/*

     File: ExpandableViewController.m

 Abstract: ExpandableViewController manages the expanding and collapsing of two different sized views which show a detail view of the current selected transaction.

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#import "ExpandableViewController.h"

@implementation ExpandableViewController

- (void) awakeFromNib {

    NSView *contentView = [[_middleBoxView window] contentView];

    // add the detail views.  Both are hidden at the start, via a setting in IB

    [contentView addSubview:_stockTransactionView];

    [contentView addSubview:_bankTransactionView];

}

- (void)dealloc {

    if (_expanded) {

        [_transactionController removeObserver:self forKeyPath:@"selection.stockTransaction"];

    }

    [super dealloc];

}

- (BOOL)showingStockTransaction {

    id stockTransactionValue = [_transactionController valueForKeyPath:@"selection.stockTransaction"];

    if ([stockTransactionValue respondsToSelector:@selector(boolValue)]) {

        return [stockTransactionValue boolValue];

    } 

    return NO;

}

// updateView is invoked to change hide/show the detail view, or to change which detail view is shown

- (void)updateView {

    NSWindow *docWindow = [_middleBoxView window];

    NSView *newView;

    CGFloat windowDelta = 0;

    NSRect newViewFrame = NSZeroRect;

    NSRect currentViewFrame = NSZeroRect;

    NSMutableArray *viewAnimations = [NSMutableArray array];

    // figure out which view we want to show, or if we want to hide the detail view

    if (!_expanded) {

        // hide the detail view

        newView = nil;

    } else if ([self showingStockTransaction]) {

        // show the stock transaction detail view

        newView = _stockTransactionView;

    } else {

        // show the bank transaction detail view

        newView = _bankTransactionView;

    }

    // if there is no change from what we are already showing, we're done

    if (newView == _currentView) return;

    // make sure any previous animation has stopped

    if (_animation) {

        // set progress to 1.0 so that animation will display its last frame (eg. to get correct window height)

        [_animation setCurrentProgress:1.0f];

        [_animation stopAnimation];

    }

    if (newView != nil) {

        // the window should grow by the size of the new view, in window coordinates

        newViewFrame = [newView frame];

        windowDelta += [newView convertSize:newViewFrame.size toView:nil].height;

    }

    if (_currentView != nil) {

        // the window should shrink by the size of the current view, in window coordinates

        currentViewFrame = [_currentView frame];

        windowDelta -= [_currentView convertSize:currentViewFrame.size toView:nil].height;

    }

    // calculate new window frame

    NSRect newWindowFrame = [docWindow frame];

    // change the window height by the delta we computed above

    newWindowFrame.size.height += windowDelta;

    // keep the upper left of the window in the same place, by moving the lower left by the same delta

    newWindowFrame.origin.y -= windowDelta;

    if (windowDelta > 0) {

        // before we start resizing the window, make sure the new size will fit onscreen

        NSRect constrainedWindowFrame = [docWindow constrainFrameRect:newWindowFrame toScreen:[docWindow screen]];

        if (!(NSEqualRects(constrainedWindowFrame, newWindowFrame))) {

            // adjust window frame so it can grow by windowDelta height 

            NSRect adjustedWindowFrame = constrainedWindowFrame;

            adjustedWindowFrame.size.height -=  windowDelta;

            adjustedWindowFrame.origin.y += windowDelta;

            [docWindow setFrame:adjustedWindowFrame display:YES animate:YES];

            newWindowFrame = constrainedWindowFrame;

        }

    }

    // temporarily pin the existing views to the top of  the window, so that they don't resize or move during the window resize below

    [_upperTableScrollView setAutoresizingMask:NSViewMinYMargin];

    [_middleBoxView setAutoresizingMask:NSViewMinYMargin];

    // hide old view, if any

    if (_currentView != nil) {

        NSRect endFrame = newViewFrame;

        endFrame.size.width = NSWidth(currentViewFrame);                // same width

        if (currentViewFrame.size.height < newViewFrame.size.height) {

            // if new view is taller than current view, set end frame for current view to be appropriate offset from bottom of window

            endFrame.origin.y = NSHeight(newViewFrame) - NSHeight(currentViewFrame);

            endFrame.size.height = NSHeight(currentViewFrame);

        }

        NSDictionary *animateOutDict = [NSDictionary dictionaryWithObjectsAndKeys:

            _currentView, NSViewAnimationTargetKey,

            NSViewAnimationFadeOutEffect, NSViewAnimationEffectKey,

            [NSValue valueWithRect:endFrame], NSViewAnimationEndFrameKey,

            nil];

        [viewAnimations addObject:animateOutDict];

    }

    // resize window

    NSDictionary *windowSizeDict = [NSDictionary dictionaryWithObjectsAndKeys:docWindow, NSViewAnimationTargetKey, [NSValue valueWithRect:newWindowFrame], NSViewAnimationEndFrameKey, nil];

    [viewAnimations addObject:windowSizeDict];

    // show new view, if any

    if (newView != nil) {

        NSRect startFrame = currentViewFrame;

        startFrame.size.width = NSWidth(newViewFrame);                                  // same width

        if (newViewFrame.size.height < currentViewFrame.size.height) {                  

            // if new view is shorter than old view, animate into appropriate offset from bottom of window

            startFrame.origin.y = NSHeight(currentViewFrame) - NSHeight(newViewFrame);

            startFrame.size.height = NSHeight(newViewFrame);

        }

        NSDictionary *animateInDict = [NSDictionary dictionaryWithObjectsAndKeys:

            newView, NSViewAnimationTargetKey, 

            NSViewAnimationFadeInEffect, NSViewAnimationEffectKey, 

            [NSValue valueWithRect:startFrame], NSViewAnimationStartFrameKey,

            [NSValue valueWithRect:newViewFrame], NSViewAnimationEndFrameKey,

            nil];

        [viewAnimations addObject:animateInDict];

    }

    _currentView = newView;

    _animation = [[NSViewAnimation alloc] initWithViewAnimations:viewAnimations];

    [_animation setDelegate:self];

    [_animation startAnimation];

}

- (void)animationDidStop:(NSAnimation*)animation {

    [self animationDidEnd:animation];

}

- (void)animationDidEnd:(NSAnimation*)animation {

    // since we may have adjusted the origin during animation, restore the correct origins.  This is important for the view that has been hidden

    [_stockTransactionView setFrameOrigin:NSZeroPoint];

    [_bankTransactionView  setFrameOrigin:NSZeroPoint];

    [_animation release];

    _animation = nil;

    // restore the resizing masks on the scrollView and middleBoxView.  

    // the scrollView should resize when the window resizes - NSViewHeightSizable|NSViewWidthSizable

    [_upperTableScrollView setAutoresizingMask:NSViewHeightSizable|NSViewWidthSizable];

    // the middleBoxView should preserve its size and position relative to lower left - NSViewNotSizable

    [_middleBoxView setAutoresizingMask:NSViewNotSizable];

}

// key value observing

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

    // if we have changed whether a transaction is a stock or bank transaction, update which detail view we show

    if ([keyPath isEqualToString:@"selection.stockTransaction"]) {

        [self updateView];

    }

}

- (IBAction)disclosureToggle:(id)sender {

    // the user has toggled the disclosure triangle to hide or show the detail view

    _expanded = ([sender state] == NSOnState);

    if (_expanded) {

        // while the detail view is shown, we need to be notified of any changes to the type of transaction (bank or stock)

        [_transactionController addObserver:self forKeyPath:@"selection.stockTransaction" options:0 context:NULL];    

    } else {

        // while the detail view is hidden, we do not need to be notified of changes to the type of transaction

        [_transactionController removeObserver:self forKeyPath:@"selection.stockTransaction"];

    }

    // hide or show the detail view

    [self updateView];

}

@end