PLT-2992 Added the ability to use different themes for each team (#3411)

* Cleaned up user_settings_theme.jsx and import_theme_modal.jsx

* Made ImportThemeModal use a callback to return the theme to the user settings modal instead of saving it directly

* Moved user theme from model to preferences

* Added serverside API to delete preferences TODO update package with client stuff

* Changed constants.jsx so that Preferences and ActionTypes can be imported on their own

* Updated ThemeProps migration code to properly rename solarized code themes

* Fixed warnings thrown by AppDispatcher

* Added clientside UI to support team-specific themes

* Removed debugging code from test

* Fixed setting a user's theme when they haven't set their theme before

webapp/actions/user_actions.jsx

@@ -1,10 +1,15 @@
 // Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
-import Client from 'utils/web_client.jsx';
+import AppDispatcher from 'dispatcher/app_dispatcher.jsx';
 import * as AsyncClient from 'utils/async_client.jsx';
+import Client from 'utils/web_client.jsx';
 
+import PreferenceStore from 'stores/preference_store.jsx';
 import TeamStore from 'stores/team_store.jsx';
+import UserStore from 'stores/user_store.jsx';
+
+import {ActionTypes, Preferences} from 'utils/constants.jsx';
 
 export function switchFromLdapToEmail(email, password, ldapPassword, onSuccess, onError) {
     Client.ldapToEmail(
@@ -28,3 +33,52 @@ export function getMoreDmList() {
     AsyncClient.getProfilesForDirectMessageList();
     AsyncClient.getTeamMembers(TeamStore.getCurrentId());
 }
+
+export function saveTheme(teamId, theme, onSuccess, onError) {
+    AsyncClient.savePreference(
+        Preferences.CATEGORY_THEME,
+        teamId,
+        JSON.stringify(theme),
+        () => {
+            onThemeSaved(teamId, theme, onSuccess);
+        },
+        (err) => {
+            onError(err);
+        }
+    );
+}
+
+function onThemeSaved(teamId, theme, onSuccess) {
+    const themePreferences = PreferenceStore.getCategory(Preferences.CATEGORY_THEME);
+
+    if (teamId !== '' && themePreferences.size > 1) {
+        // no extra handling to be done to delete team-specific themes
+        onSuccess();
+        return;
+    }
+
+    const toDelete = [];
+
+    for (const [name] of themePreferences) {
+        if (name === '') {
+            continue;
+        }
+
+        toDelete.push({
+            user_id: UserStore.getCurrentId(),
+            category: Preferences.CATEGORY_THEME,
+            name
+        });
+    }
+
+    // we're saving a new global theme so delete any team-specific ones
+    AsyncClient.deletePreferences(toDelete);
+
+    // delete them locally before we hear from the server so that the UI flow is smoother
+    AppDispatcher.handleServerAction({
+        type: ActionTypes.DELETED_PREFERENCES,
+        preferences: toDelete
+    });
+
+    onSuccess();
+}