fix mailhandler: decrease number of fetched mails on first fetch

enzevalos_iphone/MailHandler.swift

@@ -395,7 +395,7 @@
     }
     
     private func loadMessagesFromServer(_ uids: MCOIndexSet, folderPath: String, maxLoad: Int = MailHandler.MAXMAILS, completionCallback: @escaping ((_ error: MailServerConnectionError?) -> ())) {
-        guard IMAPSession != nil else {
+        guard let session = IMAPSession else {
             completionCallback(MailServerConnectionError.NoData)
             return
         }
@@ -405,7 +405,7 @@
         }
         // First fetch -> get flags
         let requestKind = MCOIMAPMessagesRequestKind(rawValue: MCOIMAPMessagesRequestKind.headers.rawValue | MCOIMAPMessagesRequestKind.flags.rawValue)
-        let fetchOperation: MCOIMAPFetchMessagesOperation = self.IMAPSession!.fetchMessagesOperation(withFolder: folderPath, requestKind: requestKind, uids: uids)
+        let fetchOperation: MCOIMAPFetchMessagesOperation = session.fetchMessagesOperation(withFolder: folderPath, requestKind: requestKind, uids: uids)
         fetchOperation.extraHeaders = MailHandler.extraHeaders
         
         fetchOperation.start{[unowned self] (err, msg, vanished) -> Void in
@@ -566,27 +566,44 @@
     }
     
     private func initFolder(folderPath: String, completionCallback: @escaping ((MailServerConnectionError?) -> ())) {
-        let requestKind = MCOIMAPMessagesRequestKind(rawValue: MCOIMAPMessagesRequestKind.headers.rawValue)
-        let uids = MCOIndexSet(range: MCORangeMake(1, UINT64_MAX))
-        let toFetchIDs = MCOIndexSet()
-        
-        let fetchOperation: MCOIMAPFetchMessagesOperation = self.IMAPSession!.fetchMessagesOperation(withFolder: folderPath, requestKind: requestKind, uids: uids)
-        fetchOperation.start {[unowned self] (err, msg, vanished) -> Void in
-            guard err == nil else {
-                let conerror = MailServerConnectionError.findErrorCode(error: err!)
+        guard let session = IMAPSession else {
+            self.errorhandling(error: .ConnectionError, originalCall: {self.initFolder(folderPath: folderPath, completionCallback: completionCallback)}, completionCallback: completionCallback)
+            return
+        }
+        session.folderStatusOperation(folderPath)?.start({error, status in
+            if let error = error {
+                let conerror = MailServerConnectionError.findErrorCode(error: error)
                 self.errorhandling(error: conerror, originalCall: {self.initFolder(folderPath: folderPath, completionCallback: completionCallback)}, completionCallback: completionCallback)
                 return
             }
-            if let msgs = msg {
-                FolderRecord.lastDate(folder: folderPath, date: Date())
-                for message in msgs {
-                    toFetchIDs.add(UInt64(message.uid))
-                }
-                self.loadMessagesFromServer(toFetchIDs, folderPath: folderPath, maxLoad: 50, completionCallback: completionCallback)
-            } else {
+            guard let status = status else {
                 completionCallback(nil)
+                return
             }
-        }
+        
+            let requestKind = MCOIMAPMessagesRequestKind(rawValue: MCOIMAPMessagesRequestKind.headers.rawValue)
+            let min =  max(status.uidNext - 1000, 1)
+            let uids = MCOIndexSet(range: MCORangeMake(UInt64(min), UInt64(status.uidNext)))
+            let toFetchIDs = MCOIndexSet()
+            
+            let fetchOperation: MCOIMAPFetchMessagesOperation = session.fetchMessagesOperation(withFolder: folderPath, requestKind: requestKind, uids: uids)
+            fetchOperation.start {[unowned self] (err, msg, vanished) -> Void in
+                guard err == nil else {
+                    let conerror = MailServerConnectionError.findErrorCode(error: err!)
+                    self.errorhandling(error: conerror, originalCall: {self.initFolder(folderPath: folderPath, completionCallback: completionCallback)}, completionCallback: completionCallback)
+                    return
+                }
+                if let msgs = msg {
+                    FolderRecord.lastDate(folder: folderPath, date: Date())
+                    for message in msgs {
+                        toFetchIDs.add(UInt64(message.uid))
+                    }
+                    self.loadMessagesFromServer(toFetchIDs, folderPath: folderPath, maxLoad: 50, completionCallback: completionCallback)
+                } else {
+                    completionCallback(nil)
+                }
+            }
+        })
     }
     
     private func initInbox(completionCallback: @escaping ((MailServerConnectionError?) -> ())) {