package rtspplugin

import (
	"crypto/md5"
	b64 "encoding/base64"
	"encoding/hex"
	"fmt"
	"io"
	"log"
	"net"
	"net/url"
	"strconv"
	"strings"
	"time"
)

var (
	VideoWidth  int
	VideoHeight int
)

type RtspClient struct {
	socket   net.Conn
	OutGoing chan []byte //out chanel
	Signals  chan bool   //Signals quit
	host     string      //host
	port     string      //port
	uri      string      //url
	auth     bool        //aut
	login    string
	password string   //password
	session  string   //rtsp session
	responce string   //responce string
	bauth    string   //string b auth
	track    []string //rtsp track
	cseq     int      //qury number
	videow   int
	videoh   int
}

//вернет пустой инициализированный обьект
func RtspClientNew() *RtspClient {
	Obj := &RtspClient{
		cseq:     1,                         //стартовый номер запроса
		Signals:  make(chan bool, 1),        //буферизируемый канал на 1 сообщение
		OutGoing: make(chan []byte, 100000), //буферизиуемый канал на 100000 байт
	}
	return Obj
}

//основная функция работы с rtsp
func (this *RtspClient) Client(rtsp_url string) (bool, string) {
	//проверить и отпарсить url
	if !this.ParseUrl(rtsp_url) {
		return false, "Не верный url"
	}
	//установить подключение к камере
	if !this.Connect() {
		return false, "Не возможно подключиться"
	}
	//фаза 1 OPTIONS первый этап общения с камерой
	//отправляем запрос OPTIONS
	if !this.Write("OPTIONS " + this.uri + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\n\r\n") {
		return false, "Не возможно отправить сообщение OPTIONS"
	}
	//читаем ответ на запрос OPTIONS
	if status, message := this.Read(); !status {
		return false, "Не возможно прочитать ответ OPTIONS соединение потеряно"
	} else if status && strings.Contains(message, "Digest") {
		if !this.AuthDigest("OPTIONS", message) {
			return false, "Требуеться авторизация Digest"
		}
	} else if status && strings.Contains(message, "Basic") {
		if !this.AuthBasic("OPTIONS", message) {
			return false, "Требуеться авторизация Basic"
		}
	} else if !strings.Contains(message, "200") {
		return false, "Ошибка OPTIONS not status code 200 OK " + message
	}

	////////////PHASE 2 DESCRIBE
	log.Println("DESCRIBE " + this.uri + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + this.bauth + "\r\n\r\n")
	if !this.Write("DESCRIBE " + this.uri + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + this.bauth + "\r\n\r\n") {
		return false, "Не возможно отправть запрос DESCRIBE"
	}
	if status, message := this.Read(); !status {
		return false, "Не возможно прочитать ответ DESCRIBE соединение потеряно ?"
	} else if status && strings.Contains(message, "Digest") {
		if !this.AuthDigest("DESCRIBE", message) {
			return false, "Требуеться авторизация Digest"
		}
	} else if status && strings.Contains(message, "Basic") {
		if !this.AuthBasic("DESCRIBE", message) {
			return false, "Требуеться авторизация Basic"
		}
	} else if !strings.Contains(message, "200") {
		return false, "Ошибка DESCRIBE not status code 200 OK " + message
	} else {
		log.Println(message)
		this.track = this.ParseMedia(message)

	}
	if len(this.track) == 0 {
		return false, "Ошибка track not found "
	}
	//PHASE 3 SETUP
	log.Println("SETUP " + this.uri + "/" + this.track[0] + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\nTransport: RTP/AVP/TCP;unicast;interleaved=0-1" + this.bauth + "\r\n\r\n")
	if !this.Write("SETUP " + this.uri + "/" + this.track[0] + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\nTransport: RTP/AVP/TCP;unicast;interleaved=0-1" + this.bauth + "\r\n\r\n") {
		return false, ""
	}
	if status, message := this.Read(); !status {
		return false, "Не возможно прочитать ответ SETUP соединение потеряно"

	} else if !strings.Contains(message, "200") {
		if strings.Contains(message, "401") {
			str := this.AuthDigest_Only("SETUP", message)
			if !this.Write("SETUP " + this.uri + "/" + this.track[0] + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\nTransport: RTP/AVP/TCP;unicast;interleaved=0-1" + this.bauth + str + "\r\n\r\n") {
				return false, ""
			}
			if status, message := this.Read(); !status {
				return false, "Не возможно прочитать ответ SETUP соединение потеряно"

			} else if !strings.Contains(message, "200") {

				return false, "Ошибка SETUP not status code 200 OK " + message

			} else {
				this.session = ParseSession(message)
			}
		} else {
			return false, "Ошибка SETUP not status code 200 OK " + message
		}
	} else {
		log.Println(message)
		this.session = ParseSession(message)
		log.Println(this.session)
	}
	if len(this.track) > 1 {

		if !this.Write("SETUP " + this.uri + "/" + this.track[1] + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\nTransport: RTP/AVP/TCP;unicast;interleaved=2-3" + "\r\nSession: " + this.session + this.bauth + "\r\n\r\n") {
			return false, ""
		}
		if status, message := this.Read(); !status {
			return false, "Не возможно прочитать ответ SETUP Audio соединение потеряно"

		} else if !strings.Contains(message, "200") {
			if strings.Contains(message, "401") {
				str := this.AuthDigest_Only("SETUP", message)
				if !this.Write("SETUP " + this.uri + "/" + this.track[1] + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\nTransport: RTP/AVP/TCP;unicast;interleaved=2-3" + this.bauth + str + "\r\n\r\n") {
					return false, ""
				}
				if status, message := this.Read(); !status {
					return false, "Не возможно прочитать ответ SETUP Audio соединение потеряно"

				} else if !strings.Contains(message, "200") {

					return false, "Ошибка SETUP not status code 200 OK " + message

				} else {
					log.Println(message)
					this.session = ParseSession(message)
				}
			} else {
				return false, "Ошибка SETUP not status code 200 OK " + message
			}
		} else {
			log.Println(message)
			this.session = ParseSession(message)
		}
	}

	//PHASE 4 SETUP
	log.Println("PLAY " + this.uri + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\nSession: " + this.session + this.bauth + "\r\n\r\n")
	if !this.Write("PLAY " + this.uri + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\nSession: " + this.session + this.bauth + "\r\n\r\n") {
		return false, ""
	}
	if status, message := this.Read(); !status {
		return false, "Не возможно прочитать ответ PLAY соединение потеряно"

	} else if !strings.Contains(message, "200") {
		//return false, "Ошибка PLAY not status code 200 OK " + message
		if strings.Contains(message, "401") {
			str := this.AuthDigest_Only("PLAY", message)
			if !this.Write("PLAY " + this.uri + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\nSession: " + this.session + this.bauth + str + "\r\n\r\n") {
				return false, ""
			}
			if status, message := this.Read(); !status {
				return false, "Не возможно прочитать ответ PLAY соединение потеряно"

			} else if !strings.Contains(message, "200") {

				return false, "Ошибка PLAY not status code 200 OK " + message

			} else {
				//this.session = ParseSession(message)
				log.Print(message)
				go this.RtspRtpLoop()
				return true, "ok"
			}
		} else {
			return false, "Ошибка PLAY not status code 200 OK " + message
		}
	} else {
		log.Print(message)
		go this.RtspRtpLoop()
		return true, "ok"
	}
	return false, "other error"
}

/*
	The RTP header has the following format:
    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |V=2|P|X|  CC   |M|     PT      |       sequence number         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           timestamp                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           synchronization source (SSRC) identifier            |
   +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
   |            contributing source (CSRC) identifiers             |
   |                             ....                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   version (V): 2 bits
      This field identifies the version of RTP.  The version defined by
      this specification is two (2).  (The value 1 is used by the first
      draft version of RTP and the value 0 is used by the protocol
      initially implemented in the "vat" audio tool.)
   padding (P): 1 bit
      If the padding bit is set, the packet contains one or more
      additional padding octets at the end which are not part of the
      payload.  The last octet of the padding contains a count of how
      many padding octets should be ignored, including itself.  Padding
      may be needed by some encryption algorithms with fixed block sizes
      or for carrying several RTP packets in a lower-layer protocol data
      unit.
   extension (X): 1 bit
      If the extension bit is set, the fixed header MUST be followed by
      exactly one header extension, with a format defined in Section
      5.3.1.
*/
func (this *RtspClient) RtspRtpLoop() {
	defer func() {
		this.Signals <- true
	}()
	header := make([]byte, 4)
	payload := make([]byte, 4096)
	//sync := make([]byte, 256)
	sync_b := make([]byte, 1)
	timer := time.Now()
	for {
		if int(time.Now().Sub(timer).Seconds()) > 50 {
			if !this.Write("OPTIONS " + this.uri + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + "\r\nSession: " + this.session + this.bauth + "\r\n\r\n") {
				return
			}
			timer = time.Now()
		}
		this.socket.SetDeadline(time.Now().Add(50 * time.Second))
		//read rtp hdr 4
		if n, err := io.ReadFull(this.socket, header); err != nil || n != 4 {
			//rtp hdr read error
			return
		}
		//log.Println(header)
		if header[0] != 36 {
			//log.Println("desync?", this.host)
			for {
				///////////////////////////skeep/////////////////////////////////////
				if n, err := io.ReadFull(this.socket, sync_b); err != nil && n != 1 {
					return
				} else if sync_b[0] == 36 {
					header[0] = 36
					if n, err := io.ReadFull(this.socket, header[1:]); err != nil && n == 3 {
						return
					}
					break
				}
			}
			/*
				//вычитываем 256 в попытке отсять мусор обрезать RTSP
				if string(header) == "RTSP" {
					if n, err := io.ReadFull(this.socket, sync); err != nil && n == 256 {
						return
					} else {
						rtsp_rtp := []byte(strings.Split(string(sync), "\r\n\r\n")[1])
						//отправим все что есть в буфере
						this.SendBufer(rtsp_rtp)
						continue
					}
				} else {
					log.Println("full desync")
					return
				}
			*/
		}

		payloadLen := (int)(header[2])<<8 + (int)(header[3])
		//log.Println("payloadLen", payloadLen)
		if payloadLen > 4096 || payloadLen < 12 {
			log.Println("desync", this.uri, payloadLen)
			return
		}
		if n, err := io.ReadFull(this.socket, payload[:payloadLen]); err != nil || n != payloadLen {
			return
		} else {
			this.OutGoing <- append(header, payload[:n]...)
		}
	}

}

//unsafe!
func (this *RtspClient) SendBufer(bufer []byte) {
	//тут надо отправлять все пакеты из буфера send all?
	payload := make([]byte, 4096)
	for {
		if len(bufer) < 4 {
			log.Fatal("bufer small")
		}
		dataLength := (int)(bufer[2])<<8 + (int)(bufer[3])
		if dataLength > len(bufer)+4 {
			if n, err := io.ReadFull(this.socket, payload[:dataLength-len(bufer)+4]); err != nil {
				return
			} else {
				this.OutGoing <- append(bufer, payload[:n]...)
				return
			}

		} else {
			this.OutGoing <- bufer[:dataLength+4]
			bufer = bufer[dataLength+4:]
		}
	}
}
func (this *RtspClient) Connect() bool {
	d := &net.Dialer{Timeout: 3 * time.Second}
	conn, err := d.Dial("tcp", this.host+":"+this.port)
	if err != nil {
		return false
	}
	this.socket = conn
	return true
}
func (this *RtspClient) Write(message string) bool {
	this.cseq += 1
	if _, e := this.socket.Write([]byte(message)); e != nil {
		return false
	}
	return true
}
func (this *RtspClient) Read() (bool, string) {
	buffer := make([]byte, 4096)
	if nb, err := this.socket.Read(buffer); err != nil || nb <= 0 {
		log.Println("socket read failed", err)
		return false, ""
	} else {
		return true, string(buffer[:nb])
	}
}
func (this *RtspClient) AuthBasic(phase string, message string) bool {
	this.bauth = "\r\nAuthorization: Basic " + b64.StdEncoding.EncodeToString([]byte(this.login+":"+this.password))
	if !this.Write(phase + " " + this.uri + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + this.bauth + "\r\n\r\n") {
		return false
	}
	if status, message := this.Read(); status && strings.Contains(message, "200") {
		this.track = ParseMedia(message)
		return true
	}
	return false
}
func (this *RtspClient) AuthDigest(phase string, message string) bool {
	nonce := ParseDirective(message, "nonce")
	realm := ParseDirective(message, "realm")
	hs1 := GetMD5Hash(this.login + ":" + realm + ":" + this.password)
	hs2 := GetMD5Hash(phase + ":" + this.uri)
	responce := GetMD5Hash(hs1 + ":" + nonce + ":" + hs2)
	dauth := "\r\n" + `Authorization: Digest username="` + this.login + `", realm="` + realm + `", nonce="` + nonce + `", uri="` + this.uri + `", response="` + responce + `"`
	if !this.Write(phase + " " + this.uri + " RTSP/1.0\r\nCSeq: " + strconv.Itoa(this.cseq) + dauth + "\r\n\r\n") {
		return false
	}
	if status, message := this.Read(); status && strings.Contains(message, "200") {
		this.track = ParseMedia(message)
		return true
	}
	return false
}
func (this *RtspClient) AuthDigest_Only(phase string, message string) string {
	nonce := ParseDirective(message, "nonce")
	realm := ParseDirective(message, "realm")
	hs1 := GetMD5Hash(this.login + ":" + realm + ":" + this.password)
	hs2 := GetMD5Hash(phase + ":" + this.uri)
	responce := GetMD5Hash(hs1 + ":" + nonce + ":" + hs2)
	dauth := "\r\n" + `Authorization: Digest username="` + this.login + `", realm="` + realm + `", nonce="` + nonce + `", uri="` + this.uri + `", response="` + responce + `"`
	return dauth
}
func (this *RtspClient) ParseUrl(rtsp_url string) bool {

	u, err := url.Parse(rtsp_url)
	if err != nil {
		return false
	}
	phost := strings.Split(u.Host, ":")
	this.host = phost[0]
	if len(phost) == 2 {
		this.port = phost[1]
	} else {
		this.port = "554"
	}
	this.login = u.User.Username()
	this.password, this.auth = u.User.Password()
	if u.RawQuery != "" {
		this.uri = "rtsp://" + this.host + ":" + this.port + u.Path + "?" + string(u.RawQuery)
	} else {
		this.uri = "rtsp://" + this.host + ":" + this.port + u.Path
	}
	return true
}
func (this *RtspClient) Close() {
	if this.socket != nil {
		this.socket.Close()
	}
}
func ParseDirective(header, name string) string {
	index := strings.Index(header, name)
	if index == -1 {
		return ""
	}
	start := 1 + index + strings.Index(header[index:], `"`)
	end := start + strings.Index(header[start:], `"`)
	return strings.TrimSpace(header[start:end])
}
func ParseSession(header string) string {
	mparsed := strings.Split(header, "\r\n")
	for _, element := range mparsed {
		if strings.Contains(element, "Session:") {
			if strings.Contains(element, ";") {
				fist := strings.Split(element, ";")[0]
				return fist[9:]
			} else {
				return element[9:]
			}
		}
	}
	return ""
}
func ParseMedia(header string) []string {
	letters := []string{}
	mparsed := strings.Split(header, "\r\n")
	paste := ""

	if true {
		log.Println("headers", header)
	}

	for _, element := range mparsed {
		if strings.Contains(element, "a=control:") && !strings.Contains(element, "*") && strings.Contains(element, "tra") {
			paste = element[10:]
			if strings.Contains(element, "/") {
				striped := strings.Split(element, "/")
				paste = striped[len(striped)-1]
			}
			letters = append(letters, paste)
		}

		dimensionsPrefix := "a=x-dimensions:"
		if strings.HasPrefix(element, dimensionsPrefix) {
			dims := []int{}
			for _, s := range strings.Split(element[len(dimensionsPrefix):], ",") {
				v := 0
				fmt.Sscanf(s, "%d", &v)
				if v <= 0 {
					break
				}
				dims = append(dims, v)
			}
			if len(dims) == 2 {
				VideoWidth = dims[0]
				VideoHeight = dims[1]
			}
		}
	}
	return letters
}
func GetMD5Hash(text string) string {
	hash := md5.Sum([]byte(text))
	return hex.EncodeToString(hash[:])
}
func (this *RtspClient) ParseMedia(header string) []string {
	letters := []string{}
	mparsed := strings.Split(header, "\r\n")
	paste := ""
	for _, element := range mparsed {
		if strings.Contains(element, "a=control:") && !strings.Contains(element, "*") && strings.Contains(element, "tra") {
			paste = element[10:]
			if strings.Contains(element, "/") {
				striped := strings.Split(element, "/")
				paste = striped[len(striped)-1]
			}
			letters = append(letters, paste)
		}

		dimensionsPrefix := "a=x-dimensions:"
		if strings.HasPrefix(element, dimensionsPrefix) {
			dims := []int{}
			for _, s := range strings.Split(element[len(dimensionsPrefix):], ",") {
				v := 0
				fmt.Sscanf(s, "%d", &v)
				if v <= 0 {
					break
				}
				dims = append(dims, v)
			}
			if len(dims) == 2 {
				this.videow = dims[0]
				this.videoh = dims[1]
			}
		}
	}
	return letters
}