using System.Collections.Generic;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

namespace DepthsOfGreed.HandbookUI
{
    public sealed class HandbookIndexController : MonoBehaviour
    {
        public HandbookTowerEntry SelectedEntry { get; private set; }
        public int VisibleEntryCount => currentFilter == 2 ? 0 : entries.Count;
        public ScrollRect ListScroll => scroll;
        private ScrollRect scroll;
        private Button[] filters;
        private readonly List<HandbookTowerEntry> entries = new List<HandbookTowerEntry>();
        private readonly List<Button> rows = new List<Button>();
        private TMP_Text detailName, description, emptyMessage;
        private Image detailIcon;
        private Sprite placeholder;
        private Color placeholderColor;
        private int currentFilter;

        public void Initialize(HandbookTowerCatalog catalog)
        {
            scroll = transform.Find("IndexLeft/EntryScrollView").GetComponent<ScrollRect>();
            filters = new[] {
                transform.Find("IndexLeft/FilterBar/Filter_All").GetComponent<Button>(),
                transform.Find("IndexLeft/FilterBar/Filter_Towers").GetComponent<Button>(),
                transform.Find("IndexLeft/FilterBar/Filter_Enemies").GetComponent<Button>()
            };
            detailName = transform.Find("IndexRight/DetailNameText").GetComponent<TMP_Text>();
            description = transform.Find("IndexRight/DetailDescriptionText").GetComponent<TMP_Text>();
            detailIcon = transform.Find("IndexRight/DetailIcon").GetComponent<Image>();
            placeholder = detailIcon.sprite;
            placeholderColor = detailIcon.color;
            var template = scroll.content.GetChild(0).GetComponent<Button>();
            if (catalog && catalog.towers != null)
                foreach (var entry in catalog.towers)
                {
                    if (!entry) continue;
                    int index = entries.Count;
                    entries.Add(entry);
                    var row = Instantiate(template, scroll.content);
                    row.name = "IndexEntry_" + entry.id;
                    row.gameObject.SetActive(true);
                    row.image.color = Color.white;
                    var label = row.transform.Find("NameText").GetComponent<TMP_Text>();
                    label.text = entry.displayName;
                    label.color = Color.black;
                    label.raycastTarget = false;
                    label.enableAutoSizing = true;
                    label.fontSizeMin = 16;
                    label.fontSizeMax = 24;
                    var icon = row.transform.Find("Icon").GetComponent<Image>();
                    if (entry.icon) { icon.sprite = entry.icon; icon.color = Color.white; }
                    icon.preserveAspect = true;
                    icon.raycastTarget = false;
                    row.onClick.RemoveAllListeners();
                    row.onClick.AddListener(() => SelectEntry(index));
                    rows.Add(row);
                }
            template.gameObject.SetActive(false);
            var empty = new GameObject("EmptyListMessage", typeof(RectTransform), typeof(TextMeshProUGUI), typeof(LayoutElement));
            empty.transform.SetParent(scroll.content, false);
            emptyMessage = empty.GetComponent<TMP_Text>();
            emptyMessage.font = description.font;
            emptyMessage.fontSize = 22;
            emptyMessage.color = new Color(0.3f, 0.3f, 0.3f);
            emptyMessage.alignment = TextAlignmentOptions.MidlineLeft;
            emptyMessage.raycastTarget = false;
            empty.GetComponent<LayoutElement>().preferredHeight = 70;
            for (int i = 0; i < filters.Length; i++)
            {
                int index = i;
                filters[i].onClick.AddListener(() => SelectFilter(index));
            }
            ResetForEntry();
        }

        public void ResetForEntry()
        {
            SelectFilter(0, true);
        }

        public void SelectFilter(int index, bool force = false)
        {
            if (index < 0 || index > 2 || (!force && currentFilter == index)) return;
            currentFilter = index;
            foreach (var row in rows) row.gameObject.SetActive(index != 2);
            bool empty = index == 2 || rows.Count == 0;
            emptyMessage.gameObject.SetActive(empty);
            emptyMessage.text = index == 2 ? "Noch keine Gegner-Einträge" : "Noch keine Einträge";
            for (int i = 0; i < filters.Length; i++)
            {
                filters[i].image.color = Color.white;
                var colors = filters[i].colors;
                colors.normalColor = i == index ? new Color(1, 0.72f, 0.2f) : new Color(0.82f, 0.82f, 0.82f);
                colors.highlightedColor = i == index ? new Color(1, 0.82f, 0.4f) : Color.white;
                colors.selectedColor = colors.normalColor;
                filters[i].colors = colors;
            }
            ClearSelection();
            ResetScroll();
        }

        public void SelectEntry(int index)
        {
            if (currentFilter == 2 || index < 0 || index >= entries.Count) return;
            SelectedEntry = entries[index];
            detailName.text = SelectedEntry.displayName;
            description.text = SelectedEntry.description;
            detailIcon.gameObject.SetActive(true);
            detailIcon.sprite = SelectedEntry.icon ? SelectedEntry.icon : placeholder;
            detailIcon.color = SelectedEntry.icon ? Color.white : placeholderColor;
            detailIcon.preserveAspect = true;
            RefreshSelectionColors();
        }

        public void ClearSelection()
        {
            SelectedEntry = null;
            detailIcon.gameObject.SetActive(false);
            detailName.text = "";
            description.text = "Wähle links einen Eintrag aus.";
            RefreshSelectionColors();
        }

        private void RefreshSelectionColors()
        {
            for (int i = 0; i < rows.Count; i++)
            {
                bool selected = entries[i] == SelectedEntry;
                var colors = rows[i].colors;
                colors.normalColor = selected ? new Color(0.58f, 0.58f, 0.58f) : new Color(0.86f, 0.86f, 0.86f);
                colors.highlightedColor = selected ? new Color(0.64f, 0.64f, 0.64f) : new Color(0.94f, 0.94f, 0.94f);
                colors.selectedColor = colors.normalColor;
                rows[i].colors = colors;
            }
        }

        public void ResetScroll()
        {
            scroll.StopMovement();
            Canvas.ForceUpdateCanvases();
            LayoutRebuilder.ForceRebuildLayoutImmediate(scroll.content);
            scroll.verticalNormalizedPosition = 1f;
        }
    }
}