/*

    File: BrowserViewController.m 

Abstract:  View controller for the service instance list.

This object manages a NSNetServiceBrowser configured to look for Bonjour

services.

It has an array of NSNetService objects that are displayed in a table view.

When the service browser reports that it has discovered a service, the

corresponding NSNetService is added to the array.

When a service goes away, the corresponding NSNetService is removed from the

array.

Selecting an item in the table view asynchronously resolves the corresponding

net service.

When that resolution completes, the delegate is called with the corresponding

NSNetService.

 Version: 2.9 

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without specific prior written permission from Apple.  Except as 

expressly stated in this notice, no other rights or licenses, express or 

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MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION 

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OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS. 

IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL 

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*/

#import "BrowserViewController.h"

#define kProgressIndicatorSize 20.0

// A category on NSNetService that's used to sort NSNetService objects by their name.

@interface NSNetService (BrowserViewControllerAdditions)

- (NSComparisonResult) localizedCaseInsensitiveCompareByName:(NSNetService*)aService;

@end

@implementation NSNetService (BrowserViewControllerAdditions)

- (NSComparisonResult) localizedCaseInsensitiveCompareByName:(NSNetService*)aService {

    return [[self name] localizedCaseInsensitiveCompare:[aService name]];

}

@end

@interface BrowserViewController()

@property (nonatomic, assign, readwrite) BOOL showDisclosureIndicators;

@property (nonatomic, retain, readwrite) NSMutableArray* services;

@property (nonatomic, retain, readwrite) NSNetServiceBrowser* netServiceBrowser;

@property (nonatomic, retain, readwrite) NSNetService* currentResolve;

@property (nonatomic, retain, readwrite) NSTimer* timer;

@property (nonatomic, assign, readwrite) BOOL needsActivityIndicator;

@property (nonatomic, assign, readwrite) BOOL initialWaitOver;

- (void)stopCurrentResolve;

- (void)initialWaitOver:(NSTimer*)timer;

@end

@implementation BrowserViewController

@synthesize delegate = _delegate;

@synthesize showDisclosureIndicators = _showDisclosureIndicators;

@synthesize currentResolve = _currentResolve;

@synthesize netServiceBrowser = _netServiceBrowser;

@synthesize services = _services;

@synthesize needsActivityIndicator = _needsActivityIndicator;

@dynamic timer;

@synthesize initialWaitOver = _initialWaitOver;

- (id)initWithTitle:(NSString*)title showDisclosureIndicators:(BOOL)show showCancelButton:(BOOL)showCancelButton {

    if ((self = [super initWithStyle:UITableViewStylePlain])) {

        self.title = title;

        _services = [[NSMutableArray alloc] init];

        self.showDisclosureIndicators = show;

        if (showCancelButton) {

            // add Cancel button as the nav bar's custom right view

            UIBarButtonItem *addButton = [[UIBarButtonItem alloc]

                                          initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelAction)];

            self.navigationItem.rightBarButtonItem = addButton;

            [addButton release];

        }

        // Make sure we have a chance to discover devices before showing the user that nothing was found (yet)

        [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(initialWaitOver:) userInfo:nil repeats:NO];

    }

    return self;

}

- (NSString *)searchingForServicesString {

    return _searchingForServicesString;

}

// Holds the string that's displayed in the table view during service discovery.

- (void)setSearchingForServicesString:(NSString *)searchingForServicesString {

    if (_searchingForServicesString != searchingForServicesString) {

        [_searchingForServicesString release];

        _searchingForServicesString = [searchingForServicesString copy];

        // If there are no services, reload the table to ensure that searchingForServicesString appears.

        if ([self.services count] == 0) {

            [self.tableView reloadData];

        }

    }

}

// Creates an NSNetServiceBrowser that searches for services of a particular type in a particular domain.

// If a service is currently being resolved, stop resolving it and stop the service browser from

// discovering other services.

- (BOOL)searchForServicesOfType:(NSString *)type inDomain:(NSString *)domain {

    [self stopCurrentResolve];

    [self.netServiceBrowser stop];

    [self.services removeAllObjects];

    NSNetServiceBrowser *aNetServiceBrowser = [[NSNetServiceBrowser alloc] init];

    if(!aNetServiceBrowser) {

        // The NSNetServiceBrowser couldn't be allocated and initialized.

        return NO;

    }

    aNetServiceBrowser.delegate = self;

    self.netServiceBrowser = aNetServiceBrowser;

    [aNetServiceBrowser release];

    [self.netServiceBrowser searchForServicesOfType:type inDomain:domain];

    [self.tableView reloadData];

    return YES;

}

- (NSTimer *)timer {

    return _timer;

}

// When this is called, invalidate the existing timer before releasing it.

- (void)setTimer:(NSTimer *)newTimer {

    [_timer invalidate];

    [newTimer retain];

    [_timer release];

    _timer = newTimer;

}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

    return 1;

}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    // If there are no services and searchingForServicesString is set, show one row to tell the user.

    NSUInteger count = [self.services count];

    if (count == 0 && self.searchingForServicesString && self.initialWaitOver)

        return 1;

    return count;

}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *tableCellIdentifier = @"UITableViewCell";

    UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:tableCellIdentifier];

    if (cell == nil) {

        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:tableCellIdentifier] autorelease];

    }

    NSUInteger count = [self.services count];

    if (count == 0 && self.searchingForServicesString) {

        // If there are no services and searchingForServicesString is set, show one row explaining that to the user.

        cell.textLabel.text = self.searchingForServicesString;

        cell.textLabel.textColor = [UIColor colorWithWhite:0.5 alpha:0.5];

        cell.accessoryType = UITableViewCellAccessoryNone;

        // Make sure to get rid of the activity indicator that may be showing if we were resolving cell zero but

        // then got didRemoveService callbacks for all services (e.g. the network connection went down).

        if (cell.accessoryView)

            cell.accessoryView = nil;

        return cell;

    }

    // Set up the text for the cell

    NSNetService* service = [self.services objectAtIndex:indexPath.row];

    cell.textLabel.text = [service name];

    cell.textLabel.textColor = [UIColor blackColor];

    cell.accessoryType = self.showDisclosureIndicators ? UITableViewCellAccessoryDisclosureIndicator : UITableViewCellAccessoryNone;

    // Note that the underlying array could have changed, and we want to show the activity indicator on the correct cell

    if (self.needsActivityIndicator && self.currentResolve == service) {

        if (!cell.accessoryView) {

            CGRect frame = CGRectMake(0.0, 0.0, kProgressIndicatorSize, kProgressIndicatorSize);

            UIActivityIndicatorView* spinner = [[UIActivityIndicatorView alloc] initWithFrame:frame];

            [spinner startAnimating];

            spinner.activityIndicatorViewStyle = UIActivityIndicatorViewStyleGray;

            [spinner sizeToFit];

            spinner.autoresizingMask = (UIViewAutoresizingFlexibleLeftMargin |

                                        UIViewAutoresizingFlexibleRightMargin |

                                        UIViewAutoresizingFlexibleTopMargin |

                                        UIViewAutoresizingFlexibleBottomMargin);

            cell.accessoryView = spinner;

            [spinner release];

        }

    } else if (cell.accessoryView) {

        cell.accessoryView = nil;

    }

    return cell;

}

- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    // Ignore the selection if there are no services as the searchingForServicesString cell

    // may be visible and tapping it would do nothing

    if ([self.services count] == 0)

        return nil;

    return indexPath;

}

- (void)stopCurrentResolve {

    self.needsActivityIndicator = NO;

    self.timer = nil;

    [self.currentResolve stop];

    self.currentResolve = nil;

}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    // If another resolve was running, stop it & remove the activity indicator from that cell

    if (self.currentResolve) {

        // Get the indexPath for the active resolve cell

        NSIndexPath* indexPath = [NSIndexPath indexPathForRow:[self.services indexOfObject:self.currentResolve] inSection:0];

        // Stop the current resolve, which will also set self.needsActivityIndicator

        [self stopCurrentResolve];

        // If we found the indexPath for the row, reload that cell to remove the activity indicator

        if (indexPath.row != NSNotFound)

            [self.tableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationNone];

    }

    // Then set the current resolve to the service corresponding to the tapped cell

    self.currentResolve = [self.services objectAtIndex:indexPath.row];

    [self.currentResolve setDelegate:self];

    // Attempt to resolve the service. A value of 0.0 sets an unlimited time to resolve it. The user can

    // choose to cancel the resolve by selecting another service in the table view.

    [self.currentResolve resolveWithTimeout:0.0];

    // Make sure we give the user some feedback that the resolve is happening.

    // We will be called back asynchronously, so we don't want the user to think we're just stuck.

    // We delay showing this activity indicator in case the service is resolved quickly.

    self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(showWaiting:) userInfo:self.currentResolve repeats:NO];

}

// If necessary, sets up state to show an activity indicator to let the user know that a resolve is occuring.

- (void)showWaiting:(NSTimer*)timer {

    if (timer == self.timer) {

        NSNetService* service = (NSNetService*)[self.timer userInfo];

        if (self.currentResolve == service) {

            self.needsActivityIndicator = YES;

            NSIndexPath* indexPath = [NSIndexPath indexPathForRow:[self.services indexOfObject:self.currentResolve] inSection:0];

            if (indexPath.row != NSNotFound) {

                [self.tableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationNone];

                // Deselect the row since the activity indicator shows the user something is happening.

                [self.tableView deselectRowAtIndexPath:indexPath animated:YES];

            }

        }

    }

}

- (void)initialWaitOver:(NSTimer*)timer {

    self.initialWaitOver= YES;

    if (![self.services count])

        [self.tableView reloadData];

}

- (void)sortAndUpdateUI {

    // Sort the services by name.

    [self.services sortUsingSelector:@selector(localizedCaseInsensitiveCompareByName:)];

    [self.tableView reloadData];

}

- (void)netServiceBrowser:(NSNetServiceBrowser*)netServiceBrowser didRemoveService:(NSNetService*)service moreComing:(BOOL)moreComing {

    // If a service went away, stop resolving it if it's currently being resolved,

    // remove it from the list and update the table view if no more events are queued.

    if (self.currentResolve && [service isEqual:self.currentResolve]) {

        [self stopCurrentResolve];

    }

    [self.services removeObject:service];

    // If moreComing is NO, it means that there are no more messages in the queue from the Bonjour daemon, so we should update the UI.

    // When moreComing is set, we don't update the UI so that it doesn't 'flash'.

    if (!moreComing) {

        [self sortAndUpdateUI];

    }

}   

- (void)netServiceBrowser:(NSNetServiceBrowser*)netServiceBrowser didFindService:(NSNetService*)service moreComing:(BOOL)moreComing {

    // If a service came online, add it to the list and update the table view if no more events are queued.

    [self.services addObject:service];

    // If moreComing is NO, it means that there are no more messages in the queue from the Bonjour daemon, so we should update the UI.

    // When moreComing is set, we don't update the UI so that it doesn't 'flash'.

    if (!moreComing) {

        [self sortAndUpdateUI];

    }

}   

// This should never be called, since we resolve with a timeout of 0.0, which means indefinite

- (void)netService:(NSNetService *)sender didNotResolve:(NSDictionary *)errorDict {

    [self stopCurrentResolve];

    [self.tableView reloadData];

}

- (void)netServiceDidResolveAddress:(NSNetService *)service {

    assert(service == self.currentResolve);

    [service retain];

    [self stopCurrentResolve];

    [self.delegate browserViewController:self didResolveInstance:service];

    [service release];

}

- (void)cancelAction {

    [self.delegate browserViewController:self didResolveInstance:nil];

}

- (void)dealloc {

    // Cleanup any running resolve and free memory

    [self stopCurrentResolve];

    self.services = nil;

    [self.netServiceBrowser stop];

    self.netServiceBrowser = nil;

    [_searchingForServicesString release];

    [super dealloc];

}

@end