BCards/src/BCards.Web/Areas/Tutoriais/Services/MarkdownService.cs

using BCards.Web.Areas.Tutoriais.Models;
using BCards.Web.Areas.Tutoriais.Models.ViewModels;
using Markdig;
using Microsoft.Extensions.Caching.Memory;
using YamlDotNet.Serialization;
using YamlDotNet.Serialization.NamingConventions;

namespace BCards.Web.Areas.Tutoriais.Services;

public class MarkdownService : IMarkdownService
{
    private readonly IMemoryCache _cache;
    private readonly ILogger<MarkdownService> _logger;
    private readonly string _contentBasePath;
    private readonly MarkdownPipeline _markdownPipeline;
    private readonly IDeserializer _yamlDeserializer;

    public MarkdownService(
        IMemoryCache cache,
        ILogger<MarkdownService> logger,
        IWebHostEnvironment environment)
    {
        _cache = cache;
        _logger = logger;
        _contentBasePath = Path.Combine(environment.ContentRootPath, "Content");

        // Pipeline Markdig com extensões avançadas
        _markdownPipeline = new MarkdownPipelineBuilder()
            .UseAdvancedExtensions()      // Tables, footnotes, etc.
            .UseAutoLinks()                // Auto-link URLs
            .UseEmphasisExtras()           // ~~strikethrough~~
            .UseGenericAttributes()        // {#id .class}
            .DisableHtml()                 // Segurança: bloqueia HTML inline
            .Build();

        // Deserializador YAML
        _yamlDeserializer = new DeserializerBuilder()
            .WithNamingConvention(CamelCaseNamingConvention.Instance)
            .IgnoreUnmatchedProperties()
            .Build();
    }

    public async Task<ArticleViewModel?> GetArticleAsync(string relativePath, string culture)
    {
        var cacheKey = $"Article_{relativePath}_{culture}";

        // Verificar cache
        if (_cache.TryGetValue(cacheKey, out ArticleViewModel? cachedArticle))
        {
            _logger.LogDebug("Artigo encontrado no cache: {Path}", relativePath);
            return cachedArticle;
        }

        // Construir caminho completo
        var fullPath = Path.Combine(_contentBasePath, $"{relativePath}.{culture}.md");

        if (!File.Exists(fullPath))
        {
            _logger.LogWarning("Arquivo não encontrado: {Path}", fullPath);
            return null;
        }

        try
        {
            var content = await File.ReadAllTextAsync(fullPath);
            var (metadata, markdownContent) = ExtractFrontmatter(content);

            if (metadata == null)
            {
                _logger.LogError("Frontmatter inválido em: {Path}", fullPath);
                return null;
            }

            // Processar markdown → HTML
            var htmlContent = Markdown.ToHtml(markdownContent, _markdownPipeline);

            // Calcular tempo de leitura (200 palavras/minuto)
            var wordCount = markdownContent.Split(' ', StringSplitOptions.RemoveEmptyEntries).Length;
            metadata.ReadingTimeMinutes = Math.Max(1, wordCount / 200);

            // Extrair slug do path
            metadata.Slug = Path.GetFileNameWithoutExtension(
                Path.GetFileNameWithoutExtension(relativePath.Split('/').Last())
            );
            metadata.Culture = culture;

            var article = new ArticleViewModel
            {
                Metadata = metadata,
                HtmlContent = htmlContent,
                Slug = metadata.Slug,
                LastModified = File.GetLastWriteTimeUtc(fullPath)
            };

            // Cache por 1 hora
            _cache.Set(cacheKey, article, TimeSpan.FromHours(1));

            _logger.LogInformation("Artigo processado e cacheado: {Path}", relativePath);
            return article;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Erro ao processar artigo: {Path}", fullPath);
            return null;
        }
    }

    public async Task<List<ArticleMetadata>> GetArticlesByCategoryAsync(string category, string culture)
    {
        var cacheKey = $"CategoryArticles_{category}_{culture}";

        if (_cache.TryGetValue(cacheKey, out List<ArticleMetadata>? cached))
        {
            return cached ?? new List<ArticleMetadata>();
        }

        var categoryPath = Path.Combine(_contentBasePath, "Tutoriais", category);

        if (!Directory.Exists(categoryPath))
        {
            _logger.LogWarning("Diretório de categoria não encontrado: {Path}", categoryPath);
            return new List<ArticleMetadata>();
        }

        var articles = new List<ArticleMetadata>();
        var files = Directory.GetFiles(categoryPath, $"*.{culture}.md");

        foreach (var file in files)
        {
            try
            {
                var content = await File.ReadAllTextAsync(file);
                var (metadata, _) = ExtractFrontmatter(content);

                if (metadata != null)
                {
                    var slug = Path.GetFileNameWithoutExtension(
                        Path.GetFileNameWithoutExtension(file)
                    );
                    metadata.Slug = slug;
                    metadata.Culture = culture;
                    metadata.Category = category;
                    articles.Add(metadata);
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Erro ao processar arquivo: {File}", file);
            }
        }

        // Ordenar por data (mais recentes primeiro)
        articles = articles.OrderByDescending(a => a.Date).ToList();

        _cache.Set(cacheKey, articles, TimeSpan.FromHours(1));
        return articles;
    }

    public async Task<List<ArticleMetadata>> GetAllArticlesAsync(string baseFolder, string culture)
    {
        var cacheKey = $"AllArticles_{baseFolder}_{culture}";

        if (_cache.TryGetValue(cacheKey, out List<ArticleMetadata>? cached))
        {
            return cached ?? new List<ArticleMetadata>();
        }

        var folderPath = Path.Combine(_contentBasePath, baseFolder);

        if (!Directory.Exists(folderPath))
        {
            _logger.LogWarning("Pasta não encontrada: {Path}", folderPath);
            return new List<ArticleMetadata>();
        }

        var articles = new List<ArticleMetadata>();
        var files = Directory.GetFiles(folderPath, $"*.{culture}.md", SearchOption.AllDirectories);

        foreach (var file in files)
        {
            try
            {
                var content = await File.ReadAllTextAsync(file);
                var (metadata, _) = ExtractFrontmatter(content);

                if (metadata != null)
                {
                    var slug = Path.GetFileNameWithoutExtension(
                        Path.GetFileNameWithoutExtension(file)
                    );
                    metadata.Slug = slug;
                    metadata.Culture = culture;
                    articles.Add(metadata);
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Erro ao processar arquivo: {File}", file);
            }
        }

        articles = articles.OrderByDescending(a => a.Date).ToList();
        _cache.Set(cacheKey, articles, TimeSpan.FromHours(1));
        return articles;
    }

    private (ArticleMetadata? metadata, string content) ExtractFrontmatter(string fileContent)
    {
        var lines = fileContent.Split('\n');

        if (lines.Length < 3 || !lines[0].Trim().Equals("---"))
        {
            _logger.LogWarning("Frontmatter não encontrado (deve começar com ---)");
            return (null, fileContent);
        }

        var endIndex = Array.FindIndex(lines, 1, line => line.Trim().Equals("---"));

        if (endIndex == -1)
        {
            _logger.LogWarning("Frontmatter mal formatado (falta --- de fechamento)");
            return (null, fileContent);
        }

        try
        {
            var yamlContent = string.Join('\n', lines[1..endIndex]);
            var metadata = _yamlDeserializer.Deserialize<ArticleMetadata>(yamlContent);

            var markdownContent = string.Join('\n', lines[(endIndex + 1)..]);

            return (metadata, markdownContent);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Erro ao deserializar YAML frontmatter");
            return (null, fileContent);
        }
    }
}