// Setup an empty localStorage or upgrade an existing one
define([
	"underscore"
], function(_) {
	
	// Create the file system if not exist
	if (localStorage["file.list"] === undefined) {
		localStorage["file.list"] = ";";
	}
	var fileIndexList = _.compact(localStorage["file.list"].split(";"));
	
	// localStorage versioning
	var version = localStorage["version"];
	
	// Upgrade from v0 to v1
	if(version === undefined) {
		
		// Not used anymore
		localStorage.removeItem("sync.queue");
		localStorage.removeItem("sync.current");
		localStorage.removeItem("file.counter");			
		
		_.each(fileIndexList, function(fileIndex) {
			localStorage[fileIndex + ".publish"] = ";";
			var syncIndexList = _.compact(localStorage[fileIndex + ".sync"].split(";"));
			_.each(syncIndexList, function(syncIndex) {
				localStorage[syncIndex + ".contentCRC"] = "0";
				// We store title CRC only for Google Drive synchronization
				if(localStorage[syncIndex + ".etag"] !== undefined) {
					localStorage[syncIndex + ".titleCRC"] = "0";
				}
			});
		});
		version = "v1";
	}
	
	// Upgrade from v1 to v2
	if(version == "v1") {
		var gdriveLastChangeId = localStorage["sync.gdrive.lastChangeId"];
		if(gdriveLastChangeId) {
			localStorage["gdrive.lastChangeId"] = gdriveLastChangeId;
			localStorage.removeItem("sync.gdrive.lastChangeId");
		}
		var dropboxLastChangeId = localStorage["sync.dropbox.lastChangeId"];
		if(dropboxLastChangeId) {
			localStorage["dropbox.lastChangeId"] = dropboxLastChangeId;
			localStorage.removeItem("sync.dropbox.lastChangeId");
		}
		
		var PROVIDER_GDRIVE = "gdrive";
		var PROVIDER_DROPBOX = "dropbox";
		var SYNC_PROVIDER_GDRIVE = "sync." + PROVIDER_GDRIVE + ".";
		var SYNC_PROVIDER_DROPBOX = "sync." + PROVIDER_DROPBOX + ".";
		_.each(fileIndexList, function(fileIndex) {
			var syncIndexList = _.compact(localStorage[fileIndex + ".sync"].split(";"));
			_.each(syncIndexList, function(syncIndex) {
				var syncAttributes = {};
				if (syncIndex.indexOf(SYNC_PROVIDER_GDRIVE) === 0) {
					syncAttributes.provider = PROVIDER_GDRIVE;
					syncAttributes.id = syncIndex.substring(SYNC_PROVIDER_GDRIVE.length);
					syncAttributes.etag = localStorage[syncIndex + ".etag"];
					syncAttributes.contentCRC = localStorage[syncIndex + ".contentCRC"];
					syncAttributes.titleCRC = localStorage[syncIndex + ".titleCRC"];
				}
				else if (syncIndex.indexOf(SYNC_PROVIDER_DROPBOX) === 0) {
					syncAttributes.provider = PROVIDER_DROPBOX;
					syncAttributes.path = decodeURIComponent(syncIndex.substring(SYNC_PROVIDER_DROPBOX.length));
					syncAttributes.version = localStorage[syncIndex + ".version"];
					syncAttributes.contentCRC = localStorage[syncIndex + ".contentCRC"];
				}
				localStorage[syncIndex] = JSON.stringify(syncAttributes);
				localStorage.removeItem(syncIndex + ".etag");
				localStorage.removeItem(syncIndex + ".version");
				localStorage.removeItem(syncIndex + ".contentCRC");
				localStorage.removeItem(syncIndex + ".titleCRC");
			});
		});
		version = "v2";
	}
	
	// Upgrade from v2 to v3
	if(version == "v2") {
		_.each(fileIndexList, function(fileIndex) {
			if(!_.has(localStorage, fileIndex + ".sync")) {
				localStorage.removeItem(fileIndex + ".title");
				localStorage.removeItem(fileIndex + ".publish");
				localStorage.removeItem(fileIndex + ".content");
				localStorage["file.list"] = localStorage["file.list"].replace(";"
					+ fileIndex + ";", ";");
			}
		});
		version = "v3";
	}
	
	// Upgrade from v3 to v4
	if(version == "v3") {
		var currentFileIndex = localStorage["file.current"];
		if(currentFileIndex !== undefined && 
			localStorage["file.list"].indexOf(";" + currentFileIndex + ";") === -1)
		{
			localStorage.removeItem("file.current");
		}
		version = "v4";
	}
	
	// Upgrade from v4 to v5
	if(version == "v4") {
		// Recreate GitHub token
		localStorage.removeItem("githubToken");
		version = "v5";
	}
	
	// Upgrade from v5 to v6
	if(version == "v5") {
		_.each(fileIndexList, function(fileIndex) {
			var publishIndexList = _.compact(localStorage[fileIndex + ".publish"].split(";"));
			_.each(publishIndexList, function(publishIndex) {
				var publishAttributes = JSON.parse(localStorage[publishIndex]);
				if(publishAttributes.provider == "gdrive") {
					// Change fileId to Id to be consistent with syncAttributes
					publishAttributes.id = publishAttributes.fileId;
					publishAttributes.fileId = undefined;
					localStorage[publishIndex] = JSON.stringify(publishAttributes);
				}
			});
		});
		version = "v6";
	}
	
	localStorage["version"] = version;
});