var assert = require('assert');
var concat = require('concat-stream');

var QueryStream = require('../');
var helper = require('./helper');

if (process.version.startsWith('v8.')) {
  console.error('warning! node less than 10lts stream closing semantics may not behave properly');
} else {
  helper('close', function (client) {
    it('emits close', function (done) {
      var stream = new QueryStream('SELECT * FROM generate_series(0, $1) num', [3], { batchSize: 2, highWaterMark: 2 });
      var query = client.query(stream);
      query.pipe(concat(function () {}));
      query.on('close', done);
    });
  });

  helper('early close', function (client) {
    it('can be closed early', function (done) {
      var stream = new QueryStream('SELECT * FROM generate_series(0, $1) num', [20000], {
        batchSize: 2,
        highWaterMark: 2,
      });
      var query = client.query(stream);
      var readCount = 0;
      query.on('readable', function () {
        readCount++;
        query.read();
      });
      query.once('readable', function () {
        query.destroy();
      });
      query.on('close', function () {
        assert(readCount < 10, 'should not have read more than 10 rows');
        done();
      });
    });

    it('can destroy stream while reading', function (done) {
      var stream = new QueryStream('SELECT * FROM generate_series(0, 100), pg_sleep(1)');
      client.query(stream);
      stream.on('data', () => done(new Error('stream should not have returned rows')));
      setTimeout(() => {
        stream.destroy();
        stream.on('close', done);
      }, 100);
    });

    it('emits an error when calling destroy with an error', function (done) {
      var stream = new QueryStream('SELECT * FROM generate_series(0, 100), pg_sleep(1)');
      client.query(stream);
      stream.on('data', () => done(new Error('stream should not have returned rows')));
      setTimeout(() => {
        stream.destroy(new Error('intentional error'));
        stream.on('error', (err) => {
          // make sure there's an error
          assert(err);
          assert.strictEqual(err.message, 'intentional error');
          done();
        });
      }, 100);
    });

    it('can destroy stream while reading an error', function (done) {
      var stream = new QueryStream('SELECT * from  pg_sleep(1), basdfasdf;');
      client.query(stream);
      stream.on('data', () => done(new Error('stream should not have returned rows')));
      stream.once('error', () => {
        stream.destroy();
        // wait a bit to let any other errors shake through
        setTimeout(done, 100);
      });
    });

    it('does not crash when destroying the stream immediately after calling read', function (done) {
      var stream = new QueryStream('SELECT * from generate_series(0, 100), pg_sleep(1);');
      client.query(stream);
      stream.on('data', () => done(new Error('stream should not have returned rows')));
      stream.destroy();
      stream.on('close', done);
    });

    it('does not crash when destroying the stream before its submitted', function (done) {
      var stream = new QueryStream('SELECT * from generate_series(0, 100), pg_sleep(1);');
      stream.on('data', () => done(new Error('stream should not have returned rows')));
      stream.destroy();
      stream.on('close', done);
    });
  });
}