package tuya

import (
	"encoding/json"
	"errors"
	"fmt"
	"net/url"
	"strconv"

	"github.com/AlexxIT/go2rtc/internal/streams"
	"github.com/AlexxIT/go2rtc/pkg/core"
	"github.com/AlexxIT/go2rtc/pkg/webrtc"
	pion "github.com/pion/webrtc/v4"
)

type Client struct {
	api       	*TuyaClient
	prod      	core.Producer
	done      chan struct{}
}

const (
	DefaultCnURL = "openapi.tuyacn.com"
	DefaultWestUsURL = "openapi.tuyaus.com"
	DefaultEastUsURL = "openapi-ueaz.tuyaus.com"
	DefaultCentralEuURL = "openapi.tuyaeu.com"
	DefaultWestEuURL = "openapi-weaz.tuyaeu.com"
	DefaultInURL = "openapi.tuyain.com"
)

func Dial(rawURL string) (core.Producer, error) {
	// Parse URL and validate basic params
	u, err := url.Parse(rawURL)
	if err != nil {
		return nil, err
	}

	query := u.Query()
	deviceID := query.Get("device_id")
	uid := query.Get("uid")
	clientID := query.Get("client_id")
	secret := query.Get("secret")
	resolution := query.Get("resolution")
	useRTSP := query.Get("rtsp") == "1"
	useHLS := query.Get("hls") == "1"

	if deviceID == "" || uid == "" || clientID == "" || secret == "" {
		return nil, errors.New("tuya: wrong query")
	}

	// Initialize Tuya API client
	tuyaAPI, err := NewTuyaClient(u.Hostname(), deviceID, uid, clientID, secret, useRTSP, useHLS)
	if err != nil {
		return nil, err
	}

	client := &Client{
		api: tuyaAPI,
		done: make(chan struct{}),
	}

	// RTSP
	if useRTSP {
		if client.api.rtspURL == "" {
			return nil, errors.New("tuya: no rtsp url")
		}

		return streams.GetProducer(client.api.rtspURL)
	}

	// HLS
	if useHLS {
		if client.api.hlsURL == "" {
			return nil, errors.New("tuya: no hls url")
		}
		return streams.GetProducer(client.api.hlsURL)
	}

	// Default to WebRTC
	conf := pion.Configuration{
		ICEServers: 		client.api.iceServers,
		ICETransportPolicy: pion.ICETransportPolicyAll,
		BundlePolicy:       pion.BundlePolicyMaxBundle,
	}

	api, err := webrtc.NewAPI()
	if err != nil {
		client.api.Close()
		return nil, err
	}

	pc, err := api.NewPeerConnection(conf)
	if err != nil {
		client.api.Close()
		return nil, err
	}

	// protect from sending ICE candidate before Offer
	var sendOffer core.Waiter

	// protect from blocking on errors
	defer sendOffer.Done(nil)

	// waiter will wait PC error or WS error or nil (connection OK)
	var connState core.Waiter

	prod := webrtc.NewConn(pc)
	prod.FormatName = "tuya/webrtc"
	prod.Mode = core.ModeActiveProducer
	prod.Protocol = "mqtt"
	prod.URL = rawURL

	client.prod = prod

	// Set up MQTT handlers
	client.api.mqtt.handleAnswer = func(answer AnswerFrame) {
		desc := pion.SessionDescription{
			Type: pion.SDPTypePranswer,
			SDP:  answer.Sdp,
		}

		if err = pc.SetRemoteDescription(desc); err != nil {
			client.Stop()
			return
		}
	
		if err = prod.SetAnswer(answer.Sdp); err != nil {
			client.Stop()
			return
		}
		
		prod.SDP = answer.Sdp
	}

	client.api.mqtt.handleCandidate = func(candidate CandidateFrame) {
		if candidate.Candidate != "" {
			prod.AddCandidate(candidate.Candidate)
			if err != nil {
				client.Stop()
			}
		}
	}

	client.api.mqtt.handleDisconnect = func() {
		client.Stop()
	}
	
	client.api.mqtt.handleError = func(err error) {
		fmt.Printf("Tuya error: %s\n", err.Error())
		client.Stop()
	}

	prod.Listen(func(msg any) {
		switch msg := msg.(type) {
		case *pion.ICECandidate:
			_ = sendOffer.Wait()
			client.api.sendCandidate("a=" + msg.ToJSON().Candidate)

		case pion.PeerConnectionState:
			switch msg {
			case pion.PeerConnectionStateNew:
				break
			case pion.PeerConnectionStateConnecting:
				break
			case pion.PeerConnectionStateConnected:
				connState.Done(nil)
			default:
				connState.Done(errors.New("webrtc: " + msg.String()))
			}
		}
	})

	// Create offer
	offer, err := prod.CreateOffer(client.api.medias)
	if err != nil {
		client.api.Close()
		return nil, err
	}

	// Send offer
	client.api.sendOffer(offer)
	sendOffer.Done(nil)

	if err = connState.Wait(); err != nil {
		return nil, err
	}

	if resolution != "" {
		value, err := strconv.Atoi(resolution)
		if err == nil {
			client.api.sendResolution(value)
		}
	}

	return client, nil
}

func (c *Client) GetMedias() []*core.Media {
	return c.prod.GetMedias()
}

func (c *Client) GetTrack(media *core.Media, codec *core.Codec) (*core.Receiver, error) {
	return c.prod.GetTrack(media, codec)
}

func (c *Client) AddTrack(media *core.Media, codec *core.Codec, track *core.Receiver) error {
	if webrtcProd, ok := c.prod.(*webrtc.Conn); ok {
		return webrtcProd.AddTrack(media, codec, track)
	}

	return fmt.Errorf("add track not supported")
}

func (c *Client) Start() error {
	return c.prod.Start()
}

func (c *Client) Stop() error {
	select {
	case <-c.done:
		return nil
	default:
		close(c.done)
	}

	if c.prod != nil {
		_ = c.prod.Stop()
	}

	if c.api != nil {
		c.api.Close()
	}

	return nil
}

func (c *Client) MarshalJSON() ([]byte, error) {
	if webrtcProd, ok := c.prod.(*webrtc.Conn); ok {
		return webrtcProd.MarshalJSON()
	}

	return json.Marshal(c.prod)
}