/*

File:       CalcController.m

Author:     AW, ES, and MCF

Copyright:  © Copyright 2000 Apple Computer, Inc. All rights reserved.

Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, 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 AppleÕs

                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 Computer, 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.

Change History (most recent first):

9 July 97 -- first version of application

7/5/00  KG  Updated for Project Builder on DP4

12/04/00 MCF    Updated for Project Builder on Mac OS X Public Beta

*/

#import "CalcController.h"

@implementation CalcController

//This method clears out the calculator display and info about the last operation, etc.

- (void)clear:(id)sender

{

    //We have to autorelease the old object and then retain the new one to not leak memory.

    [displayedNumber autorelease];

    displayedNumber = [[NSDecimalNumber zero] retain];

    [enteredNumber autorelease];

    enteredNumber = [[NSDecimalNumber zero] retain];

    [displayView setDoubleValue: 0];

    [self endEditingNumber];

    lastOperation = kNoOperator;

    usedDecimalPoint = NO;

}

- (void)equals:(id)sender

{

    if (enteringNumber)

      {

        [self endEditingNumber];

        [self performLastOperation];

        lastOperation = kNoOperator;

        [displayView setStringValue: [displayedNumber stringValue]];

      }

}

//this method is called when you click a number button on the calculator

- (void)insertDigit:(id)sender

{

    NSString* oldValue;

    if (!enteringNumber)

      {

        [self beginEditingNumber];

      }

    oldValue = [displayView stringValue];

    [displayView setStringValue: [oldValue stringByAppendingString: [sender title]]];

}

- (void)beginEditingNumber

{

    enteringNumber = YES;

    usedDecimalPoint = NO;

    [displayView setStringValue: @""];

    [enteredNumber autorelease];

    enteredNumber = [displayedNumber copy]; 

}

- (void)endEditingNumber

{

    enteringNumber = NO;

    usedDecimalPoint = NO;

    [displayedNumber autorelease];

    displayedNumber = [NSDecimalNumber decimalNumberWithString: [displayView stringValue]];

    [displayedNumber retain];

}

- (void)decimalPoint:(id)sender

{

    NSString* oldValue;

    if (!usedDecimalPoint)

      {

        usedDecimalPoint = YES;

        if (!enteringNumber)

          {

            [self beginEditingNumber];

            [displayView setStringValue: @"0."];

          }

        else

          {

            oldValue = [displayView stringValue];

            [displayView setStringValue: [oldValue stringByAppendingString: @"."]];

          }

      }

}

//This method is called when the application first launches and instantiates this 

//object from the nib file

-(void) awakeFromNib

{

    [self clear: self];

    //This next line is a work-around for a bug in Mac OS X Public Beta

    [[displayView window] makeKeyAndOrderFront:nil];

}

- (void)operation:(id)sender

{

    if (enteringNumber)

      {

        [self endEditingNumber];

        [self performLastOperation];

        [displayView setStringValue: [displayedNumber stringValue]];

      }

    // no matter what, set the new operation in case the user changes his/her mind

    lastOperation = [sender tag];

}

- (void)performLastOperation

{

    if (lastOperation == kNoOperator)

      {

        return;

      }

    // it is possible to extensively rewrite the following code.  In all cases,

    // displayedNumber is autoreleased, assigned a new value and that new value is

    // retained.  Thus it would reduce the number of lines of code to put the

    // autorelease statement before the nest of if statements, and put the retain

    // statement after the nest of if statements.  However, I've duplicated the

    // statements just to brutally drive home the point that you need to autorelease

    // before you assign over your instance variables, and you need to retain them

    // after you've assigned to them.  Even in the case that none of the if statements

    // are executed, autoreleaseing and immediately retaining the same object is

    // perfectly acceptable.

    // This way of detecting NANs is a HACK!  Unfortunately, NaN is not ordered, so

    // if you ask any number if it's equal to NaN, it'll say yes.  So, instead we'll

    // ask if it's equal to an impossible combination of numbers -- zero and one.

    // The only 'number' equal to both is NaN

    if ((([displayedNumber compare: [NSDecimalNumber zero]] == NSOrderedSame) &&

         ([displayedNumber compare: [NSDecimalNumber one]] == NSOrderedSame)) ||

        (([enteredNumber compare: [NSDecimalNumber zero]] == NSOrderedSame) &&

         ([enteredNumber compare: [NSDecimalNumber one]] == NSOrderedSame)))

      {

        [displayedNumber autorelease];

        displayedNumber = [[NSDecimalNumber notANumber] retain];

        return;

      }

    else if (lastOperation == kAddOperator)

      {

        [displayedNumber autorelease];

       displayedNumber = [enteredNumber decimalNumberByAdding: displayedNumber];

        [displayedNumber retain];

      }

    else if (lastOperation == kSubtractOperator)

      {

        [displayedNumber autorelease];

        displayedNumber = [enteredNumber decimalNumberBySubtracting: displayedNumber];

        [displayedNumber retain];

      }

    else if (lastOperation == kMultiplyOperator)

      {

        [displayedNumber autorelease];

        displayedNumber = [enteredNumber decimalNumberByMultiplyingBy: displayedNumber];

        [displayedNumber retain];

      }

    else if (lastOperation == kDivideOperator)

      {

        if ([displayedNumber compare: [NSDecimalNumber zero]] != NSOrderedSame)

          {

            [displayedNumber autorelease];

            displayedNumber = [enteredNumber decimalNumberByDividingBy: displayedNumber];

            [displayedNumber retain];

          }

        else

          {

            [displayedNumber autorelease];

            displayedNumber = [[NSDecimalNumber notANumber] retain];

            [displayedNumber retain];

          }

      }

}

- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)theApplication

{

    return YES;

}

- (void)cut:(id)sender

{

    [self copy: self];

    [self clear: self];

}

- (void)copy:(id)sender

{

    //grab the general pasteboard

    NSPasteboard* pasteboard = [NSPasteboard generalPasteboard];

    //tell the copy/paste system what type of data we'll be putting up there

    [pasteboard declareTypes: [NSArray arrayWithObject: NSStringPboardType] owner: NULL];

    //go ahead and place the display string on the pasteboard for other apps to paste

    [pasteboard setString: [displayView stringValue] forType: NSStringPboardType];

}

- (void)paste:(id)sender

{

    NSPasteboard* pasteboard;

    NSString* pasteValue;

    if (!enteringNumber)

      {

        [self beginEditingNumber];

      }

    //grab the general pasteboard

    pasteboard = [NSPasteboard generalPasteboard];

    //get the content from the pasteboard for our data type 

    pasteValue = [pasteboard stringForType: NSStringPboardType];

    //set the display of the calculator

    [displayView setStringValue: [[displayView stringValue] stringByAppendingString: pasteValue]];

}

// when self is released, it is necessary to release all of the variables we've retained

-(void)dealloc

{

    [displayedNumber release];

    [enteredNumber release];

}

@end