var assert =require('assert');
var IOWatcher = process.binding('io_watcher').IOWatcher;
var errnoException = process.binding('net').errnoException;
var close = process.binding('net').close;
var net = require('net');

var ncomplete = 0;

function test (N, b, cb) {
  var fdsSent = 0;
  var fdsRecv = 0;
  //console.trace();
  var expected = N * b.length;
  var nread = 0;

  // Create a socketpair
  var fds = process.binding('net').socketpair();

  // Use writev/dumper to send data down the one of the sockets, fds[1].
  // This requires a IOWatcher.
  var w = new IOWatcher();
  w.set(fds[1], false, true);
  w.isUnixSocket = true;

  w.callback = function (readable, writable) {
    assert.ok(!readable && writable); // not really important.
    // Insert watcher into dumpQueue
    w.next = IOWatcher.dumpQueue.next;
    IOWatcher.dumpQueue.next = w;
  }

  var ndrain = 0;
  w.ondrain = function () {
    ndrain++;
  }

  var nerror = 0;
  w.onerror = function (errno) {
    throw errnoException(errno);
    nerror++;
  }

  // The read end, fds[0], will be used to count how much comes through.
  // This sets up a readable stream on fds[0].
  var stream = new net.Stream({ fd: fds[0], type: 'unix' });
  //stream.readable = true;
  stream.resume();

  stream.on('fd', function (fd) {
    console.log('got fd %d', fd);
    fdsRecv++;
  });

  // Count the data as it arrives on the other end
  stream.on('data', function (d) {
    nread += d.length;

    if (nread >= expected) {
      assert.ok(nread === expected);
      assert.equal(1, ndrain);
      assert.equal(0, nerror);
      console.error("done. wrote %d bytes\n", nread);
      close(fds[1]);
    }
  });


  stream.on('close', function () {
    assert.equal(fdsSent, fdsRecv);
    // check to make sure the watcher isn't in the dump queue.
    for (var x = IOWatcher.dumpQueue; x; x = x.next) {
      assert.ok(x !== w);
    }
    assert.equal(null, w.next);
    // completely flushed
    assert.ok(!w.firstBucket);
    assert.ok(!w.lastBucket);

    ncomplete++;
    if (cb) cb();
  });


  // Insert watcher into dumpQueue
  w.next = IOWatcher.dumpQueue.next;
  IOWatcher.dumpQueue.next = w;

  w.firstBucket = { data: b };
  w.lastBucket = w.firstBucket;
  w.queueSize = b.length;

  for (var i = 0; i < N-1; i++) {
    var bucket = { data: b };
    w.lastBucket.next = bucket;
    w.lastBucket = bucket;
    w.queueSize += b.length;
    // Kind of randomly fill these buckets with fds.
    if (fdsSent < 5 && i % 2 == 0) {
      bucket.fd = 1; // send stdout
      fdsSent++;
    }
  }
}


function runTests (values) {
  expectedToComplete = values.length;

  function go () {
    if (ncomplete < values.length) {
      var v = values[ncomplete];
      console.log("test N=%d, size=%d", v[0], v[1].length);
      test(v[0], v[1], go);
    }
  }

  go();
}

runTests([ [30, Buffer(1000)]
         , [4, Buffer(10000)]
         , [1, "hello world\n"]
         , [50, Buffer(1024*1024)]
         , [500, Buffer(40960+1)]
         , [500, Buffer(40960-1)]
         , [500, Buffer(40960)]
         , [500, Buffer(1024*1024+1)]
         , [50000, "hello world\n"]
         ]);


process.on('exit', function () {
  assert.equal(expectedToComplete, ncomplete);
});