Merge pull request #665 from TechnologyEnhancedLearning/Develop/Feature/TD-4870-Implement-Did-you-Mean-Feature-for-Search-Search-enhancements

TD-4870 : Implemented Did you Mean Feature for Search Search enhancements

Author: ArunimaGeorge

LearningHub.Nhs.WebUI/Models/Search/SearchResultViewModel.cs

@@ -78,5 +78,10 @@ public class SearchResultViewModel
         /// Gets or sets the catalogue result paging.
         /// </summary>
         public PagingViewModel CatalogueResultPaging { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether Did You Mean Enabled or not.
+        /// </summary>
+        public bool DidYouMeanEnabled { get; set; }
     }
 }

LearningHub.Nhs.WebUI/Services/SearchService.cs

@@ -6,6 +6,7 @@ namespace LearningHub.Nhs.WebUI.Services
     using System.Net.Http;
     using System.Security.Principal;
     using System.Text;
+    using System.Text.RegularExpressions;
     using System.Threading.Tasks;
     using System.Web;
     using HtmlAgilityPack;
@@ -61,6 +62,7 @@ public async Task<SearchResultViewModel> PerformSearch(IPrincipal user, SearchRe
             var searchSortItemList = SearchHelper.GetSearchSortList();
             var selectedSortItem = searchSortItemList.Where(x => x.SearchSortType == (SearchSortTypeEnum)searchSortType).FirstOrDefault();
             var groupId = Guid.Parse(searchRequest.GroupId);
+            bool didYouMeanEnabled = false;
 
             var resourceSearchPageSize = this.settings.FindwiseSettings.ResourceSearchPageSize;
             var catalogueSearchPageSize = this.settings.FindwiseSettings.CatalogueSearchPageSize;
@@ -112,6 +114,35 @@ public async Task<SearchResultViewModel> PerformSearch(IPrincipal user, SearchRe
 
                     resourceResult = resourceResultTask.Result;
                     catalogueResult = catalogueResultTask.Result;
+
+                    // Did you mean suggestion when no hits found
+                    if (resourceResult?.TotalHits == 0 && catalogueResult?.TotalHits == 0 && (resourceResult?.Spell?.Suggestions?.Count > 0 || catalogueResult?.Spell?.Suggestions?.Count > 0))
+                    {
+                        didYouMeanEnabled = true;
+
+                        // pass the spell suggestion as new search text - resources
+                        if (resourceResult?.Spell?.Suggestions?.Count > 0)
+                        {
+                            resourceSearchRequestModel.SearchText = Regex.Replace(resourceResult?.Spell?.Suggestions?.FirstOrDefault().ToString(), "<.*?>", string.Empty);
+
+                            // calling findwise endpoint with new search text - resources
+                            resourceResultTask = this.GetSearchResultAsync(resourceSearchRequestModel);
+                        }
+
+                        // pass the spell suggestion as new search text - catalogues
+                        if (catalogueResult?.Spell?.Suggestions?.Count > 0)
+                        {
+                            catalogueSearchRequestModel.SearchText = Regex.Replace(catalogueResult?.Spell?.Suggestions?.FirstOrDefault().ToString(), "<.*?>", string.Empty);
+
+                            // calling findwise endpoint with new search text - catalogues
+                            catalogueResultTask = this.GetCatalogueSearchResultAsync(catalogueSearchRequestModel);
+                        }
+
+                        await Task.WhenAll(resourceResultTask, catalogueResultTask);
+
+                        resourceResult = resourceResultTask.Result;
+                        catalogueResult = catalogueResultTask.Result;
+                    }
                 }
 
                 var searchfilters = new List<SearchFilterModel>();
@@ -198,6 +229,7 @@ public async Task<SearchResultViewModel> PerformSearch(IPrincipal user, SearchRe
                     PageSize = catalogueSearchPageSize,
                     TotalItems = catalogueResult?.TotalHits ?? 0,
                 },
+                DidYouMeanEnabled = didYouMeanEnabled,
             };
 
             return searchResultViewModel;

LearningHub.Nhs.WebUI/Views/Search/Index.cshtml

@@ -13,6 +13,12 @@
             <h1 class="nhsuk-u-margin-top-5 nhsuk-u-margin-bottom-6">
             Search results @(!string.IsNullOrEmpty(Model.SearchString) ? "for " + Model.SearchString : string.Empty)
             </h1>
+        @if (Model.DidYouMeanEnabled)
+        {
+            <h6 class="nhsuk-u-margin-top-5 nhsuk-u-margin-bottom-6">
+                We couldn't find a match for <em>@(Model.SearchString)</em>, try adjusting your search terms or explore the suggestions below.
+            </h6>
+        }
 
         <div class="nhsuk-grid-row">
             <div class="nhsuk-grid-column-two-thirds">

WebAPI/LearningHub.Nhs.API/Controllers/SearchController.cs

@@ -319,6 +319,7 @@ private async Task<SearchViewModel> GetSearchResults(SearchRequestModel searchRe
 
             searchViewModel.Feedback = results.Feedback;
             searchViewModel.RelatedCatalogues = await this.catalogueService.GetCatalogues(catalogueIds);
+            searchViewModel.Spell = results.Spell;
 
             return searchViewModel;
         }
@@ -390,6 +391,7 @@ private async Task<SearchCatalogueViewModel> GetCatalogueSearchResults(Catalogue
 
             searchViewModel.SearchId = catalogueSearchRequestModel.SearchId > 0 ? catalogueSearchRequestModel.SearchId : results.SearchId;
             searchViewModel.Feedback = results.Feedback;
+            searchViewModel.Spell = results.Spell;
 
             return searchViewModel;
         }