using LiteDB;
using VideoStudy.Shared;

namespace VideoStudy.Shared.Services;

public class PersistenceService
{
    private readonly string _basePath;
    private readonly string _dbPath;

    public PersistenceService()
    {
        // Define a pasta base em %USERPROFILE%/MeuVideoStudy
        // Funciona em Windows, macOS e Linux (limitado pelo ambiente MAUI)
        _basePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), "MeuVideoStudy");
        _dbPath = Path.Combine(_basePath, "videostudy.db");

        if (!Directory.Exists(_basePath))
        {
            Directory.CreateDirectory(_basePath);
        }
    }

    public string GetBasePath() => _basePath;

    /// <summary>
    /// Retorna as subpastas físicas dentro do diretório base.
    /// </summary>
    public List<string> GetFolders()
    {
        if (!Directory.Exists(_basePath)) return new List<string>();
        
        return Directory.GetDirectories(_basePath)
                        .Select(Path.GetFileName)
                        .Where(name => name != null)
                        .ToList()!;
    }

    /// <summary>
    /// Cria uma nova pasta física.
    /// </summary>
    public void CreateFolder(string folderName)
    {
        var path = Path.Combine(_basePath, folderName);
        if (!Directory.Exists(path))
        {
            Directory.CreateDirectory(path);
        }
    }

    /// <summary>
    /// Salva o PDF no disco e registra no LiteDB.
    /// </summary>
    public async Task<VideoStudySession> SaveSessionAsync(byte[] pdfData, string title, string? youtubeId, string folderName = "Geral")
    {
        // Garantir que a pasta existe
        var folderPath = Path.Combine(_basePath, folderName);
        if (!Directory.Exists(folderPath))
        {
            Directory.CreateDirectory(folderPath);
        }

        // Criar nome de arquivo seguro
        var safeTitle = string.Join("_", title.Split(Path.GetInvalidFileNameChars()));
        var fileName = $"{safeTitle}_{DateTime.Now:yyyyMMdd_HHmmss}.pdf";
        var filePath = Path.Combine(folderPath, fileName);

        // Gravar arquivo físico
        await File.WriteAllBytesAsync(filePath, pdfData);

        // Registrar no LiteDB
        using var db = new LiteDatabase(_dbPath);
        var collection = db.GetCollection<VideoStudySession>("sessions");

        var session = new VideoStudySession
        {
            Title = title,
            YouTubeId = youtubeId ?? "local",
            FilePath = filePath,
            FolderName = folderName,
            CreatedAt = DateTime.Now
        };

        collection.Insert(session);
        collection.EnsureIndex(x => x.Title);

        return session;
    }

    /// <summary>
    /// Recupera todas as sessões do banco.
    /// </summary>
    public List<VideoStudySession> GetAllSessions()
    {
        using var db = new LiteDatabase(_dbPath);
        return db.GetCollection<VideoStudySession>("sessions")
                 .FindAll()
                 .OrderByDescending(x => x.CreatedAt)
                 .ToList();
    }
}