import unittest, sequtils, sugar, strformat, options, strformat, random
import chronos, nimcrypto/utils, chronicles
import ../libp2p/[connection,
                  stream/lpstream,
                  stream/bufferstream,
                  transports/tcptransport,
                  transports/transport,
                  protocols/identify,
                  multiaddress,
                  muxers/mplex/mplex,
                  muxers/mplex/coder,
                  muxers/mplex/types,
                  muxers/mplex/lpchannel]

when defined(nimHasUsed): {.used.}

suite "Mplex":
  test "encode header with channel id 0":
    proc testEncodeHeader(): Future[bool] {.async.} =
      proc encHandler(msg: seq[byte]) {.async.} =
        check msg == fromHex("000873747265616d2031")

      let stream = newBufferStream(encHandler)
      let conn = newConnection(stream)
      await conn.writeMsg(0, MessageType.New, cast[seq[byte]]("stream 1"))
      result = true

    check:
      waitFor(testEncodeHeader()) == true

  test "encode header with channel id other than 0":
    proc testEncodeHeader(): Future[bool] {.async.} =
      proc encHandler(msg: seq[byte]) {.async.} =
        check msg == fromHex("88010873747265616d2031")

      let stream = newBufferStream(encHandler)
      let conn = newConnection(stream)
      await conn.writeMsg(17, MessageType.New, cast[seq[byte]]("stream 1"))
      result = true

    check:
      waitFor(testEncodeHeader()) == true

  test "encode header and body with channel id 0":
    proc testEncodeHeaderBody(): Future[bool] {.async.} =
      var step = 0
      proc encHandler(msg: seq[byte]) {.async.} =
        check msg == fromHex("020873747265616d2031")

      let stream = newBufferStream(encHandler)
      let conn = newConnection(stream)
      await conn.writeMsg(0, MessageType.MsgOut, cast[seq[byte]]("stream 1"))
      result = true

    check:
      waitFor(testEncodeHeaderBody()) == true

  test "encode header and body with channel id other than 0":
    proc testEncodeHeaderBody(): Future[bool] {.async.} =
      var step = 0
      proc encHandler(msg: seq[byte]) {.async.} =
        check msg == fromHex("8a010873747265616d2031")

      let stream = newBufferStream(encHandler)
      let conn = newConnection(stream)
      await conn.writeMsg(17, MessageType.MsgOut, cast[seq[byte]]("stream 1"))
      await conn.close()
      result = true

    check:
      waitFor(testEncodeHeaderBody()) == true

  test "decode header with channel id 0":
    proc testDecodeHeader(): Future[bool] {.async.} =
      let stream = newBufferStream()
      let conn = newConnection(stream)
      await stream.pushTo(fromHex("000873747265616d2031"))
      let msg = await conn.readMsg()

      if msg.isSome:
        check msg.get().id == 0
        check msg.get().msgType == MessageType.New
        result = true

    check:
      waitFor(testDecodeHeader()) == true

  test "decode header and body with channel id 0":
    proc testDecodeHeader(): Future[bool] {.async.} =
      let stream = newBufferStream()
      let conn = newConnection(stream)
      await stream.pushTo(fromHex("021668656C6C6F2066726F6D206368616E6E656C20302121"))
      let msg = await conn.readMsg()

      if msg.isSome:
        check msg.get().id == 0
        check msg.get().msgType == MessageType.MsgOut
        check cast[string](msg.get().data) == "hello from channel 0!!"
        result = true

    check:
      waitFor(testDecodeHeader()) == true

  test "decode header and body with channel id other than 0":
    proc testDecodeHeader(): Future[bool] {.async.} =
      let stream = newBufferStream()
      let conn = newConnection(stream)
      await stream.pushTo(fromHex("8a011668656C6C6F2066726F6D206368616E6E656C20302121"))
      let msg = await conn.readMsg()

      if msg.isSome:
        check msg.get().id == 17
        check msg.get().msgType == MessageType.MsgOut
        check cast[string](msg.get().data) == "hello from channel 0!!"
        result = true

    check:
      waitFor(testDecodeHeader()) == true
  
  test "e2e - read/write receiver":
    proc testNewStream(): Future[bool] {.async.} =
      let
        ma: MultiAddress = Multiaddress.init("/ip4/0.0.0.0/tcp/0")
        lock = newFuture[void]()
        timeout = sleepAsync(5_000)

      proc connHandler(conn: Connection) {.async, gcsafe.} =
        proc handleMplexListen(stream: Connection) {.async, gcsafe.} =
          let msg = await stream.readLp()
          check cast[string](msg) == "Hello from stream!"
          lock.complete()
          await stream.close()

        let mplexListen = newMplex(conn)
        mplexListen.streamHandler = handleMplexListen
        discard mplexListen.handle()

      let transport1: TcpTransport = newTransport(TcpTransport)
      discard await transport1.listen(ma, connHandler)

      let transport2: TcpTransport = newTransport(TcpTransport)
      let conn = await transport2.dial(transport1.ma)

      let mplexDial = newMplex(conn)
      let stream = await mplexDial.newStream()
      let openState = cast[LPChannel](stream.stream).isOpen
      await stream.writeLp("Hello from stream!")
      await conn.close()
      check openState # not lazy
      result = true

    check:
      waitFor(testNewStream()) == true

  test "e2e - read/write receiver lazy":
    proc testNewStream(): Future[bool] {.async.} =
      let ma: MultiAddress = Multiaddress.init("/ip4/0.0.0.0/tcp/0")

      proc connHandler(conn: Connection) {.async, gcsafe.} =
        proc handleMplexListen(stream: Connection) {.async, gcsafe.} =
          let msg = await stream.readLp()
          check cast[string](msg) == "Hello from stream!"
          await stream.close()

        let mplexListen = newMplex(conn)
        mplexListen.streamHandler = handleMplexListen
        discard mplexListen.handle()

      let transport1: TcpTransport = newTransport(TcpTransport)
      discard await transport1.listen(ma, connHandler)

      let transport2: TcpTransport = newTransport(TcpTransport)
      let conn = await transport2.dial(transport1.ma)

      let mplexDial = newMplex(conn)
      let stream = await mplexDial.newStream("", true)
      let openState = cast[LPChannel](stream.stream).isOpen
      await stream.writeLp("Hello from stream!")
      await lock or timeout
      check lock.finished
      timeout.cancel()
      await conn.close()
      check not openState # assert lazy 
      result = true

    check:
      waitFor(testNewStream()) == true

  test "e2e - write limits":
    proc testNewStream(): Future[bool] {.async.} =
      let
        ma: MultiAddress = Multiaddress.init("/ip4/0.0.0.0/tcp/0")
        lock = newFuture[void]()
        timeout = sleepAsync(5_000)

      proc connHandler(conn: Connection) {.async, gcsafe.} =
        proc handleMplexListen(stream: Connection) {.async, gcsafe.} =
          let msg = await stream.readLp()
          lock.complete()
          check cast[string](msg) == "Hello from stream!"
          await stream.close()

        let mplexListen = newMplex(conn)
        mplexListen.streamHandler = handleMplexListen
        discard mplexListen.handle()

      let transport1: TcpTransport = newTransport(TcpTransport)
      discard await transport1.listen(ma, connHandler)

      let transport2: TcpTransport = newTransport(TcpTransport)
      let conn = await transport2.dial(transport1.ma)

      let mplexDial = newMplex(conn)
      let stream  = await mplexDial.newStream()
      var bigseq = newSeqOfCap[uint8](MaxMsgSize + 1)
      for _ in 0..<MaxMsgSize:
        bigseq.add(uint8(rand(int('A')..int('z'))))
      await stream.writeLp(bigseq)
      await lock or timeout
      check timeout.finished # this test has to timeout!
      lock.cancel();
      await conn.close()
      result = true

    check:
      waitFor(testNewStream()) == true

  test "e2e - read/write initiator":
    proc testNewStream(): Future[bool] {.async.} =
      let ma: MultiAddress = Multiaddress.init("/ip4/0.0.0.0/tcp/0")

      proc connHandler(conn: Connection) {.async, gcsafe.} =
        proc handleMplexListen(stream: Connection) {.async, gcsafe.} =
          await stream.writeLp("Hello from stream!")
          await stream.close()

        let mplexListen = newMplex(conn)
        mplexListen.streamHandler = handleMplexListen
        await mplexListen.handle()

      let transport1: TcpTransport = newTransport(TcpTransport)
      discard await transport1.listen(ma, connHandler)

      let transport2: TcpTransport = newTransport(TcpTransport)
      let conn = await transport2.dial(transport1.ma)

      let mplexDial = newMplex(conn)
      let dialFut = mplexDial.handle()
      let stream  = await mplexDial.newStream("DIALER")
      let msg = cast[string](await stream.readLp())
      check msg == "Hello from stream!"
      await conn.close()
      # await dialFut
      result = true

    check:
      waitFor(testNewStream()) == true

  test "e2e - multiple streams":
    proc testNewStream(): Future[bool] {.async.} =
      let ma: MultiAddress = Multiaddress.init("/ip4/0.0.0.0/tcp/0")

      var count = 1
      var listenConn: Connection
      proc connHandler(conn: Connection) {.async, gcsafe.} =
        proc handleMplexListen(stream: Connection) {.async, gcsafe.} =
          let msg = await stream.readLp()
          check cast[string](msg) == &"stream {count}!"
          count.inc
          await stream.close()

        listenConn = conn
        let mplexListen = newMplex(conn)
        mplexListen.streamHandler = handleMplexListen
        await mplexListen.handle()

      let transport1: TcpTransport = newTransport(TcpTransport)
      discard await transport1.listen(ma, connHandler)

      let transport2: TcpTransport = newTransport(TcpTransport)
      let conn = await transport2.dial(transport1.ma)

      let mplexDial = newMplex(conn)
      for i in 1..<10:
        let stream  = await mplexDial.newStream()
        await stream.writeLp(&"stream {i}!")
        await stream.close()

      await conn.close()
      await listenConn.close()
      result = true

    check:
      waitFor(testNewStream()) == true

  test "e2e - multiple read/write streams":
    proc testNewStream(): Future[bool] {.async.} =
      let ma: MultiAddress = Multiaddress.init("/ip4/0.0.0.0/tcp/0")

      var count = 1
      var listenFut: Future[void]
      var listenConn: Connection
      proc connHandler(conn: Connection) {.async, gcsafe.} =
        listenConn = conn
        proc handleMplexListen(stream: Connection) {.async, gcsafe.} =
          let msg = await stream.readLp()
          check cast[string](msg) == &"stream {count} from dialer!"
          await stream.writeLp(&"stream {count} from listener!")
          count.inc
          await stream.close()

        let mplexListen = newMplex(conn)
        mplexListen.streamHandler = handleMplexListen
        listenFut = mplexListen.handle()
        listenFut.addCallback(proc(udata: pointer) {.gcsafe.}
                                = trace "completed listener")

      let transport1: TcpTransport = newTransport(TcpTransport)
      asyncCheck transport1.listen(ma, connHandler)

      let transport2: TcpTransport = newTransport(TcpTransport)
      let conn = await transport2.dial(transport1.ma)

      let mplexDial = newMplex(conn)
      let dialFut = mplexDial.handle()
      dialFut.addCallback(proc(udata: pointer = nil) {.gcsafe.}
                            = trace "completed dialer")
      for i in 1..10:
        let stream  = await mplexDial.newStream("dialer stream")
        await stream.writeLp(&"stream {i} from dialer!")
        let msg = await stream.readLp()
        check cast[string](msg) == &"stream {i} from listener!"
        await stream.close()

      await conn.close()
      await listenConn.close()
      await allFutures(dialFut, listenFut)
      result = true

    check:
      waitFor(testNewStream()) == true

  test "half closed - channel should close for write":
    proc testClosedForWrite(): Future[void] {.async.} =
      proc writeHandler(data: seq[byte]) {.async, gcsafe.} = discard
      let chann = newChannel(1, newConnection(newBufferStream(writeHandler)), true)
      await chann.close()
      await chann.write("Hello")

    expect LPStreamEOFError:
      waitFor(testClosedForWrite())

  test "half closed - channel should close for read by remote":
    proc testClosedForRead(): Future[void] {.async.} =
      proc writeHandler(data: seq[byte]) {.async, gcsafe.} = discard
      let chann = newChannel(1, newConnection(newBufferStream(writeHandler)), true)

      await chann.pushTo(cast[seq[byte]]("Hello!"))
      await chann.closedByRemote()
      discard await chann.read() # this should work, since there is data in the buffer
      discard await chann.read() # this should throw

    expect LPStreamEOFError:
      waitFor(testClosedForRead())

  test "reset - channel should fail reading":
    proc testResetRead(): Future[void] {.async.} =
      proc writeHandler(data: seq[byte]) {.async, gcsafe.} = discard
      let chann = newChannel(1, newConnection(newBufferStream(writeHandler)), true)
      await chann.reset()
      asyncDiscard chann.read()

    expect LPStreamEOFError:
      waitFor(testResetRead())

  test "reset - channel should fail writing":
    proc testResetWrite(): Future[void] {.async.} =
      proc writeHandler(data: seq[byte]) {.async, gcsafe.} = discard
      let chann = newChannel(1, newConnection(newBufferStream(writeHandler)), true)
      await chann.reset()
      await chann.write(cast[seq[byte]]("Hello!"))

    expect LPStreamEOFError:
      waitFor(testResetWrite())

  test "should not allow pushing data to channel when remote end closed":
    proc testResetWrite(): Future[void] {.async.} =
      proc writeHandler(data: seq[byte]) {.async, gcsafe.} = discard
      let chann = newChannel(1, newConnection(newBufferStream(writeHandler)), true)
      await chann.closedByRemote()
      await chann.pushTo(@[byte(1)])

    expect LPStreamEOFError:
      waitFor(testResetWrite())