QML UI: when switching from no cloud to cloud usage, don't drop local data

This is rather simplistic, it just imports the local data into the remote
repository and therefore loses the git history of the local data - but I
wasn't able to make the git merge without shared base commit work, so I
went this much easier to implement route instead.

One thing we need to be careful about is that contacting the remote server
could fail. If we don't manage to merge the dives from cloud server and
local storage, we need to revery to no cloud status in order not to lose
the local data.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

mobile-widgets/qmlmanager.cpp

@@ -20,6 +20,7 @@
 #include "core/git-access.h"
 #include "core/cloudstorage.h"
 #include "core/subsurface-qt/SettingsObjectWrapper.h"
+#include "core/membuffer.h"
 
 QMLManager *QMLManager::m_instance = NULL;
 
@@ -154,6 +155,11 @@ void QMLManager::openLocalThenRemote(QString url)
 		DiveListModel::instance()->addAllDives();
 		appendTextToLog(QStringLiteral("%1 dives loaded from cache").arg(dive_table.nr));
 	}
+	if (oldStatus() == NOCLOUD) {
+		// if we switch to credentials from NOCLOUD, we take things online temporarily
+		prefs.git_local_only = false;
+		appendTextToLog(QStringLiteral("taking things online to be able to switch to cloud account"));
+	}
 	set_filename(fileNamePrt.data(), true);
 	if (prefs.git_local_only) {
 		appendTextToLog(QStringLiteral("have cloud credentials, but user asked not to connect to network"));
@@ -164,6 +170,13 @@ void QMLManager::openLocalThenRemote(QString url)
 	}
 }
 
+void QMLManager::mergeLocalRepo()
+{
+	char *filename = format_string("%s/cloudstorage/localrepo[master]", system_default_directory());
+	parse_file(filename);
+	process_dives(true, false);
+}
+
 void QMLManager::finishSetup()
 {
 	// Initialize cloud credentials.
@@ -346,8 +359,7 @@ void QMLManager::retrieveUserid()
 	if (reply->attribute(QNetworkRequest::HttpStatusCodeAttribute) != 302) {
 		appendTextToLog(QStringLiteral("Cloud storage connection not working correctly: %1").arg(QString(reply->readAll())));
 		setStartPageText(RED_FONT + tr("Cannot connect to cloud storage") + END_FONT);
-		setAccessingCloud(-1);
+		revertToNoCloudIfNeeded();
-		alreadySaving = false;
 		return;
 	}
 	setCredentialStatus(VALID);
@@ -355,8 +367,7 @@ void QMLManager::retrieveUserid()
 	if (userid.isEmpty()) {
 		if (same_string(prefs.cloud_storage_email, "") || same_string(prefs.cloud_storage_password, "")) {
 			appendTextToLog("cloud user name or password are empty, can't retrieve web user id");
-			setAccessingCloud(-1);
+			revertToNoCloudIfNeeded();
-			alreadySaving = false;
 			return;
 		}
 		appendTextToLog(QStringLiteral("calling getUserid with user %1").arg(prefs.cloud_storage_email));
@@ -385,12 +396,12 @@ void QMLManager::loadDiveProgress(int percent)
 void QMLManager::loadDivesWithValidCredentials()
 {
 	QString url;
+	timestamp_t currentDiveTimestamp = selectedDiveTimestamp();
 	if (getCloudURL(url)) {
 		QString errorString(get_error_string());
 		appendTextToLog(errorString);
 		setStartPageText(RED_FONT + tr("Cloud storage error: %1").arg(errorString) + END_FONT);
-		setAccessingCloud(-1);
+		revertToNoCloudIfNeeded();
-		alreadySaving = false;
 		return;
 	}
 	QByteArray fileNamePrt = QFile::encodeName(url);
@@ -400,13 +411,9 @@ void QMLManager::loadDivesWithValidCredentials()
 	if (check_git_sha(fileNamePrt.data(), &git, &branch) == 0) {
 		qDebug() << "local cache was current, no need to modify dive list";
 		appendTextToLog("Cloud sync shows local cache was current");
-		setLoadFromCloud(true);
+		goto successful_exit;
-		setAccessingCloud(-1);
-		alreadySaving = false;
-		return;
 	}
 	appendTextToLog("Cloud sync brought newer data, reloading the dive list");
-	timestamp_t currentDiveTimestamp = selectedDiveTimestamp();
 
 	clear_dive_file_data();
 	if (git != dummy_git_repository) {
@@ -426,12 +433,56 @@ void QMLManager::loadDivesWithValidCredentials()
 		report_error("failed to open file %s", fileNamePrt.data());
 		QString errorString(get_error_string());
 		appendTextToLog(errorString);
-		setStartPageText(RED_FONT + tr("Cloud storage error: %1").arg(errorString) + END_FONT);
+		revertToNoCloudIfNeeded();
-		alreadySaving = false;
 		return;
 	}
 	consumeFinishedLoad(currentDiveTimestamp);
+
+successful_exit:
+	alreadySaving = false;
 	setLoadFromCloud(true);
+	// if we came from local storage mode, let's merge the local data into the local cache
+	// for the remote data - which then later gets merged with the remote data if necessary
+	if (oldStatus() == NOCLOUD) {
+		git_storage_update_progress(false, "import dives from nocloud local storage");
+		dive_table.preexisting = dive_table.nr;
+		mergeLocalRepo();
+		DiveListModel::instance()->clear();
+		DiveListModel::instance()->addAllDives();
+		appendTextToLog(QStringLiteral("%1 dives loaded after importing nocloud local storage").arg(dive_table.nr));
+		saveChangesLocal();
+		if (syncToCloud() == false) {
+			appendTextToLog(QStringLiteral("taking things back offline now that storage is synced"));
+			prefs.git_local_only = syncToCloud();
+		}
+	}
+	setAccessingCloud(-1);
+	return;
+}
+
+void QMLManager::revertToNoCloudIfNeeded()
+{
+	if (oldStatus() == NOCLOUD) {
+		// we tried to switch to a cloud account and had previously used local data,
+		// but connecting to the cloud account (and subsequently merging the local
+		// and cloud data) failed - so let's delete the cloud credentials and go
+		// back to NOCLOUD mode in order to prevent us from losing the locally stored
+		// dives
+		if (syncToCloud() == false) {
+			appendTextToLog(QStringLiteral("taking things back offline since sync with cloud failed"));
+			prefs.git_local_only = syncToCloud();
+		}
+		free(prefs.cloud_storage_email);
+		prefs.cloud_storage_email = NULL;
+		free(prefs.cloud_storage_password);
+		prefs.cloud_storage_password = NULL;
+		setCloudUserName("");
+		setCloudPassword("");
+		setCredentialStatus(INCOMPLETE);
+		setStartPageText(RED_FONT + tr("Failed to connect to cloud server, reverting to no cloud status") + END_FONT);
+	}
+	setAccessingCloud(-1);
+	alreadySaving = false;
 }
 
 void QMLManager::consumeFinishedLoad(timestamp_t currentDiveTimestamp)
@@ -1156,6 +1207,8 @@ QMLManager::credentialStatus_t QMLManager::credentialStatus() const
 void QMLManager::setCredentialStatus(const credentialStatus_t value)
 {
 	if (m_credentialStatus != value) {
+		if (value == NOCLOUD)
+			appendTextToLog("Switching to no cloud mode");
 		m_credentialStatus = value;
 		emit credentialStatusChanged();
 	}

mobile-widgets/qmlmanager.h

@@ -128,11 +128,13 @@ public slots:
 	void clearGpsData();
 	void finishSetup();
 	void openLocalThenRemote(QString url);
+	void mergeLocalRepo();
 	QString getNumber(const QString& diveId);
 	QString getDate(const QString& diveId);
 	QString getCurrentPosition();
 	QString getVersion() const;
 	void deleteGpsFix(quint64 when);
+	void revertToNoCloudIfNeeded();
 	void consumeFinishedLoad(timestamp_t currentDiveTimestamp);
 	void refreshDiveList();
 	void screenChanged(QScreen *screen);