// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using Moq;
using System.Threading.Tasks;
using Xunit;

namespace Microsoft.AspNetCore.Routing.Matching
{
    // We get a lot of good coverage of basics since this implementation is used
    // as the default in many cases. The tests here are focused on details of the
    // implementation (boundaries, casing, non-ASCII).
    public abstract class ILEmitTreeJumpTableTestBase : MultipleEntryJumpTableTest
    {
        public abstract bool Vectorize { get; }

        internal override JumpTable CreateTable(
            int defaultDestination,
            int exitDestination,
            params (string text, int destination)[] entries)
        {
            var fallback = new DictionaryJumpTable(defaultDestination, exitDestination, entries);
            var table = new ILEmitTrieJumpTable(defaultDestination, exitDestination, entries, Vectorize, fallback);
            table.InitializeILDelegate();
            return table;
        }

        [Fact] // Not calling CreateTable here because we want to test the initialization
        public async Task InitializeILDelegateAsync_ReplacesDelegate()
        {
            // Arrange
            var table = new ILEmitTrieJumpTable(0, -1, new[] { ("hi", 1), }, Vectorize, Mock.Of<JumpTable>());
            var original = table._getDestination;

            // Act
            await table.InitializeILDelegateAsync();

            // Assert
            Assert.NotSame(original, table._getDestination);
        }

        // Tests that we can detect non-ASCII characters and use the fallback jump table.
        // Testing different indices since that affects which part of the code is running.
        // \u007F = lowest non-ASCII character
        // \uFFFF = highest non-ASCII character
        [Theory]

        // non-ASCII character in first section non-vectorized comparisons
        [InlineData("he\u007F", "he\u007Flo-world", 0, 3)]
        [InlineData("he\uFFFF", "he\uFFFFlo-world", 0, 3)]
        [InlineData("e\u007F", "he\u007Flo-world", 1, 2)]
        [InlineData("e\uFFFF", "he\uFFFFlo-world", 1, 2)]
        [InlineData("\u007F", "he\u007Flo-world", 2, 1)]
        [InlineData("\uFFFF", "he\uFFFFlo-world", 2, 1)]

        // non-ASCII character in first section vectorized comparions
        [InlineData("hel\u007F", "hel\u007Fo-world", 0, 4)]
        [InlineData("hel\uFFFF", "hel\uFFFFo-world", 0, 4)]
        [InlineData("el\u007Fo", "hel\u007Fo-world", 1, 4)]
        [InlineData("el\uFFFFo", "hel\uFFFFo-world", 1, 4)]
        [InlineData("l\u007Fo-", "hel\u007Fo-world", 2, 4)]
        [InlineData("l\uFFFFo-", "hel\uFFFFo-world", 2, 4)]
        [InlineData("\u007Fo-w", "hel\u007Fo-world", 3, 4)]
        [InlineData("\uFFFFo-w", "hel\uFFFFo-world", 3, 4)]

        // non-ASCII character in second section non-vectorized comparisons
        [InlineData("hello-\u007F", "hello-\u007Forld", 0, 7)]
        [InlineData("hello-\uFFFF", "hello-\uFFFForld", 0, 7)]
        [InlineData("ello-\u007F", "hello-\u007Forld", 1, 6)]
        [InlineData("ello-\uFFFF", "hello-\uFFFForld", 1, 6)]
        [InlineData("llo-\u007F", "hello-\u007Forld", 2, 5)]
        [InlineData("llo-\uFFFF", "hello-\uFFFFForld", 2, 5)]

        // non-ASCII character in first section vectorized comparions
        [InlineData("hello-w\u007F", "hello-w\u007Forld", 0, 8)]
        [InlineData("hello-w\uFFFF", "hello-w\uFFFForld", 0, 8)]
        [InlineData("ello-w\u007Fo", "hello-w\u007Forld", 1, 8)]
        [InlineData("ello-w\uFFFFo", "hello-w\uFFFForld", 1, 8)]
        [InlineData("llo-w\u007For", "hello-w\u007Forld", 2, 8)]
        [InlineData("llo-w\uFFFFor", "hello-w\uFFFForld", 2, 8)]
        [InlineData("lo-w\u007Forl", "hello-w\u007Forld", 3, 8)]
        [InlineData("lo-w\uFFFForl", "hello-w\uFFFForld", 3, 8)]
        public void GetDestination_Found_IncludesNonAsciiCharacters(string entry, string path, int start, int length)
        {
            // Makes it easy to spot invalid tests
            Assert.Equal(entry.Length, length);
            Assert.Equal(entry, path.Substring(start, length), ignoreCase: true);

            // Arrange
            var table = CreateTable(0, -1, new[] { (entry, 1), });

            var segment = new PathSegment(start, length);

            // Act
            var result = table.GetDestination(path, segment);

            // Assert
            Assert.Equal(1, result);
        }

        // Tests for difference in casing with ASCII casing rules. Verifies our case
        // manipulation algorthm is correct.
        //
        // We convert from upper case to lower
        // 'A' and 'a' are 32 bits apart at the low end
        // 'Z' and 'z' are 32 bits apart at the high end
        [Theory]

        // character in first section non-vectorized comparisons
        [InlineData("heA", "healo-world", 0, 3)]
        [InlineData("heZ", "hezlo-world", 0, 3)]
        [InlineData("eA", "healo-world", 1, 2)]
        [InlineData("eZ", "hezlo-world", 1, 2)]
        [InlineData("A", "healo-world", 2, 1)]
        [InlineData("Z", "hezlo-world", 2, 1)]

        // character in first section vectorized comparions
        [InlineData("helA", "helao-world", 0, 4)]
        [InlineData("helZ", "helzo-world", 0, 4)]
        [InlineData("elAo", "helao-world", 1, 4)]
        [InlineData("elZo", "helzo-world", 1, 4)]
        [InlineData("lAo-", "helao-world", 2, 4)]
        [InlineData("lZo-", "helzo-world", 2, 4)]
        [InlineData("Ao-w", "helao-world", 3, 4)]
        [InlineData("Zo-w", "helzo-world", 3, 4)]

        // character in second section non-vectorized comparisons
        [InlineData("hello-A", "hello-aorld", 0, 7)]
        [InlineData("hello-Z", "hello-zorld", 0, 7)]
        [InlineData("ello-A", "hello-aorld", 1, 6)]
        [InlineData("ello-Z", "hello-zorld", 1, 6)]
        [InlineData("llo-A", "hello-aorld", 2, 5)]
        [InlineData("llo-Z", "hello-zForld", 2, 5)]

        // character in first section vectorized comparions
        [InlineData("hello-wA", "hello-waorld", 0, 8)]
        [InlineData("hello-wZ", "hello-wzorld", 0, 8)]
        [InlineData("ello-wAo", "hello-waorld", 1, 8)]
        [InlineData("ello-wZo", "hello-wzorld", 1, 8)]
        [InlineData("llo-wAor", "hello-waorld", 2, 8)]
        [InlineData("llo-wZor", "hello-wzorld", 2, 8)]
        [InlineData("lo-wAorl", "hello-waorld", 3, 8)]
        [InlineData("lo-wZorl", "hello-wzorld", 3, 8)]
        public void GetDestination_Found_IncludesCharactersWithCasingDifference(string entry, string path, int start, int length)
        {
            // Makes it easy to spot invalid tests
            Assert.Equal(entry.Length, length);
            Assert.Equal(entry, path.Substring(start, length), ignoreCase: true);

            // Arrange
            var table = CreateTable(0, -1, new[] { (entry, 1), });

            var segment = new PathSegment(start, length);

            // Act
            var result = table.GetDestination(path, segment);

            // Assert
            Assert.Equal(1, result);
        }

        // Tests for difference in casing with ASCII casing rules. Verifies our case
        // manipulation algorthm is correct.
        //
        // We convert from upper case to lower
        // '@' and '`' are 32 bits apart at the low end
        // '[' and '}' are 32 bits apart at the high end
        //
        // How to understand these tests:
        // "an @ should not be converted to a ` since it is out of range"
        [Theory]

        // character in first section non-vectorized comparisons
        [InlineData("he@", "he`lo-world", 0, 3)]
        [InlineData("he[", "he{lo-world", 0, 3)]
        [InlineData("e@", "he`lo-world", 1, 2)]
        [InlineData("e[", "he{lo-world", 1, 2)]
        [InlineData("@", "he`lo-world", 2, 1)]
        [InlineData("[", "he{lo-world", 2, 1)]

        // character in first section vectorized comparions
        [InlineData("hel@", "hel`o-world", 0, 4)]
        [InlineData("hel[", "hel{o-world", 0, 4)]
        [InlineData("el@o", "hel`o-world", 1, 4)]
        [InlineData("el[o", "hel{o-world", 1, 4)]
        [InlineData("l@o-", "hel`o-world", 2, 4)]
        [InlineData("l[o-", "hel{o-world", 2, 4)]
        [InlineData("@o-w", "hel`o-world", 3, 4)]
        [InlineData("[o-w", "hel{o-world", 3, 4)]

        // character in second section non-vectorized comparisons
        [InlineData("hello-@", "hello-`orld", 0, 7)]
        [InlineData("hello-[", "hello-{orld", 0, 7)]
        [InlineData("ello-@", "hello-`orld", 1, 6)]
        [InlineData("ello-[", "hello-{orld", 1, 6)]
        [InlineData("llo-@", "hello-`orld", 2, 5)]
        [InlineData("llo-[", "hello-{Forld", 2, 5)]

        // character in first section vectorized comparions
        [InlineData("hello-w@", "hello-w`orld", 0, 8)]
        [InlineData("hello-w[", "hello-w{orld", 0, 8)]
        [InlineData("ello-w@o", "hello-w`orld", 1, 8)]
        [InlineData("ello-w[o", "hello-w{orld", 1, 8)]
        [InlineData("llo-w@or", "hello-w`orld", 2, 8)]
        [InlineData("llo-w[or", "hello-w{orld", 2, 8)]
        [InlineData("lo-w@orl", "hello-w`orld", 3, 8)]
        [InlineData("lo-w[orl", "hello-w{orld", 3, 8)]
        public void GetDestination_NotFound_IncludesCharactersWithCasingDifference(string entry, string path, int start, int length)
        {
            // Makes it easy to spot invalid tests
            Assert.Equal(entry.Length, length);
            Assert.NotEqual(entry, path.Substring(start, length));

            // Arrange
            var table = CreateTable(0, -1, new[] { (entry, 1), });

            var segment = new PathSegment(start, length);

            // Act
            var result = table.GetDestination(path, segment);

            // Assert
            Assert.Equal(0, result);
        }
    }
}
