using System.Text.RegularExpressions;
using Microsoft.AspNetCore.Components;
using Model;

namespace Shared.Services;

public class CardRenderingService
{
    private readonly Dictionary<string, CardData> _cardLookup;
    private readonly Dictionary<string, DocData> _docLookup;
    private readonly List<string> _allTerms;
    private readonly Regex _termRegex;

    public CardRenderingService()
    {
        var allCards = CardDatabase.Cards
            .Where(c => !string.IsNullOrWhiteSpace(c.Name))
            .ToList();

        _cardLookup = allCards
            .GroupBy(c => c.Name, StringComparer.OrdinalIgnoreCase)
            .ToDictionary(g => g.Key, g => g.First(), StringComparer.OrdinalIgnoreCase);

        var allDocs = DocDatabase.Docs
            .Where(d => !string.IsNullOrWhiteSpace(d.Title))
            .ToList();

        _docLookup = allDocs
            .GroupBy(d => d.Title, StringComparer.OrdinalIgnoreCase)
            .ToDictionary(g => g.Key, g => g.First(), StringComparer.OrdinalIgnoreCase);

        _allTerms = _cardLookup.Keys
            .Concat(_docLookup.Keys)
            .Distinct(StringComparer.OrdinalIgnoreCase)
            .OrderByDescending(n => n.Length)
            .ToList();

        var pattern = string.Join("|", _allTerms.Select(n => $@"\b{Regex.Escape(n)}\b"));
        _termRegex = new Regex(pattern, RegexOptions.IgnoreCase | RegexOptions.Compiled);
    }

    public RenderFragment RenderDescription(string description, Action<CardData?> onCardClick, Action<DocData?>? onDocClick = null, CardPreviewService? previewService = null)
    {
        return builder =>
        {
            var sequence = 0;
            var paragraphs = description.Split('\n', StringSplitOptions.RemoveEmptyEntries);

            foreach (var paragraph in paragraphs)
            {
                builder.OpenElement(sequence++, "p");

                var matches = _termRegex.Matches(paragraph);
                var lastIndex = 0;

                foreach (Match match in matches)
                {
                    if (match.Index > lastIndex)
                        builder.AddContent(sequence++, paragraph.Substring(lastIndex, match.Index - lastIndex));

                    var term = match.Value;
                    var card = LookupCard(term);
                    var doc = LookupDoc(term);

                    builder.OpenElement(sequence++, "button");
                    builder.AddAttribute(sequence++, "class", "inline-card-btn");

                    if (card != null)
                    {
                        builder.AddAttribute(sequence++, "onclick",
                            EventCallback.Factory.Create(this, () => onCardClick(card)));
                        
                        if (previewService != null)
                        {
                            builder.AddAttribute(sequence++, "onmouseenter", 
                                EventCallback.Factory.Create<Microsoft.AspNetCore.Components.Web.MouseEventArgs>(this, e => previewService.Show(card, e.ClientX, e.ClientY)));
                            builder.AddAttribute(sequence++, "onmouseleave", 
                                EventCallback.Factory.Create(this, () => previewService.Hide()));
                        }
                    }
                    else if (doc != null && onDocClick != null)
                    {
                        builder.AddAttribute(sequence++, "onclick",
                            EventCallback.Factory.Create(this, () => onDocClick(doc)));
                    }

                    builder.AddContent(sequence++, term);
                    builder.CloseElement();

                    lastIndex = match.Index + match.Length;
                }

                if (lastIndex < paragraph.Length) builder.AddContent(sequence++, paragraph.Substring(lastIndex));

                builder.CloseElement();
            }
        };
    }

    private CardData? LookupCard(string name)
    {
        return _cardLookup.GetValueOrDefault(name);
    }

    private DocData? LookupDoc(string name)
    {
        return _docLookup.GetValueOrDefault(name);
    }
}