From 44bea185699711ca01713e860df9eeea1f8c1d23 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adrien=20Coye=20de=20Brune=CC=81lis?=
 <adrien.coye@infomaniak.com>
Date: Wed, 30 Aug 2023 18:01:07 +0200
Subject: [PATCH 1/3] feat(ContactManager): reduce getRealm call count.
 feat(ContactManager): refresh realm on getRealm() to match the app.

---
 MailCore/Cache/ContactManager/ContactManager+DB.swift    | 4 +++-
 MailCore/Cache/ContactManager/ContactManager+Merge.swift | 8 +++++---
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/MailCore/Cache/ContactManager/ContactManager+DB.swift b/MailCore/Cache/ContactManager/ContactManager+DB.swift
index 7ac9e453a..b55ab6225 100644
--- a/MailCore/Cache/ContactManager/ContactManager+DB.swift
+++ b/MailCore/Cache/ContactManager/ContactManager+DB.swift
@@ -22,7 +22,9 @@ import RealmSwift
 public extension ContactManager {
     func getRealm() -> Realm {
         do {
-            return try Realm(configuration: realmConfiguration)
+            let realm = Realm(configuration: realmConfiguration)
+            realm.refresh()
+            return try
         } catch {
             // We can't recover from this error but at least we report it correctly on Sentry
             Logging.reportRealmOpeningError(error, realmConfiguration: realmConfiguration)
diff --git a/MailCore/Cache/ContactManager/ContactManager+Merge.swift b/MailCore/Cache/ContactManager/ContactManager+Merge.swift
index 23c7a51a3..30bdb56f5 100644
--- a/MailCore/Cache/ContactManager/ContactManager+Merge.swift
+++ b/MailCore/Cache/ContactManager/ContactManager+Merge.swift
@@ -62,6 +62,7 @@ extension ContactManager {
 
     // Insert Contacts indexed by email in base without check
     private func insertContactsInDB(_ input: [String: InfomaniakContact]) {
+        let realm = getRealm()
         for (email, contact) in input {
             guard !Task.isCancelled else {
                 break
@@ -72,7 +73,6 @@ extension ContactManager {
                 return
             }
 
-            let realm = getRealm()
             try? realm.safeWrite {
                 realm.add(mergedContact, update: .modified)
             }
@@ -90,7 +90,10 @@ extension ContactManager {
                 stop.pointee = true
                 return
             }
-            
+
+            // Realm to use for this contact
+            let realm = self.getRealm()
+
             // For each email of a specific contact
             for cnEmail in localContact.emailAddresses {
                 let email = String(cnEmail.value)
@@ -107,7 +110,6 @@ extension ContactManager {
                 output.removeValue(forKey: email)
 
                 // Store result
-                let realm = self.getRealm()
                 try? realm.safeWrite {
                     realm.add(mergedContact, update: .modified)
                 }

From 0709e7171c968c7de934c1cb6efe490b6f5fc42c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adrien=20Coye=20de=20Brune=CC=81lis?=
 <adrien.coye@infomaniak.com>
Date: Wed, 30 Aug 2023 18:05:15 +0200
Subject: [PATCH 2/3] chore: cleanup useless code

---
 .../Cache/ContactManager/ContactManager+Merge.swift   | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/MailCore/Cache/ContactManager/ContactManager+Merge.swift b/MailCore/Cache/ContactManager/ContactManager+Merge.swift
index 30bdb56f5..885e796f2 100644
--- a/MailCore/Cache/ContactManager/ContactManager+Merge.swift
+++ b/MailCore/Cache/ContactManager/ContactManager+Merge.swift
@@ -33,17 +33,6 @@ extension CNContact {
 
 extension ContactManager {
     func merge(localInto remote: [InfomaniakContact]) async {
-        // Refresh Realm, and trigger redraws, only if app is in foreground.
-        defer {
-            Task { @MainActor in
-                let state = UIApplication.shared.applicationState
-                if state == .active {
-                    DDLogInfo("Done merging remote and local contacts, refreshing DB…")
-                    getRealm().refresh()
-                }
-            }
-        }
-
         // index remote account per email
         var remoteContactsByEmail = [String: InfomaniakContact]()
         for contact in remote {

From cc148206bc01782ffcdb36ff4658990a4a8c3961 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adrien=20Coye=20de=20Brune=CC=81lis?=
 <adrien.coye@infomaniak.com>
Date: Thu, 31 Aug 2023 10:43:15 +0200
Subject: [PATCH 3/3] fix(ContactManager): Remove contacts from DB when does
 not exist in iphone or infomaniak

---
 .../ContactManager/ContactManager+DB.swift    |   9 +-
 .../ContactManager/ContactManager+Merge.swift | 192 ++++++++++++------
 .../Cache/ContactManager/ContactManager.swift |   4 +-
 MailCore/Models/MergedContact.swift           |   2 +-
 4 files changed, 135 insertions(+), 72 deletions(-)

diff --git a/MailCore/Cache/ContactManager/ContactManager+DB.swift b/MailCore/Cache/ContactManager/ContactManager+DB.swift
index b55ab6225..2d6744dcf 100644
--- a/MailCore/Cache/ContactManager/ContactManager+DB.swift
+++ b/MailCore/Cache/ContactManager/ContactManager+DB.swift
@@ -22,9 +22,9 @@ import RealmSwift
 public extension ContactManager {
     func getRealm() -> Realm {
         do {
-            let realm = Realm(configuration: realmConfiguration)
+            let realm = try Realm(configuration: realmConfiguration)
             realm.refresh()
-            return try
+            return realm
         } catch {
             // We can't recover from this error but at least we report it correctly on Sentry
             Logging.reportRealmOpeningError(error, realmConfiguration: realmConfiguration)
@@ -54,7 +54,7 @@ public extension ContactManager {
         // Iterate a given number of times to emulate a `LIMIT` statement.
         var iterator = lazyResults.makeIterator()
         var results = [MergedContact]()
-        for _ in 0..<fetchLimit {
+        for _ in 0 ..< fetchLimit {
             guard let next = iterator.next() else {
                 break
             }
@@ -87,8 +87,7 @@ public extension ContactManager {
 
         guard let newContact = contacts.first(where: { $0.id == String(contactId) }) else { throw MailError.contactNotFound }
 
-        let email = recipient.email
-        guard let mergedContact = MergedContact(email: email, local: nil, remote: newContact) else { return }
+        let mergedContact = MergedContact(email: recipient.email, local: nil, remote: newContact)
 
         let realm = getRealm()
         try? realm.safeWrite {
diff --git a/MailCore/Cache/ContactManager/ContactManager+Merge.swift b/MailCore/Cache/ContactManager/ContactManager+Merge.swift
index 885e796f2..2e7896dfe 100644
--- a/MailCore/Cache/ContactManager/ContactManager+Merge.swift
+++ b/MailCore/Cache/ContactManager/ContactManager+Merge.swift
@@ -32,7 +32,66 @@ extension CNContact {
 }
 
 extension ContactManager {
-    func merge(localInto remote: [InfomaniakContact]) async {
+    // MARK: - Public
+
+    /// Making sure only one update task is running or return
+    ///
+    /// This will merge Infomaniak contacts with local iPhone ones in a coherent DB.
+    /// Removed contacts from both datasets will be cleaned also.
+    public func uniqueUpdateContactDBTask(_ apiFetcher: MailApiFetcher) async {
+        // We do not run an update of contacts in extension mode as we are too resource constrained
+        guard !Bundle.main.isExtension else {
+            DDLogInfo("Skip updating contacts, we are in extension mode")
+            return
+        }
+
+        // Unique task running
+        guard currentMergeRequest == nil else {
+            DDLogInfo("UpdateContactDB is running, exiting …")
+            return
+        }
+
+        DDLogInfo("Will start updating contacts in DB")
+
+        // Track background refresh of contacts, and cancel task is system asks to.
+        let backgroundTaskTracker = await ApplicationBackgroundTaskTracker(identifier: #function + UUID().uuidString) {
+            self.currentMergeRequest?.cancel()
+        }
+
+        let updateTask = Task {
+            // Fetch remote contacts
+            let remoteContacts: [InfomaniakContact]
+            if let remote = try? await apiFetcher.contacts() {
+                remoteContacts = remote
+            } else {
+                remoteContacts = []
+            }
+
+            // Update DB with them
+            await updateContactDB(remoteContacts)
+        }
+        currentMergeRequest = updateTask
+
+        // Await for completion
+        await updateTask.finish()
+
+        // Making sure to terminate BG work tracker
+        await backgroundTaskTracker.end()
+
+        // cleanup
+        currentMergeRequest = nil
+    }
+
+    /// This reprensets the complete process of maintaining a coherent DB of contacts in realm
+    ///
+    /// This will merge InfomaniakContact with local iPhone ones in a coherent DB.
+    /// Removed contacts from both datasets will be cleaned also
+    /// - Parameter remote: a list of remote infomaniak contacts
+    internal func updateContactDB(_ remote: [InfomaniakContact]) async {
+        defer {
+            DDLogInfo("Done merging remote and local contacts in DB…")
+        }
+
         // index remote account per email
         var remoteContactsByEmail = [String: InfomaniakContact]()
         for contact in remote {
@@ -42,6 +101,9 @@ extension ContactManager {
             }
         }
 
+        // Clean contacts no longer present is remote or local iPhone contacts
+        removeDeletedContactsFromLocal(andRemote: remoteContactsByEmail)
+
         // Insert all the local contacts, while merging them with the remote version
         let remainingContacts = await insertLocalContactsInDBMerging(remote: remoteContactsByEmail)
 
@@ -49,21 +111,54 @@ extension ContactManager {
         insertContactsInDB(remainingContacts)
     }
 
-    // Insert Contacts indexed by email in base without check
-    private func insertContactsInDB(_ input: [String: InfomaniakContact]) {
-        let realm = getRealm()
-        for (email, contact) in input {
+    // MARK: - Private
+
+    /// Clean contacts no longer present is remote ik or local iPhone contacts
+    private func removeDeletedContactsFromLocal(andRemote remote: [String: InfomaniakContact]) {
+        var toDelete = [String]()
+
+        // enumerate realm contacts
+        let lazyContacts = getRealm()
+            .objects(MergedContact.self)
+
+        var contactIterator = lazyContacts.makeIterator()
+        while let mergedContact = contactIterator.next() {
             guard !Task.isCancelled else {
-                break
+                return
             }
 
-            // insert reminder of remote contacts
-            guard let mergedContact = MergedContact(email: email, local: nil, remote: contact) else {
-                return
+            let email = mergedContact.email
+
+            let remote = remote[email]
+            let local: CNContact?
+            if let localContactId = mergedContact.localIdentifier {
+                local = try? localContactsHelper.getContact(with: localContactId)
+            } else {
+                local = nil
             }
 
-            try? realm.safeWrite {
-                realm.add(mergedContact, update: .modified)
+            // If contact not in iPhone nor in remote infomaniak, then should be deleted
+            if remote == nil && local == nil {
+                toDelete.append(email)
+            }
+        }
+
+        guard !Task.isCancelled else {
+            return
+        }
+
+        // remove old contacts
+        guard !toDelete.isEmpty else {
+            return
+        }
+
+        let cleanupRealm = getRealm()
+        try? cleanupRealm.safeWrite {
+            for emailToDelete in toDelete {
+                guard let objectToDelete = cleanupRealm.object(ofType: MergedContact.self, forPrimaryKey: emailToDelete) else {
+                    continue
+                }
+                cleanupRealm.delete(objectToDelete)
             }
         }
     }
@@ -75,31 +170,28 @@ extension ContactManager {
         var output = input
 
         await localContactsHelper.enumerateContacts { localContact, stop in
-            if Task.isCancelled {
+            guard !Task.isCancelled else {
                 stop.pointee = true
                 return
             }
 
-            // Realm to use for this contact
+            // Realm to use for this contact. Do not call it outside this block, or it may crash.
             let realm = self.getRealm()
+            try? realm.safeWrite {
+                // For each email of a specific contact
+                for cnEmail in localContact.emailAddresses {
+                    let email = String(cnEmail.value)
 
-            // For each email of a specific contact
-            for cnEmail in localContact.emailAddresses {
-                let email = String(cnEmail.value)
-
-                // lookup matching remote contact for current email
-                let remoteContact = input[email]
+                    // lookup matching remote contact for current email
+                    let remoteContact = input[email]
 
-                // Create DB object
-                guard let mergedContact = MergedContact(email: email, local: localContact, remote: remoteContact) else {
-                    return
-                }
+                    // Create DB object
+                    let mergedContact = MergedContact(email: email, local: localContact, remote: remoteContact)
 
-                // Remove email from lookup table
-                output.removeValue(forKey: email)
+                    // Remove email from lookup table
+                    output.removeValue(forKey: email)
 
-                // Store result
-                try? realm.safeWrite {
+                    // Store result
                     realm.add(mergedContact, update: .modified)
                 }
             }
@@ -108,48 +200,20 @@ extension ContactManager {
         return output
     }
 
-    /// Making sure only one update task is running or return
-    func uniqueMergeLocalTask(_ apiFetcher: MailApiFetcher) async {
-        // We do not run an update of contacts in extension mode as we are too resource constrained
-        guard !Bundle.main.isExtension else {
-            DDLogInfo("Skip updating contacts, we are in extension mode")
-            return
-        }
-
-        // Unique task running
-        guard currentMergeRequest == nil else {
-            DDLogInfo("Merging contacts running exiting …")
+    // Insert Contacts indexed by email in base without check
+    private func insertContactsInDB(_ input: [String: InfomaniakContact]) {
+        guard !Task.isCancelled else {
             return
         }
 
-        DDLogInfo("Will start merging contacts cancelling previous task : \(currentMergeRequest != nil)")
-
-        // Track background refresh of contacts, and cancel task is system asks to.
-        let backgroundTaskTracker = await ApplicationBackgroundTaskTracker(identifier: #function + UUID().uuidString) {
-            self.currentMergeRequest?.cancel()
-        }
+        let realm = getRealm()
+        try? realm.safeWrite {
+            for (email, contact) in input {
+                // insert reminder of remote contacts
+                let mergedContact = MergedContact(email: email, local: nil, remote: contact)
 
-        let updateTask = Task {
-            // Fetch remote contacts
-            let remoteContacts: [InfomaniakContact]
-            if let remote = try? await apiFetcher.contacts() {
-                remoteContacts = remote
-            } else {
-                remoteContacts = []
+                realm.add(mergedContact, update: .modified)
             }
-
-            // Merge them
-            await merge(localInto: remoteContacts)
         }
-        currentMergeRequest = updateTask
-
-        // Await for completion
-        await updateTask.finish()
-
-        // Making sure to terminate BG work tracker
-        await backgroundTaskTracker.end()
-
-        // cleanup
-        currentMergeRequest = nil
     }
 }
diff --git a/MailCore/Cache/ContactManager/ContactManager.swift b/MailCore/Cache/ContactManager/ContactManager.swift
index 7cd9feb1d..55bc0927c 100644
--- a/MailCore/Cache/ContactManager/ContactManager.swift
+++ b/MailCore/Cache/ContactManager/ContactManager.swift
@@ -102,10 +102,10 @@ public final class ContactManager: ObservableObject {
             await backgroundTaskTracker.end()
 
             // Process Contacts
-            await uniqueMergeLocalTask(apiFetcher)
+            await uniqueUpdateContactDBTask(apiFetcher)
         } catch {
             // Process Contacts anyway
-            await uniqueMergeLocalTask(apiFetcher)
+            await uniqueUpdateContactDBTask(apiFetcher)
 
             throw error
         }
diff --git a/MailCore/Models/MergedContact.swift b/MailCore/Models/MergedContact.swift
index 0335cd7c4..5418e664c 100644
--- a/MailCore/Models/MergedContact.swift
+++ b/MailCore/Models/MergedContact.swift
@@ -112,7 +112,7 @@ public final class MergedContact: Object, Identifiable {
     override public init() { /* Realm needs an empty constructor */ }
 
     /// Init with what you have, it will generate the most usable contact possible
-    public init?(email: String, local: CNContact?, remote: InfomaniakContact?) {
+    public init(email: String, local: CNContact?, remote: InfomaniakContact?) {
         super.init()
 
         self.email = email