@using System.Text.RegularExpressions
@using Microsoft.AspNetCore.Components.Rendering
@namespace Chrono.Components

@if (Doc != null)
{
    <div class="modal-backdrop" @onclick="HandleBackdropClick"></div>
    <div class="card-detail card-detail-noimg">
        <button class="detail-close" @onclick="HandleClose"><i class="bi bi-x-lg"></i></button>
        <div class="detail-layout layout-noimg">
            <div class="detail-info">
                <div class="detail-header">
                    <div class="syndicate-badges">
                        <span class="syn-icon @Doc.Title.ToLowerInvariant()" title="@Doc.Title"></span>
                    </div>
                    <h2>@Doc.Title</h2>
                </div>

                @if (!string.IsNullOrWhiteSpace(Doc.Content))
                {
                    <div class="detail-field description">
                        <div class="markdown-content">
                            @RenderDescription(Doc.Content)
                        </div>
                    </div>
                }
            </div>
        </div>
    </div>
}

@code {
    [Parameter] public DocData? Doc { get; set; }
    [Parameter] public EventCallback OnClose { get; set; }
    [Parameter] public EventCallback<string> OnNavigate { get; set; }

    private void HandleClose()
    {
        _ = OnClose.InvokeAsync();
    }

    private void HandleBackdropClick()
    {
        _ = OnClose.InvokeAsync();
    }

    private void Navigate(string name)
    {
        _ = OnNavigate.InvokeAsync(name);
    }

    private static CardData? LookupCard(string cardName)
    {
        return CardDatabase.Cards.FirstOrDefault(c =>
            string.Equals(c.Name, cardName, StringComparison.OrdinalIgnoreCase));
    }

    private static DocData? LookupDoc(string title)
    {
        return DocDatabase.Docs.FirstOrDefault(d =>
            string.Equals(d.Title, title, StringComparison.OrdinalIgnoreCase));
    }

    private RenderFragment RenderDescription(string content)
    {
        return builder =>
        {
            if (string.IsNullOrWhiteSpace(content)) return;

            var seq = 0;
            var lines = content.Split(['\r', '\n'], StringSplitOptions.None);
            var inList = false;
            var tableLines = new List<string>();
            var inTable = false;

            for (var i = 0; i < lines.Length; i++)
            {
                var line = lines[i];
                var trimmedLine = line.Trim();

                // Handle Tables
                if (trimmedLine.StartsWith("|") && trimmedLine.EndsWith("|"))
                {
                    inTable = true;
                    tableLines.Add(trimmedLine);
                    continue;
                }
                else if (inTable)
                {
                    RenderTable(builder, ref seq, tableLines);
                    tableLines.Clear();
                    inTable = false;
                }

                // Handle Lists
                if (trimmedLine.StartsWith("- ") || trimmedLine.StartsWith("* "))
                {
                    if (!inList)
                    {
                        builder.OpenElement(seq++, "ul");
                        inList = true;
                    }
                    var isCardListItem = trimmedLine.Contains("[[") && trimmedLine.Contains("]]");
                    builder.OpenElement(seq++, "li");
                    RenderInlines(builder, ref seq, trimmedLine[2..], true);
                    builder.CloseElement();
                    continue;
                }
                else if (inList)
                {
                    builder.CloseElement(); // Close ul
                    inList = false;
                }

                // Handle Headings
                if (trimmedLine.StartsWith("### "))
                {
                    builder.OpenElement(seq++, "h4");
                    RenderInlines(builder, ref seq, trimmedLine[4..], false);
                    builder.CloseElement();
                }
                else if (trimmedLine.StartsWith("## "))
                {
                    builder.OpenElement(seq++, "h3");
                    RenderInlines(builder, ref seq, trimmedLine[3..], false);
                    builder.CloseElement();
                }
                else if (trimmedLine.StartsWith("# "))
                {
                    builder.OpenElement(seq++, "h2");
                    RenderInlines(builder, ref seq, trimmedLine[2..], false);
                    builder.CloseElement();
                }
                else if (!string.IsNullOrWhiteSpace(trimmedLine))
                {
                    builder.OpenElement(seq++, "p");
                    RenderInlines(builder, ref seq, line, false);
                    builder.CloseElement();
                }
            }

            if (inTable) RenderTable(builder, ref seq, tableLines);
            if (inList) builder.CloseElement();
        };
    }

    private void RenderTable(RenderTreeBuilder builder, ref int seq, List<string> lines)
    {
        if (lines.Count < 2) return;

        builder.OpenElement(seq++, "div");
        builder.AddAttribute(seq++, "class", "table-responsive");
        builder.OpenElement(seq++, "table");
        builder.AddAttribute(seq++, "class", "markdown-table");

        var hasHeader = lines.Count > 2 && lines[1].Contains("---");
        var startIdx = 0;

        if (hasHeader)
        {
            builder.OpenElement(seq++, "thead");
            builder.OpenElement(seq++, "tr");
            var cells = lines[0].Split('|', StringSplitOptions.RemoveEmptyEntries);
            foreach (var cell in cells)
            {
                builder.OpenElement(seq++, "th");
                RenderInlines(builder, ref seq, cell.Trim(), false);
                builder.CloseElement();
            }
            builder.CloseElement();
            builder.CloseElement();
            startIdx = 2;
        }

        builder.OpenElement(seq++, "tbody");
        for (var i = startIdx; i < lines.Count; i++)
        {
            if (i == 1 && hasHeader) continue;
            builder.OpenElement(seq++, "tr");
            var cells = lines[i].Split('|', StringSplitOptions.RemoveEmptyEntries);
            foreach (var cell in cells)
            {
                builder.OpenElement(seq++, "td");
                RenderInlines(builder, ref seq, cell.Trim(), false);
                builder.CloseElement();
            }
            builder.CloseElement();
        }
        builder.CloseElement();
        builder.CloseElement();
        builder.CloseElement();
    }

    private void RenderInlines(RenderTreeBuilder builder, ref int seq, string text, bool renderAsImage)
    {
        var remaining = text;
        
        while (!string.IsNullOrEmpty(remaining))
        {
            var boldMatch = Regex.Match(remaining, @"\*\*(.*?)\*\*");
            var italicMatch = Regex.Match(remaining, @"\*(.*?)\*");
            var cardMatch = Regex.Match(remaining, @"\[\[(.*?)\]\]");

            var bestIdx = int.MaxValue;
            Match? bestMatch = null;
            int matchType = 0; // 1: bold, 2: italic, 3: card

            if (boldMatch.Success && boldMatch.Index < bestIdx) { bestIdx = boldMatch.Index; bestMatch = boldMatch; matchType = 1; }
            if (italicMatch.Success && italicMatch.Index < bestIdx) { bestIdx = italicMatch.Index; bestMatch = italicMatch; matchType = 2; }
            if (cardMatch.Success && cardMatch.Index < bestIdx) { bestIdx = cardMatch.Index; bestMatch = cardMatch; matchType = 3; }

            if (bestMatch != null)
            {
                if (bestIdx > 0)
                    builder.AddContent(seq++, remaining[..bestIdx]);

                var innerText = bestMatch.Groups[1].Value;
                
                if (matchType == 1) // Bold
                {
                    builder.OpenElement(seq++, "strong");
                    builder.AddContent(seq++, innerText);
                    builder.CloseElement();
                }
                else if (matchType == 2) // Italic
                {
                    builder.OpenElement(seq++, "em");
                    builder.AddContent(seq++, innerText);
                    builder.CloseElement();
                }
                else if (matchType == 3) // Card Link / Doc Link
                {
                    var card = LookupCard(innerText);
                    var doc = LookupDoc(innerText);
                    if (card != null || doc != null)
                    {
                        builder.OpenElement(seq++, "button");
                        builder.AddAttribute(seq++, "class", "inline-card-btn");
                        builder.AddAttribute(seq++, "onclick", EventCallback.Factory.Create(this, () => Navigate(innerText)));
                        builder.AddContent(seq++, innerText);
                        builder.CloseElement();
                    }
                    else
                    {
                        builder.AddContent(seq++, innerText);
                    }
                }

                remaining = remaining[(bestIdx + bestMatch.Length)..];
            }
            else
            {
                builder.AddContent(seq++, remaining);
                remaining = "";
            }
        }
    }
}