using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.InputSystem.UI;
using UnityEngine.UI;

namespace Vanguard.UI
{
    /// <summary>
    /// Минимальная фабрика uGUI. Экраны собираются кодом, чтобы каркас
    /// запускался без префабов и ручной сцены; позже экраны можно перевести
    /// на prefab/UI Toolkit без изменения сервисов.
    /// </summary>
    public static class UiKit
    {
        private static Font _font;

        public static Font DefaultFont
        {
            get
            {
                if (_font != null)
                    return _font;

                _font = Resources.GetBuiltinResource<Font>("LegacyRuntime.ttf");
                if (_font == null)
                    _font = Resources.GetBuiltinResource<Font>("Arial.ttf");

                return _font;
            }
        }

        public static Canvas CreateCanvas(string name)
        {
            EnsureEventSystem();

            var go = new GameObject(name, typeof(Canvas), typeof(CanvasScaler), typeof(GraphicRaycaster));
            if (Application.isPlaying)
                Object.DontDestroyOnLoad(go);

            var canvas = go.GetComponent<Canvas>();
            canvas.renderMode = RenderMode.ScreenSpaceOverlay;
            canvas.sortingOrder = 0;

            var scaler = go.GetComponent<CanvasScaler>();
            scaler.uiScaleMode = CanvasScaler.ScaleMode.ScaleWithScreenSize;
            scaler.referenceResolution = new Vector2(1920f, 1080f);
            scaler.matchWidthOrHeight = 0.5f;

            return canvas;
        }

        public static void EnsureEventSystem()
        {
            if (Object.FindAnyObjectByType<EventSystem>() != null)
                return;

            var go = new GameObject("EventSystem", typeof(EventSystem));
            if (Application.isPlaying)
                Object.DontDestroyOnLoad(go);

            var module = go.AddComponent<InputSystemUIInputModule>();
            module.AssignDefaultActions();
        }

        public static RectTransform CreatePanel(Transform parent, string name, Color color)
        {
            var go = new GameObject(name, typeof(RectTransform), typeof(Image));
            var rect = (RectTransform)go.transform;
            rect.SetParent(parent, false);
            Stretch(rect);

            var image = go.GetComponent<Image>();
            image.color = color;
            image.raycastTarget = true;
            return rect;
        }

        public static RectTransform CreateCenteredCard(
            Transform parent,
            string name,
            Vector2 size,
            Color color)
        {
            var rect = CreatePanel(parent, name, color);
            rect.anchorMin = new Vector2(0.5f, 0.5f);
            rect.anchorMax = new Vector2(0.5f, 0.5f);
            rect.pivot = new Vector2(0.5f, 0.5f);
            rect.anchoredPosition = Vector2.zero;
            rect.sizeDelta = size;
            return rect;
        }

        public static VerticalLayoutGroup AddVerticalLayout(
            RectTransform rect,
            int padding,
            int spacing)
        {
            var layout = rect.gameObject.AddComponent<VerticalLayoutGroup>();
            layout.padding = new RectOffset(padding, padding, padding, padding);
            layout.spacing = spacing;
            layout.childAlignment = TextAnchor.UpperCenter;
            layout.childControlWidth = true;
            layout.childControlHeight = true;
            layout.childForceExpandWidth = true;
            layout.childForceExpandHeight = false;
            return layout;
        }

        public static HorizontalLayoutGroup AddHorizontalLayout(
            RectTransform rect,
            int padding,
            int spacing)
        {
            var layout = rect.gameObject.AddComponent<HorizontalLayoutGroup>();
            layout.padding = new RectOffset(padding, padding, padding, padding);
            layout.spacing = spacing;
            layout.childAlignment = TextAnchor.MiddleCenter;
            layout.childControlWidth = true;
            layout.childControlHeight = true;
            layout.childForceExpandWidth = true;
            layout.childForceExpandHeight = false;
            return layout;
        }

        public static Text CreateText(
            Transform parent,
            string name,
            string content,
            int fontSize,
            Color color,
            TextAnchor alignment = TextAnchor.MiddleCenter)
        {
            var go = new GameObject(name, typeof(RectTransform), typeof(Text));
            var rect = (RectTransform)go.transform;
            rect.SetParent(parent, false);

            var text = go.GetComponent<Text>();
            text.font = DefaultFont;
            text.text = content;
            text.fontSize = fontSize;
            text.color = color;
            text.alignment = alignment;
            text.horizontalOverflow = HorizontalWrapMode.Wrap;
            text.verticalOverflow = VerticalWrapMode.Overflow;
            text.raycastTarget = false;
            text.supportRichText = true;

            return text;
        }

        public static Button CreateButton(
            Transform parent,
            string name,
            string label,
            UnityEngine.Events.UnityAction onClick,
            int fontSize = 24)
        {
            var go = new GameObject(name, typeof(RectTransform), typeof(Image), typeof(Button));
            var rect = (RectTransform)go.transform;
            rect.SetParent(parent, false);

            var image = go.GetComponent<Image>();
            image.color = new Color(0.20f, 0.42f, 0.78f, 1f);
            image.raycastTarget = true;

            var button = go.GetComponent<Button>();
            button.targetGraphic = image;
            button.onClick.AddListener(onClick);

            var text = CreateText(rect, "Label", label, fontSize, Color.white);
            Stretch(text.rectTransform);

            return button;
        }

        public static InputField CreateInput(
            Transform parent,
            string name,
            string placeholder,
            bool password = false)
        {
            var go = new GameObject(
                name,
                typeof(RectTransform),
                typeof(Image),
                typeof(InputField));
            var rect = (RectTransform)go.transform;
            rect.SetParent(parent, false);

            var background = go.GetComponent<Image>();
            background.color = new Color(0.10f, 0.12f, 0.16f, 1f);
            background.raycastTarget = true;

            var input = go.GetComponent<InputField>();
            input.targetGraphic = background;
            input.lineType = InputField.LineType.SingleLine;
            input.contentType = password
                ? InputField.ContentType.Password
                : InputField.ContentType.Standard;
            input.characterLimit = password ? 128 : 64;
            input.caretColor = Color.white;
            input.customCaretColor = true;
            input.selectionColor = new Color(0.20f, 0.42f, 0.78f, 0.6f);

            var text = CreateText(rect, "Text", string.Empty, 22, Color.white, TextAnchor.MiddleLeft);
            Stretch(text.rectTransform);
            var textRect = text.rectTransform;
            textRect.offsetMin = new Vector2(16f, 0f);
            textRect.offsetMax = new Vector2(-16f, 0f);
            text.supportRichText = false;

            var hint = CreateText(rect, "Placeholder", placeholder, 22, new Color(1f, 1f, 1f, 0.45f), TextAnchor.MiddleLeft);
            Stretch(hint.rectTransform);
            hint.rectTransform.offsetMin = new Vector2(16f, 0f);
            hint.rectTransform.offsetMax = new Vector2(-16f, 0f);
            hint.supportRichText = false;

            input.textComponent = text;
            input.placeholder = hint;

            return input;
        }

        public static LayoutElement SetPreferredHeight(
            Component component,
            float height,
            float flexibleWidth = 1f)
        {
            var element = component.gameObject.GetComponent<LayoutElement>();
            if (element == null)
                element = component.gameObject.AddComponent<LayoutElement>();

            element.preferredHeight = height;
            element.flexibleWidth = flexibleWidth;
            return element;
        }

        public static RectTransform CreateScrollView(
            Transform parent,
            string name,
            out RectTransform content,
            float spacing = 8f)
        {
            var root = new GameObject(
                name,
                typeof(RectTransform),
                typeof(Image),
                typeof(ScrollRect));
            var rootRect = (RectTransform)root.transform;
            rootRect.SetParent(parent, false);
            Stretch(rootRect);

            var background = root.GetComponent<Image>();
            background.color = new Color(0f, 0f, 0f, 0.01f);
            background.raycastTarget = true;

            var viewportGo = new GameObject(
                "Viewport",
                typeof(RectTransform),
                typeof(RectMask2D));
            var viewport = (RectTransform)viewportGo.transform;
            viewport.SetParent(rootRect, false);
            Stretch(viewport);

            var contentGo = new GameObject(
                "Content",
                typeof(RectTransform),
                typeof(VerticalLayoutGroup),
                typeof(ContentSizeFitter));
            content = (RectTransform)contentGo.transform;
            content.SetParent(viewport, false);
            content.anchorMin = new Vector2(0f, 1f);
            content.anchorMax = new Vector2(1f, 1f);
            content.pivot = new Vector2(0.5f, 1f);
            content.anchoredPosition = Vector2.zero;
            content.sizeDelta = new Vector2(0f, 0f);

            var layout = contentGo.GetComponent<VerticalLayoutGroup>();
            layout.padding = new RectOffset(4, 4, 4, 4);
            layout.spacing = spacing;
            layout.childAlignment = TextAnchor.UpperCenter;
            layout.childControlWidth = true;
            layout.childControlHeight = true;
            layout.childForceExpandWidth = true;
            layout.childForceExpandHeight = false;

            var fitter = contentGo.GetComponent<ContentSizeFitter>();
            fitter.horizontalFit = ContentSizeFitter.FitMode.Unconstrained;
            fitter.verticalFit = ContentSizeFitter.FitMode.PreferredSize;

            var scroll = root.GetComponent<ScrollRect>();
            scroll.viewport = viewport;
            scroll.content = content;
            scroll.horizontal = false;
            scroll.vertical = true;
            scroll.movementType = ScrollRect.MovementType.Clamped;
            scroll.scrollSensitivity = 30f;
            scroll.inertia = true;
            scroll.decelerationRate = 0.135f;

            return rootRect;
        }

        public static void Stretch(RectTransform rect)
        {
            rect.anchorMin = Vector2.zero;
            rect.anchorMax = Vector2.one;
            rect.offsetMin = Vector2.zero;
            rect.offsetMax = Vector2.zero;
        }

        public static void SetActive(Component component, bool active)
        {
            if (component != null)
                component.gameObject.SetActive(active);
        }
    }
}