using System;
using NUnit.Framework;
using UnityEngine;
using UnityEngine.Rendering;

namespace UnityEditor.Rendering
{
    [TestFixture]
    class RenderPipelineGlobalSettingsUtilsTests
    {
        [TearDown]
        public void TearDown()
        {
            foreach(var globalsetting in CoreUtils.LoadAllAssets<DummyRenderPipelineGlobalSettings>())
            {
                AssetDatabase.DeleteAsset(AssetDatabase.GetAssetPath(globalsetting));
            }

            EditorGraphicsSettings.SetRenderPipelineGlobalSettingsAsset<DummyRenderPipeline>(null);
        }

        static TestCaseData[] s_TestsCaseDatas =
        {
            new TestCaseData(string.Empty, false, AssetState.Null, string.Empty)
                .SetName(
                    "Given an empty project, when ensuring a global settings without canCreateNewAsset, the asset is not created"),
            new TestCaseData(string.Empty, true, AssetState.NotNull, "Assets/DummyRenderPipelineGlobalSettings.asset")
                .SetName(
                    "Given an empty project, when ensuring a global settings, the asset is created with the type name"),
            new TestCaseData(DummyRenderPipelineGlobalSettings.defaultPath, false, AssetState.NotNull, DummyRenderPipelineGlobalSettings.defaultPath)
                .SetName(
                    "Given a project with an asset already created in the default path, when ensuring a global settings, the asset returned is the one at default path"),
            new TestCaseData("Assets/Tests/AnotherDummyRenderPipelineGlobalSettings.asset", false, AssetState.NotNull, "Assets/Tests/AnotherDummyRenderPipelineGlobalSettings.asset")
                .SetName(
                    "Given a project with an asset already created somewhere, when ensuring a global settings, the asset returned is that one")
        };

        public enum AssetState
        {
            Null,
            NotNull
        }

        [Test, TestCaseSource(nameof(s_TestsCaseDatas))]
        public void Ensure(string path, bool canCreateNewAsset, AssetState assetState, string expectedPath)
        {
            if (!string.IsNullOrEmpty(path))
            {
                var instance = RenderPipelineGlobalSettingsUtils.Create<DummyRenderPipelineGlobalSettings>(path);
                Assert.IsNotNull(instance);
            }

            DummyRenderPipelineGlobalSettings instanceEnsured = null;
            var ensureResult = RenderPipelineGlobalSettingsUtils.
                TryEnsure<DummyRenderPipelineGlobalSettings, DummyRenderPipeline>(ref instanceEnsured, path, canCreateNewAsset, out _);

            switch (assetState)
            {
                case AssetState.Null:
                    Assert.IsFalse(ensureResult);
                    Assert.IsNull(instanceEnsured);
                    break;
                case AssetState.NotNull:
                    Assert.IsTrue(ensureResult);
                    Assert.IsNotNull(instanceEnsured);
                    Assert.IsTrue(instanceEnsured.initializedCalled, "Initialize method has not been called");
                    break;
            }

            if (instanceEnsured == null)
            {
                Assert.IsEmpty(expectedPath);
            }
            else
            {
                var instanceInGraphics = GraphicsSettings.GetSettingsForRenderPipeline<DummyRenderPipeline>();
                Assert.AreEqual(instanceInGraphics.GetInstanceID(), instanceEnsured.GetInstanceID());
                Assert.IsTrue(expectedPath.Equals(AssetDatabase.GetAssetPath(instanceEnsured), StringComparison.InvariantCultureIgnoreCase));
            }
        }

        [Test]
        public void EnsureWithAValidInstanceReturnsTheCurrentInstance()
        {
            var path = "Assets/Tests/DummyRenderPipelineGlobalSettings.asset";
            var instanceEnsured = RenderPipelineGlobalSettingsUtils.Create<DummyRenderPipelineGlobalSettings>(path);
            Assert.IsNotNull(instanceEnsured);
            Assert.IsTrue(path.Equals(AssetDatabase.GetAssetPath(instanceEnsured), StringComparison.InvariantCultureIgnoreCase));

            var instanceIDExpected = instanceEnsured.GetInstanceID();
            var ensureResult = RenderPipelineGlobalSettingsUtils.
                TryEnsure<DummyRenderPipelineGlobalSettings, DummyRenderPipeline>(ref instanceEnsured, DummyRenderPipelineGlobalSettings.defaultPath, true, out _);

            Assert.IsTrue(ensureResult);
            Assert.IsNotNull(instanceEnsured);
            Assert.AreEqual(instanceIDExpected, instanceEnsured.GetInstanceID());
        }
    }
}