/*
   Copyright 2012 KeepSafe Software Inc.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/
package com.keepsafe.switchboard;


import android.content.Context;
import android.content.SharedPreferences;
import android.support.annotation.Nullable;

/**
 * Application preferences for SwitchBoard.
 * @author Philipp Berner
 *
 */
public class Preferences {

    private static final String switchBoardSettings = "com.keepsafe.switchboard.settings";

    private static final String CONFIG_JSON = "config-json";
    private static final String OVERRIDE_PREFIX = "experiment.override.";


    /**
     * Gets the user config as a JSON string.
     * @param c Context
     * @return Config JSON
     */
    @Nullable public static String getDynamicConfigJson(Context c) {
        final SharedPreferences prefs = c.getApplicationContext().getSharedPreferences(switchBoardSettings, Context.MODE_PRIVATE);
        return prefs.getString(CONFIG_JSON, null);
    }

    /**
     * Saves the user config as a JSON sting.
     * @param c Context
     * @param configJson Config JSON
     */
    public static void setDynamicConfigJson(Context c, String configJson) {
        final SharedPreferences.Editor editor = c.getApplicationContext().
                getSharedPreferences(switchBoardSettings, Context.MODE_PRIVATE).edit();
        editor.putString(CONFIG_JSON, configJson);
        editor.apply();
    }

    /**
     * Gets the override value for an experiment.
     *
     * @param c Context
     * @param experimentName Experiment name
     * @return Whether or not the experiment should be enabled, or null if there is no override.
     */
    @Nullable public static Boolean getOverrideValue(Context c, String experimentName) {
        final SharedPreferences prefs = c.getApplicationContext().
                getSharedPreferences(switchBoardSettings, Context.MODE_PRIVATE);

        final String key = OVERRIDE_PREFIX + experimentName;
        if (prefs.contains(key)) {
            // This will never fall back to the default value.
            return prefs.getBoolean(key, false);
        }

        // Default to returning null if no override was found.
        return null;
    }

    /**
     * Saves an override value for an experiment.
     *
     * @param c Context
     * @param experimentName Experiment name
     * @param isEnabled Whether or not to enable the experiment
     */
    public static void setOverrideValue(Context c, String experimentName, boolean isEnabled) {
        final SharedPreferences.Editor editor = c.getApplicationContext().
                getSharedPreferences(switchBoardSettings, Context.MODE_PRIVATE).edit();
        editor.putBoolean(OVERRIDE_PREFIX + experimentName, isEnabled);
        editor.apply();
    }

    /**
     * Clears the override value for an experiment.
     *
     * @param c Context
     * @param experimentName Experiment name
     */
    public static void clearOverrideValue(Context c, String experimentName) {
        final SharedPreferences.Editor editor = c.getApplicationContext().
                getSharedPreferences(switchBoardSettings, Context.MODE_PRIVATE).edit();
        editor.remove(OVERRIDE_PREFIX + experimentName);
        editor.apply();
    }
}