using Massenger.Server.Data.Entities;

namespace Massenger.Server.Infrastructure.Storage;

public sealed class AttachmentStorageService(IWebHostEnvironment environment)
{
    private readonly string _rootPath = Path.Combine(environment.ContentRootPath, "Data", "Attachments");

    public async Task<MessageAttachment> SaveAsync(Guid messageId, IFormFile file, CancellationToken cancellationToken)
    {
        if (file.Length <= 0)
        {
            throw new InvalidOperationException("Attachment is empty.");
        }

        Directory.CreateDirectory(_rootPath);

        var attachmentId = Guid.NewGuid();
        var extension = Path.GetExtension(file.FileName);
        var year = DateTime.UtcNow.ToString("yyyy");
        var month = DateTime.UtcNow.ToString("MM");
        var targetDirectory = Path.Combine(_rootPath, year, month);
        Directory.CreateDirectory(targetDirectory);

        var storedFileName = $"{attachmentId:N}{extension}";
        var physicalPath = Path.Combine(targetDirectory, storedFileName);

        await using (var source = file.OpenReadStream())
        await using (var target = File.Create(physicalPath))
        {
            await source.CopyToAsync(target, cancellationToken);
        }

        return new MessageAttachment
        {
            Id = attachmentId,
            MessageId = messageId,
            OriginalFileName = string.IsNullOrWhiteSpace(file.FileName) ? "attachment" : Path.GetFileName(file.FileName),
            ContentType = string.IsNullOrWhiteSpace(file.ContentType) ? "application/octet-stream" : file.ContentType,
            FileSizeBytes = file.Length,
            StoragePath = physicalPath,
            UploadedAt = DateTimeOffset.UtcNow
        };
    }

    public void DeleteIfExists(string? physicalPath)
    {
        if (!string.IsNullOrWhiteSpace(physicalPath) && File.Exists(physicalPath))
        {
            File.Delete(physicalPath);
        }
    }
}