using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace Lagerbestand.Models;

/// <summary>
/// Represents a file attachment on a Kanban task
/// </summary>
public class KanbanTaskAttachment
{
    public Guid Id { get; set; } = Guid.NewGuid();

    public Guid TaskId { get; set; }

    [Required]
    [MaxLength(255)]
    public string FileName { get; set; } = string.Empty;

    [Required]
    [MaxLength(100)]
    public string ContentType { get; set; } = "application/octet-stream";

    /// <summary>
    /// File size in bytes
    /// </summary>
    public long FileSize { get; set; }

    /// <summary>
    /// Relative path to the file in the storage system (NFS/disk)
    /// </summary>
    [MaxLength(500)]
    public string? FilePath { get; set; }

    /// <summary>
    /// Legacy: File content stored as binary (being migrated to file-based storage)
    /// </summary>
    [Obsolete("Use FilePath instead. This property is retained for migration purposes only.")]
    public byte[]? FileContent { get; set; }

    /// <summary>
    /// User who uploaded the file
    /// </summary>
    public Guid? UploadedByUserId { get; set; }

    public DateTime CreatedAt { get; set; } = DateTime.UtcNow;

    // Navigation properties
    public virtual KanbanTask? Task { get; set; }
    public virtual AppUser? UploadedByUser { get; set; }

    // Computed properties
    [NotMapped]
    public string FileSizeDisplay
    {
        get
        {
            if (FileSize < 1024) return $"{FileSize} B";
            if (FileSize < 1024 * 1024) return $"{FileSize / 1024.0:F1} KB";
            return $"{FileSize / (1024.0 * 1024.0):F1} MB";
        }
    }

    [NotMapped]
    public string FileIcon
    {
        get
        {
            var ext = Path.GetExtension(FileName).ToLowerInvariant();
            return ext switch
            {
                ".pdf" => "📄",
                ".doc" or ".docx" => "📝",
                ".xls" or ".xlsx" => "📊",
                ".ppt" or ".pptx" => "📽️",
                ".jpg" or ".jpeg" or ".png" or ".gif" or ".webp" => "🖼️",
                ".zip" or ".rar" or ".7z" => "📦",
                ".txt" => "📃",
                _ => "📎"
            };
        }
    }

    [NotMapped]
    public bool IsImage => ContentType.StartsWith("image/");

    /// <summary>
    /// Whether the file is stored on disk (vs legacy database storage)
    /// </summary>
    [NotMapped]
    public bool IsFileBasedStorage => !string.IsNullOrEmpty(FilePath);

    /// <summary>
    /// Maximum file size allowed (10 MB)
    /// </summary>
    public const long MaxFileSize = 10 * 1024 * 1024;
}