/*
    File:  CollapsibleBox.m

    Abstract:  An NSBox subclass that can toggle its frame size using animation
     
    Version:  1.0

    Copyright:  © Copyright 2005 Apple Computer, Inc. All rights reserved.

    Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.
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*/

#import "CollapsibleBox.h"

#define ANIMATION_DURATION           0.25
#define DEFAULT_COLLAPSED_HEIGHT    38.0

@implementation CollapsibleBox

// Initializes the attributes that CollapsibleBox adds to NSBox.  This method is called by -initWithFrame:, and is also used by our Interface Builder palette.
- (void)initAddedProperties {
    expanded = YES;
    otherFrameSize = NSMakeSize([self frame].size.width, DEFAULT_COLLAPSED_HEIGHT);
}

- (id)initWithFrame:(NSRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        [self setTitlePosition:NSNoTitle];
        [self initAddedProperties];
    }
    return self;
}

#pragma mark -
#pragma mark *** Key-Value Binding Support ***

+ (void)initialize {
    if (self == [CollapsibleBox class]) {
        // Declare the attributes of this class that should be shown in the Bindings inspector in Interface Builder.
        [self exposeBinding:@"expanded"];
    }
}

#pragma mark -
#pragma mark *** NSView Method Overrides ***

- (BOOL)isFlipped {
    return YES;
}

#pragma mark -
#pragma mark *** State Accessors ***

- (BOOL)isExpanded {
    return expanded;
}

- (void)setExpanded:(BOOL)flag {
    [self setExpanded:flag animate:YES];
}

- (void)setExpanded:(BOOL)flag animate:(BOOL)animate {
    if (expanded != flag) {

        // Save new state.
        expanded = flag;

        // Get frame size for new state, and remember the frame size for the state we're leaving.
        NSSize newFrameSize = otherFrameSize;
        otherFrameSize = [self frame].size;

        // Resize self, possibly using animation.
        [self setFrameSize:newFrameSize animate:animate];
    }
}

#pragma mark -
#pragma mark *** Resizing / Animation Support ***

- (NSRect)frameForNewSizePinnedToTopLeft:(NSSize)newFrameSize {
    NSRect frame = [self frame];
    if (![[self superview] isFlipped]) {
        float yOffset = newFrameSize.height - frame.size.height;
        frame.origin.y -= yOffset;
    }
    frame.size = newFrameSize;
    return frame;
}

- (void)setFrameSizeWithPinningToTopLeft:(NSSize)newFrameSize {
    NSRect oldFrame = [self frame];
    NSRect newFrame = [self frameForNewSizePinnedToTopLeft:newFrameSize];
    [self setFrame:newFrame];

    // Offset all children of box's contentView to match.
    float yOffset = newFrame.size.height - oldFrame.size.height;
    NSArray *subviews = [[self contentView] subviews];
    unsigned count = [subviews count];
    unsigned index;
    for (index = 0; index < count; index++) {
        NSView *subview = [subviews objectAtIndex:index];
        NSPoint origin = [subview frame].origin;
        origin.y += yOffset;
        [subview setFrameOrigin:origin];
    }
}

- (void)setFrameSize:(NSSize)newFrameSize animate:(BOOL)animate {
    NSView *superview = [self superview];
    if (animate) {
        // Compute the new frame.
        NSRect newFrame = [self frameForNewSizePinnedToTopLeft:newFrameSize];

        // Give animationDelegate, if any, first shot at animating the resize (in case the app needs to coordinate with other animations).
        if (animationDelegate != nil && [animationDelegate respondsToSelector:@selector(collapsibleBox:shouldAnimateToFrame:expanding:)]) {
            if (![animationDelegate collapsibleBox:self shouldAnimateToFrame:newFrame expanding:expanded]) {
                return;
            }
        }

        // Else, do the animation ourselves.
        NSMutableArray *animationArray = [NSMutableArray arrayWithObject:[NSDictionary dictionaryWithObjectsAndKeys:self, NSViewAnimationTargetKey, [NSValue valueWithRect:newFrame], NSViewAnimationEndFrameKey, nil]];
        NSAnimation *animation = [[NSViewAnimation alloc] initWithViewAnimations:animationArray];
        [animation setAnimationBlockingMode:NSAnimationBlocking];
        [animation setDuration:ANIMATION_DURATION];
        [animation startAnimation];
        [animation release];
    } else {
        [superview setNeedsDisplayInRect:[self frame]];
        [self setFrameSizeWithPinningToTopLeft:newFrameSize];
        [self setNeedsDisplay:YES];
    }
}

#pragma mark -
#pragma mark *** Archiving ***

// A view must know how to archive and unarchive itself in order to be placed in a custom Interface Builder palette.

- (void)encodeWithCoder:(NSCoder *)aCoder {
    [super encodeWithCoder:aCoder];
    if ([aCoder allowsKeyedCoding]) {
        [aCoder encodeBool:expanded forKey:@"expanded"];
        [aCoder encodeSize:otherFrameSize forKey:@"otherFrameSize"];
        [aCoder encodeConditionalObject:animationDelegate forKey:@"animationDelegate"];
    }
}

- (id)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        if ([aDecoder allowsKeyedCoding]) {
            // Read archived attributes.
            expanded = [aDecoder decodeBoolForKey:@"expanded"];
            otherFrameSize = [aDecoder decodeSizeForKey:@"otherFrameSize"];
            animationDelegate = [aDecoder decodeObjectForKey:@"animationDelegate"];
        }
    }
    return self;
}

@end
