// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#import "CTPresentationModeController.h"

#import "CTBrowserWindowController.h"
#import "GTMNSAnimation+Duration.h"
#import "common.h"

NSString* const kWillEnterFullscreenNotification = @"WillEnterFullscreenNotification";
NSString* const kWillLeaveFullscreenNotification = @"WillLeaveFullscreenNotification";

// Full screen modes, in increasing order of priority.  More permissive modes
// take predecence.
typedef enum {
	kFullScreenModeHideAll = 0,
	kFullScreenModeHideDock = 1,
	kFullScreenModeAutoHideAll = 2,
	kNumFullScreenModes = 3,
	
	// kFullScreenModeNormal is not a valid FullScreenMode, but it is useful to
	// other classes, so we include it here.
	kFullScreenModeNormal = 10,
} FullScreenMode;

// The activation zone for the main menu is 4 pixels high; if we make it any
// smaller, then the menu can be made to appear without the bar sliding down.
const CGFloat kDropdownActivationZoneHeight = 4;
const NSTimeInterval kDropdownAnimationDuration = 0.12;
const NSTimeInterval kMouseExitCheckDelay = 0.1;
// This show delay attempts to match the delay for the main menu.
const NSTimeInterval kDropdownShowDelay = 0.3;
const NSTimeInterval kDropdownHideDelay = 0.2;

// The amount by which the floating bar is offset downwards (to avoid the menu)
// in presentation mode. (We can't use |-[NSMenu menuBarHeight]| since it
// returns 0 when the menu bar is hidden.)
const CGFloat kFloatingBarVerticalOffset = 22;

// Helper class to manage animations for the dropdown bar.  Calls
// [PresentationModeController changeFloatingBarShownFraction] once per
// animation step.
@interface DropdownAnimation : NSAnimation {
@private
	__weak CTPresentationModeController* controller_;
	CGFloat startFraction_;
	CGFloat endFraction_;
}

@property(readonly, nonatomic) CGFloat startFraction;
@property(readonly, nonatomic) CGFloat endFraction;

// Designated initializer.  Asks |controller| for the current shown fraction, so
// if the bar is already partially shown or partially hidden, the animation
// duration may be less than |fullDuration|.
- (id)initWithFraction:(CGFloat)fromFraction
          fullDuration:(CGFloat)fullDuration
        animationCurve:(NSInteger)animationCurve
            controller:(CTPresentationModeController*)controller;

@end

@implementation DropdownAnimation

@synthesize startFraction = startFraction_;
@synthesize endFraction = endFraction_;

- (id)initWithFraction:(CGFloat)toFraction
          fullDuration:(CGFloat)fullDuration
        animationCurve:(NSInteger)animationCurve
            controller:(CTPresentationModeController*)controller {
	// Calculate the effective duration, based on the current shown fraction.
	DCHECK(controller);
	CGFloat fromFraction = [controller floatingBarShownFraction];
	CGFloat effectiveDuration = fabs(fullDuration * (fromFraction - toFraction));
	
	if ((self = [super gtm_initWithDuration:effectiveDuration
								  eventMask:NSLeftMouseDownMask
							 animationCurve:animationCurve])) {
		startFraction_ = fromFraction;
		endFraction_ = toFraction;
		controller_ = controller;
	}
	return self;
}

// Called once per animation step.  Overridden to change the floating bar's
// position based on the animation's progress.
- (void)setCurrentProgress:(NSAnimationProgress)progress {
	CGFloat fraction =
	startFraction_ + (progress * (endFraction_ - startFraction_));
	[controller_ changeFloatingBarShownFraction:fraction];
}

@end


@interface CTPresentationModeController (PrivateMethods)

// Returns YES if the window is on the primary screen.
- (BOOL)isWindowOnPrimaryScreen;

// Returns YES if it is ok to show and hide the menu bar in response to the
// overlay opening and closing.  Will return NO if the window is not main or not
// on the primary monitor.
- (BOOL)shouldToggleMenuBar;

// Returns |kFullScreenModeHideAll| when the overlay is hidden and
// |kFullScreenModeHideDock| when the overlay is shown.
- (FullScreenMode)desiredSystemFullscreenMode;

// Change the overlay to the given fraction, with or without animation. Only
// guaranteed to work properly with |fraction == 0| or |fraction == 1|. This
// performs the show/hide (animation) immediately. It does not touch the timers.
- (void)changeOverlayToFraction:(CGFloat)fraction
                  withAnimation:(BOOL)animate;

// Schedule the floating bar to be shown/hidden because of mouse position.
- (void)scheduleShowForMouse;
- (void)scheduleHideForMouse;

// Set up the tracking area used to activate the sliding bar or keep it active
// using with the rectangle in |trackingAreaBounds_|, or remove the tracking
// area if one was previously set up.
- (void)setupTrackingArea;
- (void)removeTrackingAreaIfNecessary;

// Returns YES if the mouse is currently in any current tracking rectangle, NO
// otherwise.
- (BOOL)mouseInsideTrackingRect;

// The tracking area can "falsely" report exits when the menu slides down over
// it. In that case, we have to monitor for a "real" mouse exit on a timer.
// |-setupMouseExitCheck| schedules a check; |-cancelMouseExitCheck| cancels any
// scheduled check.
- (void)setupMouseExitCheck;
- (void)cancelMouseExitCheck;

// Called (after a delay) by |-setupMouseExitCheck|, to check whether the mouse
// has exited or not; if it hasn't, it will schedule another check.
- (void)checkForMouseExit;

// Start timers for showing/hiding the floating bar.
- (void)startShowTimer;
- (void)startHideTimer;
- (void)cancelShowTimer;
- (void)cancelHideTimer;
- (void)cancelAllTimers;

// Methods called when the show/hide timers fire. Do not call directly.
- (void)showTimerFire:(NSTimer*)timer;
- (void)hideTimerFire:(NSTimer*)timer;

// Stops any running animations, removes tracking areas, etc.
- (void)cleanup;

// Shows and hides the UI associated with this window being active (having main
// status).  This includes hiding the menu bar.  These functions are called when
// the window gains or loses main status as well as in |-cleanup|.
- (void)showActiveWindowUI;
- (void)hideActiveWindowUI;

@end


@implementation CTPresentationModeController  {
@private
	// Our parent controller.
	__weak CTBrowserWindowController* browserController_;  // weak
	
	// The content view for the window.  This is nil when not in presentation
	// mode.
	__weak NSView* contentView_;  // weak
	
	// YES while this controller is in the process of entering presentation mode.
	BOOL enteringPresentationMode_;
	
	// Whether or not we are in presentation mode.
	BOOL inPresentationMode_;
	
	// The tracking area associated with the floating dropdown bar.  This tracking
	// area is attached to |contentView_|, because when the dropdown is completely
	// hidden, we still need to keep a 1px tall tracking area visible.  Attaching
	// to the content view allows us to do this.  |trackingArea_| can be nil if
	// not in presentation mode or during animations.
	NSTrackingArea* trackingArea_;
	
	// Pointer to the currently running animation.  Is nil if no animation is
	// running.
	DropdownAnimation* currentAnimation_;
	
	// Timers for scheduled showing/hiding of the bar (which are always done with
	// animation).
	NSTimer* showTimer_;
	NSTimer* hideTimer_;
	
	// Holds the current bounds of |trackingArea_|, even if |trackingArea_| is
	// currently nil.  Used to restore the tracking area when an animation
	// completes.
	NSRect trackingAreaBounds_;
	
	// Tracks the currently requested system fullscreen mode, used to show or hide
	// the menubar.  This should be |kFullScreenModeNormal| when the window is not
	// main or not fullscreen, |kFullScreenModeHideAll| while the overlay is
	// hidden, and |kFullScreenModeHideDock| while the overlay is shown.  If the
	// window is not on the primary screen, this should always be
	// |kFullScreenModeNormal|.  This value can get out of sync with the correct
	// state if we miss a notification (which can happen when a window is closed).
	// Used to track the current state and make sure we properly restore the menu
	// bar when this controller is destroyed.
	FullScreenMode systemFullscreenMode_;
}

@synthesize inPresentationMode = inPresentationMode_;

- (id)initWithBrowserController:(CTBrowserWindowController*)controller {
	if ((self = [super init])) {
		browserController_ = controller;
		systemFullscreenMode_ = kFullScreenModeNormal;
	}
	
	// Let the world know what we're up to.
	[[NSNotificationCenter defaultCenter] postNotificationName:kWillEnterFullscreenNotification
														object:nil];
	
	return self;
}

- (void)enterPresentationModeForContentView:(NSView*)contentView
                               showDropdown:(BOOL)showDropdown {
	DCHECK(!inPresentationMode_);
	enteringPresentationMode_ = YES;
	inPresentationMode_ = YES;
	contentView_ = contentView;
	[self changeFloatingBarShownFraction:(showDropdown ? 1 : 0)];
	
	// Register for notifications.  Self is removed as an observer in |-cleanup|.
	NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
	NSWindow* window = [browserController_ window];
		
	[nc addObserver:self
		   selector:@selector(windowDidBecomeMain:)
			   name:NSWindowDidBecomeMainNotification
			 object:window];
	
	[nc addObserver:self
		   selector:@selector(windowDidResignMain:)
			   name:NSWindowDidResignMainNotification
			 object:window];
	
	enteringPresentationMode_ = NO;
}

- (void)exitPresentationMode {
	[[NSNotificationCenter defaultCenter]
	 postNotificationName:kWillLeaveFullscreenNotification
	 object:nil];
	DCHECK(inPresentationMode_);
	inPresentationMode_ = NO;
	[self cleanup];
}

- (void)windowDidChangeScreen:(NSNotification*)notification {
	[browserController_ resizeFullscreenWindow];
}

- (void)windowDidMove:(NSNotification*)notification {
	[browserController_ resizeFullscreenWindow];
}

- (void)windowDidBecomeMain:(NSNotification*)notification {
	[self showActiveWindowUI];
}

- (void)windowDidResignMain:(NSNotification*)notification {
	[self hideActiveWindowUI];
}

- (CGFloat)floatingBarVerticalOffset {
	return [self isWindowOnPrimaryScreen] ? kFloatingBarVerticalOffset : 0;
}

- (void)overlayFrameChanged:(NSRect)frame {
	if (!inPresentationMode_)
		return;
	
	// Make sure |trackingAreaBounds_| always reflects either the tracking area or
	// the desired tracking area.
	trackingAreaBounds_ = frame;
	// The tracking area should always be at least the height of activation zone.
	NSRect contentBounds = [contentView_ bounds];
	trackingAreaBounds_.origin.y =
		MIN(trackingAreaBounds_.origin.y,
			 NSMaxY(contentBounds) - kDropdownActivationZoneHeight);
	trackingAreaBounds_.size.height =
		NSMaxY(contentBounds) - trackingAreaBounds_.origin.y + 1;
	
	// If an animation is currently running, do not set up a tracking area now.
	// Instead, leave it to be created it in |-animationDidEnd:|.
	if (currentAnimation_)
		return;
	
	// If this is part of the initial setup, lock bar visibility if the mouse is
	// within the tracking area bounds.
	if (enteringPresentationMode_ && [self mouseInsideTrackingRect])
		[browserController_ lockBarVisibilityForOwner:self
										withAnimation:NO
												delay:NO];
	[self setupTrackingArea];
}

- (void)ensureOverlayShownWithAnimation:(BOOL)animate 
								  delay:(BOOL)delay {
	if (!inPresentationMode_)
		return;
	
	if (animate) {
		if (delay) {
			[self startShowTimer];
		} else {
			[self cancelAllTimers];
			[self changeOverlayToFraction:1 withAnimation:YES];
		}
	} else {
		DCHECK(!delay);
		[self cancelAllTimers];
		[self changeOverlayToFraction:1 withAnimation:NO];
	}
}

- (void)ensureOverlayHiddenWithAnimation:(BOOL)animate delay:(BOOL)delay {
	if (!inPresentationMode_)
		return;
	
	if (animate) {
		if (delay) {
			[self startHideTimer];
		} else {
			[self cancelAllTimers];
			[self changeOverlayToFraction:0 withAnimation:YES];
		}
	} else {
		DCHECK(!delay);
		[self cancelAllTimers];
		[self changeOverlayToFraction:0 withAnimation:NO];
	}
}

- (void)cancelAnimationAndTimers {
	[self cancelAllTimers];
	[currentAnimation_ stopAnimation];
	currentAnimation_ = nil;
}

- (CGFloat)floatingBarShownFraction {
	return [browserController_ floatingBarShownFraction];
}

- (void)changeFloatingBarShownFraction:(CGFloat)fraction {
	[browserController_ setFloatingBarShownFraction:fraction];
	
	FullScreenMode desiredMode = [self desiredSystemFullscreenMode];
	if (desiredMode != systemFullscreenMode_ && [self shouldToggleMenuBar]) {
		// TODO: check what these stuffs do
//		if (systemFullscreenMode_ == kFullScreenModeNormal)
//			[self requestFullScreen(desiredMode)];
//		else
//			base::mac::SwitchFullScreenModes(systemFullscreenMode_, desiredMode);
		systemFullscreenMode_ = desiredMode;
	}
}

// Used to activate the floating bar in presentation mode.
- (void)mouseEntered:(NSEvent*)event {
	DCHECK(inPresentationMode_);
	
	// Having gotten a mouse entered, we no longer need to do exit checks.
	[self cancelMouseExitCheck];
	
	NSTrackingArea* trackingArea = [event trackingArea];
	if (trackingArea == trackingArea_) {
		// The tracking area shouldn't be active during animation.
		DCHECK(!currentAnimation_);
		[self scheduleShowForMouse];
	}
}

// Used to deactivate the floating bar in presentation mode.
- (void)mouseExited:(NSEvent*)event {
	DCHECK(inPresentationMode_);
	
	NSTrackingArea* trackingArea = [event trackingArea];
	if (trackingArea == trackingArea_) {
		// The tracking area shouldn't be active during animation.
		DCHECK(!currentAnimation_);
		
		// We can get a false mouse exit when the menu slides down, so if the mouse
		// is still actually over the tracking area, we ignore the mouse exit, but
		// we set up to check the mouse position again after a delay.
		if ([self mouseInsideTrackingRect]) {
			[self setupMouseExitCheck];
			return;
		}
		
		[self scheduleHideForMouse];
	}
}

- (void)animationDidStop:(NSAnimation*)animation {
	// Reset the |currentAnimation_| pointer now that the animation is over.
	currentAnimation_ = nil;
	
	// Invariant says that the tracking area is not installed while animations are
	// in progress. Ensure this is true.
	DCHECK(!trackingArea_);
	[self removeTrackingAreaIfNecessary];  // For paranoia.
	
	// Don't automatically set up a new tracking area. When explicitly stopped,
	// either another animation is going to start immediately or the state will be
	// changed immediately.
}

- (void)animationDidEnd:(NSAnimation*)animation {
	[self animationDidStop:animation];
	
	// |trackingAreaBounds_| contains the correct tracking area bounds, including
	// |any updates that may have come while the animation was running. Install a
	// new tracking area with these bounds.
	[self setupTrackingArea];
	
	// TODO(viettrungluu): Better would be to check during the animation; doing it
	// here means that the timing is slightly off.
	if (![self mouseInsideTrackingRect])
		[self scheduleHideForMouse];
}

@end


@implementation CTPresentationModeController (PrivateMethods)

- (BOOL)isWindowOnPrimaryScreen {
	NSScreen* screen = [[browserController_ window] screen];
	NSScreen* primaryScreen = [[NSScreen screens] objectAtIndex:0];
	return (screen == primaryScreen);
}

- (BOOL)shouldToggleMenuBar {
	return NO && [self isWindowOnPrimaryScreen] && [[browserController_ window] isMainWindow];
}

- (FullScreenMode)desiredSystemFullscreenMode {
	if ([browserController_ floatingBarShownFraction] >= 1.0)
		return kFullScreenModeHideDock;
	return kFullScreenModeHideAll;
}

- (void)changeOverlayToFraction:(CGFloat)fraction
                  withAnimation:(BOOL)animate {
	// The non-animated case is really simple, so do it and return.
	if (!animate) {
		[currentAnimation_ stopAnimation];
		[self changeFloatingBarShownFraction:fraction];
		return;
	}
	
	// If we're already animating to the given fraction, then there's nothing more
	// to do.
	if (currentAnimation_ && [currentAnimation_ endFraction] == fraction)
		return;
	
	// In all other cases, we want to cancel any running animation (which may be
	// to show or to hide).
	[currentAnimation_ stopAnimation];
	
	// Now, if it happens to already be in the right state, there's nothing more
	// to do.
	if ([browserController_ floatingBarShownFraction] == fraction)
		return;
	
	// Create the animation and set it up.
	currentAnimation_ = [[DropdownAnimation alloc] initWithFraction:fraction 
													   fullDuration:kDropdownAnimationDuration
													 animationCurve:NSAnimationEaseOut
														 controller:self];
	DCHECK(currentAnimation_);
	[currentAnimation_ setAnimationBlockingMode:NSAnimationNonblocking];
	[currentAnimation_ setDelegate:self];
	
	// If there is an existing tracking area, remove it. We do not track mouse
	// movements during animations (see class comment in the header file).
	[self removeTrackingAreaIfNecessary];
	
	[currentAnimation_ startAnimation];
}

- (void)scheduleShowForMouse {
	[browserController_ lockBarVisibilityForOwner:self
									withAnimation:YES
											delay:YES];
}

- (void)scheduleHideForMouse {
	[browserController_ releaseBarVisibilityForOwner:self
									   withAnimation:YES
											   delay:YES];
}

- (void)setupTrackingArea {
	if (trackingArea_) {
		// If the tracking rectangle is already |trackingAreaBounds_|, quit early.
		NSRect oldRect = [trackingArea_ rect];
		if (NSEqualRects(trackingAreaBounds_, oldRect))
			return;
		
		// Otherwise, remove it.
		[self removeTrackingAreaIfNecessary];
	}
	
	// Create and add a new tracking area for |frame|.
	trackingArea_ = [[NSTrackingArea alloc] initWithRect:trackingAreaBounds_
												 options:NSTrackingMouseEnteredAndExited |					 NSTrackingActiveInKeyWindow
												   owner:self
												userInfo:nil];
	DCHECK(contentView_);
	[contentView_ addTrackingArea:trackingArea_];
}

- (void)removeTrackingAreaIfNecessary {
	if (trackingArea_) {
		DCHECK(contentView_);  // |contentView_| better be valid.
		[contentView_ removeTrackingArea:trackingArea_];
		trackingArea_ = nil;
	}
}

- (BOOL)mouseInsideTrackingRect {
	NSWindow* window = [browserController_ window];
	NSPoint mouseLoc = [window mouseLocationOutsideOfEventStream];
	NSPoint mousePos = [contentView_ convertPoint:mouseLoc fromView:nil];
	return NSMouseInRect(mousePos, trackingAreaBounds_, [contentView_ isFlipped]);
}

- (void)setupMouseExitCheck {
	[self performSelector:@selector(checkForMouseExit)
			   withObject:nil
			   afterDelay:kMouseExitCheckDelay];
}

- (void)cancelMouseExitCheck {
	[NSObject cancelPreviousPerformRequestsWithTarget:self
											 selector:@selector(checkForMouseExit) object:nil];
}

- (void)checkForMouseExit {
	if ([self mouseInsideTrackingRect])
		[self setupMouseExitCheck];
	else
		[self scheduleHideForMouse];
}

- (void)startShowTimer {
	// If there's already a show timer going, just keep it.
	if (showTimer_) {
		DCHECK([showTimer_ isValid]);
		DCHECK(!hideTimer_);
		return;
	}
	
	// Cancel the hide timer (if necessary) and set up the new show timer.
	[self cancelHideTimer];
	showTimer_ = [NSTimer scheduledTimerWithTimeInterval:kDropdownShowDelay 
												  target:self
												selector:@selector(showTimerFire:)
												userInfo:nil
												 repeats:NO];
	DCHECK([showTimer_ isValid]);  // This also checks that |showTimer_ != nil|.
}

- (void)startHideTimer {
	// If there's already a hide timer going, just keep it.
	if (hideTimer_) {
		DCHECK([hideTimer_ isValid]);
		DCHECK(!showTimer_);
		return;
	}
	
	// Cancel the show timer (if necessary) and set up the new hide timer.
	[self cancelShowTimer];
	hideTimer_ = [NSTimer scheduledTimerWithTimeInterval:kDropdownHideDelay
												  target:self
												selector:@selector(hideTimerFire:)
												userInfo:nil
												 repeats:NO];
	DCHECK([hideTimer_ isValid]);  // This also checks that |hideTimer_ != nil|.
}

- (void)cancelShowTimer {
	[showTimer_ invalidate];
	showTimer_ = nil;
}

- (void)cancelHideTimer {
	[hideTimer_ invalidate];
	hideTimer_ = nil;
}

- (void)cancelAllTimers {
	[self cancelShowTimer];
	[self cancelHideTimer];
}

- (void)showTimerFire:(NSTimer*)timer {
	DCHECK_EQ(showTimer_, timer);  // This better be our show timer.
	[showTimer_ invalidate];       // Make sure it doesn't repeat.
	showTimer_ = nil;            // And get rid of it.
	[self changeOverlayToFraction:1 withAnimation:YES];
}

- (void)hideTimerFire:(NSTimer*)timer {
	DCHECK_EQ(hideTimer_, timer);  // This better be our hide timer.
	[hideTimer_ invalidate];       // Make sure it doesn't repeat.
	hideTimer_ = nil;            // And get rid of it.
	[self changeOverlayToFraction:0 withAnimation:YES];
}

- (void)cleanup {
	[self cancelMouseExitCheck];
	[self cancelAnimationAndTimers];
	[[NSNotificationCenter defaultCenter] removeObserver:self];
	
	[self removeTrackingAreaIfNecessary];
	contentView_ = nil;
	
	// This isn't tracked when not in presentation mode.
	[browserController_ releaseBarVisibilityForOwner:self
									   withAnimation:NO
											   delay:NO];
	
	// Call the main status resignation code to perform the associated cleanup,
	// since we will no longer be receiving actual status resignation
	// notifications.
	[self hideActiveWindowUI];
	
	// No more calls back up to the BWC.
	browserController_ = nil;
}

- (void)showActiveWindowUI {
	DCHECK_EQ(systemFullscreenMode_, kFullScreenModeNormal);
	if (systemFullscreenMode_ != kFullScreenModeNormal)
		return;
	
	if ([self shouldToggleMenuBar]) {
		FullScreenMode desiredMode = [self desiredSystemFullscreenMode];
		// TODO: check this!
//		base::mac::RequestFullScreen(desiredMode);
		systemFullscreenMode_ = desiredMode;
	}
	
	// TODO(rohitrao): Insert the Exit Fullscreen button.  http://crbug.com/35956
}

- (void)hideActiveWindowUI {
	if (systemFullscreenMode_ != kFullScreenModeNormal) {
		// TODO: check this!
//		base::mac::ReleaseFullScreen(systemFullscreenMode_);
		systemFullscreenMode_ = kFullScreenModeNormal;
	}
	
	// TODO(rohitrao): Remove the Exit Fullscreen button.  http://crbug.com/35956
}

@end