using TMPro;
using UnityEngine;

namespace BrewMonster.Scripts.ChatUI
{
    /// <summary>
    /// Controls typing preview visibility/content and keyboard-anchored position.
    /// Kept standalone so other chat/input UIs can reuse the same behavior.
    /// </summary>
    [System.Serializable]
    public class TypingPreviewController
    {
        [Tooltip("Root của box xem trước nội dung đang gõ.")]
        [SerializeField] private GameObject typingPreviewRoot;
        [Tooltip("Text hiển thị nội dung đang gõ realtime.")]
        [SerializeField] private TMP_InputField typingPreviewText;
        [Tooltip("Rect của preview box để neo theo keyboard.")]
        [SerializeField] private RectTransform typingPreviewRect;
        [Tooltip("Khoảng cách dọc cộng thêm cho preview box.")]
        [SerializeField] private float previewVerticalOffset = 8f;

        private Vector2 _baseAnchoredPos;
        private bool _cachedAnchor;

        public void CacheInitialAnchor()
        {
            if (_cachedAnchor)
                return;

            if (typingPreviewRect != null)
                _baseAnchoredPos = typingPreviewRect.anchoredPosition;

            _cachedAnchor = true;
        }

        public void ApplyKeyboardOffset(float yOffset)
        {
            if (typingPreviewRect == null)
                return;

            CacheInitialAnchor();
            var previewPos = _baseAnchoredPos;
            previewPos.y += yOffset + previewVerticalOffset;
            typingPreviewRect.anchoredPosition = previewPos;
        }

        public void UpdatePreview(bool isInputFocused, string body)
        {
            if (typingPreviewRoot == null || typingPreviewText == null)
                return;

            string previewBody = body ?? string.Empty;
            bool keyboardVisible = IsMobileKeyboardVisible();
            bool shouldShow = keyboardVisible && isInputFocused;
            typingPreviewRoot.SetActive(shouldShow);
            if (shouldShow)
                typingPreviewText.text = previewBody;
        }

        bool IsMobileKeyboardVisible()
        {
            if (!Application.isMobilePlatform)
                return false;
            return GetVisibleKeyboardHeight() > 0f || TouchScreenKeyboard.visible;
        }

        float GetVisibleKeyboardHeight()
        {
            if (!TouchScreenKeyboard.visible)
                return 0f;

            Rect area = TouchScreenKeyboard.area;
            return area.height > 0f ? area.height : 0f;
        }
    }
}