using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;

namespace UserService.ImageUpload
{
    public class ImageUploadService : IImageUploadService
    {
        private readonly ILogger<ImageUploadService> _logger;
        private static readonly string[] AllowedExtensions = { ".jpg", ".jpeg", ".png", ".gif", ".bmp", ".webp" };
        private const long MaxFileSize = 5 * 1024 * 1024; // 5MB
        private const string UploadFolder = "wwwroot/uploads";

        public ImageUploadService(ILogger<ImageUploadService> logger)
        {
            _logger = logger;
        }

        public bool ValidateImage(IFormFile file, out string errorMessage)
        {
            errorMessage = string.Empty;

            if (file == null || file.Length == 0)
            {
                errorMessage = "请选择要上传的文件";
                return false;
            }

            var ext = Path.GetExtension(file.FileName).ToLowerInvariant();
            if (!AllowedExtensions.Contains(ext))
            {
                errorMessage = "只支持上传图片格式：jpg、jpeg、png、gif、bmp、webp";
                return false;
            }

            if (file.Length > MaxFileSize)
            {
                errorMessage = "文件大小不能超过5MB";
                return false;
            }

            return true;
        }

        public async Task<(bool isOk, string path, string fileName, string errorMessage)> UploadImageAsync(IFormFile file)
        {
            if (!ValidateImage(file, out var errorMessage))
            {
                return (false, string.Empty, string.Empty, errorMessage);
            }

            try
            {
                var ext = Path.GetExtension(file.FileName).ToLowerInvariant();
                var fileName = Guid.NewGuid().ToString("N") + ext;

                var uploadPath = Path.Combine(Directory.GetCurrentDirectory(), UploadFolder);
                if (!Directory.Exists(uploadPath))
                {
                    Directory.CreateDirectory(uploadPath);
                }

                var filePath = Path.Combine(uploadPath, fileName);
                using (var stream = new FileStream(filePath, FileMode.Create))
                {
                    await file.CopyToAsync(stream);
                }

                var relativePath = $"/uploads/{fileName}";
return (true, relativePath, fileName, string.Empty);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "图片上传失败: {Message}", ex.Message);
                return (false, string.Empty, string.Empty, $"上传失败：{ex.Message}");
            }
        }
    }
}