package torrent

import (
	"crypto/rand"
	"log/slog"
	"os"

	"git.kmsign.ru/royalcat/tstor/src/config"
	"git.kmsign.ru/royalcat/tstor/src/logwrap"
	"github.com/anacrolix/dht/v2/bep44"
	tlog "github.com/anacrolix/log"
	"github.com/anacrolix/torrent"
	"github.com/anacrolix/torrent/storage"
	"github.com/anacrolix/torrent/types/infohash"
)

func newClientConfig(st storage.ClientImpl, fis bep44.Store, cfg *config.TorrentClient, id [20]byte) *torrent.ClientConfig {
	l := slog.With("component", "torrent-client")

	// TODO download and upload limits
	torrentCfg := torrent.NewDefaultClientConfig()
	torrentCfg.PeerID = string(id[:])
	torrentCfg.DefaultStorage = st
	// torrentCfg.AlwaysWantConns = true
	torrentCfg.DropMutuallyCompletePeers = true
	// torrentCfg.TorrentPeersLowWater = 100
	// torrentCfg.TorrentPeersHighWater = 1000
	// torrentCfg.AcceptPeerConnections = true
	torrentCfg.Seed = true
	torrentCfg.DisableAggressiveUpload = false

	torrentCfg.PeriodicallyAnnounceTorrentsToDht = true
	// torrentCfg.ConfigureAnacrolixDhtServer = func(cfg *dht.ServerConfig) {
	// 	cfg.Store = fis
	// 	cfg.Exp = dhtTTL
	// 	cfg.PeerStore = fis
	// }

	tl := tlog.NewLogger("torrent-client")
	tl.SetHandlers(&logwrap.Torrent{L: l})

	torrentCfg.Logger = tl
	torrentCfg.Callbacks.NewPeer = append(torrentCfg.Callbacks.NewPeer, func(p *torrent.Peer) {
		l.With(peerAttrs(p)...).Debug("new peer")
	})
	torrentCfg.Callbacks.PeerClosed = append(torrentCfg.Callbacks.PeerClosed, func(p *torrent.Peer) {
		l.With(peerAttrs(p)...).Debug("peer closed")
	})
	torrentCfg.Callbacks.CompletedHandshake = func(pc *torrent.PeerConn, ih infohash.T) {
		attrs := append(peerAttrs(&pc.Peer), slog.String("infohash", ih.HexString()))
		l.With(attrs...).Debug("completed handshake")
	}
	torrentCfg.Callbacks.PeerConnAdded = append(torrentCfg.Callbacks.PeerConnAdded, func(pc *torrent.PeerConn) {
		l.With(peerAttrs(&pc.Peer)...).Debug("peer conn added")
	})
	torrentCfg.Callbacks.PeerConnClosed = func(pc *torrent.PeerConn) {
		l.With(peerAttrs(&pc.Peer)...).Debug("peer conn closed")
	}
	torrentCfg.Callbacks.CompletedHandshake = func(pc *torrent.PeerConn, ih infohash.T) {
		attrs := append(peerAttrs(&pc.Peer), slog.String("infohash", ih.HexString()))
		l.With(attrs...).Debug("completed handshake")
	}
	torrentCfg.Callbacks.ReceivedRequested = append(torrentCfg.Callbacks.ReceivedRequested, func(pme torrent.PeerMessageEvent) {
		l.With(peerAttrs(pme.Peer)...).Debug("received requested")
	})
	torrentCfg.Callbacks.ReceivedUsefulData = append(torrentCfg.Callbacks.ReceivedUsefulData, func(pme torrent.PeerMessageEvent) {
		l.With(peerAttrs(pme.Peer)...).Debug("received useful data")
	})

	return torrentCfg
}

var emptyBytes [20]byte

func getOrCreatePeerID(p string) ([20]byte, error) {
	idb, err := os.ReadFile(p)
	if err == nil {
		var out [20]byte
		copy(out[:], idb)

		return out, nil
	}

	if !os.IsNotExist(err) {
		return emptyBytes, err
	}

	var out [20]byte
	_, err = rand.Read(out[:])
	if err != nil {
		return emptyBytes, err
	}

	return out, os.WriteFile(p, out[:], 0755)
}

func peerAttrs(peer *torrent.Peer) []any {
	out := []any{
		slog.String("ip", peer.RemoteAddr.String()),
		slog.String("discovery", string(peer.Discovery)),
		slog.Int("max-requests", peer.PeerMaxRequests),
		slog.Bool("prefers-encryption", peer.PeerPrefersEncryption),
	}

	if peer.Torrent() != nil {
		out = append(out, slog.String("torrent", peer.Torrent().Name()))
	}

	return out
}