//     File: DecisionAgent.m

// Abstract: Implementation of the Agent protocol.

//  Version: 1.1

// 

// Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple

// Inc. ("Apple") in consideration of your agreement to the following

// terms, and your use, installation, modification or redistribution of

// this Apple software constitutes acceptance of these terms.  If you do

// not agree with these terms, please do not use, install, modify or

// redistribute this Apple software.

// 

// In consideration of your agreement to abide by the following terms, and

// subject to these terms, Apple grants you a personal, non-exclusive

// license, under Apple's copyrights in this original Apple software (the

// "Apple Software"), to use, reproduce, modify and redistribute the Apple

// Software, with or without modifications, in source and/or binary forms;

// provided that if you redistribute the Apple Software in its entirety and

// without modifications, you must retain this notice and the following

// text and disclaimers in all such redistributions of the Apple Software.

// Neither the name, trademarks, service marks or logos of Apple Inc. may

// be used to endorse or promote products derived from the Apple Software

// without specific prior written permission from Apple.  Except as

// expressly stated in this notice, no other rights or licenses, express or

// implied, are granted by Apple herein, including but not limited to any

// patent rights that may be infringed by your derivative works or by other

// works in which the Apple Software may be incorporated.

// 

// The Apple Software is provided by Apple on an "AS IS" basis.  APPLE

// MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

// THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS

// FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND

// OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

// 

// IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL

// OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

// INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,

// MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED

// AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),

// STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE

// POSSIBILITY OF SUCH DAMAGE.

// 

// Copyright (C) 2012 Apple Inc. All Rights Reserved.

// 

#import <Foundation/Foundation.h>

#import "DecisionAgent.h"

#include <stdlib.h>

@implementation DecisionAgent

#pragma mark -

#pragma mark NSXPCConnection method overrides

- (BOOL)listener:(NSXPCListener *)listener shouldAcceptNewConnection:(NSXPCConnection *)newConnection

{

    // This method is called by the NSXPCListener to filter/configure

    // incoming connections.

    newConnection.exportedInterface = [NSXPCInterface interfaceWithProtocol:@protocol(Agent)];

    newConnection.exportedObject = self;

    // Start processing incoming messages.

    [newConnection resume];

    return YES;

}

#pragma mark -

#pragma mark Public interface

static BOOL

looksLikeAQuestion(NSString *query)

{

    NSRange questionMark = [query rangeOfString:@"?"];

    return questionMark.location != NSNotFound;

}

static BOOL

couldBeBooleanQuestion(NSString *query)

{

    static NSPredicate *interrogatives;

    static dispatch_once_t once;

    dispatch_once(&once, ^{

        interrogatives = [NSPredicate predicateWithFormat:

                  @"SELF BEGINSWITH[c] 'who' OR "

                   "SELF BEGINSWITH[c] 'whom' OR "

                   "SELF BEGINSWITH[c] 'what' OR "

                   "SELF BEGINSWITH[c] 'which' OR "

                   "SELF BEGINSWITH[c] 'when' OR "

                   "SELF BEGINSWITH[c] 'where' OR "

                   "SELF BEGINSWITH[c] 'why' OR "

                   "SELF BEGINSWITH[c] 'how'"];

    });

    return ![interrogatives evaluateWithObject:query];

}

static NSString *

randomSelection(NSArray *options)

{

    NSUInteger numOptions = [options count];

    NSUInteger selectedOption = arc4random_uniform((u_int32_t)numOptions);

    return [options objectAtIndex:selectedOption];

}

- (void)adviseOn:(NSString *)query reply:(void (^)(NSString *advice))reply

{

    query = [query stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

    if (!looksLikeAQuestion(query)) {

        reply(@"Please re-phrase in the form of a question.");

    } else if (!couldBeBooleanQuestion(query)) {

        reply(@"I can only answer yes/no questions.");

    } else {

        reply(randomSelection(@[

            @"It is certain.",

            @"It is decidedly so.",

            @"Without a doubt.",

            @"Yes – definitely.",

            @"You may rely on it.",

            @"As I see it, yes.",

            @"Most likely.",

            @"Outlook good.",

            @"Yes.",

            @"Signs point to yes.",

            @"Reply hazy, try again.",

            @"Ask again later.",

            @"Better not tell you now.",

            @"Cannot predict now.",

            @"Concentrate and ask again.",

            @"Don't count on it.",

            @"My reply is no.",

            @"My sources say no.",

            @"Outlook not so good.",

            @"Very doubtful."

        ]));

    }

}

@end