		return nil
	}
}

// Ping will configure libp2p to support the ping service; enable by default.
func Ping(enable bool) Option {
	return func(cfg *Config) error {
		cfg.DisablePing = !enable
		return nil
	}
}

// Routing will configure libp2p to use routing.
func Routing(rt config.RoutingC) Option {
	return func(cfg *Config) error {
		if cfg.Routing != nil {
			return fmt.Errorf("cannot specify multiple routing options")
		}
		cfg.Routing = rt
		return nil
	}
}

// NoListenAddrs will configure libp2p to not listen by default.
//
// This will both clear any configured listen addrs and prevent libp2p from
// applying the default listen address option. It also disables relay, unless the
// user explicitly specifies with an option, as the transport creates an implicit
// listen address that would make the node dialable through any relay it was connected to.
var NoListenAddrs = func(cfg *Config) error {
	cfg.ListenAddrs = []ma.Multiaddr{}
	if !cfg.RelayCustom {
		cfg.RelayCustom = true
		cfg.Relay = false
	}
	return nil
}

// NoTransports will configure libp2p to not enable any transports.
//
// This will both clear any configured transports (specified in prior libp2p
// options) and prevent libp2p from applying the default transports.
var NoTransports = func(cfg *Config) error {
	cfg.Transports = []config.TptC{}
	return nil
}

// UserAgent sets the libp2p user-agent sent along with the identify protocol
func UserAgent(userAgent string) Option {
	return func(cfg *Config) error {
		cfg.UserAgent = userAgent
		return nil
	}
}

// MultiaddrResolver sets the libp2p dns resolver
func MultiaddrResolver(rslv *madns.Resolver) Option {
	return func(cfg *Config) error {
		cfg.MultiaddrResolver = rslv
		return nil
	}
}

// Experimental
// EnableHolePunching enables NAT traversal by enabling NATT'd peers to both initiate and respond to hole punching attempts
// to create direct/NAT-traversed connections with other peers. (default: disabled)
//
// Dependencies:
//  * Relay (enabled by default)
//
// This subsystem performs two functions:
//
// 1. On receiving an inbound Relay connection, it attempts to create a direct connection with the remote peer
//    by initiating and co-ordinating a hole punch over the Relayed connection.
// 2. If a peer sees a request to co-ordinate a hole punch on an outbound Relay connection,
//    it will participate in the hole-punch to create a direct connection with the remote peer.
//
// If the hole punch is successful, all new streams will thereafter be created on the hole-punched connection.
// The Relayed connection will eventually be closed after a grace period.
//
// All existing indefinite long-lived streams on the Relayed connection will have to re-opened on the hole-punched connection by the user.
// Users can make use of the `Connected`/`Disconnected` notifications emitted by the Network for this purpose.
//
// It is not mandatory but nice to also enable the `AutoRelay` option (See `EnableAutoRelay`)
// so the peer can discover and connect to Relay servers  if it discovers that it is NATT'd and has private reachability via AutoNAT.
// This will then enable it to advertise Relay addresses which can be used to accept inbound Relay connections to then co-ordinate
// a hole punch.
//
// If `EnableAutoRelay` is configured and the user is confident that the peer has private reachability/is NATT'd,
// the `ForceReachabilityPrivate` option can be configured to short-circuit reachability discovery via AutoNAT
// so the peer can immediately start connecting to Relay servers.
//
// If `EnableAutoRelay` is configured, the `StaticRelays` option can be used to configure a static set of Relay servers
// for `AutoRelay` to connect to so that it does not need to discover Relay servers via Routing.
func EnableHolePunching(opts ...holepunch.Option) Option {
	return func(cfg *Config) error {
		cfg.EnableHolePunching = true
		cfg.HolePunchingOptions = opts
		return nil
	}
}

func WithDialTimeout(t time.Duration) Option {
	return func(cfg *Config) error {
		if t <= 0 {
			return errors.New("dial timeout needs to be non-negative")
		}
		cfg.DialTimeout = t
		return nil
	}
}