//go:build !js
// +build !js

package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"sync"
	"time"

	"connectrpc.com/connect"
	pb "github.com/chathaway-codes/home-sensors/v2/gen"
	servicepb "github.com/chathaway-codes/home-sensors/v2/gen/genconnect"
	"github.com/google/uuid"
	"github.com/pion/webrtc/v3"
	"github.com/pion/webrtc/v3/pkg/media"
	"github.com/pion/webrtc/v3/pkg/media/ivfreader"
	"google.golang.org/protobuf/encoding/prototext"
	"google.golang.org/protobuf/proto"
)

var (
	videoFileName = flag.String("in", "/home/charles/Downloads/simpsons_movie_1080p_hddvd_trailer/output.ivf", "Where to load data from; if set to -, stdin will be used")
)

func withAuth[T any](token string, v *T) *connect.Request[T] {
	req := connect.NewRequest[T](v)
	req.Header().Add("Authorization", "Bearer "+token)
	return req
}

func main() { //nolint
	flag.Parse()
	ctx := context.Background()

	/*httpClient := &http.Client{
		Transport: &http2.Transport{
			AllowHTTP: true,
			DialTLS: func(network, addr string, _ *tls.Config) (net.Conn, error) {
				// If you're also using this client for non-h2c traffic, you may want
				// to delegate to tls.Dial if the network isn't TCP or the addr isn't
				// in an allowlist.
				log.Printf("Connecting to %s : %s", network, addr)
				return net.Dial(network, addr)
			},
			// Don't forget timeouts!
		},
	}*/
	vid, err := newVideo(ctx)
	if err != nil {
		log.Fatalf("Failed to start video: %v", err)
	}
	client := servicepb.NewSignalerServiceClient(http.DefaultClient, "http://192.168.0.65:8080/")
	authToken, err := client.CreateAuthToken(ctx, connect.NewRequest(&pb.CreateAuthTokenRequest{
		Home: "home1234",
		Type: &pb.CreateAuthTokenRequest_Camera_{
			Camera: &pb.CreateAuthTokenRequest_Camera{
				Id: "movie",
			},
		},
	}))
	if err != nil {
		log.Fatalf("Failed to get auth token: %v", err)
	}
	token := authToken.Msg.GetToken()
	log.Printf("Got token %s", prototext.Format(authToken.Msg))

	// Create a new RTCPeerConnection
	log.Printf("Waiting for connections")

	for {
		// Wait for a session request
		session, err := client.PopSession(ctx, withAuth(token, &pb.PopSessionRequest{}))
		if err != nil {
			log.Fatalf("error creating session: %v", err)
		}
		go handleSession(ctx, client, token, session, vid)
	}
}

type video struct {
	mu        sync.Mutex
	listeners map[string]chan<- []byte
	codec     string
}

func newVideo(ctx context.Context) (*video, error) {
	var err error
	// Assert that we have an audio or video file
	videoFileName := *videoFileName
	var videoIn io.Reader
	if videoFileName == "-" {
		videoIn = os.Stdin
	} else {
		videoIn, err = os.Open(videoFileName)
		if err != nil {
			return nil, fmt.Errorf("failed to open %q: %v", videoFileName, err)
		}

	}

	ivf, header, err := ivfreader.NewWith(videoIn)
	if err != nil {
		return nil, fmt.Errorf("failed to read video: %v", err)
	}

	// Determine video codec
	var trackCodec string
	switch header.FourCC {
	case "AV01":
		trackCodec = webrtc.MimeTypeAV1
	case "VP90":
		trackCodec = webrtc.MimeTypeVP9
	case "VP80":
		trackCodec = webrtc.MimeTypeVP8
	default:
		return nil, fmt.Errorf("unable to handle FourCC %s", header.FourCC)
	}

	vid := &video{
		listeners: make(map[string]chan<- []byte),
		codec:     trackCodec,
	}
	go func() {
		// Send our video file frame at a time. Pace our sending so we send it at the same speed it should be played back as.
		// This isn't required since the video is timestamped, but we will such much higher loss if we send all at once.
		//
		// It is important to use a time.Ticker instead of time.Sleep because
		// * avoids accumulating skew, just calling time.Sleep didn't compensate for the time spent parsing the data
		// * works around latency issues with Sleep (see https://github.com/golang/go/issues/44343)
		ticker := time.NewTicker(time.Millisecond * time.Duration((float32(header.TimebaseNumerator)/float32(header.TimebaseDenominator))*1000))
		for ; true; <-ticker.C {
			frame, _, ivfErr := ivf.ParseNextFrame()
			if errors.Is(ivfErr, io.EOF) {
				fmt.Printf("All video frames parsed and sent")
			}

			if ivfErr != nil {
				panic(ivfErr)
			}

			vid.mu.Lock()
			for _, lis := range vid.listeners {
				lis <- frame
			}
			vid.mu.Unlock()
		}
	}()

	return vid, nil
}

func (v *video) Join() (<-chan []byte, string, func()) {
	v.mu.Lock()
	defer v.mu.Unlock()

	myID := uuid.New().String()
	ch := make(chan []byte)
	v.listeners[myID] = ch

	return ch, v.codec, func() {
		v.mu.Lock()
		defer v.mu.Unlock()

		delete(v.listeners, myID)
	}
}

func handleSession(ctx context.Context, client servicepb.SignalerServiceClient, token string, session *connect.Response[pb.Session], vid *video) {
	var err error
	log.Printf("New session")

	peerConnection, err := webrtc.NewPeerConnection(webrtc.Configuration{
		ICEServers: []webrtc.ICEServer{
			{
				URLs: []string{"stun:stun.l.google.com:19302"},
			},
		},
	})

	// We use the cancel func to signal that the stream is ready
	iceConnectedCtx, iceConnectedCtxCancel := context.WithCancel(context.Background())
	defer func() {
		if err := peerConnection.Close(); err != nil {
			fmt.Printf("cannot close peerConnection: %v\n", err)
		}
	}()

	// connect to the video stream; the cleanup is done in the goroutine which
	// consumes the framess
	ch, trackCodec, cleanUp := vid.Join()
	// Create a video track
	videoTrack, videoTrackErr := webrtc.NewTrackLocalStaticSample(webrtc.RTPCodecCapability{MimeType: trackCodec}, "video", "pion")
	if videoTrackErr != nil {
		log.Printf("Failed to create video track: %v", err)
	}

	rtpSender, err := peerConnection.AddTrack(videoTrack)
	if err != nil {
		log.Printf("Failed to add track to connection: %v", err)
	}

	// Read incoming RTCP packets
	// Before these packets are returned they are processed by interceptors. For things
	// like NACK this needs to be called.
	go func() {
		rtcpBuf := make([]byte, 1500)
		for {
			if _, _, err := rtpSender.Read(rtcpBuf); err != nil {
				return
			}
		}
	}()

	go func() {
		defer cleanUp()
		readyToSend := false
		for frame := range ch {
			select {
			case <-iceConnectedCtx.Done():
				readyToSend = true
			default:
				// do nothing
			}
			if !readyToSend {
				continue
			}
			if err := videoTrack.WriteSample(media.Sample{Data: frame, Duration: time.Second}); err != nil {
				panic(err)
			}
		}
	}()

	// Set the handler for ICE connection state
	// This will notify you when the peer has connected/disconnected
	peerConnection.OnICEConnectionStateChange(func(connectionState webrtc.ICEConnectionState) {
		fmt.Printf("Connection State has changed %s \n", connectionState.String())
		if connectionState == webrtc.ICEConnectionStateConnected {
			iceConnectedCtxCancel()
		}
	})

	// Set the handler for Peer connection state
	// This will notify you when the peer has connected/disconnected
	peerConnection.OnConnectionStateChange(func(s webrtc.PeerConnectionState) {
		fmt.Printf("Peer Connection State has changed: %s\n", s.String())

		if s == webrtc.PeerConnectionStateFailed {
			// Wait until PeerConnection has had no network activity for 30 seconds or another failure. It may be reconnected using an ICE Restart.
			// Use webrtc.PeerConnectionStateDisconnected if you are interested in detecting faster timeout.
			// Note that the PeerConnection may come back from PeerConnectionStateDisconnected.
			fmt.Println("Peer Connection has gone to failed exiting")
			return
		}
	})

	peerConnection.OnICECandidate(func(i *webrtc.ICECandidate) {
		if i == nil {
			if _, err := client.CreateIceMessage(ctx, withAuth(token, &pb.CreateIceMessageRequest{
				SessionIdentifier: session.Msg.GetId(),
				IceMessage: &pb.IceMessage{
					Type: &pb.IceMessage_NoMoreCandidates{},
				},
			})); err != nil {
				log.Fatalf("Error sending done w/ candidates: %v", err)
			}
			return
		}
		c := i.ToJSON()
		var usernameFragment *string
		if c.UsernameFragment != nil {
			usernameFragment = proto.String(*c.UsernameFragment)
		}
		client.CreateIceMessage(ctx, withAuth(token, &pb.CreateIceMessageRequest{
			SessionIdentifier: session.Msg.GetId(),
			IceMessage: &pb.IceMessage{
				Type: &pb.IceMessage_Candidate{
					Candidate: &pb.IceCandidate{
						Candidate:        c.Candidate,
						SdpMid:           c.SDPMid,
						SdpLineIndex:     proto.Int32(int32(*c.SDPMLineIndex)),
						UsernameFragment: usernameFragment,
					},
				},
			},
		}))
	})
	log.Printf("Spawning helper")

	// helper which sends answers, waits for

	// Add ICE candidates from remote
	for {
		msg, err := client.PopIceMessage(ctx, withAuth(token, &pb.PopIceMessageRequest{
			SessionIdentifier: session.Msg.GetId(),
		}))
		if err != nil {
			log.Printf("failed to pop ice message: %v", err)
		}
		//log.Printf("Got ice message: %v", prototext.Format(msg.Msg))
		switch msg.Msg.Type.(type) {
		case *pb.IceMessage_Candidate:
			candidate := msg.Msg.GetCandidate()
			var sdpMLine *uint16
			if candidate.SdpLineIndex != nil {
				t := uint16(candidate.GetSdpLineIndex())
				sdpMLine = &t
			}
			if err := peerConnection.AddICECandidate(webrtc.ICECandidateInit{
				Candidate:     candidate.GetCandidate(),
				SDPMid:        candidate.SdpMid,
				SDPMLineIndex: sdpMLine,
			}); err != nil {
				log.Fatalf("Failed to add ice candidate: %v", err)
			}

			// Send back an answer
			answer, err := peerConnection.CreateAnswer(nil)
			if err != nil {
				log.Printf("Candidate failed")
				continue
			}

			if err := peerConnection.SetLocalDescription(answer); err != nil {
				log.Printf("Failed to set local description: %v", err)
			}

			_, err = client.CreateIceMessage(ctx, withAuth(token, &pb.CreateIceMessageRequest{
				SessionIdentifier: session.Msg.GetId(),
				IceMessage: &pb.IceMessage{
					Type: &pb.IceMessage_Session{
						Session: &pb.IceSessionDescription{
							SdpType: int64(answer.Type),
							Sdp:     answer.SDP,
						},
					},
				},
			}))
			if err != nil {
				log.Printf("Failed to send answer: %v", err)
			}
		case *pb.IceMessage_Session:
			iceSession := msg.Msg.GetSession()

			switch iceSession.SdpType {
			case int64(webrtc.SDPTypeOffer):
				offer := webrtc.SessionDescription{
					Type: webrtc.SDPType(iceSession.SdpType),
					SDP:  iceSession.Sdp,
				}

				if err := peerConnection.SetRemoteDescription(offer); err != nil {
					log.Fatalf("Failed to set remote description: %v", err)
				}
			default:
				log.Printf("unexpected sdp type: %v", webrtc.SDPType(iceSession.SdpType).String())
			}
			log.Printf("Accepted promise!")
		case *pb.IceMessage_NoMoreCandidates:
			// do nothing
		}
	}
}