using System;
using System.IO;
using System.Net;
using System.Net.Http;
using Umbraco.Core.IO;
using Umbraco.Web.Mvc;
using Umbraco.Web.WebApi;
using Constants = Umbraco.Core.Constants;

namespace Umbraco.Web.Editors
{
    /// <summary>
    /// A controller used to return images for media
    /// </summary>
    [PluginController("UmbracoApi")]
    public class ImagesController : UmbracoAuthorizedApiController
    {
        private readonly MediaFileSystem _mediaFileSystem;

        public ImagesController(MediaFileSystem mediaFileSystem)
        {
            _mediaFileSystem = mediaFileSystem;
        }

        /// <summary>
        /// Gets the big thumbnail image for the media id
        /// </summary>
        /// <param name="mediaId"></param>
        /// <returns></returns>
        /// <remarks>
        /// If there is no media, image property or image file is found then this will return not found.
        /// </remarks>
        public HttpResponseMessage GetBigThumbnail(int mediaId)
        {
            var media = Services.MediaService.GetById(mediaId);
            if (media == null)
                return Request.CreateResponse(HttpStatusCode.NotFound);

            var imageProp = media.Properties[Constants.Conventions.Media.File];
            if (imageProp == null)
                return Request.CreateResponse(HttpStatusCode.NotFound);

            //fixme doesn't take into account variants
            var imagePath = imageProp.GetValue().ToString();
            return GetBigThumbnail(imagePath);
        }

        /// <summary>
        /// Gets the big thumbnail image for the original image path
        /// </summary>
        /// <param name="originalImagePath"></param>
        /// <returns></returns>
        /// <remarks>
        /// If there is no original image is found then this will return not found.
        /// </remarks>
        public HttpResponseMessage GetBigThumbnail(string originalImagePath)
        {
            return string.IsNullOrWhiteSpace(originalImagePath)
                ? Request.CreateResponse(HttpStatusCode.OK)
                : GetResized(originalImagePath, 500, "big-thumb");
        }

        /// <summary>
        /// Gets a resized image for the media id
        /// </summary>
        /// <param name="mediaId"></param>
        /// <param name="width"></param>
        /// <returns></returns>
        /// <remarks>
        /// If there is no media, image property or image file is found then this will return not found.
        /// </remarks>
        public HttpResponseMessage GetResized(int mediaId, int width)
        {
            var media = Services.MediaService.GetById(mediaId);
            if (media == null)
                return new HttpResponseMessage(HttpStatusCode.NotFound);

            var imageProp = media.Properties[Constants.Conventions.Media.File];
            if (imageProp == null)
                return new HttpResponseMessage(HttpStatusCode.NotFound);

            //fixme doesn't take into account variants
            var imagePath = imageProp.GetValue().ToString();
            return GetResized(imagePath, width);
        }

        /// <summary>
        /// Gets a resized image for the image at the given path
        /// </summary>
        /// <param name="imagePath"></param>
        /// <param name="width"></param>
        /// <returns></returns>
        /// <remarks>
        /// If there is no media, image property or image file is found then this will return not found.
        /// </remarks>
        public HttpResponseMessage GetResized(string imagePath, int width)
        {
            return GetResized(imagePath, width, Convert.ToString(width));
        }

        /// <summary>
        /// Gets a resized image - if the requested max width is greater than the original image, only the original image will be returned.
        /// </summary>
        /// <param name="imagePath"></param>
        /// <param name="width"></param>
        /// <param name="sizeName"></param>
        /// <returns></returns>
        private HttpResponseMessage GetResized(string imagePath, int width, string sizeName)
        {
            var ext = Path.GetExtension(imagePath);

            // we need to check if it is an image by extension
            if (_mediaFileSystem.IsImageFile(ext) == false)
                return Request.CreateResponse(HttpStatusCode.NotFound);

            //redirect to ImageProcessor thumbnail with rnd generated from last modified time of original media file
            var response = Request.CreateResponse(HttpStatusCode.Found);
            var imageLastModified = _mediaFileSystem.GetLastModified(imagePath);
            response.Headers.Location = new Uri($"{imagePath}?rnd={imageLastModified:yyyyMMddHHmmss}&width={width}", UriKind.Relative );
            return response;
        }
    }
}