Add Summary Count for History Endpoints (#3661)

* Added count for all history

* Added necessary extra tests

* Added E2E Test

* Addressed PR comments

* Fixed E2E Tests

* fix test build issue

* Fixed test name

* Updated tests

* Fixed test issue

* Fix test date/time format

src/Microsoft.Health.Fhir.Api/Models/HistoryModel.cs

@@ -23,6 +23,9 @@ public class HistoryModel
     [FromQuery(Name = KnownQueryParameterNames.Count)]
     public int? Count { get; set; }
 
+    [FromQuery(Name = KnownQueryParameterNames.Summary)]
+    public string Summary { get; set; }
+
     [FromQuery(Name = KnownQueryParameterNames.ContinuationToken)]
     public string ContinuationToken { get; set; }
 

src/Microsoft.Health.Fhir.Core/Features/Search/ISearchService.cs

@@ -69,6 +69,7 @@ namespace Microsoft.Health.Fhir.Core.Features.Search
             PartialDateTime since,
             PartialDateTime before,
             int? count,
+            string summary,
             string continuationToken,
             string sort,
             CancellationToken cancellationToken,

src/Microsoft.Health.Fhir.Core/Features/Search/SearchService.cs

@@ -10,6 +10,7 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using EnsureThat;
+using Hl7.Fhir.Rest;
 using Microsoft.Health.Core;
 using Microsoft.Health.Fhir.Core.Exceptions;
 using Microsoft.Health.Fhir.Core.Extensions;
@@ -77,6 +78,7 @@ namespace Microsoft.Health.Fhir.Core.Features.Search
             PartialDateTime since,
             PartialDateTime before,
             int? count,
+            string summary,
             string continuationToken,
             string sort,
             CancellationToken cancellationToken,
@@ -157,6 +159,10 @@ namespace Microsoft.Health.Fhir.Core.Features.Search
             {
                 queryParameters.Add(Tuple.Create(KnownQueryParameterNames.Count, count.ToString()));
             }
+            else if ((count.HasValue && count == 0) || (summary is not null && summary.Equals(SummaryType.Count.ToString(), StringComparison.OrdinalIgnoreCase)))
+            {
+                queryParameters.Add(Tuple.Create(KnownQueryParameterNames.Summary, SummaryType.Count.ToString()));
+            }
 
             if (!string.IsNullOrEmpty(sort))
             {

src/Microsoft.Health.Fhir.Core/Messages/Search/SearchResourceHistoryRequest.cs

@@ -15,20 +15,21 @@ namespace Microsoft.Health.Fhir.Core.Messages.Search
     {
         private readonly string _capability;
 
-        public SearchResourceHistoryRequest(PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string continuationToken = null, string sort = null)
+        public SearchResourceHistoryRequest(PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string summary = null, string continuationToken = null, string sort = null)
         {
             Since = since;
             Before = before;
             At = at;
             Count = count;
+            Summary = summary;
             ContinuationToken = continuationToken;
             Sort = sort;
 
             _capability = "CapabilityStatement.rest.interaction.where(code = 'history-system').exists()";
         }
 
-        public SearchResourceHistoryRequest(string resourceType, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string continuationToken = null, string sort = null)
-            : this(since, before, at, count, continuationToken, sort)
+        public SearchResourceHistoryRequest(string resourceType, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string summary = null, string continuationToken = null, string sort = null)
+            : this(since, before, at, count, summary, continuationToken, sort)
         {
             EnsureArg.IsNotNullOrWhiteSpace(resourceType, nameof(resourceType));
 
@@ -37,8 +38,8 @@ namespace Microsoft.Health.Fhir.Core.Messages.Search
             _capability = $"CapabilityStatement.rest.resource.where(type = '{resourceType}').interaction.where(code = 'history-type').exists()";
         }
 
-        public SearchResourceHistoryRequest(string resourceType, string resourceId, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string continuationToken = null, string sort = null)
-            : this(resourceType, since, before, at, count, continuationToken, sort)
+        public SearchResourceHistoryRequest(string resourceType, string resourceId, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string summary = null, string continuationToken = null, string sort = null)
+            : this(resourceType, since, before, at, count, summary, continuationToken, sort)
         {
             EnsureArg.IsNotNullOrWhiteSpace(resourceType, nameof(resourceType));
             EnsureArg.IsNotNullOrWhiteSpace(resourceId, nameof(resourceId));
@@ -60,6 +61,8 @@ namespace Microsoft.Health.Fhir.Core.Messages.Search
 
         public int? Count { get; }
 
+        public string Summary { get; }
+
         public string ContinuationToken { get; }
 
         public string Sort { get; }

src/Microsoft.Health.Fhir.Shared.Api/Controllers/FhirController.cs

@@ -295,6 +295,7 @@ namespace Microsoft.Health.Fhir.Api.Controllers
                 historyModel.Before,
                 historyModel.At,
                 historyModel.Count,
+                historyModel.Summary,
                 historyModel.ContinuationToken,
                 historyModel.Sort,
                 HttpContext.RequestAborted);
@@ -320,6 +321,7 @@ namespace Microsoft.Health.Fhir.Api.Controllers
                 historyModel.Before,
                 historyModel.At,
                 historyModel.Count,
+                historyModel.Summary,
                 historyModel.ContinuationToken,
                 historyModel.Sort,
                 HttpContext.RequestAborted);
@@ -348,6 +350,7 @@ namespace Microsoft.Health.Fhir.Api.Controllers
                 historyModel.Before,
                 historyModel.At,
                 historyModel.Count,
+                historyModel.Summary,
                 historyModel.ContinuationToken,
                 historyModel.Sort,
                 HttpContext.RequestAborted);

src/Microsoft.Health.Fhir.Shared.Core.UnitTests/Features/Operations/Everything/PatientEverythingServiceTests.cs

@@ -80,6 +80,7 @@ namespace Microsoft.Health.Fhir.Core.UnitTests.Features.Operations.Everything
                 Arg.Any<int?>(),
                 Arg.Any<string>(),
                 Arg.Any<string>(),
+                Arg.Any<string>(),
                 CancellationToken.None,
                 Arg.Any<bool>()).Returns(searchResult);
 

src/Microsoft.Health.Fhir.Shared.Core.UnitTests/Features/Search/SearchResourceHistoryHandlerTests.cs

@@ -45,7 +45,7 @@ namespace Microsoft.Health.Fhir.Core.UnitTests.Features.Search
 
             var searchResult = new SearchResult(Enumerable.Empty<SearchResultEntry>(), null, null, new Tuple<string, string>[0]);
 
-            _searchService.SearchHistoryAsync(request.ResourceType, null, null, null, null, null, null, null, CancellationToken.None).Returns(searchResult);
+            _searchService.SearchHistoryAsync(request.ResourceType, null, null, null, null, null, null, null, null, CancellationToken.None).Returns(searchResult);
 
             var expectedBundle = new Bundle().ToResourceElement();
 

src/Microsoft.Health.Fhir.Shared.Core.UnitTests/Features/Search/SearchServiceTests.cs

@@ -5,13 +5,16 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
 using Hl7.Fhir.Model;
+using Hl7.Fhir.Rest;
 using Hl7.Fhir.Serialization;
 using Microsoft.Health.Fhir.Core.Exceptions;
 using Microsoft.Health.Fhir.Core.Extensions;
+using Microsoft.Health.Fhir.Core.Features;
 using Microsoft.Health.Fhir.Core.Features.Persistence;
 using Microsoft.Health.Fhir.Core.Features.Search;
 using Microsoft.Health.Fhir.Core.Models;
@@ -104,7 +107,7 @@ namespace Microsoft.Health.Fhir.Core.UnitTests.Features.Search
 
             _searchService.SearchImplementation = options => SearchResult.Empty(_unsupportedQueryParameters);
 
-            await Assert.ThrowsAsync<ResourceNotFoundException>(() => _searchService.SearchHistoryAsync(resourceType, resourceId, null, null, null, null, null, null, CancellationToken.None));
+            await Assert.ThrowsAsync<ResourceNotFoundException>(() => _searchService.SearchHistoryAsync(resourceType, resourceId, null, null, null, null, null, null, null, CancellationToken.None));
         }
 
         [Fact]
@@ -121,11 +124,49 @@ namespace Microsoft.Health.Fhir.Core.UnitTests.Features.Search
 
             _fhirDataStore.GetAsync(Arg.Any<ResourceKey>(), Arg.Any<CancellationToken>()).Returns(resourceWrapper);
 
-            SearchResult searchResult = await _searchService.SearchHistoryAsync(resourceType, resourceId, PartialDateTime.Parse("2018"), null, null, null, null, null, CancellationToken.None);
+            SearchResult searchResult = await _searchService.SearchHistoryAsync(resourceType, resourceId, PartialDateTime.Parse("2018"), null, null, null, null, null, null, CancellationToken.None);
 
             Assert.Empty(searchResult.Results);
         }
 
+        [Fact]
+        public async Task GivenAHistorySearch_WhenUsingSummaryCountOrCountZero_ThenSearchOptionsShouldBeProperlyFormed()
+        {
+            var expectedSearchOptions = new SearchOptions();
+
+            _searchOptionsFactory.Create(
+                Arg.Any<string>(),
+                Arg.Is<IReadOnlyList<Tuple<string, string>>>(list => list.Any(item => item.Item1 == KnownQueryParameterNames.Summary && item.Item2 == SummaryType.Count.ToString())),
+                resourceVersionTypes: ResourceVersionType.Latest | ResourceVersionType.History | ResourceVersionType.SoftDeleted).Returns(expectedSearchOptions);
+
+            var expectedSearchResult = SearchResult.Empty(_unsupportedQueryParameters);
+
+            _searchService.SearchImplementation = options =>
+            {
+                Assert.Same(expectedSearchOptions, options);
+
+                return expectedSearchResult;
+            };
+
+            var observation = new Observation { Id = "123" }.ToResourceElement();
+            _fhirDataStore.GetAsync(
+                Arg.Is<ResourceKey>(key => key.ResourceType == observation.InstanceType && key.Id == observation.Id),
+                Arg.Any<CancellationToken>()).Returns(new ResourceWrapper(observation, _rawResourceFactory.Create(observation, keepMeta: true), _resourceRequest, false, null, null, null));
+
+            SearchResult allCountZero = await _searchService.SearchHistoryAsync(null, null, null, null, null, 0, null, null, null, CancellationToken.None);
+            SearchResult allSummaryCount = await _searchService.SearchHistoryAsync(null, null, null, null, null, null, "count", null, null, CancellationToken.None);
+            SearchResult allPatientCountZero = await _searchService.SearchHistoryAsync(observation.InstanceType, null, null, null, null, 0, null, null, null, CancellationToken.None);
+            SearchResult allPatientSummaryCount = await _searchService.SearchHistoryAsync(observation.InstanceType, null, null, null, null, null, "count", null, null, CancellationToken.None);
+            SearchResult singlePatientCountZero = await _searchService.SearchHistoryAsync(observation.InstanceType, observation.Id, null, null, null, 0, null, null, null, CancellationToken.None);
+            SearchResult singlePatientSummaryCount = await _searchService.SearchHistoryAsync(observation.InstanceType, observation.Id, null, null, null, null, "count", null, null, CancellationToken.None);
+            Assert.Same(expectedSearchResult, allCountZero);
+            Assert.Same(expectedSearchResult, allPatientCountZero);
+            Assert.Same(expectedSearchResult, allPatientCountZero);
+            Assert.Same(expectedSearchResult, allPatientSummaryCount);
+            Assert.Same(expectedSearchResult, singlePatientCountZero);
+            Assert.Same(expectedSearchResult, singlePatientSummaryCount);
+        }
+
         [Theory]
         [InlineData(true)]
         [InlineData(false)]

src/Microsoft.Health.Fhir.Shared.Core/Extensions/FhirMediatorExtensions.cs

@@ -114,29 +114,29 @@ namespace Microsoft.Health.Fhir.Core.Extensions
             return result.Bundle;
         }
 
-        public static async Task<ResourceElement> SearchResourceHistoryAsync(this IMediator mediator, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string continuationToken = null, string sort = null, CancellationToken cancellationToken = default)
+        public static async Task<ResourceElement> SearchResourceHistoryAsync(this IMediator mediator, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string summary = null, string continuationToken = null, string sort = null, CancellationToken cancellationToken = default)
         {
             EnsureArg.IsNotNull(mediator, nameof(mediator));
 
-            var result = await mediator.Send(new SearchResourceHistoryRequest(since, before, at, count, continuationToken, sort), cancellationToken);
+            var result = await mediator.Send(new SearchResourceHistoryRequest(since, before, at, count, summary, continuationToken, sort), cancellationToken);
 
             return result.Bundle;
         }
 
-        public static async Task<ResourceElement> SearchResourceHistoryAsync(this IMediator mediator, string resourceType, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string continuationToken = null, string sort = null, CancellationToken cancellationToken = default)
+        public static async Task<ResourceElement> SearchResourceHistoryAsync(this IMediator mediator, string resourceType, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string summary = null, string continuationToken = null, string sort = null, CancellationToken cancellationToken = default)
         {
             EnsureArg.IsNotNull(mediator, nameof(mediator));
 
-            var result = await mediator.Send(new SearchResourceHistoryRequest(resourceType, since, before, at, count, continuationToken, sort), cancellationToken);
+            var result = await mediator.Send(new SearchResourceHistoryRequest(resourceType, since, before, at, count, summary, continuationToken, sort), cancellationToken);
 
             return result.Bundle;
         }
 
-        public static async Task<ResourceElement> SearchResourceHistoryAsync(this IMediator mediator, string resourceType, string resourceId, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string continuationToken = null, string sort = null, CancellationToken cancellationToken = default)
+        public static async Task<ResourceElement> SearchResourceHistoryAsync(this IMediator mediator, string resourceType, string resourceId, PartialDateTime since = null, PartialDateTime before = null, PartialDateTime at = null, int? count = null, string summary = null, string continuationToken = null, string sort = null, CancellationToken cancellationToken = default)
         {
             EnsureArg.IsNotNull(mediator, nameof(mediator));
 
-            var result = await mediator.Send(new SearchResourceHistoryRequest(resourceType, resourceId, since, before, at, count, continuationToken, sort), cancellationToken);
+            var result = await mediator.Send(new SearchResourceHistoryRequest(resourceType, resourceId, since, before, at, count, summary, continuationToken, sort), cancellationToken);
 
             return result.Bundle;
         }

src/Microsoft.Health.Fhir.Shared.Core/Features/Search/SearchResourceHistoryHandler.cs

@@ -51,6 +51,7 @@ namespace Microsoft.Health.Fhir.Core.Features.Search
                 request.Since,
                 request.Before,
                 request.Count,
+                request.Summary,
                 request.ContinuationToken,
                 request.Sort,
                 cancellationToken);

test/Microsoft.Health.Fhir.Shared.Tests.E2E/Rest/HistoryTests.cs

@@ -93,6 +93,49 @@ namespace Microsoft.Health.Fhir.Tests.E2E.Rest
                 userMessage: $"Record 0's latest update ({readResponse[0].Resource.Meta.LastUpdated}) is not greater or equal than Record's 1 latest update ({readResponse[1].Resource.Meta.LastUpdated}).");
         }
 
+        [Fact]
+        [Trait(Traits.Priority, Priority.One)]
+        public async Task GivenTestResourcesWithUpdatesAndDeletes_WhenGettingResourceHistoryCount_TheServerShouldReturnCorrectCount()
+        {
+            // 3 versions, 2 history 1 delete
+            _createdResource.Resource.Effective = new FhirDateTime(DateTimeOffset.UtcNow);
+            await _client.UpdateAsync(_createdResource.Resource);
+            await _client.DeleteAsync(_createdResource.Resource);
+
+            // 3 base exta resources
+            await _client.CreateAsync(Samples.GetDefaultPatient().ToPoco<Patient>());
+            var extraResource2 = await _client.CreateAsync(Samples.GetDefaultPatient().ToPoco<Patient>());
+            var extraResource3 = await _client.CreateAsync(Samples.GetDefaultObservation().ToPoco<Observation>());
+
+            // 3 more versions on the extras
+            extraResource2.Resource.BirthDate = "2022-12-02";
+            await _client.UpdateAsync(extraResource2.Resource);
+            await _client.DeleteAsync(extraResource2.Resource);
+            extraResource3.Resource.Effective = new FhirDateTime(DateTimeOffset.UtcNow);
+            await _client.UpdateAsync(extraResource3.Resource);
+
+            var sinceTime = HttpUtility.UrlEncode(_createdResource.Resource.Meta.LastUpdated.Value.AddMilliseconds(-1).ToString("o"));
+
+            var allSummaryCountResult = await _client.SearchAsync($"/_history?_since={sinceTime}&_summary=count");
+            var allSummaryCountZero = await _client.SearchAsync($"/_history?_since={sinceTime}&_count=0");
+            var allObservationSummaryCountResult = await _client.SearchAsync($"/Observation/_history?_since={sinceTime}&_summary=count");
+            var allObservationSummaryCountZero = await _client.SearchAsync($"/Observation/_history?_since={sinceTime}&_count=0");
+            var observationSummaryCountResult = await _client.SearchAsync($"/Observation/{_createdResource.Resource.Id}/_history?_since={sinceTime}&_summary=count");
+            var observationSummaryCountZero = await _client.SearchAsync($"/Observation/{_createdResource.Resource.Id}/_history?_since={sinceTime}&_count=0");
+
+            // 9 versions total for all resources.
+            Assert.Equal(9, allSummaryCountResult.Resource.Total);
+            Assert.Equal(9, allSummaryCountZero.Resource.Total);
+
+            // 5 versions across only observations (first one create, update, delete - second create, update).
+            Assert.Equal(5, allObservationSummaryCountResult.Resource.Total);
+            Assert.Equal(5, allObservationSummaryCountZero.Resource.Total);
+
+            // 3 versions across single observation (create, update, delete).
+            Assert.Equal(3, observationSummaryCountResult.Resource.Total);
+            Assert.Equal(3, observationSummaryCountZero.Resource.Total);
+        }
+
         [Fact]
         [Trait(Traits.Priority, Priority.One)]
         public async Task GivenATypeAndId_WhenGettingResourceHistoryWithAlternateSort_TheServerShouldReturnTheAppropriateBundleSuccessfully()