using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using System.Web.Http;
using iiie.Logs.DataAccess;
using iiie.Logs.DBO;
using iiie.WebApiUtils.DBO;

namespace iiie.WebApiUtils.BusinessManager
{
    /// <summary>
    /// Handle business manager results
    /// </summary>
    public class BMRHandler : ApiController
    {
        /// <summary>
        /// Converts ResultStatus codes to HttpStatusCodes codes
        /// </summary>
        /// <param name="status">The status code</param>
        /// <returns>The http code</returns>
        public static HttpStatusCode ResultStatusToHttp(ResultStatus status)
        {
            if (status == ResultStatus.LoginError)
                return HttpStatusCode.Unauthorized;
            if (status == ResultStatus.PermissionError)
                return HttpStatusCode.Forbidden;
            if (status == ResultStatus.InputError)
                return HttpStatusCode.BadRequest;
            if (status == ResultStatus.NotFound)
                return HttpStatusCode.NotFound;
            return HttpStatusCode.InternalServerError;
        }

        /// <summary>
        /// Returns a string corresponding to the error
        /// </summary>
        /// <param name="result">The result of the operation</param>
        /// <returns>The error string</returns>
        public static string OpResultToString<T>(OpResult<T> result)
        {
            if (result.PublicDetails != null)
                return result.PublicDetails;

            if (result.Status == ResultStatus.LoginError)
                return "Bad username/password";
            if (result.Status == ResultStatus.PermissionError)
                return "You don\'t have the permission to do this action";
            if (result.Status == ResultStatus.InputError)
                return "Invalid data was provided";
            if (result.Status == ResultStatus.NotFound)
                return "Ressource not found";

            return "Internal error";
        }

        /// <summary>
        /// Handle business manager results
        /// </summary>
        /// <param name="result">The result to handle</param>
        /// <returns>The data to return to the user</returns>
        [NonAction]
        public T Handle<T>(OpResult<T> result)
        {
            if (result.Status == ResultStatus.Success)
                return result.Data;
            result.Log();
            var msg = Request.CreateErrorResponse(ResultStatusToHttp(result.Status), OpResultToString(result));
            throw new HttpResponseException(msg);
        }

        /// <summary>
        /// Handle business manager results
        /// </summary>
        /// <param name="result">The result to handle</param>
        /// <returns>The data to return to the user</returns>
        [NonAction]
        public DboGetSingle<T> HandleSingle<T>(OpResult<T> result)
        {
            return new DboGetSingle<T>
            {
                Value = Handle(result)
            };
        }

        /// <summary>
        /// Save the uploaded file to the temp dir
        /// </summary>
        /// <returns>The file path</returns>
        [NonAction]
        public async Task<OpResult<string>> SaveFileToTemp()
        {
            IEnumerable<HttpContent> parts = null;
            try
            {
                Task.Factory.StartNew(() => parts = Request.Content.ReadAsMultipartAsync().Result.Contents,
                        CancellationToken.None, TaskCreationOptions.LongRunning, TaskScheduler.Default).Wait();
            }
            catch (Exception e)
            {
                return OpResult<string>.Error(ResultStatus.InputError, e, "Failed to read post parts (maximum size exceeded?)");
            }
            HttpContent file = parts.FirstOrDefault();
            if (file == null)
            {
                return OpResult<string>.Error(ResultStatus.InputError, "No uploaded file", "");
            }
            try
            {
                var path = Path.GetTempFileName();
                using (var memoryStream = new MemoryStream(await file.ReadAsByteArrayAsync()))
                {
                    using (var streamWriter = new FileStream(path, FileMode.OpenOrCreate))
                    {
                        memoryStream.WriteTo(streamWriter);
                        memoryStream.Close();
                        streamWriter.Close();
                    }
                }
                return OpResult<string>.Ok(path);
            }
            catch (Exception e)
            {
                return OpResult<string>.Error(ResultStatus.InputError, e, "Failed to write uploaded file");
            }
        }
    }
}