using System.Diagnostics.CodeAnalysis;
using System.IO;
using NUnit.Framework;
using StardewModdingAPI.Toolkit.Utilities;

namespace SMAPI.Tests.Utilities
{
    /// <summary>Unit tests for <see cref="PathUtilities"/>.</summary>
    [TestFixture]
    [SuppressMessage("ReSharper", "StringLiteralTypo", Justification = "These are standard game install paths.")]
    internal class PathUtilitiesTests
    {
        /*********
        ** Sample data
        *********/
        /// <summary>Sample paths used in unit tests.</summary>
        public static readonly SamplePath[] SamplePaths = {
            // Windows absolute path
            new(
                OriginalPath: @"C:\Program Files (x86)\Steam\steamapps\common\Stardew Valley",

                Segments: new[] { "C:", "Program Files (x86)", "Steam", "steamapps", "common", "Stardew Valley" },
                SegmentsLimit3: new [] { "C:", "Program Files (x86)", @"Steam\steamapps\common\Stardew Valley" },

                NormalizedOnWindows: @"C:\Program Files (x86)\Steam\steamapps\common\Stardew Valley",
                NormalizedOnUnix: @"C:/Program Files (x86)/Steam/steamapps/common/Stardew Valley"
            ),

            // Windows absolute path (with trailing slash)
            new(
                OriginalPath: @"C:\Program Files (x86)\Steam\steamapps\common\Stardew Valley\",

                Segments: new[] { "C:", "Program Files (x86)", "Steam", "steamapps", "common", "Stardew Valley" },
                SegmentsLimit3: new [] { "C:", "Program Files (x86)", @"Steam\steamapps\common\Stardew Valley\" },

                NormalizedOnWindows: @"C:\Program Files (x86)\Steam\steamapps\common\Stardew Valley\",
                NormalizedOnUnix: @"C:/Program Files (x86)/Steam/steamapps/common/Stardew Valley/"
            ),

            // Windows relative path
            new(
                OriginalPath: @"Content\Characters\Dialogue\Abigail",

                Segments: new [] { "Content", "Characters", "Dialogue", "Abigail" },
                SegmentsLimit3: new [] { "Content", "Characters", @"Dialogue\Abigail" },

                NormalizedOnWindows: @"Content\Characters\Dialogue\Abigail",
                NormalizedOnUnix: @"Content/Characters/Dialogue/Abigail"
            ),

            // Windows relative path (with directory climbing)
            new(
                OriginalPath: @"..\..\Content",

                Segments: new [] { "..", "..", "Content" },
                SegmentsLimit3: new [] { "..", "..", "Content" },

                NormalizedOnWindows: @"..\..\Content",
                NormalizedOnUnix: @"../../Content"
            ),

            // Windows UNC path
            new(
                OriginalPath: @"\\unc\path",

                Segments: new [] { "unc", "path" },
                SegmentsLimit3: new [] { "unc", "path" },

                NormalizedOnWindows: @"\\unc\path",
                NormalizedOnUnix: "/unc/path" // there's no good way to normalize this on Unix since UNC paths aren't supported; path normalization is meant for asset names anyway, so this test only ensures it returns some sort of sane value
            ),

            // Linux absolute path
            new(
                OriginalPath: @"/home/.steam/steam/steamapps/common/Stardew Valley",

                Segments: new [] { "home", ".steam", "steam", "steamapps", "common", "Stardew Valley" },
                SegmentsLimit3: new [] { "home", ".steam", "steam/steamapps/common/Stardew Valley" },

                NormalizedOnWindows: @"\home\.steam\steam\steamapps\common\Stardew Valley",
                NormalizedOnUnix: @"/home/.steam/steam/steamapps/common/Stardew Valley"
            ),

            // Linux absolute path (with trailing slash)
            new(
                OriginalPath: @"/home/.steam/steam/steamapps/common/Stardew Valley/",

                Segments: new [] { "home", ".steam", "steam", "steamapps", "common", "Stardew Valley" },
                SegmentsLimit3: new [] { "home", ".steam", "steam/steamapps/common/Stardew Valley/" },

                NormalizedOnWindows: @"\home\.steam\steam\steamapps\common\Stardew Valley\",
                NormalizedOnUnix: @"/home/.steam/steam/steamapps/common/Stardew Valley/"
            ),

            // Linux absolute path (with ~)
            new(
                OriginalPath: @"~/.steam/steam/steamapps/common/Stardew Valley",

                Segments: new [] { "~", ".steam", "steam", "steamapps", "common", "Stardew Valley" },
                SegmentsLimit3: new [] { "~", ".steam", "steam/steamapps/common/Stardew Valley" },

                NormalizedOnWindows: @"~\.steam\steam\steamapps\common\Stardew Valley",
                NormalizedOnUnix: @"~/.steam/steam/steamapps/common/Stardew Valley"
            ),

            // Linux relative path
            new(
                OriginalPath: @"Content/Characters/Dialogue/Abigail",

                Segments: new [] { "Content", "Characters", "Dialogue", "Abigail" },
                SegmentsLimit3: new [] { "Content", "Characters", "Dialogue/Abigail" },

                NormalizedOnWindows: @"Content\Characters\Dialogue\Abigail",
                NormalizedOnUnix: @"Content/Characters/Dialogue/Abigail"
            ),

            // Linux relative path (with directory climbing)
            new(
                OriginalPath: @"../../Content",

                Segments: new [] { "..", "..", "Content" },
                SegmentsLimit3: new [] { "..", "..", "Content" },

                NormalizedOnWindows: @"..\..\Content",
                NormalizedOnUnix: @"../../Content"
            ),

            // Mixed directory separators
            new(
                OriginalPath: @"C:\some/mixed\path/separators",

                Segments: new [] { "C:", "some", "mixed", "path", "separators" },
                SegmentsLimit3: new [] { "C:", "some", @"mixed\path/separators" },

                NormalizedOnWindows: @"C:\some\mixed\path\separators",
                NormalizedOnUnix: @"C:/some/mixed/path/separators"
            )
        };


        /*********
        ** Unit tests
        *********/
        /****
        ** GetSegments
        ****/
        [Test(Description = "Assert that PathUtilities.GetSegments splits paths correctly.")]
        [TestCaseSource(nameof(PathUtilitiesTests.SamplePaths))]
        public void GetSegments(SamplePath path)
        {
            // act
            string[] segments = PathUtilities.GetSegments(path.OriginalPath);

            // assert
            Assert.AreEqual(path.Segments, segments);
        }

        [Test(Description = "Assert that PathUtilities.GetSegments splits paths correctly when given a limit.")]
        [TestCaseSource(nameof(PathUtilitiesTests.SamplePaths))]
        public void GetSegments_WithLimit(SamplePath path)
        {
            // act
            string[] segments = PathUtilities.GetSegments(path.OriginalPath, 3);

            // assert
            Assert.AreEqual(path.SegmentsLimit3, segments);
        }

        /****
        ** NormalizeAssetName
        ****/
        [Test(Description = "Assert that PathUtilities.NormalizeAssetName normalizes paths correctly.")]
        [TestCaseSource(nameof(PathUtilitiesTests.SamplePaths))]
        public void NormalizeAssetName(SamplePath path)
        {
            if (Path.IsPathRooted(path.OriginalPath) || path.OriginalPath.StartsWith('/') || path.OriginalPath.StartsWith('\\'))
                Assert.Ignore("Absolute paths can't be used as asset names.");

            // act
            string normalized = PathUtilities.NormalizeAssetName(path.OriginalPath);

            // assert
            Assert.AreEqual(path.NormalizedOnUnix, normalized); // MonoGame uses the Linux format
        }

        /****
        ** NormalizePath
        ****/
        [Test(Description = "Assert that PathUtilities.NormalizePath normalizes paths correctly.")]
        [TestCaseSource(nameof(PathUtilitiesTests.SamplePaths))]
        public void NormalizePath(SamplePath path)
        {
            // act
            string normalized = PathUtilities.NormalizePath(path.OriginalPath);

            // assert
#if SMAPI_FOR_WINDOWS
            Assert.AreEqual(path.NormalizedOnWindows, normalized);
#else
            Assert.AreEqual(path.NormalizedOnUnix, normalized);
#endif
        }

        /****
        ** GetRelativePath
        ****/
        [Test(Description = "Assert that PathUtilities.GetRelativePath returns the expected values.")]
#if SMAPI_FOR_WINDOWS
        [TestCase(
            @"C:\Program Files (x86)\Steam\steamapps\common\Stardew Valley",
            @"C:\Program Files (x86)\Steam\steamapps\common\Stardew Valley\Mods\Automate",
            ExpectedResult = @"Mods\Automate"
        )]
        [TestCase(
            @"C:\Program Files (x86)\Steam\steamapps\common\Stardew Valley\Mods\Automate",
            @"C:\Program Files (x86)\Steam\steamapps\common\Stardew Valley\Content",
            ExpectedResult = @"..\..\Content"
        )]
        [TestCase(
            @"C:\Program Files (x86)\Steam\steamapps\common\Stardew Valley\Mods\Automate",
            @"D:\another-drive",
            ExpectedResult = @"D:\another-drive"
        )]
        [TestCase(
            @"\\parent\unc",
            @"\\parent\unc\path\to\child",
            ExpectedResult = @"path\to\child"
        )]
        [TestCase(
            @"C:\same\path",
            @"C:\same\path",
            ExpectedResult = @"."
        )]
        [TestCase(
            @"C:\parent",
            @"C:\PARENT\child",
            ExpectedResult = @"child"
        )]
#else
        [TestCase(
            @"~/.steam/steam/steamapps/common/Stardew Valley",
            @"~/.steam/steam/steamapps/common/Stardew Valley/Mods/Automate",
            ExpectedResult = @"Mods/Automate"
        )]
        [TestCase(
            @"~/.steam/steam/steamapps/common/Stardew Valley/Mods/Automate",
            @"~/.steam/steam/steamapps/common/Stardew Valley/Content",
            ExpectedResult = @"../../Content"
        )]
        [TestCase(
            @"~/.steam/steam/steamapps/common/Stardew Valley/Mods/Automate",
            @"/mnt/another-drive",
            ExpectedResult = @"/mnt/another-drive"
        )]
        [TestCase(
            @"~/same/path",
            @"~/same/path",
            ExpectedResult = @"."
        )]
        [TestCase(
            @"~/parent",
            @"~/PARENT/child",
            ExpectedResult = @"child" // note: incorrect on Linux and sometimes macOS, but not worth the complexity of detecting whether the filesystem is case-sensitive for SMAPI's purposes
        )]
#endif
        public string GetRelativePath(string sourceDir, string targetPath)
        {
            return PathUtilities.GetRelativePath(sourceDir, targetPath);
        }


        /*********
        ** Private classes
        *********/
        /// <summary>A sample path in multiple formats.</summary>
        /// <param name="OriginalPath">The original path to pass to the <see cref="PathUtilities"/>.</param>
        /// <param name="Segments">The normalized path segments.</param>
        /// <param name="SegmentsLimit3">The normalized path segments, if we stop segmenting after the second one.</param>
        /// <param name="NormalizedOnWindows">The normalized form on Windows.</param>
        /// <param name="NormalizedOnUnix">The normalized form on Linux or macOS.</param>
        public record SamplePath(string OriginalPath, string[] Segments, string[] SegmentsLimit3, string NormalizedOnWindows, string NormalizedOnUnix)
        {
            public override string ToString()
            {
                return this.OriginalPath;
            }
        }
    }
}