<?php

namespace Amp\ByteStream\Test;

use Amp\ByteStream\InMemoryStream;
use Amp\ByteStream\IteratorStream;
use Amp\ByteStream\Payload;
use Amp\ByteStream\PendingReadError;
use Amp\Emitter;
use Amp\Loop;
use Amp\PHPUnit\TestCase;
use Amp\PHPUnit\TestException;

class PayloadTest extends TestCase
{
    public function testBufferingAll()
    {
        Loop::run(function () {
            $values = ["abc", "def", "ghi"];

            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            foreach ($values as $value) {
                $emitter->emit($value);
            }

            $emitter->complete();

            $this->assertSame(\implode($values), yield $stream->buffer());
        });
    }

    public function testFullStreamConsumption()
    {
        Loop::run(function () use (&$invoked) {
            $values = ["abc", "def", "ghi"];

            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            foreach ($values as $value) {
                $emitter->emit($value);
            }

            Loop::delay(5, function () use ($emitter) {
                $emitter->complete();
            });

            $buffer = "";
            while (($chunk = yield $stream->read()) !== null) {
                $buffer .= $chunk;
            }

            $this->assertSame(\implode($values), $buffer);
            $this->assertSame("", yield $stream->buffer());
        });
    }

    public function testFastResolvingStream()
    {
        Loop::run(function () {
            $values = ["abc", "def", "ghi"];

            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            foreach ($values as $value) {
                $emitter->emit($value);
            }

            $emitter->complete();

            $emitted = [];
            while (($chunk = yield $stream->read()) !== null) {
                $emitted[] = $chunk;
            }

            $this->assertSame($values, $emitted);
            $this->assertSame("", yield $stream->buffer());
        });
    }

    public function testFastResolvingStreamBufferingOnly()
    {
        Loop::run(function () {
            $values = ["abc", "def", "ghi"];

            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            foreach ($values as $value) {
                $emitter->emit($value);
            }

            $emitter->complete();

            $this->assertSame(\implode($values), yield $stream->buffer());
        });
    }

    public function testPartialStreamConsumption()
    {
        Loop::run(function () {
            $values = ["abc", "def", "ghi"];

            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            $emitter->emit($values[0]);

            $chunk = yield $stream->read();

            $this->assertSame(\array_shift($values), $chunk);

            foreach ($values as $value) {
                $emitter->emit($value);
            }

            $emitter->complete();

            $this->assertSame(\implode($values), yield $stream->buffer());
        });
    }

    public function testFailingStream()
    {
        Loop::run(function () {
            $exception = new TestException;
            $value = "abc";

            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            $emitter->emit($value);
            $emitter->fail($exception);

            $callable = $this->createCallback(1);

            try {
                while (($chunk = yield $stream->read()) !== null) {
                    $this->assertSame($value, $chunk);
                }

                $this->fail("No exception has been thrown");
            } catch (TestException $reason) {
                $this->assertSame($exception, $reason);
                $callable(); // <-- ensure this point is reached
            }
        });
    }

    public function testFailingStreamWithPendingRead()
    {
        Loop::run(function () {
            $exception = new TestException;
            $value = "abc";

            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            $readPromise = $stream->read();
            $emitter->fail($exception);

            $callable = $this->createCallback(1);

            try {
                yield $readPromise;

                $this->fail("No exception has been thrown");
            } catch (TestException $reason) {
                $this->assertSame($exception, $reason);
                $callable(); // <-- ensure this point is reached
            }
        });
    }

    public function testEmptyStream()
    {
        Loop::run(function () {
            $emitter = new Emitter;
            $emitter->complete();
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            $this->assertNull(yield $stream->read());
        });
    }

    public function testEmptyStringStream()
    {
        Loop::run(function () {
            $value = "";

            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            $emitter->emit($value);

            $emitter->complete();

            $this->assertSame("", yield $stream->buffer());
        });
    }

    public function testReadAfterCompletion()
    {
        Loop::run(function () {
            $value = "abc";

            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            $emitter->emit($value);
            $emitter->complete();

            $this->assertSame($value, yield $stream->read());
            $this->assertNull(yield $stream->read());
        });
    }

    public function testPendingRead()
    {
        Loop::run(function () {
            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));

            Loop::delay(0, function () use ($emitter) {
                $emitter->emit("test");
            });

            $this->assertSame("test", yield $stream->read());
        });
    }

    public function testPendingReadError()
    {
        Loop::run(function () {
            $emitter = new Emitter;
            $stream = new Payload(new IteratorStream($emitter->iterate()));
            $stream->read();

            $this->expectException(PendingReadError::class);

            $stream->read();
        });
    }

    public function testReadAfterBuffer()
    {
        Loop::run(function () {
            $stream = new Payload(new InMemoryStream("test"));
            $stream->buffer();

            $this->expectException(\Error::class);
            $this->expectExceptionMessage("Cannot stream message data once a buffered message has been requested");

            yield $stream->read();
        });
    }

    public function testFurtherCallsToBufferReturnSameData()
    {
        Loop::run(function () {
            $data = "test";
            $stream = new Payload(new InMemoryStream($data));
            $this->assertSame($data, yield $stream->buffer());
            $this->assertSame($data, yield $stream->buffer());
        });
    }
}