RKSearchEngine.m

//
//  RKSearchEngine.m
//  RestKit
//
//  Created by Blake Watters on 8/26/09.
//  Copyright (c) 2009-2012 RestKit. All rights reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

#import "RKSearchEngine.h"

@implementation RKSearchEngine

@synthesize mode;
@synthesize tokenizeQuery;
@synthesize stripsWhitespace;
@synthesize caseSensitive;

+ (id)searchEngine
{
    return [[[RKSearchEngine alloc] init] autorelease];
}

- (id)init
{
    self = [super init];
    if (self) {
        mode = RKSearchModeOr;
        tokenizeQuery = YES;
        stripsWhitespace = YES;
        caseSensitive = NO;
    }

    return self;
}

#pragma mark Private
#pragma mark -

- (NSString *)stripWhitespaceIfNecessary:(NSString *)string
{
    if (stripsWhitespace) {
        return [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    }

    return string;
}

- (NSArray *)tokenizeOrCollect:(NSString *)string
{
    if (self.tokenizeQuery) {
        return [string componentsSeparatedByString:@" "];
    }

    return [NSArray arrayWithObject:string];
}

- (NSArray *)searchWithTerms:(NSArray *)searchTerms onProperties:(NSArray *)properties inCollection:(NSArray *)collection compoundSelector:(SEL)selector
{
    NSPredicate *searchPredicate = nil;

    // do any of these properties contain all of these terms
    NSMutableArray *propertyPredicates = [NSMutableArray array];
    for (NSString *property in properties) {
        NSMutableArray *termPredicates = [NSMutableArray array];
        for (NSString *searchTerm in searchTerms) {
            NSPredicate *predicate;
            if (self.isCaseSensitive) {
                predicate = [NSPredicate predicateWithFormat:@"(%K contains %@)", property, searchTerm];
            } else {
                predicate = [NSPredicate predicateWithFormat:@"(%K contains[cd] %@)", property, searchTerm];
            }
            [termPredicates addObject:predicate];
        }

        // build a predicate for all of the search terms
        NSPredicate *termsPredicate = [NSCompoundPredicate performSelector:selector withObject:termPredicates];
        [propertyPredicates addObject:termsPredicate];
    }

    searchPredicate = [NSCompoundPredicate orPredicateWithSubpredicates:propertyPredicates];
    return [collection filteredArrayUsingPredicate:searchPredicate];
}

#pragma mark Public
#pragma mark -

- (NSArray *)searchFor:(NSString *)searchText inCollection:(NSArray *)collection
{
    NSArray *properties = [NSArray arrayWithObject:@"searchableText"];
    return [self searchFor:searchText onProperties:properties inCollection:collection];
}

- (NSArray *)searchFor:(NSString *)searchText onProperties:(NSArray *)properties inCollection:(NSArray *)collection
{
    NSString *searchQuery = [[searchText copy] autorelease];
    searchQuery = [self stripWhitespaceIfNecessary:searchQuery];
    NSArray *searchTerms = [self tokenizeOrCollect:searchQuery];

    if (mode == RKSearchModeOr) {
        return [self searchWithTerms:searchTerms onProperties:properties inCollection:collection compoundSelector:@selector(orPredicateWithSubpredicates:)];
    } else if (mode == RKSearchModeAnd) {
        return [self searchWithTerms:searchTerms onProperties:properties inCollection:collection compoundSelector:@selector(andPredicateWithSubpredicates:)];
    } else {
        return nil;
    }
}

@end