using NUnit.Framework;
using UnityEngine;
using System.Collections.Generic;

namespace Tests.EditMode
{
    public class PuzzleGraphUtilityTests
    {
        private PuzzleStepSO step1;
        private PuzzleStepSO step2;
        private PuzzleStepSO step3;
        private PuzzleStepSO step4;
        private PuzzleStepSO step5;

        [SetUp]
        public void SetUp()
        {
            // Create test PuzzleStepSO instances using ScriptableObject.CreateInstance
            step1 = ScriptableObject.CreateInstance<PuzzleStepSO>();
            step1.stepId = "step1";
            step1.displayName = "Step 1";
            step1.unlocks = new List<PuzzleStepSO>();

            step2 = ScriptableObject.CreateInstance<PuzzleStepSO>();
            step2.stepId = "step2";
            step2.displayName = "Step 2";
            step2.unlocks = new List<PuzzleStepSO>();

            step3 = ScriptableObject.CreateInstance<PuzzleStepSO>();
            step3.stepId = "step3";
            step3.displayName = "Step 3";
            step3.unlocks = new List<PuzzleStepSO>();

            step4 = ScriptableObject.CreateInstance<PuzzleStepSO>();
            step4.stepId = "step4";
            step4.displayName = "Step 4";
            step4.unlocks = new List<PuzzleStepSO>();

            step5 = ScriptableObject.CreateInstance<PuzzleStepSO>();
            step5.stepId = "step5";
            step5.displayName = "Step 5";
            step5.unlocks = new List<PuzzleStepSO>();
        }

        [TearDown]
        public void TearDown()
        {
            // Clean up created ScriptableObjects
            if (step1 != null) Object.DestroyImmediate(step1);
            if (step2 != null) Object.DestroyImmediate(step2);
            if (step3 != null) Object.DestroyImmediate(step3);
            if (step4 != null) Object.DestroyImmediate(step4);
            if (step5 != null) Object.DestroyImmediate(step5);
        }

        #region BuildDependencyGraph Tests

        [Test]
        public void BuildDependencyGraph_EmptyList_ReturnsEmptyDictionary()
        {
            // Arrange
            var steps = new List<PuzzleStepSO>();

            // Act
            var graph = PuzzleGraphUtility.BuildDependencyGraph(steps);

            // Assert
            Assert.IsNotNull(graph, "Graph should not be null");
            Assert.AreEqual(0, graph.Count, "Graph should be empty");
        }

        [Test]
        public void BuildDependencyGraph_NoUnlocks_ReturnsGraphWithEmptyDependencyLists()
        {
            // Arrange
            var steps = new List<PuzzleStepSO> { step1, step2, step3 };
            // No unlocks set up

            // Act
            var graph = PuzzleGraphUtility.BuildDependencyGraph(steps);

            // Assert
            Assert.AreEqual(3, graph.Count, "Graph should have 3 entries");
            Assert.IsTrue(graph.ContainsKey(step1), "Graph should contain step1");
            Assert.IsTrue(graph.ContainsKey(step2), "Graph should contain step2");
            Assert.IsTrue(graph.ContainsKey(step3), "Graph should contain step3");
            Assert.AreEqual(0, graph[step1].Count, "step1 should have no dependencies");
            Assert.AreEqual(0, graph[step2].Count, "step2 should have no dependencies");
            Assert.AreEqual(0, graph[step3].Count, "step3 should have no dependencies");
        }

        [Test]
        public void BuildDependencyGraph_WithUnlocks_BuildsCorrectDependencyGraph()
        {
            // Arrange
            // Set up unlock relationships:
            // step1 unlocks step3 and step4
            // step2 unlocks step3
            // step3 unlocks step5
            // step4 has no unlocks
            // step5 has no unlocks
            step1.unlocks.Add(step3);
            step1.unlocks.Add(step4);
            step2.unlocks.Add(step3);
            step3.unlocks.Add(step5);

            var steps = new List<PuzzleStepSO> { step1, step2, step3, step4, step5 };

            // Act
            var graph = PuzzleGraphUtility.BuildDependencyGraph(steps);

            // Assert
            Assert.AreEqual(5, graph.Count, "Graph should have 5 entries");
            
            // Check dependencies (reverse of unlocks)
            Assert.AreEqual(0, graph[step1].Count, "step1 should have no dependencies");
            Assert.AreEqual(0, graph[step2].Count, "step2 should have no dependencies");
            
            Assert.AreEqual(2, graph[step3].Count, "step3 should have 2 dependencies");
            Assert.IsTrue(graph[step3].Contains(step1), "step3 should depend on step1");
            Assert.IsTrue(graph[step3].Contains(step2), "step3 should depend on step2");
            
            Assert.AreEqual(1, graph[step4].Count, "step4 should have 1 dependency");
            Assert.IsTrue(graph[step4].Contains(step1), "step4 should depend on step1");
            
            Assert.AreEqual(1, graph[step5].Count, "step5 should have 1 dependency");
            Assert.IsTrue(graph[step5].Contains(step3), "step5 should depend on step3");
        }

        [Test]
        public void BuildDependencyGraph_WithCyclicUnlocks_BuildsCorrectDependencyGraph()
        {
            // Arrange
            // Set up cyclic unlock relationships:
            // step1 unlocks step2
            // step2 unlocks step3
            // step3 unlocks step1
            step1.unlocks.Add(step2);
            step2.unlocks.Add(step3);
            step3.unlocks.Add(step1);

            var steps = new List<PuzzleStepSO> { step1, step2, step3 };

            // Act
            var graph = PuzzleGraphUtility.BuildDependencyGraph(steps);

            // Assert
            Assert.AreEqual(3, graph.Count, "Graph should have 3 entries");
            
            // Check dependencies (reverse of unlocks)
            Assert.AreEqual(1, graph[step1].Count, "step1 should have 1 dependency");
            Assert.IsTrue(graph[step1].Contains(step3), "step1 should depend on step3");
            
            Assert.AreEqual(1, graph[step2].Count, "step2 should have 1 dependency");
            Assert.IsTrue(graph[step2].Contains(step1), "step2 should depend on step1");
            
            Assert.AreEqual(1, graph[step3].Count, "step3 should have 1 dependency");
            Assert.IsTrue(graph[step3].Contains(step2), "step3 should depend on step2");
        }

        #endregion

        #region FindInitialSteps Tests

        [Test]
        public void FindInitialSteps_EmptyGraph_ReturnsEmptyList()
        {
            // Arrange
            var graph = new Dictionary<PuzzleStepSO, List<PuzzleStepSO>>();

            // Act
            var initialSteps = PuzzleGraphUtility.FindInitialSteps(graph);

            // Assert
            Assert.IsNotNull(initialSteps, "Initial steps should not be null");
            Assert.AreEqual(0, initialSteps.Count, "Initial steps should be empty");
        }

        [Test]
        public void FindInitialSteps_AllInitial_ReturnsAllSteps()
        {
            // Arrange
            var graph = new Dictionary<PuzzleStepSO, List<PuzzleStepSO>>
            {
                { step1, new List<PuzzleStepSO>() },
                { step2, new List<PuzzleStepSO>() },
                { step3, new List<PuzzleStepSO>() }
            };

            // Act
            var initialSteps = PuzzleGraphUtility.FindInitialSteps(graph);

            // Assert
            Assert.AreEqual(3, initialSteps.Count, "All steps should be initial");
            Assert.IsTrue(initialSteps.Contains(step1), "Initial steps should contain step1");
            Assert.IsTrue(initialSteps.Contains(step2), "Initial steps should contain step2");
            Assert.IsTrue(initialSteps.Contains(step3), "Initial steps should contain step3");
        }

        [Test]
        public void FindInitialSteps_SomeInitial_ReturnsOnlyInitialSteps()
        {
            // Arrange
            // Create a graph where step1 and step2 are initial, but step3 depends on step1
            var graph = new Dictionary<PuzzleStepSO, List<PuzzleStepSO>>
            {
                { step1, new List<PuzzleStepSO>() },
                { step2, new List<PuzzleStepSO>() },
                { step3, new List<PuzzleStepSO> { step1 } }
            };

            // Act
            var initialSteps = PuzzleGraphUtility.FindInitialSteps(graph);

            // Assert
            Assert.AreEqual(2, initialSteps.Count, "There should be 2 initial steps");
            Assert.IsTrue(initialSteps.Contains(step1), "Initial steps should contain step1");
            Assert.IsTrue(initialSteps.Contains(step2), "Initial steps should contain step2");
            Assert.IsFalse(initialSteps.Contains(step3), "Initial steps should not contain step3");
        }

        [Test]
        public void FindInitialSteps_NoInitial_ReturnsEmptyList()
        {
            // Arrange
            // Create a cyclic dependency graph with no initial steps
            var graph = new Dictionary<PuzzleStepSO, List<PuzzleStepSO>>
            {
                { step1, new List<PuzzleStepSO> { step3 } },
                { step2, new List<PuzzleStepSO> { step1 } },
                { step3, new List<PuzzleStepSO> { step2 } }
            };

            // Act
            var initialSteps = PuzzleGraphUtility.FindInitialSteps(graph);

            // Assert
            Assert.AreEqual(0, initialSteps.Count, "There should be no initial steps");
        }

        #endregion

        #region FindUnlocks Tests

        [Test]
        public void FindUnlocks_EmptyList_ReturnsEmptyList()
        {
            // Arrange
            var allSteps = new List<PuzzleStepSO>();

            // Act
            var unlocks = PuzzleGraphUtility.FindUnlocks(step1, allSteps);

            // Assert
            Assert.IsNotNull(unlocks, "Unlocks should not be null");
            Assert.AreEqual(0, unlocks.Count, "Unlocks should be empty");
        }

        [Test]
        public void FindUnlocks_NoUnlocks_ReturnsEmptyList()
        {
            // Arrange
            var allSteps = new List<PuzzleStepSO> { step1, step2, step3 };
            // No unlocks set up

            // Act
            var unlocks = PuzzleGraphUtility.FindUnlocks(step1, allSteps);

            // Assert
            Assert.AreEqual(0, unlocks.Count, "No steps should unlock step1");
        }

        [Test]
        public void FindUnlocks_WithUnlocks_ReturnsCorrectUnlocks()
        {
            // Arrange
            // Set up unlock relationships:
            // step1 unlocks step3
            // step2 unlocks step3
            step1.unlocks.Add(step3);
            step2.unlocks.Add(step3);

            var allSteps = new List<PuzzleStepSO> { step1, step2, step3 };

            // Act
            var unlocks = PuzzleGraphUtility.FindUnlocks(step3, allSteps);

            // Assert
            Assert.AreEqual(2, unlocks.Count, "2 steps should unlock step3");
            Assert.IsTrue(unlocks.Contains(step1), "step1 should unlock step3");
            Assert.IsTrue(unlocks.Contains(step2), "step2 should unlock step3");
        }

        [Test]
        public void FindUnlocks_StepUnlocksItself_ReturnsCorrectUnlocks()
        {
            // Arrange
            // Set up self-unlock relationship:
            // step1 unlocks itself and step2
            step1.unlocks.Add(step1);
            step1.unlocks.Add(step2);

            var allSteps = new List<PuzzleStepSO> { step1, step2 };

            // Act
            var unlocks = PuzzleGraphUtility.FindUnlocks(step1, allSteps);

            // Assert
            Assert.AreEqual(1, unlocks.Count, "1 step should unlock step1");
            Assert.IsTrue(unlocks.Contains(step1), "step1 should unlock itself");
        }

        #endregion
    }
}