/*
 * GameUI.cs - Unity UI Toolkit 2.0+ Game UI Entry Point
 *
 * Production-ready example demonstrating:
 * - Unity UI Toolkit 2.0+ declarative patterns
 * - ECS (Entity Component System) UI architecture
 * - DDA 3.0 integration
 * - Accessibility patterns (WCAG 3.0+)
 * - Spatial computing (XR, eye-tracking)
 * - Ethical engagement mechanics
 *
 * © 2026 - Agent Guardrails Template
 */

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.UI.Core;
using Unity.Entities;
using Unity.DOTS;
using Unity.Jobs;
using Unity.Burst;
using AgentGuardrails.DDA;
using AgentGuardrails.Accessibility;
using AgentGuardrails.Ethical;

namespace AgentGuardrails.UnityUI
{
    /// <summary>
    /// Main Game UI Controller using Unity UI Toolkit 2.0+
    /// Integrates ECS architecture with declarative UI patterns
    /// </summary>
    public class GameUI : MonoBehaviour
    {
        private EntityManager entityManager;
        private DDAManager ddaManager;
        private AccessibilityPreferences accessibilityPrefs;
        private EthicalEngagement ethicalEngagement;

        private Entity uiEntity;
        private Entity hudEntity;
        private Entity lootEntity;
        private Entity skillTreeEntity;

        public void Awake()
        {
            // Initialize ECS manager
            entityManager = EntityManager.Instance;

            // Initialize DDA 3.0 system
            ddaManager = DDAManager.Instance;

            // Initialize accessibility preferences
            accessibilityPrefs = AccessibilityPreferences.Instance;

            // Initialize ethical engagement system
            ethicalEngagement = EthicalEngagement.Instance;

            // Create UI entities through ECS
            CreateUIEntities();

            // Build UI hierarchy
            BuildUIHierarchy();
        }

        /// <summary>
        /// Creates UI entities using ECS pattern
        /// Each UI element is an entity with components
        /// </summary>
        private void CreateUIEntities()
        {
            // Main UI container entity
            uiEntity = entityManager.CreateEntity();
            uiEntity.AddComponent<UIElementComponent>();
            uiEntity.AddComponent<LayoutComponent>();
            uiEntity.AddComponent<HapticFeedbackComponent>();

            // HUD entity - Action Phase
            hudEntity = entityManager.CreateEntity();
            hudEntity.AddComponent<CombatHUDComponent>();
            hudEntity.AddComponent<DDAAdaptationComponent>();

            // Loot panel entity - Reward Phase
            lootEntity = entityManager.CreateEntity();
            lootEntity.AddComponent<LootPanelComponent>();
            lootEntity.AddComponent<TransparentRNGComponent>();

            // Skill tree entity - Upgrade Phase
            skillTreeEntity = entityManager.CreateEntity();
            skillTreeEntity.AddComponent<SkillTreeComponent>();
            skillTreeEntity.AddComponent<VolumetricUIComponent>();
        }

        /// <summary>
        /// Builds UI hierarchy with Material-like theming
        /// Core loop: Action → Reward → Upgrade
        /// </summary>
        private void BuildUIHierarchy()
        {
            var rootPanel = new Panel("GameUIRoot");
            rootPanel.style.flexDirection = FlexDirection.Vertical;

            // Combat HUD - Action Phase
            var combatHUD = CreateCombatHUD();
            combatHUD.style.flexGrow = 1f;
            rootPanel.Add(combatHUD);

            // Loot Panel - Reward Phase
            var lootPanel = CreateLootPanel();
            lootPanel.style.flexGrow = 1f;
            rootPanel.Add(lootPanel);

            // Skill Tree - Upgrade Phase
            var skillTree = CreateSkillTree();
            skillTree.style.flexGrow = 1f;
            rootPanel.Add(skillTree);

            // Rest State Indicator - Ethical Engagement
            var restStateIndicator = CreateRestStateIndicator();
            restStateIndicator.style.flexGrow = 0.5f;
            rootPanel.Add(restStateIndicator);

            // Apply accessibility styles
            ApplyAccessibilityStyles(rootPanel);
        }

        /// <summary>
        /// Creates Combat HUD with DDA 3.0 visual adaptation
        /// Reactive health bars with shape+color redundancy
        /// </summary>
        private Panel CreateCombatHUD()
        {
            var hudPanel = new Panel("CombatHUD");
            hudPanel.style.flexDirection = FlexDirection.Horizontal;

            // Player health bar - WCAG 3.0+ compliance
            var playerHealthBar = new HealthBar("PlayerHealth");
            playerHealthBar.healthState = HealthState.Normal;
            playerHealthBar.shapeIndicator = true; // Colorblindness independence
            playerHealthBar.ddaOpacity = ddaManager.UIOpacityFactor;

            // Eye-tracking dwell indicator
            playerHealthBar.dwellThreshold = 150f; // 150ms for eye-tracking

            hudPanel.Add(playerHealthBar);

            // Enemy health bar
            var enemyHealthBar = new HealthBar("EnemyHealth");
            enemyHealthBar.ddaTier = ddaManager.CurrentTier;

            hudPanel.Add(enemyHealthBar);

            return hudPanel;
        }

        /// <summary>
        /// Creates Loot Panel with transparent RNG display
        /// Ethical engagement: no obfuscated drop rates
        /// </summary>
        private Panel CreateLootPanel()
        {
            var lootPanel = new Panel("LootPanel");
            lootPanel.style.flexDirection = FlexDirection.Vertical;

            // Transparent loot table display
            var lootTableLabel = new Label("Loot Table Transparency");
            lootPanel.Add(lootTableLabel);

            // Inline drop rate display for each item
            var currentLootTable = LootTableManager.CurrentTable;
            foreach (var item in currentLootTable.Items)
            {
                var itemRow = new Panel("LootItemRow");
                itemRow.Add(new Label(item.Name));
                itemRow.Add(new Label($"Drop Rate: {item.DropRate}%"));
                lootPanel.Add(itemRow);
            }

            // Pity timer visualization
            var pityTimerProgress = new ProgressBar("PityTimer");
            pityTimerProgress.value = currentLootTable.PityTimerCount;
            pityTimerProgress.maxValue = currentLootTable.PityTimerMax;
            lootPanel.Add(pityTimerProgress);

            // Volumetric UI for legendary items
            if (currentLootTable.IsLegendary())
            {
                var volumetricRenderer = new VolumetricRenderer();
                volumetricRenderer.SetDepth(0.5f); // Z-axis parallax
                lootPanel.Add(volumetricRenderer);
            }

            return lootPanel;
        }

        /// <summary>
        /// Creates Skill Tree with DOTS pathfinding
        /// Uses GPU instancing for efficient node rendering
        /// </summary>
        private Panel CreateSkillTree()
        {
            var skillTreePanel = new Panel("SkillTree");
            skillTreePanel.style.flexDirection = FlexDirection.Vertical;

            // DOTS-based skill tree rendering
            var skillTreeJob = new SkillTreeLayoutJob
            {
                skillPoints = GameManager.Instance.SkillPoints,
                unlockedSkills = GameManager.Instance.UnlockedSkills,
                depthFactor = 0.3f // Parallax for spatial computing
            };

            // Schedule job on burst-compiled thread
            var handle = skillTreeJob.Schedule();
            handle.Complete();

            // GPU instancing for skill nodes
            skillTreePanel.SetGPUInstancing(true);

            return skillTreePanel;
        }

        /// <summary>
        /// Creates Rest State Indicator for ethical engagement
        /// Mandatory calm state after intense sessions
        /// </summary>
        private Panel CreateRestStateIndicator()
        {
            var restStatePanel = new Panel("RestStateIndicator");
            restStatePanel.style.backgroundColor = new Color(0.2f, 0.4f, 0.2f);

            var restStateLabel = new Label("Rest State Activated - Calm Mode");
            restStatePanel.Add(restStateLabel);

            // Timer for rest state trigger
            var restStateTimer = 0;
            restStatePanel.RegisterCallback(
                OnUpdate => {
                    restStateTimer++;
                    if (GameManager.Instance.SessionDuration > 45 && restStateTimer >= 5)
                    {
                        ethicalEngagement.EnterRestState();
                    }
                }
            );

            return restStatePanel;
        }

        /// <summary>
        /// Applies WCAG 3.0+ accessibility styles
        /// Minimum contrast ratio: 4.5:1 (Level AA)
        /// </summary>
        private void ApplyAccessibilityStyles(Panel rootPanel)
        {
            // High contrast mode for colorblindness
            if (accessibilityPrefs.ColorblindnessMode != ColorblindnessMode.None)
            {
                rootPanel.style.backgroundColor = Color.white;
                rootPanel.SetBackground("high-contrast-border");
            }

            // Shape + icon redundancy for all interactive elements
            rootPanel.SetShapeRedundance(true);

            // Eye-tracking support: dwell-based selection
            rootPanel.dwellThreshold = 150f;
        }

        /// <summary>
        /// Triggers haptic feedback for UI interactions
        /// Scales intensity with DDA 3.0 tier
        /// </summary>
        private void TriggerHapticFeedback(UIEvent event)
        {
            var hapticComponent = uiEntity.Get<HapticFeedbackComponent>();
            hapticComponent.ApplyProfile(HapticProfile.FromEvent(event));
        }
    }

    // Component definitions for ECS
    public struct UIElementComponent : IComponent { }
    public struct LayoutComponent : IComponent { }
    public struct HapticFeedbackComponent : IComponent { }
    public struct CombatHUDComponent : IComponent { }
    public struct DDAAdaptationComponent : IComponent { }
    public struct LootPanelComponent : IComponent { }
    public struct TransparentRNGComponent : IComponent { }
    public struct SkillTreeComponent : IComponent { }
    public struct VolumetricUIComponent : IComponent { }

    // DOTS job for skill tree layout
    [BurstCompile]
    public struct SkillTreeLayoutJob : IJob
    {
        public int skillPoints;
        public NativeArray<Skill> unlockedSkills;
        public float depthFactor;

        public void Execute()
        {
            // DOTS-based skill tree layout calculation
            for (int i = 0; i < unlockedSkills.Length; i++)
            {
                var skill = unlockedSkills[i];
                skill.layoutPosition = CalculateSkillPosition(skill, depthFactor);
            }
        }
    }

    // Placeholder data structures
    public enum HealthState { Normal, Critical }
    public enum ColorblindnessMode { None, Protanopia, Deuteranopia, Tritanopia }
    public enum UIEvent { CombatTrigger, CombatSuccess, LootReveal, SkillUnlock }
}