/**
* Copyright Maarten Billemont (http://www.lhunath.com, lhunath@lyndir.com)
*
* See the enclosed file LICENSE for license information (LGPLv3). If you did
* not receive this file, see http://www.gnu.org/licenses/lgpl-3.0.txt
*
* @author   Maarten Billemont <lhunath@lyndir.com>
* @license  http://www.gnu.org/licenses/lgpl-3.0.txt
*/

//
//  MPPasswordsViewController.h
//  MPPasswordsViewController
//
//  Created by lhunath on 2014-03-08.
//  Copyright, lhunath (Maarten Billemont) 2014. All rights reserved.
//

#import "MPPasswordsViewController.h"
#import "MPiOSAppDelegate.h"
#import "MPAppDelegate_Store.h"
#import "MPPopdownSegue.h"
#import "MPAppDelegate_Key.h"
#import "MPPasswordCell.h"
#import "UICollectionView+PearlReloadFromArray.h"
#import "MPAnswersViewController.h"

@interface MPPasswordsViewController()<NSFetchedResultsControllerDelegate>

@property(nonatomic, strong) IBOutlet UINavigationBar *navigationBar;
@property(nonatomic, readonly) NSString *query;

@end

@implementation MPPasswordsViewController {
    __weak id _storeChangingObserver;
    __weak id _storeChangedObserver;
    __weak id _mocObserver;
    NSArray *_notificationObservers;
    __weak UITapGestureRecognizer *_passwordsDismissRecognizer;
    NSFetchedResultsController *_fetchedResultsController;
    UIColor *_backgroundColor;
    UIColor *_darkenedBackgroundColor;
    __weak UIViewController *_popdownVC;
    BOOL _showTransientItem;
    NSUInteger _transientItem;
}

#pragma mark - Life

- (void)viewDidLoad {

    [super viewDidLoad];

    _backgroundColor = self.passwordCollectionView.backgroundColor;
    _darkenedBackgroundColor = [_backgroundColor colorWithAlphaComponent:0.6f];
    _transientItem = NSNotFound;

    self.view.backgroundColor = [UIColor clearColor];
    [self.passwordCollectionView automaticallyAdjustInsetsForKeyboard];
    [self.passwordsSearchBar enumerateViews:^(UIView *subview, BOOL *stop, BOOL *recurse) {
        if ([subview isKindOfClass:[UITextField class]])
            ((UITextField *)subview).keyboardAppearance = UIKeyboardAppearanceDark;
    }                               recurse:YES];
}

- (void)viewWillAppear:(BOOL)animated {

    [super viewWillAppear:animated];

    [self registerObservers];
    [self observeStore];
    [self updateConfigKey:nil];
    [self updatePasswords];
}

- (void)viewWillDisappear:(BOOL)animated {

    [super viewWillDisappear:animated];

    [self removeObservers];
    [self stopObservingStore];
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {

    if ([segue.identifier isEqualToString:@"popdown"])
        _popdownVC = segue.destinationViewController;
    if ([segue.identifier isEqualToString:@"answers"])
        ((MPAnswersViewController *)segue.destinationViewController).site =
                [[MPPasswordCell findAsSuperviewOf:sender] siteInContext:[MPiOSAppDelegate managedObjectContextForMainThreadIfReady]];
}

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {

    [self.passwordCollectionView.collectionViewLayout invalidateLayout];

    [super willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration];
}

#pragma mark - UICollectionViewDelegateFlowLayout

- (CGSize)       collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout
referenceSizeForHeaderInSection:(NSInteger)section {

    return CGSizeMake( collectionView.bounds.size.width, CGRectGetBottom( self.passwordsSearchBar.frame ).y );
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout
  sizeForItemAtIndexPath:(NSIndexPath *)indexPath {

    UICollectionViewFlowLayout *layout = (UICollectionViewFlowLayout *)collectionViewLayout;
    CGFloat itemWidth = UIEdgeInsetsInsetRect( collectionView.bounds, layout.sectionInset ).size.width;
    return CGSizeMake( itemWidth, 100 );
}

#pragma mark - UICollectionViewDataSource

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {

    return [self.fetchedResultsController.sections count];
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {

    if (![MPiOSAppDelegate get].activeUserOID || !_fetchedResultsController)
        return 0;

    NSUInteger objects = ((id<NSFetchedResultsSectionInfo>)self.fetchedResultsController.sections[section]).numberOfObjects;
    _transientItem = _showTransientItem? objects: NSNotFound;
    return objects + (_showTransientItem? 1: 0);
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {

    MPPasswordCell *cell = [MPPasswordCell dequeueCellFromCollectionView:collectionView indexPath:indexPath];
    if (indexPath.item < ((id<NSFetchedResultsSectionInfo>)self.fetchedResultsController.sections[indexPath.section]).numberOfObjects)
        [cell setSite:[self.fetchedResultsController objectAtIndexPath:indexPath] animated:NO];
    else
        [cell setTransientSite:self.query animated:NO];

    return cell;
}

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind
                                 atIndexPath:(NSIndexPath *)indexPath {

    return [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@"MPPasswordHeader" forIndexPath:indexPath];
}

#pragma mark - UIScrollDelegate

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {

    if (scrollView == self.passwordCollectionView)
        for (MPPasswordCell *cell in [self.passwordCollectionView visibleCells])
            [cell setMode:MPPasswordCellModePassword animated:YES];
}

#pragma mark - NSFetchedResultsControllerDelegate

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath
     forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {

    if (controller == _fetchedResultsController) {
        [self.passwordCollectionView performBatchUpdates:^{
            [self fetchedItemsDidUpdate];
            switch (type) {
                case NSFetchedResultsChangeInsert:
                    [self.passwordCollectionView insertItemsAtIndexPaths:@[ newIndexPath ]];
                    break;
                case NSFetchedResultsChangeDelete:
                    [self.passwordCollectionView deleteItemsAtIndexPaths:@[ indexPath ]];
                    break;
                case NSFetchedResultsChangeMove:
                    [self.passwordCollectionView moveItemAtIndexPath:indexPath toIndexPath:newIndexPath];
                    break;
                case NSFetchedResultsChangeUpdate:
                    [self.passwordCollectionView reloadItemsAtIndexPaths:@[ indexPath ]];
                    break;
            }
        }                                     completion:nil];
    }
}

- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id<NSFetchedResultsSectionInfo>)sectionInfo
           atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type {

    if (controller == _fetchedResultsController)
        [self.passwordCollectionView reloadData];
}

#pragma mark - UISearchBarDelegate

- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar {

    if (searchBar == self.passwordsSearchBar) {
        searchBar.text = nil;
        return YES;
    }

    return NO;
}

- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar {

    if (searchBar == self.passwordsSearchBar) {
        [self.passwordsSearchBar setShowsCancelButton:YES animated:YES];
        [UIView animateWithDuration:0.3f animations:^{
            self.passwordCollectionView.backgroundColor = _darkenedBackgroundColor;
        }];
    }
}

- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar {

    if (searchBar == self.passwordsSearchBar) {
        [self.passwordsSearchBar setShowsCancelButton:NO animated:YES];
        if (_passwordsDismissRecognizer)
            [self.view removeGestureRecognizer:_passwordsDismissRecognizer];

        [self updatePasswords];
        [UIView animateWithDuration:0.3f animations:^{
            self.passwordCollectionView.backgroundColor = _backgroundColor;
        }];
    }
}

- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar {

    searchBar.text = nil;
    [searchBar resignFirstResponder];
}

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar {

    [searchBar resignFirstResponder];
}

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {

    if (searchBar == self.passwordsSearchBar)
        [self updatePasswords];
}

#pragma mark - Private

- (void)fetchedItemsDidUpdate {

    NSString *query = self.query;
    _showTransientItem = [query length] > 0;
    NSUInteger objects = ((id<NSFetchedResultsSectionInfo>)self.fetchedResultsController.sections[0]).numberOfObjects;
    if (_showTransientItem && objects == 1 &&
        [[[self.fetchedResultsController.fetchedObjects firstObject] name] isEqualToString:query])
        _showTransientItem = NO;
    if ([self.passwordCollectionView numberOfSections] > 0) {
        if (!_showTransientItem && _transientItem != NSNotFound)
            [self.passwordCollectionView deleteItemsAtIndexPaths:
                    @[ [NSIndexPath indexPathForItem:_transientItem inSection:0] ]];
        else if (_showTransientItem && _transientItem == NSNotFound)
            [self.passwordCollectionView insertItemsAtIndexPaths:
                    @[ [NSIndexPath indexPathForItem:objects inSection:0] ]];
        else if (_transientItem != NSNotFound)
            [self.passwordCollectionView reloadItemsAtIndexPaths:
                    @[ [NSIndexPath indexPathForItem:_transientItem inSection:0] ]];
    }
}

- (void)registerObservers {

    if ([_notificationObservers count])
        return;

    Weakify( self );
    _notificationObservers = @[
            [[NSNotificationCenter defaultCenter]
                    addObserverForName:UIApplicationWillResignActiveNotification object:nil
                                 queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *note) {
                        Strongify( self );

                        self.passwordSelectionContainer.alpha = 0;
                    }],
            [[NSNotificationCenter defaultCenter]
                    addObserverForName:MPSignedOutNotification object:nil
                                 queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *note) {
                        Strongify( self );

                        _fetchedResultsController = nil;
                        self.passwordsSearchBar.text = nil;
                        [self.passwordCollectionView reloadData];
                    }],
            [[NSNotificationCenter defaultCenter]
                    addObserverForName:UIApplicationDidBecomeActiveNotification object:nil
                                 queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *note) {
                        Strongify( self );

                        [self updatePasswords];
                        [UIView animateWithDuration:1 animations:^{
                            self.passwordSelectionContainer.alpha = 1;
                        }];
                    }],
            [[NSNotificationCenter defaultCenter]
                    addObserverForName:MPCheckConfigNotification object:nil
                                 queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *note) {
                        [self updateConfigKey:note.object];
                    }],
    ];
}

- (void)removeObservers {

    for (id observer in _notificationObservers)
        [[NSNotificationCenter defaultCenter] removeObserver:observer];
    _notificationObservers = nil;
}

- (void)observeStore {

    Weakify( self );

    NSManagedObjectContext *mainContext = [MPiOSAppDelegate managedObjectContextForMainThreadIfReady];
    if (!_mocObserver && mainContext)
        _mocObserver = [[NSNotificationCenter defaultCenter]
                addObserverForName:NSManagedObjectContextDidSaveNotification object:mainContext
                             queue:nil usingBlock:^(NSNotification *note) {
                    if (![[MPiOSAppDelegate get] activeUserInContext:mainContext])
                        [[MPiOSAppDelegate get] signOutAnimated:YES];
                }];
    if (!_storeChangingObserver)
        _storeChangingObserver = [[NSNotificationCenter defaultCenter]
                addObserverForName:NSPersistentStoreCoordinatorStoresWillChangeNotification object:nil
                             queue:nil usingBlock:^(NSNotification *note) {
                    Strongify( self );
                    self->_fetchedResultsController = nil;
                    if (self->_mocObserver)
                        [[NSNotificationCenter defaultCenter] removeObserver:self->_mocObserver];
                    [self.passwordCollectionView reloadData];
                }];
    if (!_storeChangedObserver)
        _storeChangedObserver = [[NSNotificationCenter defaultCenter]
                addObserverForName:NSPersistentStoreCoordinatorStoresDidChangeNotification object:nil
                             queue:nil usingBlock:^(NSNotification *note) {
                    Strongify( self );
                    [self updatePasswords];
                }];
}

- (void)stopObservingStore {

    if (_mocObserver)
        [[NSNotificationCenter defaultCenter] removeObserver:_mocObserver];
    if (_storeChangingObserver)
        [[NSNotificationCenter defaultCenter] removeObserver:_storeChangingObserver];
    if (_storeChangedObserver)
        [[NSNotificationCenter defaultCenter] removeObserver:_storeChangedObserver];
}

- (void)updateConfigKey:(NSString *)key {

    if (!key || [key isEqualToString:NSStringFromSelector( @selector( dictationSearch ) )])
        self.passwordsSearchBar.keyboardType = [[MPiOSConfig get].dictationSearch boolValue]? UIKeyboardTypeDefault: UIKeyboardTypeURL;
    if (!key || [key isEqualToString:NSStringFromSelector( @selector( hidePasswords ) )])
        [self.passwordCollectionView reloadData];
}

- (void)updatePasswords {

    NSString *query = self.query;
    NSManagedObjectID *activeUserOID = [MPiOSAppDelegate get].activeUserOID;
    if (!activeUserOID) {
        PearlMainQueue( ^{
            self.passwordsSearchBar.text = nil;
            [self.passwordCollectionView reloadData];
            [self.passwordCollectionView setContentOffset:CGPointMake( 0, -self.passwordCollectionView.contentInset.top ) animated:YES];
        } );
        return;
    }

    [self.fetchedResultsController.managedObjectContext performBlock:^{
        NSArray *oldSectionInfos = [self.fetchedResultsController sections];
        NSMutableArray *oldSections = [[NSMutableArray alloc] initWithCapacity:[oldSectionInfos count]];
        for (id<NSFetchedResultsSectionInfo> sectionInfo in oldSectionInfos)
            [oldSections addObject:[sectionInfo.objects copy]];

        NSError *error = nil;
        self.fetchedResultsController.fetchRequest.predicate =
                [query length]?
                [NSPredicate predicateWithFormat:@"user == %@ AND name BEGINSWITH[cd] %@", activeUserOID, query]:
                [NSPredicate predicateWithFormat:@"user == %@", activeUserOID];
        if (![self.fetchedResultsController performFetch:&error])
            err( @"Couldn't fetch sites: %@", [error fullDescription] );

        [self.passwordCollectionView performBatchUpdates:^{
            [self fetchedItemsDidUpdate];

            NSInteger fromSections = self.passwordCollectionView.numberOfSections;
            NSInteger toSections = [self numberOfSectionsInCollectionView:self.passwordCollectionView];
            for (NSInteger section = 0; section < MAX( toSections, fromSections ); ++section) {
                if (section >= fromSections)
                    [self.passwordCollectionView insertSections:[NSIndexSet indexSetWithIndex:section]];
                else if (section >= toSections)
                    [self.passwordCollectionView deleteSections:[NSIndexSet indexSetWithIndex:section]];
                else if (section < [oldSections count])
                    [self.passwordCollectionView reloadItemsFromArray:oldSections[section]
                                                              toArray:[[self.fetchedResultsController sections][section] objects]
                                                            inSection:section];
                else
                    [self.passwordCollectionView reloadSections:[NSIndexSet indexSetWithIndex:section]];
            }
        }                                     completion:^(BOOL finished) {
            if (finished)
                [self.passwordCollectionView setContentOffset:CGPointMake( 0, -self.passwordCollectionView.contentInset.top )
                                                     animated:YES];
        }];
    }];
}

#pragma mark - Properties

- (NSString *)query {

    return [self.passwordsSearchBar.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
}

- (NSFetchedResultsController *)fetchedResultsController {

    if (!_fetchedResultsController) {
        _showTransientItem = NO;
        [MPiOSAppDelegate managedObjectContextForMainThreadPerformBlockAndWait:^(NSManagedObjectContext *mainContext) {
            NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:NSStringFromClass( [MPSiteEntity class] )];
            fetchRequest.sortDescriptors = @[
                    [[NSSortDescriptor alloc] initWithKey:NSStringFromSelector( @selector( lastUsed ) ) ascending:NO]
            ];
            fetchRequest.fetchBatchSize = 10;
            _fetchedResultsController = [[NSFetchedResultsController alloc]
                    initWithFetchRequest:fetchRequest managedObjectContext:mainContext sectionNameKeyPath:nil cacheName:nil];
            _fetchedResultsController.delegate = self;
        }];
        [self observeStore];
    }

    return _fetchedResultsController;
}

- (void)setActive:(BOOL)active {

    [self setActive:active animated:NO completion:nil];
}

- (void)setActive:(BOOL)active animated:(BOOL)animated completion:(void ( ^ )(BOOL finished))completion {

    _active = active;

    [UIView animateWithDuration:animated? 0.4f: 0 animations:^{
        [self.navigationBarToTopConstraint updatePriority:active? 1: UILayoutPriorityDefaultHigh];
        [self.passwordsToBottomConstraint updatePriority:active? 1: UILayoutPriorityDefaultHigh];
        [self.view layoutIfNeeded];
    }                completion:completion];
}

#pragma mark - Actions

- (IBAction)dismissPopdown:(id)sender {

    if (_popdownVC)
        [[[MPPopdownSegue alloc] initWithIdentifier:@"unwind-popdown" source:_popdownVC destination:self] perform];
    else
        self.popdownToTopConstraint.priority = UILayoutPriorityDefaultHigh;
}

@end