/*

    Copyright (C) 2015 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    This is the "FileTreeWatcherThread" class implementation.

*/

#import "AAPLFileTreeWatcherThread.h"

static void AAPLFileTreeWatcherEventStreamCallback(ConstFSEventStreamRef streamRef, void *clientCallBackInfo, size_t numEvents, void *eventPaths, const FSEventStreamEventFlags eventFlags[], const FSEventStreamEventId eventIds[]);

@implementation AAPLFileTreeWatcherThread

- initWithPath:(NSString *)pathToWatch changeHandler:(void (^)(void))changeHandler {

    NSParameterAssert(pathToWatch);

    NSParameterAssert(changeHandler);

    self = [self init];

    if (self) {

        [self setName:@"AAPLFileTreeWatcherThread"];

        paths = @[pathToWatch];

        @synchronized(self) {

            handler = [changeHandler copy];

        }

    }

    return self;

}

- (void)invokeChangeHandler {

    @synchronized(self) {

        if (handler) {

            [[NSOperationQueue mainQueue] addOperationWithBlock:handler];

        }

    }

}

- (void)detachChangeHandler {

    @synchronized(self) {

        handler = nil;

    }

}

- (void)main {

    @autoreleasepool {

        // Create our fsEventStream.

        FSEventStreamContext context;

        context.version = 0;

        context.info = (__bridge void *)self;

        context.retain = NULL;

        context.release = NULL;

        context.copyDescription = NULL;

        fsEventStream = FSEventStreamCreate(kCFAllocatorDefault, AAPLFileTreeWatcherEventStreamCallback, &context, CFBridgingRetain(paths), kFSEventStreamEventIdSinceNow, 1.0, kFSEventStreamCreateFlagUseCFTypes | kFSEventStreamCreateFlagWatchRoot | kFSEventStreamCreateFlagIgnoreSelf);

        if (fsEventStream != NULL) {

            // Schedule the fsEventStream on our thread's run loop.

            NSRunLoop *runLoop = [NSRunLoop currentRunLoop];

            CFRunLoopRef cfRunLoop = [runLoop getCFRunLoop];

            FSEventStreamScheduleWithRunLoop(fsEventStream, cfRunLoop, kCFRunLoopCommonModes);

            // Open the faucet.

            FSEventStreamStart(fsEventStream);

            // Run until we're asked to stop.

            while (![self isCancelled]) {

                [runLoop runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.25]];

            }

            // Shut off the faucet.

            FSEventStreamStop(fsEventStream);

            // Unschedule the fsEventStream on our thread's run loop.

            FSEventStreamUnscheduleFromRunLoop(fsEventStream, cfRunLoop, kCFRunLoopCommonModes);

            // Invalidate and release fsEventStream.

            FSEventStreamInvalidate(fsEventStream);

            FSEventStreamRelease(fsEventStream);

            fsEventStream = NULL;

        }

    }

}

@end

static void AAPLFileTreeWatcherEventStreamCallback(ConstFSEventStreamRef streamRef, void *clientCallBackInfo, size_t numEvents, void *eventPaths, const FSEventStreamEventFlags eventFlags[], const FSEventStreamEventId eventIds[]) {

    if (numEvents > 0) {

        AAPLFileTreeWatcherThread *thread = (__bridge AAPLFileTreeWatcherThread *)clientCallBackInfo;

        [thread invokeChangeHandler];

    }

}