package httpflv

import (
	"bufio"
	"github.com/q191201771/lal/pkg/util/connstat"
	"github.com/q191201771/lal/pkg/util/log"
	"github.com/q191201771/lal/pkg/util/unique"
	"net"
	url2 "net/url"
	"strings"
	"sync"
	"sync/atomic"
	"time"
)

var flvHTTPResponseHeaderStr = "HTTP/1.1 200 OK\r\n" +
	"Cache-Control: no-cache\r\n" +
	"Content-Type: video/x-flv\r\n" +
	"Connection: close\r\n" +
	"Expires: -1\r\n" +
	"Pragma: no-cache\r\n" +
	"\r\n"

var flvHTTPResponseHeader = []byte(flvHTTPResponseHeaderStr)

var flvHeaderBuf13 = []byte{0x46, 0x4c, 0x56, 0x01, 0x05, 0x0, 0x0, 0x0, 0x09, 0x0, 0x0, 0x0, 0x0}

var wChanSize = 1024 // TODO chef: 1024

type SubSession struct {
	UniqueKey string

	ConnStat     connstat.ConnStat
	writeTimeout int64

	StartTick  int64
	StreamName string
	AppName    string
	URI        string
	Headers    map[string]string

	HasKeyFrame bool

	conn  net.Conn
	rb    *bufio.Reader
	wChan chan []byte

	closeOnce     sync.Once
	exitChan      chan struct{}
	hasClosedFlag uint32
}

func NewSubSession(conn net.Conn, writeTimeout int64) *SubSession {
	uk := unique.GenUniqueKey("FLVSUB")
	log.Infof("lifecycle new SubSession. [%s] remoteAddr=%s", uk, conn.RemoteAddr().String())
	return &SubSession{
		writeTimeout: writeTimeout,
		conn:         conn,
		rb:           bufio.NewReaderSize(conn, readBufSize),
		wChan:        make(chan []byte, wChanSize),
		exitChan:     make(chan struct{}),
		UniqueKey:    uk,
	}
}

// TODO chef: read request timeout
func (session *SubSession) ReadRequest() (err error) {
	session.StartTick = time.Now().Unix()

	defer func() {
		if err != nil {
			session.Dispose(err)
		}
	}()

	var firstLine string
	_, firstLine, session.Headers, err = parseHTTPHeader(session.rb)
	if err != nil {
		return
	}

	items := strings.Split(string(firstLine), " ")
	if len(items) != 3 || items[0] != "GET" {
		err = httpFlvErr
		return
	}

	session.URI = items[1]
	var urlObj *url2.URL
	urlObj, err = url2.Parse(session.URI)
	if err != nil {
		return
	}
	if !strings.HasSuffix(urlObj.Path, ".flv") {
		err = httpFlvErr
		return
	}

	items = strings.Split(urlObj.Path, "/")
	if len(items) != 3 {
		err = httpFlvErr
		return
	}
	session.AppName = items[1]
	items = strings.Split(items[2], ".")
	if len(items) < 2 {
		err = httpFlvErr
		return
	}
	session.StreamName = items[0]

	return nil
}

func (session *SubSession) RunLoop() error {
	session.ConnStat.Start(0, session.writeTimeout)
	go func() {
		buf := make([]byte, 128)
		if _, err := session.conn.Read(buf); err != nil {
			log.Errorf("read failed. [%s] err=%v", session.UniqueKey, err)
			session.Dispose(err)
		}
	}()

	return session.runWriteLoop()
}

func (session *SubSession) WriteHTTPResponseHeader() {
	log.Infof("<----- http response header. [%s]", session.UniqueKey)
	session.WriteRawPacket(flvHTTPResponseHeader)
}

func (session *SubSession) WriteFlvHeader() {
	log.Infof("<----- http flv header. [%s]", session.UniqueKey)
	session.WriteRawPacket(flvHeaderBuf13)
}

func (session *SubSession) WriteTag(tag *Tag) {
	session.WriteRawPacket(tag.Raw)
}

func (session *SubSession) WriteRawPacket(pkt []byte) {
	if session.hasClosed() {
		return
	}
	for {
		select {
		case session.wChan <- pkt:
			return
		default:
			if session.hasClosed() {
				return
			}
		}
	}
}

func (session *SubSession) Dispose(err error) {
	session.closeOnce.Do(func() {
		log.Infof("lifecycle dispose SubSession. [%s] reason=%v", session.UniqueKey, err)
		atomic.StoreUint32(&session.hasClosedFlag, 1)
		close(session.exitChan)
		if err := session.conn.Close(); err != nil {
			log.Error("conn close error. [%s] err=%v", session.UniqueKey, err)
		}
	})
}

func (session *SubSession) runWriteLoop() error {
	for {
		select {
		case <-session.exitChan:
			return httpFlvErr
		case pkt := <-session.wChan:
			if session.hasClosed() {
				return httpFlvErr
			}

			// TODO chef: use bufio.Writer
			n, err := session.conn.Write(pkt)
			if err != nil {
				session.Dispose(err)
				return err
			}
			session.ConnStat.Write(n)
		}
	}
}

func (session *SubSession) hasClosed() bool {
	return atomic.LoadUint32(&session.hasClosedFlag) == 1
}