using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Reflection;
using Moq;
using NUnit.Framework;
using UnityEditor;
using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.TestTools;
using Object = UnityEngine.Object;

namespace BracerLib.Utility.Testing
{
    [ExcludeFromCodeCoverage, ExcludeFromCoverage]
    public class TestBase
    {
        // private readonly IDictionary<Object, SerializedObject> globalPropertyCache;
        private readonly IDictionary<Object, SerializedObject> objectPropertyCache;
        private readonly Queue<Object> destroyOnTestEnd;
        private readonly Stack<Scene> closeOnTestEnd;
        private readonly Queue<IDisposable> disposeOnTestEnd;
        private readonly Queue<Object> destroyOnOneTimeEnd;
        private readonly Stack<Scene> closeOnOneTimeEnd;
        private readonly Queue<IDisposable> disposeOnOneTimeEnd;

        [ExcludeFromCoverage]
        protected TestBase()
        {
            // globalPropertyCache = new Dictionary<Object, SerializedObject>();
            objectPropertyCache = new Dictionary<Object, SerializedObject>();
            destroyOnTestEnd = new Queue<Object>();
            closeOnTestEnd = new Stack<Scene>();
            disposeOnTestEnd = new Queue<IDisposable>();
            destroyOnOneTimeEnd = new Queue<Object>();
            closeOnOneTimeEnd = new Stack<Scene>();
            disposeOnOneTimeEnd =  new Queue<IDisposable>();
        }

        /// <summary>
        /// Called as part of NUnit framework. Override <see cref="OneTimeSetUp"/> instead.
        /// </summary>
        [OneTimeSetUp, ExcludeFromCoverage]
        public void DoOneTimeSetUp()
        {
            OneTimeSetUp();
        }

        [UnityOneTimeSetUp, ExcludeFromCoverage]
        public IEnumerator DoUnityOneTimeSetUp()
        {
            yield return UnityOneTimeSetUp();
        }

        /// <summary>
        /// Called as part of NUnit framework. Override <see cref="SetUp"/> instead.
        /// </summary>
        [SetUp, ExcludeFromCoverage]
        public void DoSetUp()
        {
            SetUp();
        }

        [UnitySetUp, ExcludeFromCoverage]
        public IEnumerator DoUnitySetUp()
        {
            yield return UnitySetUp();
        }

        /// <summary>
        /// Called as part of NUnit framework. Override <see cref="TearDown"/> instead.
        /// </summary>
        [TearDown, ExcludeFromCoverage]
        public void DoTearDown()
        {
            TearDown();

            objectPropertyCache.Clear();
        }

        [UnityTearDown, ExcludeFromCoverage]
        public IEnumerator DoUnityTearDown()
        {
            yield return UnityTearDown();

            Reset();

            while (closeOnTestEnd.Count > 0)
                yield return CloseLatestScene();
        }

        /// <summary>
        /// Called as part of NUnit framework. Override <see cref="OneTimeTearDown"/> instead.
        /// </summary>
        [OneTimeTearDown, ExcludeFromCoverage]
        public void DoOneTimeTearDown()
        {
            OneTimeTearDown();
        }

        [UnityOneTimeTearDown, ExcludeFromCoverage]
        public IEnumerator DoUnityOneTimeTearDown()
        {
            yield return UnityOneTimeTearDown();

            CleanupUnityObjects(destroyOnOneTimeEnd);
            CleanupDisposableObjects(disposeOnOneTimeEnd);

            while (closeOnOneTimeEnd.Count > 0)
                yield return CloseLatestScene(true);
        }

        /// <summary>
        /// Pass a Unity object that will be destroyed at the end of the test.
        /// </summary>
        protected T RegisterTempTestObject<T>(T obj) where T : Object
        {
            destroyOnTestEnd.Enqueue(obj);

            return obj;
        }

        /// <summary>
        /// Pass a function that generates or returns a Unity object that will be destroyed at the end of the test.
        /// </summary>
        protected T RegisterTempTestObject<T>(Func<T> generator) where T : Object
        {
            var obj = generator();

            return RegisterTempTestObject(obj);
        }

        /// <summary>
        /// Pass a Unity object that will be destroyed at the end of all the tests in a given suite.
        /// </summary>
        protected T RegisterOneTimeTestObject<T>(T obj) where T : Object
        {
            destroyOnOneTimeEnd.Enqueue(obj);

            return obj;
        }

        /// <summary>
        /// Pass a function that generates or returns a Unity object that will be destroyed at the end of all the tests in a given suite.
        /// </summary>
        protected T RegisterOneTimeTestObject<T>(Func<T> generator) where T : Object
        {
            var obj = generator();

            return RegisterOneTimeTestObject(obj);
        }

        /// <summary>
        /// Pass a disposable object that will be cleaned up at the end of the test.
        /// </summary>
        protected T RegisterDisposableTempTestObject<T>(T obj) where T : IDisposable
        {
            disposeOnTestEnd.Enqueue(obj);

            return obj;
        }

        /// <summary>
        /// Pass a function that generates or returns a disposable object that will be cleaned up at the end of the test.
        /// </summary>
        /// <param name="generator"></param>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        protected T RegisterDisposableTempTestObject<T>(Func<T> generator) where T : IDisposable
        {
            var obj = generator();

            return RegisterDisposableTempTestObject(obj);
        }

        /// <summary>
        /// Pass a disposable object that will be cleaned up at the end of the test.
        /// </summary>
        protected T RegisterDisposableOneTimeTestObject<T>(T obj) where T : IDisposable
        {
            disposeOnOneTimeEnd.Enqueue(obj);

            return obj;
        }

        /// <summary>
        /// Pass a function that generates or returns a disposable object that will be cleaned up at the end of the test.
        /// </summary>
        /// <param name="generator"></param>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        protected T RegisterDisposableOneTimeTestObject<T>(Func<T> generator) where T : IDisposable
        {
            var obj = generator();

            return RegisterDisposableOneTimeTestObject(obj);
        }

        protected IEnumerator OpenScene(string scenePath, bool isOneTime = false)
        {
            var asyncOp = SceneManager.LoadSceneAsync(scenePath, LoadSceneMode.Additive);
            asyncOp!.completed += SetLoadedSceneActive;

            yield return asyncOp;

            var loadedScene = SceneManager.GetSceneAt(SceneManager.loadedSceneCount - 1);
            if (!isOneTime)
                closeOnTestEnd.Push(loadedScene);
            else
                closeOnOneTimeEnd.Push(loadedScene);
        }

        protected IEnumerator CloseLatestScene(bool isOneTime = false)
        {
            var targetStack = !isOneTime ? closeOnTestEnd : closeOnOneTimeEnd;

            if (!targetStack.TryPop(out var targetScene))
                yield break;

            var asyncOp = SceneManager.UnloadSceneAsync(targetScene);
            asyncOp!.completed += SetLoadedSceneActive;

            yield return asyncOp;
        }

        protected void SetLoadedSceneActive(AsyncOperation asyncOperation)
        {
            SceneManager.SetActiveScene(SceneManager.GetSceneAt(SceneManager.loadedSceneCount - 1));
        }

        [ExcludeFromCoverage]
        protected virtual void OneTimeSetUp() { }

        [ExcludeFromCoverage]
        protected virtual IEnumerator UnityOneTimeSetUp()
        {
            yield return null;
        }

        protected virtual void SetUp() { }

        protected virtual IEnumerator UnitySetUp()
        {
            yield return null;
        }

        protected virtual void TearDown() { }

        protected virtual IEnumerator UnityTearDown()
        {
            yield return null;
        }

        [ExcludeFromCoverage]
        protected virtual void OneTimeTearDown() { }

        [ExcludeFromCoverage]
        protected virtual IEnumerator UnityOneTimeTearDown()
        {
            yield return null;
        }

        /// <summary>
        /// Set a private value member of an object via C# reflection.
        /// </summary>
        /// <example><code>
        /// public class SomeObject {
        ///     private int item;
        /// }
        ///
        /// var obj = new SomeObject();
        /// SetReflectedValue(obj, "item", 25);
        /// </code></example>
        protected internal void SetReflectedValue(object targetObject, string targetProperty, object targetValue)
        {
            SetReflectedValue(targetObject, targetObject.GetType(), targetProperty, targetValue);
        }

        protected internal void SetReflectedValues(object targetObject, params ValueTuple<string, object>[] properties)
        {
            var type = targetObject.GetType();

            for (var i = 0; i < properties.Length; i++)
                SetReflectedValue(targetObject, type, properties[i].Item1, properties[i].Item2);
        }

        /// <summary>
        /// Set a non-interface reference member of a MonoBehaviour via Unity reflection.
        /// Will be applied depending on context of Test setup being used.
        /// </summary>
        /// <example><code>
        /// public class SomeOtherObject { }
        ///
        /// public class SomeObject : MonoBehaviour {
        ///     private SomeOtherObject item;
        /// }
        ///
        /// var gameObj = new GameObject("SomeObj");
        /// var c = gameObj.AddComponent(typeof(SomeObject));
        /// var someOtherObj = new SomeOtherObj();
        ///
        /// SetObjectReference(c, "item", someOtherObj);
        /// </code></example>
        protected internal void SetObjectReference(Object targetObj, string targetValue, Object value)
        {
            if (!objectPropertyCache.TryGetValue(targetObj, out var serializedObject))
            {
                serializedObject = new SerializedObject(targetObj);
                objectPropertyCache.Add(targetObj, serializedObject);
            }

            var property = serializedObject.FindProperty(targetValue);
            property.objectReferenceValue = value;

            serializedObject.ApplyModifiedProperties();
        }

        /// <summary>
        /// Set a non-interface reference member of a MonoBehaviour via Unity reflection.
        /// Will be applied depending on context of Test setup being used.
        /// </summary>
        /// <example><code>
        /// public class SomeObject : MonoBehaviour {
        ///     private SomeOtherObject item1;
        ///     private SomeAdditionalObject item2;
        /// }
        ///
        /// var gameObj = new GameObject("SomeObj");
        /// var c = gameObj.AddComponent(typeof(SomeObject));
        ///
        /// SetObjectReference(c, a);
        /// </code></example>
        protected internal void SetObjectReferences(Object targetObj, params ValueTuple<string, Object>[] properties)
        {
            for (var i = 0; i < properties.Length; i++)
                SetObjectReference(targetObj, properties[i].Item1, properties[i].Item2);
        }

        private void SetReflectedValue(object targetObject, Type type, string targetProperty, object targetValue)
        {
            var fieldProperty = type.GetField(targetProperty, BindingFlags.NonPublic | BindingFlags.Instance);

            if (fieldProperty == null)
            {
                Debug.LogWarning($"There is no property {targetProperty} to the target object.");

                return;
            }

            fieldProperty.SetValue(targetObject, targetValue);
        }

        private void Reset()
        {
            ResetAllMocks();
            CleanupDisposableObjects(disposeOnTestEnd);
            CleanupUnityObjects(destroyOnTestEnd);
        }

        private void CleanupUnityObjects(Queue<Object> unityObjects)
        {
            if (unityObjects.Count == 0)
                return;

            while (unityObjects.Count != 0)
            {
                var temp = unityObjects.Dequeue();
                if (temp != null)
                    Object.DestroyImmediate(temp);
            }
        }

        private void CleanupDisposableObjects(Queue<IDisposable> disposableObjects)
        {
            if (disposableObjects.Count == 0)
                return;

            while (disposableObjects.Count != 0)
            {
                var temp = disposableObjects.Dequeue();
                temp?.Dispose();
            }
        }

        [ExcludeFromCoverage]
        private void ResetAllMocks()
        {
            var mocks = GetType().GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
                .Where(f => f.FieldType == typeof(Mock)).Select(f => (Mock)f.GetValue(this));

            foreach (var m in mocks)
                m.Reset();
        }

        // [ExcludeFromCoverage]
        // private void Apply(bool isGlobal = false)
        // {
        //     ApplyPropertyCache(objectPropertyCache);
        // }
        //
        // [ExcludeFromCoverage]
        // private void ApplyPropertyCache(IDictionary<Object, SerializedObject> cache)
        // {
        //     if (cache.Count == 0)
        //         return;
        //
        //     foreach (var pair in cache)
        //         pair.Value.ApplyModifiedProperties();
        // }
    }
}