/*
Copyright 2013-2017 appPlant GmbH

Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you 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.
*/

#import "APPMethodMagic.h"
#import "APPBackgroundMode.h"
#import <Cordova/CDVAvailability.h>

@implementation APPBackgroundMode

#pragma mark -
#pragma mark Constants

NSString* const kAPPBackgroundJsNamespace = @"cordova.plugins.backgroundMode";
NSString* const kAPPBackgroundEventActivate = @"activate";
NSString* const kAPPBackgroundEventDeactivate = @"deactivate";

#pragma mark -
#pragma mark Life Cycle

/**
* Called by runtime once the Class has been loaded.
* Exchange method implementations to hook into their execution.
*/
+ (void) load
{
[self swizzleWKWebViewEngine];
}

/**
* Initialize the plugin.
*/
- (void) pluginInitialize
{
enabled = NO;
[self configureAudioPlayer];
[self configureAudioSession];
[self observeLifeCycle];
}

/**
* Register the listener for pause and resume events.
*/
- (void) observeLifeCycle
{
NSNotificationCenter* listener = [NSNotificationCenter
defaultCenter];

[listener addObserver:self
selector:@selector(keepAwake)
name:UIApplicationDidEnterBackgroundNotification
object:nil];

[listener addObserver:self
selector:@selector(stopKeepingAwake)
name:UIApplicationWillEnterForegroundNotification
object:nil];

[listener addObserver:self
selector:@selector(handleAudioSessionInterruption:)
name:AVAudioSessionInterruptionNotification
object:nil];
}

#pragma mark -
#pragma mark Interface

/**
* Enable the mode to stay awake
* when switching to background for the next time.
*/
- (void) enable:(CDVInvokedUrlCommand*)command
{
if (enabled)
return;

enabled = YES;
[self execCallback:command];
}

/**
* Disable the background mode
* and stop being active in background.
*/
- (void) disable:(CDVInvokedUrlCommand*)command
{
if (!enabled)
return;

enabled = NO;
[self stopKeepingAwake];
[self execCallback:command];
}

#pragma mark -
#pragma mark Core

/**
* Keep the app awake.
*/
- (void) keepAwake
{
if (!enabled)
return;

[audioPlayer play];
[self fireEvent:kAPPBackgroundEventActivate];
}

/**
* Let the app going to sleep.
*/
- (void) stopKeepingAwake
{
if (TARGET_IPHONE_SIMULATOR) {
NSLog(@"BackgroundMode: On simulator apps never pause in background!");
}

if (audioPlayer.isPlaying) {
[self fireEvent:kAPPBackgroundEventDeactivate];
}

[audioPlayer pause];
}

/**
* Configure the audio player.
*/
- (void) configureAudioPlayer
{
NSString* path = [[NSBundle mainBundle]
pathForResource:@"appbeep" ofType:@"wav"];

NSURL* url = [NSURL fileURLWithPath:path];

audioPlayer = [[AVAudioPlayer alloc]
initWithContentsOfURL:url error:NULL];

audioPlayer.volume = 0;
audioPlayer.numberOfLoops = -1;
};

/**
* Configure the audio session.
*/
- (void) configureAudioSession
{
AVAudioSession* session = [AVAudioSession
sharedInstance];

// Don't activate the audio session yet
[session setActive:NO error:NULL];

// Play music even in background and dont stop playing music
// even another app starts playing sound
[session setCategory:AVAudioSessionCategoryPlayback
error:NULL];

// Active the audio session
[session setActive:YES error:NULL];
};

#pragma mark -
#pragma mark Helper

/**
* Simply invokes the callback without any parameter.
*/
- (void) execCallback:(CDVInvokedUrlCommand*)command
{
CDVPluginResult *result = [CDVPluginResult
resultWithStatus:CDVCommandStatus_OK];

[self.commandDelegate sendPluginResult:result
callbackId:command.callbackId];
}

/**
* Restart playing sound when interrupted by phone calls.
*/
- (void) handleAudioSessionInterruption:(NSNotification*)notification
{
[self fireEvent:kAPPBackgroundEventDeactivate];
[self keepAwake];
}

/**
* Find out if the app runs inside the webkit powered webview.
*/
+ (BOOL) isRunningWebKit
{
return IsAtLeastiOSVersion(@"8.0") && NSClassFromString(@"CDVWKWebViewEngine");
}

/**
* Method to fire an event with some parameters in the browser.
*/
- (void) fireEvent:(NSString*)event
{
NSString* active =
[event isEqualToString:kAPPBackgroundEventActivate] ? @"true" : @"false";

NSString* flag = [NSString stringWithFormat:@"%@._isActive=%@;",
kAPPBackgroundJsNamespace, active];

NSString* depFn = [NSString stringWithFormat:@"%@.on('%@');",
kAPPBackgroundJsNamespace, event];

NSString* fn = [NSString stringWithFormat:@"%@.fireEvent('%@');",
kAPPBackgroundJsNamespace, event];

NSString* js = [NSString stringWithFormat:@"%@%@%@", flag, depFn, fn];

[self.commandDelegate evalJs:js];
}

#pragma mark -
#pragma mark Swizzling

/**
* Method to swizzle.
*/
+ (NSString*) wkProperty
{
NSString* str = @"YWx3YXlzUnVuc0F0Rm9yZWdyb3VuZFByaW9yaXR5";
NSData* data = [[NSData alloc] initWithBase64EncodedString:str options:0];

return [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
}

/**
* Swizzle some implementations of CDVWKWebViewEngine.
*/
+ (void) swizzleWKWebViewEngine
{
if (![self isRunningWebKit])
return;

Class wkWebViewEngineCls = NSClassFromString(@"CDVWKWebViewEngine");
SEL selector = NSSelectorFromString(@"createConfigurationFromSettings:");

SwizzleSelectorWithBlock_Begin(wkWebViewEngineCls, selector)
^(CDVPlugin *self, NSDictionary *settings) {
id obj = ((id (*)(id, SEL, NSDictionary*))_imp)(self, _cmd, settings);

[obj setValue:[NSNumber numberWithBool:YES]
forKey:[APPBackgroundMode wkProperty]];

[obj setValue:[NSNumber numberWithBool:NO]
forKey:@"requiresUserActionForMediaPlayback"];

return obj;
}
SwizzleSelectorWithBlock_End;
}

@end