//
// Copyright (c) 2012-2021 Antmicro
//
// This file is licensed under the MIT License.
// Full license text is available in the LICENSE file.

using NUnit.Framework;
using System.IO;
using System;
using System.Linq;

namespace Antmicro.Migrant.Tests
{
    [TestFixture(true)]
    [TestFixture(false)]
	public class PrimitiveReaderWriterTests
	{
        public PrimitiveReaderWriterTests(bool buffered)
        {
            this.buffered = buffered;
        }

		[Test]
		public void ShouldWriteAndReadInts(
			[Values(1, 10, 100, 10000, 1000*1000)]
			int numberOfInts)
		{
			var randomInts = Helpers.GetRandomIntegers(numberOfInts);

			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				for(var i = 0; i < randomInts.Length; i++)
				{
					writer.Write(randomInts[i]);
				}
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
			{
				for(var i = 0; i < randomInts.Length; i++)
				{
					Assert.AreEqual(randomInts[i], reader.ReadInt32());
				}
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

		[Test]
		public void ShouldWriteAndReadLongs(
			[Values(1, 10, 100, 10000, 1000*1000)]
			int numberOfLongs)
		{
			var randomLongs = Helpers.GetRandomLongs(numberOfLongs);
			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				for(var i = 0; i < randomLongs.Length; i++)
				{
					writer.Write(randomLongs[i]);
				}
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
			{
				for(var i = 0; i < randomLongs.Length; i++)
				{
					var read = reader.ReadInt64();
					Assert.AreEqual(randomLongs[i], read);
				}
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

        [Test]
        public void ShouldWriteAndReadULongs(
            [Values(1, 10, 100, 10000, 1000*1000)]
            int numberOfULongs)
        {
            var randomULongs = Helpers.GetRandomLongs(numberOfULongs).Select(x=>(ulong)x).ToArray();
            var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
            {
                for(var i = 0; i < randomULongs.Length; i++)
                {
                    writer.Write(randomULongs[i]);
                }
            }
            var position = stream.Position;
            stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
            {
                for(var i = 0; i < randomULongs.Length; i++)
                {
                    var read = reader.ReadUInt64();
                    Assert.AreEqual(randomULongs[i], read);
                }
            }
            Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
        }

		[Test]
		public void ShouldWriteAndReadStrings(
			[Values(1, 100, 10000)]
			int numberOfStrings,
			[Values(true, false)]
			bool withLongStrings)
		{
			const int maxLength = 100;
			const int longStringLength = 8000;
			const int longStringProbability = 10;

			var random = Helpers.Random;
			var strings = new string[numberOfStrings];
			for(var i = 0; i < strings.Length; i++)
			{
				int length;
				if(withLongStrings && random.Next()%longStringProbability == 0)
				{
					length  = longStringLength;
				}
				else
				{
					length = random.Next(maxLength);
				}
				strings[i] = Helpers.GetRandomString(length);
			}

			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				for(var i = 0; i < strings.Length; i++)
				{
					writer.Write(strings[i]);
				}
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
			{
				for(var i = 0; i < strings.Length; i++)
				{
					Assert.AreEqual(strings[i], reader.ReadString());
				}
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

		[Test]
		public void ShouldWriteAndReadNegativeInt()
		{
			var value = -Helpers.Random.Next();
			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				writer.Write(value);
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
			{
				Assert.AreEqual(value, reader.ReadInt32());
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

		[Test]
		public void ShouldWriteAndReadDoubles(
			[Values(1, 10, 100, 10000, 1000*1000)]
			int numberOfDoubles)
		{
			var randomDoubles = Helpers.GetRandomDoubles(numberOfDoubles);
		
			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				for(var i = 0; i < randomDoubles.Length; i++)
				{
					writer.Write(randomDoubles[i]);
				}
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
			{
				for(var i = 0; i < randomDoubles.Length; i++)
				{
					Assert.AreEqual(randomDoubles[i], reader.ReadDouble());
				}
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

        [Test]
        public void ShouldWriteAndReadDecimal(
            [Values(1, 10, 100, 10000, 1000*1000)]
            int numberOfDecimals)
        {
            var randomDecimals = Helpers.GetRandomDecimals(numberOfDecimals);
            var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
            {
                for(var i = 0; i < randomDecimals.Length; i++)
                {
                    writer.Write(randomDecimals[i]);
                }
            }
            var position = stream.Position;
            stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
            {
                for(var i = 0; i < randomDecimals.Length; i++)
                {
                    Assert.AreEqual(randomDecimals[i], reader.ReadDecimal());
                }
            }
            Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
        }

		[Test]
		public void ShouldSerializeDateTime(
			[Values(1, 10, 100, 10000)]
			int numberOfEntries)
		{
			var randomDateTimes = Helpers.GetRandomDateTimes(numberOfEntries);
		
			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				for(var i = 0; i < randomDateTimes.Length; i++)
				{
					writer.Write(randomDateTimes[i]);
				}
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
			{
				for(var i = 0; i < randomDateTimes.Length; i++)
				{
					Assert.AreEqual(randomDateTimes[i], reader.ReadDateTime());
				}
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

		[Test]
		public void ShouldSerializeTimeSpan(
			[Values(1, 10, 100, 10000)]
			int numberOfEntries)
		{
			var randomDateTimes = Helpers.GetRandomDateTimes(numberOfEntries);
		
			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				for(var i = 0; i < randomDateTimes.Length; i++)
				{
					writer.Write(randomDateTimes[i]);
				}
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
			{
				for(var i = 0; i < randomDateTimes.Length; i++)
				{
					Assert.AreEqual(randomDateTimes[i], reader.ReadDateTime());
				}
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

		[Test]
		public void ShouldWriteAndReadByteArray(
			[Values(10, 1000, 100000)]
			int count
			)
		{
			var stream = new MemoryStream();
			byte[] array;
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				array = new byte[count];
				Helpers.Random.NextBytes(array);
				writer.Write(array);
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);

			byte[] copy;
            using(var reader = new PrimitiveReader(stream, buffered))
			{
				copy = reader.ReadBytes(count);
			}
			CollectionAssert.AreEqual(array, copy);
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

		[Test]
		public void ShouldWriteAndReadGuid(
			[Values(10, 1000, 100000)]
			int count
			)
		{
			var stream = new MemoryStream();
			var array = new Guid[count];
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				for(var i = 0; i < count; i++)
				{
					var guid = Guid.NewGuid();
					array[i] = guid;
					writer.Write(guid);
				}
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);

            using(var reader = new PrimitiveReader(stream, buffered))
			{
				for(var i = 0; i < count; i++)
				{
					Assert.AreEqual(array[i], reader.ReadGuid());
				}
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

		[Test]
		public void ShouldWriteAndReadPartsOfByteArrays()
		{
			var arrays = new byte[100][];
			for(var i = 0; i < arrays.Length; i++)
			{
				arrays[i] = Enumerable.Range(0, 256).Select(x => (byte)x).ToArray();
			}

			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				for(var i = 0; i < arrays.Length; i++)
				{
					writer.Write(arrays[i], i, arrays[i].Length - i);
				}
			}

			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);
            using(var reader = new PrimitiveReader(stream, buffered))
			{
				for(var i = 0; i < arrays.Length; i++)
				{
					var writtenLength = arrays[i].Length - i;
					var writtenArray = reader.ReadBytes(writtenLength);
					var subarray = new byte[writtenLength];
					Array.Copy(arrays[i], i, subarray, 0, writtenLength);
					CollectionAssert.AreEqual(subarray, writtenArray);
				}
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

		[Test]
		public void ShouldReadAndWriteLimits()
		{
			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				writer.Write(byte.MinValue);
				writer.Write(byte.MaxValue);
				writer.Write(sbyte.MinValue);
				writer.Write(sbyte.MaxValue);
				writer.Write(short.MinValue);
				writer.Write(short.MaxValue);
				writer.Write(ushort.MinValue);
				writer.Write(ushort.MaxValue);
				writer.Write(int.MinValue);
				writer.Write(int.MaxValue);
				writer.Write(uint.MinValue);
				writer.Write(uint.MaxValue);
				writer.Write(long.MinValue);
				writer.Write(long.MaxValue);
				writer.Write(ulong.MinValue);
				writer.Write(ulong.MaxValue);
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);
            using(var reader = new PrimitiveReader(stream, buffered))
			{
				Assert.AreEqual(byte.MinValue, reader.ReadByte());
				Assert.AreEqual(byte.MaxValue, reader.ReadByte());
				Assert.AreEqual(sbyte.MinValue, reader.ReadSByte());
				Assert.AreEqual(sbyte.MaxValue, reader.ReadSByte());
				Assert.AreEqual(short.MinValue, reader.ReadInt16());
				Assert.AreEqual(short.MaxValue, reader.ReadInt16());
				Assert.AreEqual(ushort.MinValue, reader.ReadUInt16());
				Assert.AreEqual(ushort.MaxValue, reader.ReadUInt16());
				Assert.AreEqual(int.MinValue, reader.ReadInt32());
				Assert.AreEqual(int.MaxValue, reader.ReadInt32());
				Assert.AreEqual(uint.MinValue, reader.ReadUInt32());
				Assert.AreEqual(uint.MaxValue, reader.ReadUInt32());
				Assert.AreEqual(long.MinValue, reader.ReadInt64());
				Assert.AreEqual(long.MaxValue, reader.ReadInt64());
				Assert.AreEqual(ulong.MinValue, reader.ReadUInt64());
				Assert.AreEqual(ulong.MaxValue, reader.ReadUInt64());
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

		[Test]
		public void ShouldHandleNotAlignedWrites()
		{
			const int iterationCount = 80000;
			var stream = new MemoryStream();
            using(var writer = new PrimitiveWriter(stream, buffered))
			{
				writer.Write((byte)1);
				for(var i = 0; i < iterationCount; i++)
				{
					writer.Write(int.MaxValue);
				}
			}
			var position = stream.Position;
			stream.Seek(0, SeekOrigin.Begin);
            using(var reader = new PrimitiveReader(stream, buffered))
			{
				Assert.AreEqual((byte)1, reader.ReadByte());
				for(var i = 0; i < iterationCount; i++)
				{
					Assert.AreEqual(int.MaxValue, reader.ReadInt32());
				}
			}
			Assert.AreEqual(position, stream.Position, StreamCorruptedMessage);
		}

        [Test]
        public void ShouldCopyFromStream()
        {
            var stream = new MemoryStream();
            var testArray = Enumerable.Range(0, 1000).Select(x => (byte)x).ToArray();
            var testStream = new MemoryStream(testArray);
            using(var writer = new PrimitiveWriter(stream, buffered))
            {
                writer.CopyFrom(testStream, testArray.Length);
            }
            stream.Seek(0, SeekOrigin.Begin);
            var secondStream = new MemoryStream(testArray.Length);
            using(var reader = new PrimitiveReader(stream, buffered))
            {
                reader.CopyTo(secondStream, testArray.Length);
            }
            CollectionAssert.AreEqual(testArray, secondStream.ToArray());
        }

        [Test]
        public void ShouldThrowIfStreamPrematurelyFinishes()
        {
            var streamToRead = new MemoryStream();
            var streamToWrite = new MemoryStream();
            using(var reader = new PrimitiveReader(streamToRead, buffered))
            {
                Assert.Throws<EndOfStreamException>(() => reader.CopyTo(streamToWrite, 100));
            }
        }

        private readonly bool buffered;

		private const string StreamCorruptedMessage = "Stream was corrupted during read (in terms of position).";
	}
}