Aggregate facets_stats (#522)

* Aggregate facets_stats

* Change loop index. facets_stats starts from 0, disjunctiveFacets starts from 1.

* Remove duplicated code

* Fix bug: when i == 0, result["facets"] is nil, so only do this when i >= 1

* After rebase: put back unit test for facet_stats

* Fix memory leak

* Reverse 965204c

* Fix memory leak (this time it works)

* Fix UT

Author: XiaowenVC

Sources/AlgoliaSearch-Client/AbstractClient.swift

@@ -270,6 +270,10 @@ internal struct HostStatus {
         // WARNING: `didSet` not called during initialization => we need to update the headers manually here.
         updateHeadersFromAPIKey()
     }
+    
+    deinit {
+        session.finishTasksAndInvalidate()
+    }
 
     /// Set read and write hosts to the same value (convenience method).
     ///

Sources/AlgoliaSearch-Client/Helpers/DisjunctiveFaceting.swift

@@ -96,8 +96,22 @@ internal class DisjunctiveFaceting {
         }
         // Following answers are just used for their facet counts.
         var disjunctiveFacetCounts = [String: Any]()
-        for i in 1..<results.count { // for each answer (= each disjunctive facet)
-            guard let result = results[i] as? [String: Any], let allFacetCounts = result["facets"] as? [String: [String: Any]] else {
+        var facetsStats = [String: Any]()
+        for i in 0..<results.count { // for each answer (= each disjunctive facet)
+            guard let result = results[i] as? [String: Any] else {
+                throw InvalidJSONError(description:  "Invalid results in response")
+            }
+            // Facets stats, starts from element 0
+            if let allStats = result["facets_stats"] as? [String: [String: Any]] {
+                for (facetName, stats) in allStats {
+                    facetsStats[facetName] = stats
+                }
+            }
+            // Disjunctive facet should start from element 1
+            if i <= 0 {
+                continue
+            }
+            guard let allFacetCounts = result["facets"] as? [String: [String: Any]] else {
                 throw InvalidJSONError(description:  "Invalid results in response")
             }
             // NOTE: Iterating, but there should be just one item.
@@ -125,6 +139,7 @@ internal class DisjunctiveFaceting {
             }
         }
         mainContent["disjunctiveFacets"] = disjunctiveFacetCounts
+        mainContent["facets_stats"] = facetsStats
         return mainContent
     }
 

Sources/AlgoliaSearch-Client/Network.swift

@@ -35,6 +35,7 @@ internal enum HTTPMethod: String {
 /// Only for the sake of unit tests.
 internal protocol URLSession {
     func dataTask(with request: URLRequest, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Void) -> URLSessionDataTask
+    func finishTasksAndInvalidate()
 }
 
 // Convince the compiler that NSURLSession does implements our custom protocol.
@@ -131,6 +132,10 @@ internal class URLSessionLogger: NSObject, URLSession {
         return task
     }
 
+    func finishTasksAndInvalidate() {
+        session.finishTasksAndInvalidate()
+    }
+    
     override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
         if let task = object as? URLSessionTask {
             if keyPath == "state" {

Tests/Helpers/MockURLSession.swift

@@ -74,6 +74,7 @@ public struct MockResponse {
 /// A replacement for `NSURLSession` used for mocking network requests.
 ///
 public class MockURLSession: AlgoliaSearch.URLSession {
+    
     /// Predefined set of responses for the specified URLs.
     public var responses: [String: MockResponse] = [String: MockResponse]()
 
@@ -88,6 +89,10 @@ public class MockURLSession: AlgoliaSearch.URLSession {
         task.cancellable = self.cancellable
         return task
     }
+    
+    public func finishTasksAndInvalidate() {
+        // do nothing
+    }
 }
 
 /// A mock replacement for `NSURLSessionDataTask`.

Tests/Integration Tests/IndexTests.swift

@@ -868,6 +868,10 @@ class IndexTests: OnlineTestCase {
       XCTAssertEqual(brandFacetCounts!["Apple"] as? Int, 2)
       XCTAssertEqual(brandFacetCounts!["Samsung"] as? Int, 1)
       XCTAssertEqual(brandFacetCounts!["Whatever"] as? Int, 1)
+      let facetsStats = content["facets_stats"] as? [String: [String: Any]]
+      let starStats = facetsStats!["stars"]
+      XCTAssertEqual(starStats!["max"] as? Int, 5)
+      XCTAssertEqual(starStats!["min"] as? Int, 4)
     }
 
     self.waitForExpectations(timeout: expectationTimeout, handler: nil)