package tracker

import (
	"context"
	"errors"
	"fmt"
	"net"
	"net/http"
	"net/url"
	"time"

	"github.com/anacrolix/dht/v2/krpc"
	"github.com/anacrolix/log"

	trHttp "github.com/anacrolix/torrent/tracker/http"
	"github.com/anacrolix/torrent/tracker/shared"
	"github.com/anacrolix/torrent/tracker/udp"
)

const (
	None      = shared.None
	Started   = shared.Started
	Stopped   = shared.Stopped
	Completed = shared.Completed
)

type AnnounceRequest = udp.AnnounceRequest

type AnnounceResponse = trHttp.AnnounceResponse

type Peer = trHttp.Peer

type AnnounceEvent = shared.AnnounceEvent

var ErrBadScheme = errors.New("unknown scheme")

type Announce struct {
	TrackerUrl          string
	Request             AnnounceRequest
	HostHeader          string
	HttpProxy           func(*http.Request) (*url.URL, error)
	HttpRequestDirector func(*http.Request) error
	DialContext         func(ctx context.Context, network, addr string) (net.Conn, error)
	ListenPacket        func(network, addr string) (net.PacketConn, error)
	ServerName          string
	UserAgent           string
	UdpNetwork          string
	// If the port is zero, it's assumed to be the same as the Request.Port.
	ClientIp4 krpc.NodeAddr
	// If the port is zero, it's assumed to be the same as the Request.Port.
	ClientIp6 krpc.NodeAddr
	Context   context.Context
	Logger    log.Logger
}

// The code *is* the documentation.
const DefaultTrackerAnnounceTimeout = 15 * time.Second

func (me Announce) Do() (res AnnounceResponse, err error) {
	cl, err := NewClient(me.TrackerUrl, NewClientOpts{
		Http: trHttp.NewClientOpts{
			Proxy:       me.HttpProxy,
			DialContext: me.DialContext,
			ServerName:  me.ServerName,
		},
		UdpNetwork:   me.UdpNetwork,
		Logger:       me.Logger.WithContextValue(fmt.Sprintf("tracker client for %q", me.TrackerUrl)),
		ListenPacket: me.ListenPacket,
	})
	if err != nil {
		return
	}
	defer cl.Close()
	if me.Context == nil {
		// This is just to maintain the old behaviour that should be a timeout of 15s. Users can
		// override it by providing their own Context. See comments elsewhere about longer timeouts
		// acting as rate limiting overloaded trackers.
		ctx, cancel := context.WithTimeout(context.Background(), DefaultTrackerAnnounceTimeout)
		defer cancel()
		me.Context = ctx
	}
	return cl.Announce(me.Context, me.Request, trHttp.AnnounceOpt{
		UserAgent:           me.UserAgent,
		HostHeader:          me.HostHeader,
		ClientIp4:           me.ClientIp4.IP,
		ClientIp6:           me.ClientIp6.IP,
		HttpRequestDirector: me.HttpRequestDirector,
	})
}
