using System.Windows;
using System.Windows.Threading;
using Microsoft.EntityFrameworkCore;
using SimpleWiki.Data;
using SimpleWiki.Models;
using SimpleWiki.Services;

namespace SimpleWiki.Views;

public partial class ArticleEditorWindow : Window
{
    private readonly User _currentUser;
    private readonly int? _articleId;
    private bool _isPreviewBrowserReady;
    private string _pendingPreviewHtml = string.Empty;

    public ArticleEditorWindow(User currentUser, int? articleId = null)
    {
        InitializeComponent();
        _currentUser = currentUser;
        _articleId = articleId;
        _pendingPreviewHtml = MarkdownService.ToHtmlDocument("Предпросмотр", "# Предпросмотр\n\nПодготовка предпросмотра...");
        Loaded += ArticleEditorWindow_Loaded;
        ContentRendered += ArticleEditorWindow_ContentRendered;
    }


    private void ArticleEditorWindow_ContentRendered(object? sender, EventArgs e)
    {
        _isPreviewBrowserReady = true;
        Dispatcher.BeginInvoke(RenderPreviewIfReady, DispatcherPriority.ApplicationIdle);
    }

    private void ArticleEditorWindow_Loaded(object sender, RoutedEventArgs e)
    {
        if (_articleId.HasValue)
        {
            using var db = new AppDbContext();
            var article = db.Articles.AsNoTracking().FirstOrDefault(x => x.Id == _articleId.Value);
            if (article is not null)
            {
                TitleTextBox.Text = article.Title;
                SummaryTextBox.Text = article.Summary;
                MarkdownTextBox.Text = article.MarkdownContent;
            }
        }

        UpdatePreview();
    }

    private void AnyInput_TextChanged(object sender, System.Windows.Controls.TextChangedEventArgs e)
    {
        UpdatePreview();
    }

    private void UpdatePreview()
    {
        var title = string.IsNullOrWhiteSpace(TitleTextBox.Text) ? "Новая статья" : TitleTextBox.Text.Trim();
        var content = string.IsNullOrWhiteSpace(MarkdownTextBox.Text)
            ? "# Предпросмотр\n\nЗдесь появится отрендеренный markdown."
            : MarkdownTextBox.Text;

        _pendingPreviewHtml = MarkdownService.ToHtmlDocument(title, content);
        RenderPreviewIfReady();
    }

    private void RenderPreviewIfReady()
    {
        if (!_isPreviewBrowserReady)
        {
            return;
        }

        PreviewBrowser.NavigateToString(_pendingPreviewHtml);
    }

    private void SaveButton_Click(object sender, RoutedEventArgs e)
    {
        var titleError = InputValidator.ValidateArticleTitle(TitleTextBox.Text);
        var summaryError = InputValidator.ValidateArticleSummary(SummaryTextBox.Text);
        var markdownError = InputValidator.ValidateArticleMarkdown(MarkdownTextBox.Text);
        var errors = InputValidator.JoinErrors(titleError, summaryError, markdownError);

        if (!string.IsNullOrWhiteSpace(errors))
        {
            MessageBox.Show(errors, "Ошибка валидации", MessageBoxButton.OK, MessageBoxImage.Warning);
            return;
        }

        using var db = new AppDbContext();
        var slug = SlugHelper.Generate(TitleTextBox.Text);

        if (_articleId.HasValue)
        {
            var article = db.Articles.FirstOrDefault(x => x.Id == _articleId.Value);
            if (article is null)
            {
                MessageBox.Show("Статья не найдена.", "Ошибка", MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }

            var duplicate = db.Articles.AsNoTracking().Any(x => x.Slug == slug && x.Id != article.Id);
            if (duplicate)
            {
                MessageBox.Show("Статья с таким заголовком уже существует.", "Ошибка", MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }

            article.Title = TitleTextBox.Text.Trim();
            article.Summary = SummaryTextBox.Text.Trim();
            article.MarkdownContent = MarkdownTextBox.Text.Trim();
            article.Slug = slug;
            article.UpdatedAt = DateTime.UtcNow;
        }
        else
        {
            var duplicate = db.Articles.AsNoTracking().Any(x => x.Slug == slug);
            if (duplicate)
            {
                MessageBox.Show("Статья с таким заголовком уже существует.", "Ошибка", MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }

            var article = new Article
            {
                Title = TitleTextBox.Text.Trim(),
                Summary = SummaryTextBox.Text.Trim(),
                MarkdownContent = MarkdownTextBox.Text.Trim(),
                Slug = slug,
                AuthorId = _currentUser.Id,
                CreatedAt = DateTime.UtcNow
            };

            db.Articles.Add(article);
        }

        db.SaveChanges();
        DialogResult = true;
        Close();
    }

    private void CancelButton_Click(object sender, RoutedEventArgs e)
    {
        DialogResult = false;
        Close();
    }
}