cog/Spotlight/SpotlightSearchController.m

//
//  SpotlightSearchController.m
//  Cog
//
//  Created by Matthew Grinshpun on 10/02/08.
//  Copyright 2008 __MyCompanyName__. All rights reserved.
//

#import "SpotlightSearchController.h"
#import "SpotlightWindowController.h"
#import "PlaylistLoader.h"
#import "SpotlightPlaylistEntry.h"

// Store a class predicate for searching for music
static NSPredicate * musicOnlyPredicate = nil;

@implementation SpotlightSearchController

+ (void)initialize
{
	musicOnlyPredicate = [[NSPredicate predicateWithFormat:
                        @"kMDItemContentTypeTree==\'public.audio\'"] retain];
    
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    
    // Set the home directory as the default search directory
    NSString * homeDir = @"~";
    homeDir = [homeDir stringByExpandingTildeInPath];
    homeDir = [[NSURL fileURLWithPath:homeDir isDirectory:YES] absoluteString];
    NSDictionary *searchDefault = 
                        [NSDictionary dictionaryWithObject:homeDir
                                                    forKey:@"spotlightSearchPath"];
    [defaults registerDefaults:searchDefault];
}

- (id)init
{
	if (self = [super init]) {
		self.query = [[NSMetadataQuery alloc] init];
        [self.query setDelegate:self];
	}

    return self;
}

- (void)performSearch
{
    // Process the search string into a compound predicate
    NSPredicate *searchPredicate = [self processSearchString];
    
    // Set scope to contents of pathControl
    [self.query setSearchScopes:[NSArray arrayWithObjects:pathControl.URL, nil]];

    // spotlightPredicate, which is what will finally be used for the spotlight search
    // is the union of the (potentially) compound searchPredicate and the static 
    // musicOnlyPredicate
    
    NSPredicate *spotlightPredicate = [NSCompoundPredicate andPredicateWithSubpredicates:
                                       [NSArray arrayWithObjects: musicOnlyPredicate,
                                                            searchPredicate,
                                                            nil]];
    if([self.query isStarted])
        [self.query stopQuery];
    self.query.predicate = spotlightPredicate;
    [self.query startQuery];
    NSLog(@"Started query: %@", [self.query.predicate description], [[self.query class]description]);
}

- (NSPredicate *)processSearchString
{
    // a somewhat dumb way to collapse the whitespace in searchString
    // TODO: write a more elegant way of accomplishing this
    NSString * compareString = [self.searchString 
        stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
        
    NSString * collapsedString = [compareString stringByReplacingOccurrencesOfString:@"  "
                                                                         withString:@" "];
    while (![collapsedString isEqualToString:compareString])
    {
        compareString = [collapsedString copy];
        collapsedString = [compareString stringByReplacingOccurrencesOfString:@"  "
                                                                  withString:@" "];
    }
    
    // break the string up into an array of each word
    NSArray * searchComponents = [collapsedString
        componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    
    // create an array of all the predicates to join together
    NSMutableArray * subpredicates = [NSMutableArray 
        arrayWithCapacity:[searchComponents count]];
    
    // we will ignore case and diacritics
    unsigned options = (NSCaseInsensitivePredicateOption|
						NSDiacriticInsensitivePredicateOption);
    
    for(NSString *s in searchComponents)
    {
        // convert each "word" into "*word*"
        NSString *processedKey = [NSString stringWithFormat: @"*%@*", s];
        
        // Search all tags for something like word
        NSPredicate *predicate = [NSComparisonPredicate
                predicateWithLeftExpression:[NSExpression expressionForKeyPath:@"*"]
                            rightExpression:[NSExpression expressionForConstantValue:processedKey]
                                   modifier:NSDirectPredicateModifier
                                       type:NSLikePredicateOperatorType
                                       options:options];
        
        //TODO: Ability to search only artist, albums, etc.
        [subpredicates addObject: predicate];
    }
    
    if ([subpredicates count] == 1)
        return [subpredicates objectAtIndex: 0];
    
    // Create a compound predicate from subPredicates
    return [NSCompoundPredicate andPredicateWithSubpredicates: subpredicates];
}

- (void)dealloc
{
	[self.query stopQuery];
	[self.query release];
	[self.searchString release];
    [musicOnlyPredicate release];
	[super dealloc];
}

- (IBAction)changeSearchPath:(id)sender
{
    // When the search path is changed, restart search
    if([self.query isStarted]) {
        [self performSearch];
    }
}

- (IBAction)addToPlaylist:(id)sender
{
    [self.query disableUpdates];
    
    NSArray *urls = [[playlistController selectedObjects]valueForKey:@"url"];
    [spotlightWindowController.playlistLoader addURLs:urls sort:NO];
   
   [self.query enableUpdates];
}

#pragma mark NSMetadataQuery delegate methods

// replace the NSMetadataItem with a PlaylistEntry
- (id)metadataQuery:(NSMetadataQuery*)query
replacementObjectForResultObject:(NSMetadataItem*)result
{
    return [SpotlightPlaylistEntry playlistEntryWithMetadataItem: result];
}

#pragma mark Getters and setters

@synthesize query;

@synthesize searchString;
- (void)setSearchString:(NSString *)aString 
{
	if (searchString != aString) {
		searchString = [aString copy];
        [self performSearch];
	}
}

@end