using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Moq;
using Newtonsoft.Json;
using NUnit.Framework;
using StardewModdingAPI.Framework.Models;
using StardewModdingAPI.Framework.ModLoading;
using StardewModdingAPI.Framework.Serialisation;
using StardewModdingAPI.Tests.Framework;

namespace StardewModdingAPI.Tests
{
    [TestFixture]
    public class ModResolverTests
    {
        /*********
        ** Unit tests
        *********/
        [Test(Description = "Assert that the resolver correctly returns an empty list if there are no mods installed.")]
        public void ReadBasicManifest_NoMods_ReturnsEmptyList()
        {
            // arrange
            string rootFolder = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N"));
            Directory.CreateDirectory(rootFolder);

            // act
            IModMetadata[] mods = new ModResolver().ReadManifests(rootFolder, new JsonHelper(), new ModCompatibility[0]).ToArray();

            // assert
            Assert.AreEqual(0, mods.Length, 0, $"Expected to find zero manifests, found {mods.Length} instead.");
        }

        [Test(Description = "Assert that the resolver correctly returns a failed metadata if there's an empty mod folder.")]
        public void ReadBasicManifest_EmptyModFolder_ReturnsFailedManifest()
        {
            // arrange
            string rootFolder = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N"));
            string modFolder = Path.Combine(rootFolder, Guid.NewGuid().ToString("N"));
            Directory.CreateDirectory(modFolder);

            // act
            IModMetadata[] mods = new ModResolver().ReadManifests(rootFolder, new JsonHelper(), new ModCompatibility[0]).ToArray();
            IModMetadata mod = mods.FirstOrDefault();

            // assert
            Assert.AreEqual(1, mods.Length, 0, $"Expected to find one manifest, found {mods.Length} instead.");
            Assert.AreEqual(ModMetadataStatus.Failed, mod.Status, "The mod metadata was not marked failed.");
            Assert.IsNotNull(mod.Error, "The mod metadata did not have an error message set.");
        }

        [Test(Description = "Assert that the resolver correctly reads manifest data from a randomised file.")]
        public void ReadBasicManifest_CanReadFile()
        {
            // create manifest data
            IDictionary<string, object> originalDependency = new Dictionary<string, object>
            {
                [nameof(IManifestDependency.UniqueID)] = Sample.String()
            };
            IDictionary<string, object> original = new Dictionary<string, object>
            {
                [nameof(IManifest.Name)] = Sample.String(),
                [nameof(IManifest.Author)] = Sample.String(),
                [nameof(IManifest.Version)] = new SemanticVersion(Sample.Int(), Sample.Int(), Sample.Int(), Sample.String()),
                [nameof(IManifest.Description)] = Sample.String(),
                [nameof(IManifest.UniqueID)] = $"{Sample.String()}.{Sample.String()}",
                [nameof(IManifest.EntryDll)] = $"{Sample.String()}.dll",
                [nameof(IManifest.MinimumApiVersion)] = $"{Sample.Int()}.{Sample.Int()}-{Sample.String()}",
                [nameof(IManifest.Dependencies)] = new[] { originalDependency },
                ["ExtraString"] = Sample.String(),
                ["ExtraInt"] = Sample.Int()
            };

            // write to filesystem
            string rootFolder = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N"));
            string modFolder = Path.Combine(rootFolder, Guid.NewGuid().ToString("N"));
            string filename = Path.Combine(modFolder, "manifest.json");
            Directory.CreateDirectory(modFolder);
            File.WriteAllText(filename, JsonConvert.SerializeObject(original));

            // act
            IModMetadata[] mods = new ModResolver().ReadManifests(rootFolder, new JsonHelper(), new ModCompatibility[0]).ToArray();
            IModMetadata mod = mods.FirstOrDefault();

            // assert
            Assert.AreEqual(1, mods.Length, 0, $"Expected to find one manifest, found {mods.Length} instead.");
            Assert.IsNotNull(mod, "The loaded manifest shouldn't be null.");
            Assert.AreEqual(null, mod.Compatibility, "The compatibility record should be null since we didn't provide one.");
            Assert.AreEqual(modFolder, mod.DirectoryPath, "The directory path doesn't match.");
            Assert.AreEqual(ModMetadataStatus.Found, mod.Status, "The status doesn't match.");
            Assert.AreEqual(null, mod.Error, "The error should be null since parsing should have succeeded.");

            Assert.AreEqual(original[nameof(IManifest.Name)], mod.DisplayName, "The display name should use the manifest name.");
            Assert.AreEqual(original[nameof(IManifest.Name)], mod.Manifest.Name, "The manifest's name doesn't match.");
            Assert.AreEqual(original[nameof(IManifest.Author)], mod.Manifest.Author, "The manifest's author doesn't match.");
            Assert.AreEqual(original[nameof(IManifest.Description)], mod.Manifest.Description, "The manifest's description doesn't match.");
            Assert.AreEqual(original[nameof(IManifest.EntryDll)], mod.Manifest.EntryDll, "The manifest's entry DLL doesn't match.");
            Assert.AreEqual(original[nameof(IManifest.MinimumApiVersion)], mod.Manifest.MinimumApiVersion, "The manifest's minimum API version doesn't match.");
            Assert.AreEqual(original[nameof(IManifest.Version)]?.ToString(), mod.Manifest.Version?.ToString(), "The manifest's version doesn't match.");

            Assert.IsNotNull(mod.Manifest.ExtraFields, "The extra fields should not be null.");
            Assert.AreEqual(2, mod.Manifest.ExtraFields.Count, "The extra fields should contain two values.");
            Assert.AreEqual(original["ExtraString"], mod.Manifest.ExtraFields["ExtraString"], "The manifest's extra fields should contain an 'ExtraString' value.");
            Assert.AreEqual(original["ExtraInt"], mod.Manifest.ExtraFields["ExtraInt"], "The manifest's extra fields should contain an 'ExtraInt' value.");

            Assert.IsNotNull(mod.Manifest.Dependencies, "The dependencies field should not be null.");
            Assert.AreEqual(1, mod.Manifest.Dependencies.Length, "The dependencies field should contain one value.");
            Assert.AreEqual(originalDependency[nameof(IManifestDependency.UniqueID)], mod.Manifest.Dependencies[0].UniqueID, "The first dependency's unique ID doesn't match.");
        }

        [Test(Description = "Assert that validation doesn't fail if there are no mods installed.")]
        public void ValidateManifests_NoMods_DoesNothing()
        {
            new ModResolver().ValidateManifests(new ModMetadata[0], apiVersion: new SemanticVersion("1.0"));
        }

        [Test(Description = "Assert that validation skips manifests that have already failed without calling any other properties.")]
        public void ValidateManifests_Skips_Failed()
        {
            // arrange
            Mock<IModMetadata> mock = new Mock<IModMetadata>(MockBehavior.Strict);
            mock.Setup(p => p.Status).Returns(ModMetadataStatus.Failed);

            // act
            new ModResolver().ValidateManifests(new[] { mock.Object }, apiVersion: new SemanticVersion("1.0"));

            // assert
            mock.VerifyGet(p => p.Status, Times.Once, "The validation did not check the manifest status.");
        }

        [Test(Description = "Assert that validation fails if the mod has 'assume broken' compatibility.")]
        public void ValidateManifests_ModCompatibility_AssumeBroken_Fails()
        {
            // arrange
            Mock<IModMetadata> mock = new Mock<IModMetadata>(MockBehavior.Strict);
            mock.Setup(p => p.Status).Returns(ModMetadataStatus.Found);
            mock.Setup(p => p.Compatibility).Returns(new ModCompatibility { Compatibility = ModCompatibilityType.AssumeBroken });
            mock.Setup(p => p.SetStatus(ModMetadataStatus.Failed, It.IsAny<string>())).Returns(() => mock.Object);

            // act
            new ModResolver().ValidateManifests(new[] { mock.Object }, apiVersion: new SemanticVersion("1.0"));

            // assert
            mock.Verify(p => p.SetStatus(ModMetadataStatus.Failed, It.IsAny<string>()), Times.Once, "The validation did not fail the metadata.");
        }

        [Test(Description = "Assert that validation fails when the minimum API version is higher than the current SMAPI version.")]
        public void ValidateManifests_MinimumApiVersion_Fails()
        {
            // arrange
            Mock<IModMetadata> mock = new Mock<IModMetadata>(MockBehavior.Strict);
            mock.Setup(p => p.Status).Returns(ModMetadataStatus.Found);
            mock.Setup(p => p.Compatibility).Returns(() => null);
            mock.Setup(p => p.Manifest).Returns(this.GetRandomManifest("1.1"));
            mock.Setup(p => p.SetStatus(ModMetadataStatus.Failed, It.IsAny<string>())).Returns(() => mock.Object);

            // act
            new ModResolver().ValidateManifests(new[] { mock.Object }, apiVersion: new SemanticVersion("1.0"));

            // assert
            mock.Verify(p => p.SetStatus(ModMetadataStatus.Failed, It.IsAny<string>()), Times.Once, "The validation did not fail the metadata.");
        }

        [Test(Description = "Assert that validation fails when the manifest references a DLL that does not exist.")]
        public void ValidateManifests_MissingEntryDLL_Fails()
        {
            // arrange
            Mock<IModMetadata> mock = new Mock<IModMetadata>(MockBehavior.Strict);
            mock.Setup(p => p.Status).Returns(ModMetadataStatus.Found);
            mock.Setup(p => p.Compatibility).Returns(() => null);
            mock.Setup(p => p.Manifest).Returns(this.GetRandomManifest());
            mock.Setup(p => p.DirectoryPath).Returns(Path.GetTempPath());
            mock.Setup(p => p.SetStatus(ModMetadataStatus.Failed, It.IsAny<string>())).Returns(() => mock.Object);

            // act
            new ModResolver().ValidateManifests(new[] { mock.Object }, apiVersion: new SemanticVersion("1.0"));

            // assert
            mock.Verify(p => p.SetStatus(ModMetadataStatus.Failed, It.IsAny<string>()), Times.Once, "The validation did not fail the metadata.");
        }

        [Test(Description = "Assert that validation fails when the manifest references a DLL that does not exist.")]
        public void ValidateManifests_Valid_Passes()
        {
            // set up manifest
            IManifest manifest = this.GetRandomManifest();

            // create DLL
            string modFolder = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N"));
            Directory.CreateDirectory(modFolder);
            File.WriteAllText(Path.Combine(modFolder, manifest.EntryDll), "");

            // arrange
            Mock<IModMetadata> mock = new Mock<IModMetadata>(MockBehavior.Strict);
            mock.Setup(p => p.Status).Returns(ModMetadataStatus.Found);
            mock.Setup(p => p.Compatibility).Returns(() => null);
            mock.Setup(p => p.Manifest).Returns(manifest);
            mock.Setup(p => p.DirectoryPath).Returns(modFolder);

            // act
            new ModResolver().ValidateManifests(new[] { mock.Object }, apiVersion: new SemanticVersion("1.0"));

            // assert
            // if Moq doesn't throw a method-not-setup exception, the validation didn't override the status.
        }


        /*********
        ** Private methods
        *********/
        /// <summary>Get a randomised basic manifest.</summary>
        /// <param name="minVersion">The minimum API version.</param>
        private Manifest GetRandomManifest(string minVersion = null)
        {
            return new Manifest
            {
                Name = Sample.String(),
                Author = Sample.String(),
                Version = new SemanticVersion(Sample.Int(), Sample.Int(), Sample.Int(), Sample.String()),
                Description = Sample.String(),
                UniqueID = $"{Sample.String()}.{Sample.String()}",
                EntryDll = $"{Sample.String()}.dll",
                MinimumApiVersion = minVersion
            };
        }
    }
}