using System.IO;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.FileProviders;
using Microsoft.Extensions.Logging;

namespace ETFileServer
{
    [Route("")]
    [ApiController]
    public class DownLoadController : Controller
    {
        private readonly IFileProvider _fileProvider;
        private readonly ILogger<DownLoadController> _logger;
        private readonly IConfiguration _configuration;

        public DownLoadController(ILogger<DownLoadController> logger, IFileProvider fileProvider, IConfiguration configuration)
        {
            _logger = logger;
            _fileProvider = fileProvider;
            _configuration = configuration;
        }

        [HttpGet("{*filePath}")]
        public IActionResult Get(string filePath)
        {
            if (string.IsNullOrEmpty(filePath))
            {
                return BadRequest("A file path must be provided.");
            }

            var fileInfo = _fileProvider.GetFileInfo(filePath);

            if (!fileInfo.Exists || fileInfo.IsDirectory)
            {
                _logger.LogWarning($"File not found or is a directory: {filePath}");
                return NotFound();
            }

            // 检查文件大小是否超出限制
            long maxFileSizeInBytes = _configuration.GetValue<long>("MaxFileSizeMb", 100) * 1024 * 1024;
            if (fileInfo.Length > maxFileSizeInBytes)
            {
                _logger.LogWarning($"File '{filePath}' exceeds the size limit of {maxFileSizeInBytes} bytes.");
                return new StatusCodeResult(413); // 413 Payload Too Large
            }

            _logger.LogInformation($"Serving file: {fileInfo.PhysicalPath}");
            
            return PhysicalFile(fileInfo.PhysicalPath, "application/octet-stream", fileInfo.Name);
        }

        public override void OnActionExecuting(ActionExecutingContext context)
        {
            var httpContext = context.HttpContext;
            if (httpContext.Request.Method != "GET")
            {
                context.Result = new StatusCodeResult(405);
                return;
            }

            if (httpContext.WebSockets.IsWebSocketRequest)
            {
                context.Result = new BadRequestResult();
                return;
            }

            if (httpContext.Request.HasFormContentType)
            {
                context.Result = new BadRequestResult();
                return;
            }
        }

        public override void OnActionExecuted(ActionExecutedContext context)
        {
        }
    }
}