<?php

namespace Amp\Parallel\Test\Sync;

use Amp\ByteStream\InputStream;
use Amp\ByteStream\OutputStream;
use Amp\ByteStream\StreamException;
use Amp\Loop;
use Amp\Parallel\Sync\ChannelledStream;
use Amp\PHPUnit\TestCase;
use Amp\Promise;
use Amp\Success;

class ChannelledStreamTest extends TestCase
{
    /**
     * @return \Amp\ByteStream\InputStream|\Amp\ByteStream\OutputStream
     */
    protected function createMockStream()
    {
        return new class implements InputStream, OutputStream {
            private $buffer = "";

            public function read(): Promise
            {
                $data = $this->buffer;
                $this->buffer = "";
                return new Success($data);
            }

            public function write(string $data): Promise
            {
                $this->buffer .= $data;
                return new Success(\strlen($data));
            }

            public function end(string $finalData = ""): Promise
            {
                throw new \BadMethodCallException;
            }

            public function close()
            {
                throw new \BadMethodCallException;
            }
        };
    }

    public function testSendReceive()
    {
        Loop::run(function () {
            $mock = $this->createMockStream();
            $a = new ChannelledStream($mock, $mock);
            $b = new ChannelledStream($mock, $mock);

            $message = 'hello';

            yield $a->send($message);
            $data = yield $b->receive();
            $this->assertSame($message, $data);
        });
    }

    /**
     * @depends testSendReceive
     */
    public function testSendReceiveLongData()
    {
        Loop::run(function () {
            $mock = $this->createMockStream();
            $a = new ChannelledStream($mock, $mock);
            $b = new ChannelledStream($mock, $mock);

            $length = 0xffff;
            $message = '';
            for ($i = 0; $i < $length; ++$i) {
                $message .= \chr(\mt_rand(0, 255));
            }

            yield $a->send($message);
            $data = yield $b->receive();
            $this->assertSame($message, $data);
        });
    }

    /**
     * @depends testSendReceive
     * @expectedException \Amp\Parallel\Sync\ChannelException
     */
    public function testInvalidDataReceived()
    {
        Loop::run(function () {
            $mock = $this->createMockStream();
            $a = new ChannelledStream($mock, $mock);
            $b = new ChannelledStream($mock, $mock);

            // Close $a. $b should close on next read...
            yield $mock->write(\pack('L', 10) . '1234567890');
            $data = yield $b->receive();
        });
    }

    /**
     * @depends testSendReceive
     * @expectedException \Amp\Parallel\Sync\ChannelException
     */
    public function testSendUnserializableData()
    {
        Loop::run(function () {
            $mock = $this->createMockStream();
            $a = new ChannelledStream($mock, $mock);
            $b = new ChannelledStream($mock, $mock);

            // Close $a. $b should close on next read...
            yield $a->send(function () {});
            $data = yield $b->receive();
        });
    }

    /**
     * @depends testSendReceive
     * @expectedException \Amp\Parallel\Sync\ChannelException
     */
    public function testSendAfterClose()
    {
        Loop::run(function () {
            $mock = $this->createMock(OutputStream::class);
            $mock->expects($this->once())
                ->method('write')
                ->will($this->throwException(new StreamException));

            $a = new ChannelledStream($this->createMock(InputStream::class), $mock);
            $b = new ChannelledStream(
                $this->createMock(InputStream::class),
                $this->createMock(OutputStream::class)
            );

            yield $a->send('hello');
        });
    }

    /**
     * @depends testSendReceive
     * @expectedException \Amp\Parallel\Sync\ChannelException
     */
    public function testReceiveAfterClose()
    {
        Loop::run(function () {
            $mock = $this->createMock(InputStream::class);
            $mock->expects($this->once())
                ->method('read')
                ->willReturn(new Success(null));

            $a = new ChannelledStream($mock, $this->createMock(OutputStream::class));

            $data = yield $a->receive();
        });
    }
}