/*

     File: Document.m

 Abstract: The document class. This setups up the AVPlayer used by the document’s AVPlayerView. It also handles showing/hiding the action menu, trim, export, and chapter navigation actions.

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#import "Document.h"

#import "ExportProgressWindowController.h"

#import <AVFoundation/AVFoundation.h>

#import <AVKit/AVKit.h>

#import <objc/runtime.h>

@interface Document () <ExportProgressWindowControllerDelegate>

@property (weak) IBOutlet AVPlayerView *playerView;

@property AVPlayer *player;

@property AVAssetExportSession *exportSession;

@property ExportProgressWindowController *exportProgressWindowController;

@property NSArray *chapterMetadataGroups;

@end

@implementation Document

- (NSString *)windowNibName

{

    return @"Document";

}

- (void)windowControllerDidLoadNib:(NSWindowController *)windowController

{

    [super windowControllerDidLoadNib:windowController];

    // Associate AVPlayer with AVPlayerView once the NIB is loaded

    self.playerView.player = _player;

}

- (BOOL)readFromURL:(NSURL *)absoluteURL ofType:(NSString *)typeName error:(NSError **)outError

{

    _player = [AVPlayer playerWithURL:absoluteURL];

    // Load chapters to be used by the next/previous chapter menu items

    [_player.currentItem.asset loadValuesAsynchronouslyForKeys:@[@"availableChapterLocales"] completionHandler:^{

        self.chapterMetadataGroups = [_player.currentItem.asset chapterMetadataGroupsBestMatchingPreferredLanguages:[NSLocale preferredLanguages]];

    }];

    return YES;

}

#pragma mark Trim and Export

- (void)trim:(id)sender

{

    // Show trim controls

    [self.playerView beginTrimmingWithCompletionHandler:NULL];

}

- (IBAction)startExport:(id)sender

{

    // Pause playback before starting the export since the user will not be able to interact with transport controls to pause it themselves once the export has started

    [self.playerView.player pause];

    NSSavePanel *savePanel = [NSSavePanel savePanel];

    [savePanel beginSheetModalForWindow:self.windowForSheet completionHandler:^(NSInteger result) {

        if (result == NSFileHandlingPanelOKButton)

        {

            // Order out the save panel here because the export sheet is about to be shown

            [savePanel orderOut:nil];

            AVPlayerItem *playerItem = self.player.currentItem;

            AVAsset *asset = playerItem.asset;

            self.exportSession = [AVAssetExportSession exportSessionWithAsset:asset presetName:[AVAssetExportSession exportPresetsCompatibleWithAsset:asset].firstObject];

            self.exportSession.timeRange = CMTimeRangeFromTimeToTime(playerItem.reversePlaybackEndTime, playerItem.forwardPlaybackEndTime);

            self.exportSession.outputFileType = self.exportSession.supportedFileTypes.firstObject;

            self.exportSession.outputURL = savePanel.URL;

            self.exportProgressWindowController = [[ExportProgressWindowController alloc] initWithWindowNibName:@"ExportProgress"];

            self.exportProgressWindowController.exportSession = self.exportSession;

            self.exportProgressWindowController.delegate = self;

            [self.windowForSheet beginSheet:self.exportProgressWindowController.window completionHandler:nil];

            [self.exportSession exportAsynchronouslyWithCompletionHandler:^{

                [self.windowForSheet endSheet:self.exportProgressWindowController.window];

                self.exportProgressWindowController = nil;

                self.exportSession = nil;

            }];

        }

    }];

}

- (void)exportProgressWindowControllerDidCancel:(ExportProgressWindowController *)exportProgressWindowController

{

    // Ending the sheet will be handled in the export session completion handler

    [self.exportSession cancelExport];

}

#pragma mark Chapter Navigation

- (AVTimedMetadataGroup *)nextChapterTime

{

    AVTimedMetadataGroup *nextChapterGroup;

    CMTime currentTime = self.player.currentItem.currentTime;

    CMTime nextChapterTime = kCMTimePositiveInfinity;

    for (AVTimedMetadataGroup *timedMetadataGroup in self.chapterMetadataGroups)

    {

        if (CMTIME_COMPARE_INLINE(timedMetadataGroup.timeRange.start, >, currentTime) && CMTIME_COMPARE_INLINE(timedMetadataGroup.timeRange.start, <, nextChapterTime))

        {

            nextChapterTime = timedMetadataGroup.timeRange.start;

            nextChapterGroup = timedMetadataGroup;

        }

    }

    return nextChapterGroup;

}

- (AVTimedMetadataGroup *)previousChapterTime

{

    AVTimedMetadataGroup *previousChapterGroup;

    // Give a second of time to seek to the previous chapter, as opposed to the beginning of the current chapter

    CMTime currentTimeMinusASecond = CMTimeSubtract(self.player.currentItem.currentTime, CMTimeMakeWithSeconds(1, 300));

    CMTime previousChapterTime = kCMTimeNegativeInfinity;

    for (AVTimedMetadataGroup *timedMetadataGroup in self.chapterMetadataGroups)

    {

        if (CMTIME_COMPARE_INLINE(timedMetadataGroup.timeRange.start, <, currentTimeMinusASecond) && CMTIME_COMPARE_INLINE(timedMetadataGroup.timeRange.start, >, previousChapterTime))

        {

            previousChapterTime = timedMetadataGroup.timeRange.start;

            previousChapterGroup = timedMetadataGroup;

        }

    }

    return previousChapterGroup;

}

- (NSUInteger)chapterNumberForChapterGroup:(AVTimedMetadataGroup *)chapterGroup

{

    return [self.chapterMetadataGroups indexOfObject:chapterGroup] + 1;

}

- (void)seekToChapterTime:(AVTimedMetadataGroup *)chapterGroup

{

    CMTime chapterTime = chapterGroup.timeRange.start;

    if (CMTIME_IS_NUMERIC(chapterTime))

    {

        [self.player.currentItem seekToTime:chapterTime completionHandler:^(BOOL finished) {

            // Flash the current chapter number and title

            [self.playerView flashChapterNumber:[self chapterNumberForChapterGroup:chapterGroup] chapterTitle:[[AVMetadataItem metadataItemsFromArray:chapterGroup.items withKey:AVMetadataCommonKeyTitle keySpace:AVMetadataKeySpaceCommon].firstObject value]];

        }];

    }

}

- (IBAction)nextChapter:(id)sender

{

    [self seekToChapterTime:self.nextChapterTime];

}

- (IBAction)previousChapter:(id)sender

{

    [self seekToChapterTime:self.previousChapterTime];

}

#pragma mark Action Menu

- (void)toggleActionMenu:(id)sender

{

    NSMenu *menu;

    if (self.playerView.actionPopUpButtonMenu == nil)

    {

        // In a real application, these menu items would do something more interesting

        menu = [[NSMenu alloc] initWithTitle:@""];

        [menu addItem:[[NSMenuItem alloc] initWithTitle:@"this" action:NULL keyEquivalent:@""]];

        [menu addItem:[[NSMenuItem alloc] initWithTitle:@"is" action:NULL keyEquivalent:@""]];

        [menu addItem:[[NSMenuItem alloc] initWithTitle:@"the" action:NULL keyEquivalent:@""]];

        [menu addItem:[[NSMenuItem alloc] initWithTitle:@"action" action:NULL keyEquivalent:@""]];

        [menu addItem:[[NSMenuItem alloc] initWithTitle:@"menu" action:NULL keyEquivalent:@""]];

    }

    self.playerView.actionPopUpButtonMenu = menu;

}

#pragma mark UI Validation

- (BOOL)validateUserInterfaceItem:(id <NSValidatedUserInterfaceItem>)item

{

    SEL action = [item action];

    if (sel_isEqual(action, @selector(trim:)))

    {

        // -canBeginTrimming will return NO when the current AVPlayerItem cannot be trimmed or the trim controls are already shown

        return self.playerView.canBeginTrimming;

    }

    else if (sel_isEqual(action, @selector(startExport:)))

    {

        // Cannot export if there is not an AVAsset

        return self.player.currentItem.asset ? YES : NO;

    }

    else if (sel_isEqual(action, @selector(toggleActionMenu:)))

    {

        // Show a check mark on the menu item when the action popup button is being displayed, otherwise do not

        if ([(NSMenuItem *)item respondsToSelector:@selector(setState:)])

            [(NSMenuItem *)item setState:self.playerView.actionPopUpButtonMenu != nil ? NSOnState : NSOffState];

        return YES;

    }

    else if (sel_isEqual(action, @selector(nextChapter:)) || sel_isEqual(action, @selector(previousChapter:)))

    {

        // Cannot seek chapters if there is no chapter metadata

        return self.chapterMetadataGroups ? YES : NO;

    }

    return [super validateUserInterfaceItem:item];

}

@end