//

//  MYTask.m

//  Murky

//

//  Copyright 2008 Jens Alfke. All rights reserved.

//

#import "MYTask.h"

//FIX: NOTICE: This code was written assuming garbage collection. It will currently leak like a sieve without it.

NSString* const MYTaskErrorDomain = @"MYTaskError";

NSString* const MYTaskExitCodeKey = @"MYTaskExitCode";

NSString* const MYTaskObjectKey = @"MYTask";

#define MYTaskSynchronousRunLoopMode @"MYTask"

@interface MYTask ()

@property (readwrite,nonatomic) BOOL isRunning;

@property (readwrite,retain,nonatomic) NSError *error;

- (void) _finishUp;

@end

@implementation MYTask

- (id) initWithCommand: (NSString*)command

             arguments: (NSArray*)arguments

{

    NSParameterAssert(command);

    self = [super init];

    if (self != nil) {

        _command = command;

        _arguments = arguments ?[arguments mutableCopy] :[NSMutableArray array];

        _modes = [NSMutableArray arrayWithObjects: NSDefaultRunLoopMode, NSModalPanelRunLoopMode, nil];

    }

    return self;

}

- (id) initWithCommand: (NSString*)command, ...

{

    NSMutableArray *arguments = [NSMutableArray array];

    va_list args;

    va_start(args,command);

    id arg;

    while( nil != (arg=va_arg(args,id)) )

        [arguments addObject: [arg description]];

    va_end(args);

    return [self initWithCommand: command arguments: arguments];

}

- (id) initWithError: (NSError*)error

{

    self = [super init];

    if( self ) {

        _error = error;

    }

    return self;

}

- (NSString*) description

{

    return [NSString stringWithFormat: @"%@ %@", 

            _command, [_arguments componentsJoinedByString: @" "]];

}

- (void) addArgument: (id)argument

{

    [_arguments addObject: [argument description]];

}

- (void) addArgumentsFromArray: (NSArray*)arguments

{

    for( id arg in arguments )

        [_arguments addObject: [arg description]];

}

- (void) addArguments: (id)arg, ...

{

    va_list args;

    va_start(args,arg);

    while( arg ) {

        [_arguments addObject: [arg description]];

        arg = va_arg(args,id);

    }

    va_end(args);

}

- (void) prependArguments: (id)arg, ...

{

    va_list args;

    va_start(args,arg);

    int i=0;

    while( arg ) {

        [_arguments insertObject: [arg description] atIndex: i++];

        arg = va_arg(args,id);

    }

    va_end(args);

}

- (void) ignoreOutput

{

    _ignoreOutput = YES;

}

- (BOOL) makeError: (NSString*)fmt, ...

{

    va_list args;

    va_start(args,fmt);

    NSString *message = [[NSString alloc] initWithFormat: fmt arguments: args];

    Log(@"MYTask Error: %@",message);

    NSMutableDictionary *info = [NSMutableDictionary dictionaryWithObject: message

                                                                   forKey: NSLocalizedDescriptionKey];

    _error = [NSError errorWithDomain: MYTaskErrorDomain code: kMYTaskError userInfo: info];

    va_end(args);

    return NO;

}

- (NSPipe*) _openPipeAndHandle: (NSFileHandle**)handle notifying: (SEL)selector

{

    NSPipe *pipe = [NSPipe pipe];

    *handle = [pipe fileHandleForReading];

    [[NSNotificationCenter defaultCenter] addObserver: self selector: selector

                                                 name: NSFileHandleReadCompletionNotification

                                               object: *handle];

    [*handle readInBackgroundAndNotifyForModes: _modes];

    return pipe;

}

- (void) _close

{

    // No need to call -closeFile on file handles obtained from NSPipe (in fact, it can hang)

    _outHandle = nil;

    _errHandle = nil;

    [[NSNotificationCenter defaultCenter] removeObserver: self 

                                                    name: NSFileHandleReadCompletionNotification

                                                  object: nil];

}

/** Subclasses can override this. */

- (NSTask*) createTask

{

    NSAssert(!_task,@"createTask called twice");

    NSTask *task = [[NSTask alloc] init];

    task.launchPath = _command;

    task.arguments = _arguments;

    if( _currentDirectoryPath )

        task.currentDirectoryPath = _currentDirectoryPath;

    return task;

}    

- (BOOL) start

{

    NSAssert(!_task, @"Task has already been run");

    if( _error )

        return NO;

    _task = [self createTask];

    NSAssert(_task,@"createTask returned nil");

    Log(@"Task: %@ %@",_task.launchPath,[_task.arguments componentsJoinedByString: @" "]);

    _task.standardOutput = [self _openPipeAndHandle: &_outHandle notifying: @selector(_gotOutput:)];

    _outputData =  [[NSMutableData alloc] init];

    _task.standardError  = [self _openPipeAndHandle: &_errHandle notifying: @selector(_gotStderr:)];

    _errorData =  [[NSMutableData alloc] init];

    [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(_exited:)

                                                 name: NSTaskDidTerminateNotification

                                               object: _task];

    @try{

        [_task launch];

    }@catch( id x ) {

        Log(@"Task failed to launch: %@",x);

        _resultCode = 666;

        [self _close];

        return [self makeError: @"Exception launching %@: %@",_task.launchPath,x];

    }

    _taskRunning = YES;

    self.isRunning = YES;

    return YES;

}

- (void) stop

{

    [_task interrupt];

    [self _close];

    _taskRunning = NO;

    self.isRunning = NO;

}

- (BOOL) _shouldFinishUp

{

    return !_task.isRunning && (_ignoreOutput || (!_outHandle && !_errHandle));

}

- (void) _gotOutput: (NSNotification*)n

{

    NSData *data = [n.userInfo objectForKey: NSFileHandleNotificationDataItem];

    if( n.object == _outHandle ) {

        if( data.length > 0 ) {

            [_outHandle readInBackgroundAndNotifyForModes: _modes];

            LogTo(Task,@"Got %u bytes of output",data.length);

            if( _outputData ) {

                [self willChangeValueForKey: @"output"];

                [self willChangeValueForKey: @"outputData"];

                [_outputData appendData: data];

                _output = nil;

                [self didChangeValueForKey: @"outputData"];

                [self didChangeValueForKey: @"output"];

            }

        } else {

            LogTo(Task,@"Closed output");

            _outHandle = nil;

            if( [self _shouldFinishUp] )

                [self _finishUp];

        }

    }

}

- (void) _gotStderr: (NSNotification*)n

{

    if( n.object == _errHandle ) {

        NSData *data = [n.userInfo objectForKey: NSFileHandleNotificationDataItem];

        if( data.length > 0 ) {

            [_errHandle readInBackgroundAndNotifyForModes: _modes];

            LogTo(Task,@"Got %u bytes of stderr",data.length);

            [self willChangeValueForKey: @"errorData"];

            [_errorData appendData: data];

            [self didChangeValueForKey: @"errorData"];

        } else {

            LogTo(Task,@"Closed stderr");

            _errHandle = nil;

            if( [self _shouldFinishUp] )

                [self _finishUp];

        }

    }

}

- (void) _exited: (NSNotification*)n

{

    _resultCode = _task.terminationStatus;

    LogTo(Task,@"Exited with result=%i",_resultCode);

    _taskRunning = NO;

    if( [self _shouldFinishUp] )

        [self _finishUp];

    else

        [self performSelector: @selector(_finishUp) withObject: nil afterDelay: 1.0];

}

- (void) _finishUp

{

    [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @selector(_finishUp) object: nil];

    [self _close];

    LogTo(Task,@"Finished!");

    if( _resultCode != 0 ) {

        // Handle errors:

        NSString *errStr = nil;

        if( _errorData.length > 0 )

            errStr = [[NSString alloc] initWithData: _errorData encoding: NSUTF8StringEncoding];

        Log(@"    *** task returned %i: %@",_resultCode,errStr);

        if( errStr.length == 0 )

            errStr = [NSString stringWithFormat: @"Command returned status %i",_resultCode];

        NSString *desc = [NSString stringWithFormat: @"%@ command error", _task.launchPath.lastPathComponent];

        // For some reason the body text in the alert shown by -presentError: is taken from the

        // NSLocalizedRecoverySuggestionErrorKey, not the NSLocalizedFailureReasonKey...

        NSMutableDictionary *info = [NSMutableDictionary dictionaryWithObjectsAndKeys:

                                     desc,                                  NSLocalizedDescriptionKey,

                                     errStr,                                NSLocalizedRecoverySuggestionErrorKey,

                                     [NSNumber numberWithInt: _resultCode], MYTaskExitCodeKey,

                                     self,                                  MYTaskObjectKey,

                                     nil];

        self.error = [[NSError alloc] initWithDomain: MYTaskErrorDomain 

                                                code: kMYTaskError

                                            userInfo: info];

    }

    [self finished];

    self.isRunning = NO;

}

- (void) finished

{

    // This is a hook that subclasses can override to do post-processing.

}

- (BOOL) _waitTillFinishedInMode: (NSString*)runLoopMode

{

    // wait for task to exit:

    while( _task.isRunning || self.isRunning )

        [[NSRunLoop currentRunLoop] runMode: MYTaskSynchronousRunLoopMode

                                 beforeDate: [NSDate dateWithTimeIntervalSinceNow: 1.0]];

    return (_resultCode==0);

}

- (BOOL) waitTillFinished

{

    return [self _waitTillFinishedInMode: _modes.lastObject];

}

- (BOOL) run

{

    [_modes addObject: MYTaskSynchronousRunLoopMode];

    return [self start] && [self _waitTillFinishedInMode: MYTaskSynchronousRunLoopMode];

}    

- (BOOL) run: (NSError**)outError

{

    BOOL result = [self run];

    if( outError ) *outError = self.error;

    return result;

}

@synthesize currentDirectoryPath=_currentDirectoryPath, outputData=_outputData, error=_error, isRunning=_isRunning;

- (NSString*) output

{

    if( ! _output && _outputData ) {

        _output = [[NSString alloc] initWithData: _outputData encoding: NSUTF8StringEncoding];

        // If output isn't valid UTF-8, fall back to CP1252, aka WinLatin1, a superset of ISO-Latin-1.

        if( ! _output ) {

            _output = [[NSString alloc] initWithData: _outputData encoding: NSWindowsCP1252StringEncoding];

            Log(@"Warning: Output of '%@' was not valid UTF-8; interpreting as CP1252",self);

        }

    }

    return _output;

}

- (NSString*) outputAndError

{

    NSString *result = self.output ?: @"";

    NSString *errorStr = nil;

    if( _error )

        errorStr = [NSString stringWithFormat: @"%@:\n%@",

                    _error.localizedDescription,_error.localizedRecoverySuggestion];

    else if( _errorData.length > 0 )

        errorStr = [[NSString alloc] initWithData: _errorData encoding: NSUTF8StringEncoding];

    if( errorStr )

        result = [NSString stringWithFormat: @"%@\n\n%@", errorStr,result];

    return result;

}

+ (NSArray*) keyPathsForValuesAffectingOutputAndError

{

    return [NSArray arrayWithObjects: @"output", @"error", @"errorData",nil];

}

@end