// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Globalization;
using System.Linq;
using Microsoft.AspNetCore.Testing;
using Xunit;

namespace Microsoft.AspNetCore.Http
{
    public class PathStringTests
    {
        [Fact]
        public void CtorThrows_IfPathDoesNotHaveLeadingSlash()
        {
            // Act and Assert
            ExceptionAssert.ThrowsArgument(() => new PathString("hello"), "value", "The path in 'value' must start with '/'.");
        }

        [Fact]
        public void Equals_EmptyPathStringAndDefaultPathString()
        {
            // Act and Assert
            Assert.Equal(default(PathString), PathString.Empty);
            Assert.Equal(default(PathString), PathString.Empty);
            Assert.True(PathString.Empty == default(PathString));
            Assert.True(default(PathString) == PathString.Empty);
            Assert.True(PathString.Empty.Equals(default(PathString)));
            Assert.True(default(PathString).Equals(PathString.Empty));
        }

        [Fact]
        public void NotEquals_DefaultPathStringAndNonNullPathString()
        {
            // Arrange
            var pathString = new PathString("/hello");

            // Act and Assert
            Assert.NotEqual(default(PathString), pathString);
        }

        [Fact]
        public void NotEquals_EmptyPathStringAndNonNullPathString()
        {
            // Arrange
            var pathString = new PathString("/hello");

            // Act and Assert
            Assert.NotEqual(pathString, PathString.Empty);
        }

        [Fact]
        public void HashCode_CheckNullAndEmptyHaveSameHashcodes()
        {
            Assert.Equal(PathString.Empty.GetHashCode(), default(PathString).GetHashCode());
        }

        [Theory]
        [InlineData(null, null)]
        [InlineData("", null)]
        public void AddPathString_HandlesNullAndEmptyStrings(string appString, string concatString)
        {
            // Arrange
            var appPath = new PathString(appString);
            var concatPath = new PathString(concatString);

            // Act
            var result = appPath.Add(concatPath);

            // Assert
            Assert.False(result.HasValue);
        }

        [Theory]
        [InlineData("", "/", "/")]
        [InlineData("/", null, "/")]
        [InlineData("/", "", "/")]
        [InlineData("/", "/test", "/test")]
        [InlineData("/myapp/", "/test/bar", "/myapp/test/bar")]
        [InlineData("/myapp/", "/test/bar/", "/myapp/test/bar/")]
        public void AddPathString_HandlesLeadingAndTrailingSlashes(string appString, string concatString, string expected)
        {
            // Arrange
            var appPath = new PathString(appString);
            var concatPath = new PathString(concatString);

            // Act
            var result = appPath.Add(concatPath);

            // Assert
            Assert.Equal(expected, result.Value);
        }

        [Fact]
        public void ImplicitStringConverters_WorksWithAdd()
        {
            var scheme = "http";
            var host = new HostString("localhost:80");
            var pathBase = new PathString("/base");
            var path = new PathString("/path");
            var query = new QueryString("?query");
            var fragment = new FragmentString("#frag");

            var result = scheme + "://" + host + pathBase + path + query + fragment;
            Assert.Equal("http://localhost:80/base/path?query#frag", result);

            result = pathBase + path + query + fragment;
            Assert.Equal("/base/path?query#frag", result);

            result = path + "text";
            Assert.Equal("/pathtext", result);
        }

        [Theory]
        [InlineData("/test/path", "/TEST", true)]
        [InlineData("/test/path", "/TEST/pa", false)]
        [InlineData("/TEST/PATH", "/test", true)]
        [InlineData("/TEST/path", "/test/pa", false)]
        [InlineData("/test/PATH/path/TEST", "/TEST/path/PATH", true)]
        public void StartsWithSegments_DoesACaseInsensitiveMatch(string sourcePath, string testPath, bool expectedResult)
        {
            var source = new PathString(sourcePath);
            var test = new PathString(testPath);

            var result = source.StartsWithSegments(test);

            Assert.Equal(expectedResult, result);
        }

        [Theory]
        [InlineData("/test/path", "/TEST", true)]
        [InlineData("/test/path", "/TEST/pa", false)]
        [InlineData("/TEST/PATH", "/test", true)]
        [InlineData("/TEST/path", "/test/pa", false)]
        [InlineData("/test/PATH/path/TEST", "/TEST/path/PATH", true)]
        public void StartsWithSegmentsWithRemainder_DoesACaseInsensitiveMatch(string sourcePath, string testPath, bool expectedResult)
        {
            var source = new PathString(sourcePath);
            var test = new PathString(testPath);

            var result = source.StartsWithSegments(test, out var remaining);

            Assert.Equal(expectedResult, result);
        }

        [Theory]
        [InlineData("/test/path", "/TEST", StringComparison.OrdinalIgnoreCase, true)]
        [InlineData("/test/path", "/TEST", StringComparison.Ordinal, false)]
        [InlineData("/test/path", "/TEST/pa", StringComparison.OrdinalIgnoreCase, false)]
        [InlineData("/test/path", "/TEST/pa", StringComparison.Ordinal, false)]
        [InlineData("/TEST/PATH", "/test", StringComparison.OrdinalIgnoreCase, true)]
        [InlineData("/TEST/PATH", "/test", StringComparison.Ordinal, false)]
        [InlineData("/TEST/path", "/test/pa", StringComparison.OrdinalIgnoreCase, false)]
        [InlineData("/TEST/path", "/test/pa", StringComparison.Ordinal, false)]
        [InlineData("/test/PATH/path/TEST", "/TEST/path/PATH", StringComparison.OrdinalIgnoreCase, true)]
        [InlineData("/test/PATH/path/TEST", "/TEST/path/PATH", StringComparison.Ordinal, false)]
        public void StartsWithSegments_DoesMatchUsingSpecifiedComparison(string sourcePath, string testPath, StringComparison comparison, bool expectedResult)
        {
            var source = new PathString(sourcePath);
            var test = new PathString(testPath);

            var result = source.StartsWithSegments(test, comparison);

            Assert.Equal(expectedResult, result);
        }

        [Theory]
        [InlineData("/test/path", "/TEST", StringComparison.OrdinalIgnoreCase, true)]
        [InlineData("/test/path", "/TEST", StringComparison.Ordinal, false)]
        [InlineData("/test/path", "/TEST/pa", StringComparison.OrdinalIgnoreCase, false)]
        [InlineData("/test/path", "/TEST/pa", StringComparison.Ordinal, false)]
        [InlineData("/TEST/PATH", "/test", StringComparison.OrdinalIgnoreCase, true)]
        [InlineData("/TEST/PATH", "/test", StringComparison.Ordinal, false)]
        [InlineData("/TEST/path", "/test/pa", StringComparison.OrdinalIgnoreCase, false)]
        [InlineData("/TEST/path", "/test/pa", StringComparison.Ordinal, false)]
        [InlineData("/test/PATH/path/TEST", "/TEST/path/PATH", StringComparison.OrdinalIgnoreCase, true)]
        [InlineData("/test/PATH/path/TEST", "/TEST/path/PATH", StringComparison.Ordinal, false)]
        public void StartsWithSegmentsWithRemainder_DoesMatchUsingSpecifiedComparison(string sourcePath, string testPath, StringComparison comparison, bool expectedResult)
        {
            var source = new PathString(sourcePath);
            var test = new PathString(testPath);

            var result = source.StartsWithSegments(test, comparison, out var remaining);

            Assert.Equal(expectedResult, result);
        }

        [Theory]
        // unreserved
        [InlineData("/abc123.-_~", "/abc123.-_~")]
        // colon
        [InlineData("/:", "/:")]
        // at
        [InlineData("/@", "/@")]
        // sub-delims
        [InlineData("/!$&'()*+,;=", "/!$&'()*+,;=")]
        // reserved
        [InlineData("/?#[]", "/%3F%23%5B%5D")]
        // pct-encoding
        [InlineData("/单行道", "/%E5%8D%95%E8%A1%8C%E9%81%93")]
        // mixed
        [InlineData("/index/单行道=(x*y)[abc]", "/index/%E5%8D%95%E8%A1%8C%E9%81%93=(x*y)%5Babc%5D")]
        [InlineData("/index/单行道=(x*y)[abc]_", "/index/%E5%8D%95%E8%A1%8C%E9%81%93=(x*y)%5Babc%5D_")]
        // encoded
        [InlineData("/http%3a%2f%2f[foo]%3A5000/", "/http%3a%2f%2f%5Bfoo%5D%3A5000/")]
        [InlineData("/http%3a%2f%2f[foo]%3A5000/%", "/http%3a%2f%2f%5Bfoo%5D%3A5000/%25")]
        [InlineData("/http%3a%2f%2f[foo]%3A5000/%2", "/http%3a%2f%2f%5Bfoo%5D%3A5000/%252")]
        [InlineData("/http%3a%2f%2f[foo]%3A5000/%2F", "/http%3a%2f%2f%5Bfoo%5D%3A5000/%2F")]
        public void ToUriComponentEscapeCorrectly(string input, string expected)
        {
            var path = new PathString(input);

            Assert.Equal(expected, path.ToUriComponent());
        }

        [Fact]
        public void PathStringConvertsOnlyToAndFromString()
        {
            var converter = TypeDescriptor.GetConverter(typeof(PathString));
            PathString result = (PathString)converter.ConvertFromInvariantString("/foo")!;
            Assert.Equal("/foo", result.ToString());
            Assert.Equal("/foo", converter.ConvertTo(result, typeof(string)));
            Assert.True(converter.CanConvertFrom(typeof(string)));
            Assert.False(converter.CanConvertFrom(typeof(int)));
            Assert.False(converter.CanConvertFrom(typeof(bool)));
            Assert.True(converter.CanConvertTo(typeof(string)));
            Assert.False(converter.CanConvertTo(typeof(int)));
            Assert.False(converter.CanConvertTo(typeof(bool)));
        }

        [Fact]
        public void PathStringStaysEqualAfterAssignments()
        {
            PathString p1 = "/?";
            string s1 = p1;
            PathString p2 = s1;
            Assert.Equal(p1, p2);
        }

        [Theory]
        [InlineData("/a%2Fb")]
        [InlineData("/a%2F")]
        [InlineData("/%2fb")]
        [InlineData("/a%2Fb/c%2Fd/e")]
        public void StringFromUriComponentLeavesForwardSlashEscaped(string input)
        {
            var sut = PathString.FromUriComponent(input);
            Assert.Equal(input, sut.Value);
        }

        [Theory]
        [InlineData("/a%2Fb")]
        [InlineData("/a%2F")]
        [InlineData("/%2fb")]
        [InlineData("/a%2Fb/c%2Fd/e")]
        public void UriFromUriComponentLeavesForwardSlashEscaped(string input)
        {
            var uri = new Uri($"https://localhost:5001{input}");
            var sut = PathString.FromUriComponent(uri);
            Assert.Equal(input, sut.Value);
        }

        [Theory]
        [InlineData("/a%20b", "/a b")]
        [InlineData("/thisMustBeAVeryLongPath/SoLongThatItCouldActuallyBeLargerToTheStackAllocThresholdValue/PathsShorterToThisAllocateLessOnHeapByUsingStackAllocation/api/a%20b",
            "/thisMustBeAVeryLongPath/SoLongThatItCouldActuallyBeLargerToTheStackAllocThresholdValue/PathsShorterToThisAllocateLessOnHeapByUsingStackAllocation/api/a b")]
        public void StringFromUriComponentUnescapes(string input, string expected)
        {
            var sut = PathString.FromUriComponent(input);
            Assert.Equal(expected, sut.Value);
        }

        [Theory]
        [InlineData("/a%20b", "/a b")]
        [InlineData("/thisMustBeAVeryLongPath/SoLongThatItCouldActuallyBeLargerToTheStackAllocThresholdValue/PathsShorterToThisAllocateLessOnHeapByUsingStackAllocation/api/a%20b",
    "/thisMustBeAVeryLongPath/SoLongThatItCouldActuallyBeLargerToTheStackAllocThresholdValue/PathsShorterToThisAllocateLessOnHeapByUsingStackAllocation/api/a b")]
        public void UriFromUriComponentUnescapes(string input, string expected)
        {
            var uri = new Uri($"https://localhost:5001{input}");
            var sut = PathString.FromUriComponent(uri);
            Assert.Equal(expected, sut.Value);
        }

        [Theory]
        [InlineData("/a%2Fb")]
        [InlineData("/a%2F")]
        [InlineData("/%2fb")]
        [InlineData("/%2Fb%20c")]
        [InlineData("/a%2Fb%20c")]
        [InlineData("/a%20b")]
        [InlineData("/a%2Fb/c%2Fd/e%20f")]
        [InlineData("/%E4%BD%A0%E5%A5%BD")]
        public void FromUriComponentToUriComponent(string input)
        {
            var sut = PathString.FromUriComponent(input);
            Assert.Equal(input, sut.ToUriComponent());
        }

        [Theory]
        [MemberData(nameof(CharsToUnescape))]
        [InlineData("/%E4%BD%A0%E5%A5%BD", "/你好")]
        public void FromUriComponentUnescapesAllExceptForwardSlash(string input, string expected)
        {
            var sut = PathString.FromUriComponent(input);
            Assert.Equal(expected, sut.Value);
        }

        [Theory]
        [InlineData(-1)]
        [InlineData(0)]
        [InlineData(1)]
        public void ExercisingStringFromUriComponentOnStackAllocLimit(int offset)
        {
            var path = "/";
            var testString = new string('a', PathString.StackAllocThreshold + offset - path.Length);
            var sut = PathString.FromUriComponent(path + testString);
            Assert.Equal(PathString.StackAllocThreshold + offset, sut.Value!.Length);
        }

        [Theory]
        [InlineData(-1)]
        [InlineData(0)]
        [InlineData(1)]
        public void ExercisingUriFromUriComponentOnStackAllocLimit(int offset)
        {
            var localhost = "https://localhost:5001/";
            var testString = new string('a', PathString.StackAllocThreshold + offset);
            var sut = PathString.FromUriComponent(new Uri(localhost + testString));
            Assert.Equal(PathString.StackAllocThreshold + offset + 1, sut.Value!.Length);
        }

        public static IEnumerable<object[]> CharsToUnescape
        {
            get
            {
                foreach (var item in Enumerable.Range(1, 127))
                {
                    // %2F is '/' not escaped for paths
                    if (item != 0x2f)
                    {
                        var hexEscapedValue = "%" + item.ToString("x2", CultureInfo.InvariantCulture);
                        var expected = Uri.UnescapeDataString(hexEscapedValue);
                        yield return new object[] { "/a" + hexEscapedValue, "/a" + expected };
                    }
                }
            }
        }
    }
}
