using IVFileServer.Contracts;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Security.Cryptography;
using System.Web.Http;

namespace IVFileServer.Controllers
{
    public class FilesController : ApiController
    {
        private const string FilesDirectory = @"C:\files";

        /// <summary>
        /// Fetches a file.  Should return the file only if the user doesn't already have it.
        /// </summary>
        [HttpGet]
        [Route("api/files/{*fileName}")]
        public HttpResponseMessage GetFile(string fileName /*, ... */)
        {
            // TODO: Implement
            throw new NotImplementedException();
        }

        /// <summary>
        /// Computes a SHA1 hash for a file.  Will throw if the file does not exist.
        /// </summary>
        private string ComputeFileHash(string filePath)
        {
            using (var shaManaged = new SHA1Managed())
            using (Stream fileStream = File.Open(filePath, FileMode.Open))
            using (Stream sourceStream = new CryptoStream(fileStream, shaManaged, CryptoStreamMode.Read))
            {
                // Read all the bytes and return the hash
                while (sourceStream.ReadByte() != -1) ;
                return BitConverter.ToString(shaManaged.Hash).Replace("-", string.Empty).ToLower();
            }
        }

        /// <summary>
        /// Builds a HTTP response containing the contents of a file.
        /// </summary>
        private HttpResponseMessage CreateFileResponse(string filePath)
        {
            var file = File.Open(filePath, FileMode.Open);
            var content = new StreamContent(file);
            content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
            {
                FileName = Path.GetFileName(filePath)
            };

            return new HttpResponseMessage
            {
                StatusCode = HttpStatusCode.OK,
                Content = content
            };
        }

        private HttpResponseMessage CreateStatusCodeResponse(HttpStatusCode statusCode)
        {
            return new HttpResponseMessage(statusCode);
        }
    }
}