// ============================================================================
// YooAssetServiceTests.cs — YooAssetService 核心逻辑单元测试
// 覆盖：初始化状态机、LoadAssetAsync null/invalid 处理、ReleaseHandle 幂等性
// ============================================================================

using System;
using NUnit.Framework;
using ProjSG.Resource;

namespace ProjSG.Resource.Tests
{
    [TestFixture]
    public class YooAssetServiceTests
    {
        private YooAssetService _service;

        [SetUp]
        public void SetUp()
        {
            // 确保每个测试开始时销毁旧实例
            if (YooAssetService.IsValid())
            {
                YooAssetService.Destroy();
            }
            _service = YooAssetService.Instance;
        }

        [TearDown]
        public void TearDown()
        {
            if (YooAssetService.IsValid())
            {
                YooAssetService.Destroy();
            }
        }

        // ====================================================================
        // 初始化状态机测试
        // ====================================================================

        [Test]
        public void IsInitialized_BeforeInit_ReturnsFalse()
        {
            Assert.IsFalse(_service.IsInitialized);
        }

        [Test]
        public void ThrowsIfNotInitialized_LoadAssetAsync()
        {
            // 未初始化时调用加载方法应抛出 InvalidOperationException
            // ThrowIfNotInitialized 在异步方法同步部分抛出，GetAwaiter().GetResult() 会立即重新抛出
            Assert.Throws<InvalidOperationException>(() =>
            {
                _service.LoadAssetAsync<UnityEngine.Object>("test_location").GetAwaiter().GetResult();
            });
        }

        [Test]
        public void ThrowsIfNotInitialized_LoadAssetAsyncByType()
        {
            Assert.Throws<InvalidOperationException>(() =>
            {
                _service.LoadAssetAsync("test_location", typeof(UnityEngine.Object)).GetAwaiter().GetResult();
            });
        }

        [Test]
        public void ThrowsIfNotInitialized_LoadRawFileTextAsync()
        {
            Assert.Throws<InvalidOperationException>(() =>
            {
                _service.LoadRawFileTextAsync("test_location").GetAwaiter().GetResult();
            });
        }

        [Test]
        public void ThrowsIfNotInitialized_LoadRawFileBytesAsync()
        {
            Assert.Throws<InvalidOperationException>(() =>
            {
                _service.LoadRawFileBytesAsync("test_location").GetAwaiter().GetResult();
            });
        }

        [Test]
        public void ThrowsIfNotInitialized_CheckLocationValid()
        {
            Assert.Throws<InvalidOperationException>(() =>
            {
                _service.CheckLocationValid("test_location");
            });
        }

        [Test]
        public void ThrowsIfNotInitialized_GetAssetInfosByTag()
        {
            Assert.Throws<InvalidOperationException>(() =>
            {
                _service.GetAssetInfosByTag("test_tag");
            });
        }

        [Test]
        public void ThrowsIfNotInitialized_IsNeedDownloadFromRemote()
        {
            Assert.Throws<InvalidOperationException>(() =>
            {
                _service.IsNeedDownloadFromRemote("test_location");
            });
        }

        [Test]
        public void ThrowsIfNotInitialized_UnloadUnusedAssetsAsync()
        {
            Assert.Throws<InvalidOperationException>(() =>
            {
                _service.UnloadUnusedAssetsAsync().GetAwaiter().GetResult();
            });
        }

        [Test]
        public void ThrowsIfNotInitialized_UnloadAllAssetsAsync()
        {
            Assert.Throws<InvalidOperationException>(() =>
            {
                _service.UnloadAllAssetsAsync().GetAwaiter().GetResult();
            });
        }

        // ====================================================================
        // ReleaseHandle 幂等性测试
        // ====================================================================

        [Test]
        public void ReleaseHandle_WithNull_DoesNotThrow()
        {
            // ReleaseHandle(null) 应安全返回，不抛异常
            Assert.DoesNotThrow(() =>
            {
                _service.ReleaseHandle(null);
            });
        }

        [Test]
        public void ReleaseHandle_CalledTwiceWithNull_StillDoesNotThrow()
        {
            // 多次调用 null 仍安全
            Assert.DoesNotThrow(() =>
            {
                _service.ReleaseHandle(null);
                _service.ReleaseHandle(null);
            });
        }

        // ====================================================================
        // Singleton 行为测试
        // ====================================================================

        [Test]
        public void Singleton_Instance_ReturnsSameInstance()
        {
            var instance1 = YooAssetService.Instance;
            var instance2 = YooAssetService.Instance;
            Assert.AreSame(instance1, instance2);
        }

        [Test]
        public void Singleton_IsValid_ReturnsTrue()
        {
            _ = YooAssetService.Instance;
            Assert.IsTrue(YooAssetService.IsValid());
        }

        [Test]
        public void Singleton_AfterDestroy_IsValidReturnsFalse()
        {
            _ = YooAssetService.Instance;
            YooAssetService.Destroy();
            Assert.IsFalse(YooAssetService.IsValid());
        }

        [Test]
        public void Singleton_AfterDestroy_NewInstanceCreated()
        {
            var instance1 = YooAssetService.Instance;
            YooAssetService.Destroy();
            var instance2 = YooAssetService.Instance;
            Assert.AreNotSame(instance1, instance2);
        }

        // ====================================================================
        // IYooAssetBridge 接口行为测试
        // ====================================================================

        [Test]
        public void IYooAssetBridge_GetCached_ReturnsNull_BeforeUS4()
        {
            // GetCached 在 US4 集成前返回 null
            IYooAssetBridge bridge = _service;
            var result = bridge.GetCached<UnityEngine.Object>("test_location");
            Assert.IsNull(result);
        }

        [Test]
        public void IYooAssetBridge_IsRegistered_ReturnsFalse_BeforeInit()
        {
            IYooAssetBridge bridge = _service;
            Assert.IsFalse(bridge.IsRegistered);
        }
    }
}