vlc-ios/VLC for iOS WatchKit Extension/VLCWatchTableController.m

/*****************************************************************************
 * VLCWatchTableController.m
 * VLC for iOS
 *****************************************************************************
 * Copyright (c) 2015 VideoLAN. All rights reserved.
 * $Id$
 *
 * Author: Tobias Conradi <videolan # tobias-conradi.de>
 *
 * Refer to the COPYING file of the official project for license.
 *****************************************************************************/

#import "VLCWatchTableController.h"


@interface VLCWatchTableController()

@property (nonatomic, copy, readwrite) NSArray *displayedObjects;
@property (nonatomic, copy, readwrite) NSIndexSet *displayedIndexes;

@end

@implementation VLCWatchTableController


- (void)setObjects:(NSArray *)objects {
    _objects = [objects copy];
    [self updateTable];
}


- (void)updateTable {

    NSUInteger pageSize = self.pageSize;
    NSUInteger currentPage = self.currentPage;
    NSUInteger startIndex = self.currentPage*pageSize;
    NSUInteger objectsCount = self.objects.count;

    /* calculate a valid start index and reset current page if needed */
    while (startIndex > objectsCount) {
        if (startIndex < pageSize) {
            startIndex = 0;
            currentPage = 0;
        } else {
            startIndex -= pageSize;
            currentPage--;
        }
    }

    /* calculate valid end index */
    NSUInteger endIndex = startIndex+pageSize;
    if (endIndex > objectsCount) {
        endIndex = objectsCount;
    }

    /* set starte for previous and next buttons */
    self.previousPageButton.hidden = currentPage > 0;
    self.nextPageButton.hidden = endIndex < objectsCount;

    /* get new dispayed objects */
    NSRange range = NSMakeRange(startIndex, endIndex-startIndex);
    NSArray *newObjects = [self.objects subarrayWithRange:range];
    NSMutableSet *newSet = [[NSMutableSet alloc] initWithArray:newObjects];

    NSArray *oldObjects = self.displayedObjects;
    NSSet *oldSet = [[NSSet alloc] initWithArray:oldObjects];

    WKInterfaceTable *table = self.table;

    [oldObjects enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        if (![newSet containsObject:obj]) {
            [table removeRowsAtIndexes:[NSIndexSet indexSetWithIndex:idx]];
        }
    }];

    [newObjects enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        if (![oldSet containsObject:obj]) {
            NSString *rowType = [self rowTypeForObject:obj];
            [table insertRowsAtIndexes:[NSIndexSet indexSetWithIndex:idx] withRowType:rowType];
        }
        [self configureTableCellAtIndex:idx withObject:obj];
    }];

    self.displayedObjects = newObjects;
    self.displayedIndexes = [NSIndexSet indexSetWithIndexesInRange:range];
}


- (void)nextPageButtonPressed {
    NSUInteger nextPageStartIndex = self.pageSize * (self.currentPage+1);
    if (nextPageStartIndex > self.objects.count) {
        return;
    }
    self.currentPage = self.currentPage+1;
    [self updateTable];
}

- (void)previousPageButtonPressed {
    if (self.pageSize>0) {
        self.pageSize = self.pageSize-1;
        [self updateTable];
    }
}

#pragma mark - internal helper

- (NSString *)rowTypeForObject:(id)object {
    if (self.rowTypeForObjectBlock) {
        return self.rowTypeForObjectBlock(object);
    }
    NSAssert(self.rowType, @"Either rowTypeForObjectBlock or rowType must be set");
    return self.rowType;
}

- (void)configureTableCellAtIndex:(NSUInteger)index withObject:(id)object {
    VLCWatchTableControllerConfigureRowControllerWithObjectBlock configureBlock = self.configureRowControllerWithObjectBlock;
    NSAssert(configureBlock, @"configureRowControllerWithObjectBlock must be set");
    if (configureBlock) {
        id rowController = [self.table rowControllerAtIndex:index];
        configureBlock(rowController, object);
    }
}

@end