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

namespace AdminService.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/temp";

        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, string? customName = null)
        {
            if (!ValidateImage(file, out var errorMessage))
            {
                return (false, string.Empty, string.Empty, errorMessage);
            }

            try
            {
                var timestamp = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
                string fileName;
                string relativePath;

                if (!string.IsNullOrWhiteSpace(customName))
                {
                    fileName = customName + ".png";
                    var uploadPath = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot", "uploads");
                    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);
                    }
                    relativePath = $"/uploads/{fileName}?timespan={timestamp}";
                }
                else
                {
                    var ext = Path.GetExtension(file.FileName).ToLowerInvariant();
                    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);
                    }
                    relativePath = $"/uploads/temp/{fileName}?timespan={timestamp}";
                }

                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}");
            }
        }

        public async Task<List<BatchUploadResult>> UploadBatchImagesAsync(IFormFile[] files)
        {
            var results = new List<BatchUploadResult>();

            foreach (var file in files)
            {
                var result = new BatchUploadResult
                {
                    OriginalFileName = file.FileName
                };

                if (file.Length == 0)
                {
                    result.Success = false;
                    result.Message = "文件为空";
                    results.Add(result);
                    continue;
                }

                if (!ValidateImage(file, out var errorMessage))
                {
                    result.Success = false;
                    result.Message = errorMessage;
                    results.Add(result);
                    continue;
                }

                try
                {
                    var uploadResult = await UploadImageAsync(file);
                    result.Success = uploadResult.isOk;
                    result.Path = uploadResult.path;
                    result.FileName = uploadResult.fileName;
                    result.Message = uploadResult.errorMessage;
                }
                catch (Exception ex)
                {
                    result.Success = false;
                    result.Message = "上传失败";
                    _logger.LogError(ex, "批量上传中单个文件上传失败: {FileName}", file.FileName);
                }

                results.Add(result);
            }

            return results;
        }
    }
}