var tcp = require('net')
var Select = require('multistream-select').Select
var Interactive = require('multistream-select').Interactive
var spdy = require('spdy-transport')
var identify = require('./identify')
var log = require('ipfs-logger').group('swarm')
var async = require('async')

exports = module.exports

var connections = {}
var handles = []

// set the listener

exports.listen = function () {
  tcp.createServer(function (socket) {
    var ms = new Select()
    ms.handle(socket)
    ms.addHandler('/spdy/3.1.0', function (ds) {
      log.info('Negotiated spdy with incoming socket')
      log.info('Buffer should be clean  - ', ds.read())
      var spdyConnection = spdy.connection.create(ds, {
        protocol: 'spdy',
        isServer: true
      })

      spdyConnection.start(3.1)

      // attach multistream handlers to incoming streams
      spdyConnection.on('stream', function (spdyStream) {
        registerHandles(spdyStream)
      })

      // learn about the other peer Identity
      /* TODO(daviddias)
      identify.inquiry(spdyConnection, function (err, spdyConnection, peerIdB58) {
        if (err) {
          return log.error(err)
        }
        if (connections[peerIdB58]) {
          return log.error('New connection established with a peer(' + peerIdB58 + ') that we already had a connection')
        }
        spdyConnection.peerId = peerIdB58
        connections[peerIdB58] = spdyConnection
      })
      */

      // close the connection when all the streams close
      spdyConnection.on('close', function () {
        delete connections[spdyConnection.peerId]
      })
    })
  }).listen(process.env.IPFS_PORT || 4001)
}

// interface

exports.openStream = function (peer, protocol, cb) {
  // if Connection already open, open a new stream, otherwise, create a new Connection
  // then negoatite the protocol and return the opened stream

  // If no connection open yet, open it
  if (!connections[peer.id.toB58String()]) {
    // Establish a socket with one of the addresses
    var gotOne = false
    async.eachSeries(peer.multiaddrs, function (multiaddr, callback) {
      if (gotOne) {
        return callback()
      }
      var socket = tcp.connect(multiaddr.toOptions(), function connected () {
        gotSocket(socket)
      })

      socket.once('error', function (err) {
        log.warn('Could not connect using one of the address of peer - ', peer.id.toB58String(), err)
        callback()
      })

    }, function done () {
      if (!gotOne) {
        cb(new Error('Not able to open a scoket with peer - ', peer.id.toB58String()))
      }
    })

  } else {
    createStream(peer, protocol, cb)
  }

  // do the spdy people dance (multistream-select into spdy)
  function gotSocket (socket) {
    gotOne = true
    var msi = new Interactive()
    msi.handle(socket, function () {
      msi.select('/spdy/3.1.0', function (err, ds) {
        var spdyConnection = spdy.connection.create(ds, {
          protocol: 'spdy',
          isServer: false
        })
        spdyConnection.start(3.1)
        connections[peer.id.toB58String()] = spdyConnection

        // attach multistream handlers to incoming streams
        spdyConnection.on('stream', function (spdyStream) {
          registerHandles(spdyStream)
        })

        createStream(peer, protocol, cb)
      })
    })
  }

  function createStream (peer, protocol, cb) {
    // 1. to pop a new stream on the connection
    // 2. negotiate the requested protocol through multistream
    // 3. return back the stream when that is negotiated
    var conn = connections[peer.id.toB58String()]
    conn.request({path: '/', method: 'GET'}, function (err, stream) {
      if (err) {
        return cb(err)
      }
      var msi = new Interactive()
      msi.handle(stream, function () {
        msi.select(protocol, function (err, ds) {
          if (err) {
            return cb(err)
          }
          cb(null, ds) // wohoo we finally delivered the stream the user wanted
        })
      })
    })

    conn.on('close', function () {
      // TODO(daviddias) remove it from collections
    })

  }

}

exports.registerHandle = function (protocol, cb) {
  if (handles[protocol]) {
    var err = new Error('Handle for protocol already exists', protocol)
    log.error(err)
    return cb(err)
  }
  handles.push({ protocol: protocol, func: cb })
  log.info('Registered handler for protocol:', protocol)
}

function registerHandles (spdyStream) {
  log.info('Preparing stream to handle the registered protocols')
  var msH = new Select()
  msH.handle(spdyStream)
  handles.forEach(function (handle) {
    msH.addHandler(handle.protocol, handle.func)
  })
}