ilyrics/iLyrics/Songtexte.m

//
//  Songtexte.m
//  iLyrics
//
//  Created by Kim Wittenburg on 22.06.12.
//  Copyright (c) 2012 __MyCompanyName__. All rights reserved.
//
//  TODO: Implement parsing of multi-page results

#import "Songtexte.h"
#import "SearchResult.h"

@implementation Songtexte {
    NSString *resultsPage;
    BOOL hasMoreResults;
    BOOL hadMoreResults;
}

@synthesize enabled;

-(NSString *) name {
    return @"Songtexte.com";
}

-(NSDate *)hosterVersion {
    return [NSDate dateWithString:@"2012-06-22 15:00:00 +0100"];
}

-(void) startNewSearchForQuery: (NSString *)query {
    NSString *searchPath = [NSString stringWithFormat:@"http://www.songtexte.com/search?c=songs&q=%@", [query stringByFormattingForURL]];
    NSURL *searchURL = [NSURL URLWithString:searchPath];
    NSError *error;
    NSString *page = [NSString stringWithContentsOfURL:searchURL encoding:NSUTF8StringEncoding error:&error];
    if (error || page == nil) {
        //Network or other error
        resultsPage = nil;
        hasMoreResults = hadMoreResults = NO;
    }
    resultsPage = page;
    if ([resultsPage rangeOfString:@"</label>\n</div>\n</div>"].location == NSNotFound) {
        //No Results
        hasMoreResults = hadMoreResults = NO;
    } else {
        hasMoreResults = hadMoreResults = YES;
    }
}

-(BOOL)hasMoreResults {
    return hasMoreResults;
}

-(NSArray *)nextResults {
    if (resultsPage == nil) {
        //Network or other error
        return nil;
    }
    NSRange tableStartRange = [resultsPage rangeOfString:@"</label>\n</div>\n</div>"];
    if (tableStartRange.location == NSNotFound) {
        //No Results
        return [[NSArray alloc] init];
    }
    NSRange tableRange = [self restRangeFromString:resultsPage subtractingRange:tableStartRange];
    int resultsTableStart = NSMaxRange([resultsPage rangeOfString:@"<ul>" options:NSCaseInsensitiveSearch range:tableRange]);
    NSRange resultsTableEndRange = [resultsPage rangeOfString:@"<li id=\"" options:NSCaseInsensitiveSearch range:tableRange];
    if (resultsTableEndRange.location == NSNotFound) {
        resultsTableEndRange = [resultsPage rangeOfString:@"</ul>" options:NSCaseInsensitiveSearch range:tableRange];
    }
    int resultsTableEnd = resultsTableEndRange.location;
    hasMoreResults = NO;
    return [self resultsFromTable:[resultsPage substringWithRange:NSMakeRange(resultsTableStart, resultsTableEnd-resultsTableStart)]];
}

-(NSArray *)resultsFromTable:(NSString *)table {
    NSRange restRange = NSMakeRange(0, [table length]);
    NSMutableArray *tags = [[NSMutableArray alloc] init];
    NSUInteger currentIndex = [table rangeOfString:@"<li>"].location;
    while (currentIndex != NSNotFound) {
        int startIndex = currentIndex + [@"<li>" length];
        int endIndex = [table rangeOfString:@"</li>" options:NSCaseInsensitiveSearch range:restRange].location;
        NSRange tagRange = NSMakeRange(startIndex, endIndex-startIndex);
        SearchResult *result = [self searchResultFromTag:[table substringWithRange:tagRange]];
        if (result) {
            [tags addObject:result];
        }
        restRange = [self restRangeFromString:table subtractingRange:tagRange];
        restRange.length -= [@"</li>" length];
        restRange.location += [@"</li>" length];
        currentIndex = [table rangeOfString:@"<li>" options:NSCaseInsensitiveSearch range:restRange].location;
    }
    return tags;
}

-(SearchResult *) searchResultFromTag: (NSString *)tag {
    NSRange artistStartRange = [tag rangeOfString:@"Songtexte, Übersetzungen, Lyrics\"><span>"];
    NSRange artistEndRange = [tag rangeOfString:@"</span>" options:NSCaseInsensitiveSearch range:[self restRangeFromString:tag subtractingRange:artistStartRange]];
    int artistStart = NSMaxRange(artistStartRange);
    NSString *artist = [[tag substringWithRange:NSMakeRange(artistStart, artistEndRange.location-artistStart)] stringByRemovingHTMLTags];
    NSRange songLinkStartRange = [tag rangeOfString:@"<a" options:NSCaseInsensitiveSearch range:[self restRangeFromString:tag subtractingRange:artistEndRange]];
    /*if ([tag rangeOfString:@"title=\"zum Song (noch kein Songtext vorhanden)\"" options:NSCaseInsensitiveSearch range:[self restRangeFromString:tag subtractingRange:songLinkStartRange]].location != NSNotFound) {
        return nil;
    }*/
    //This would remove entries which does not exist anymore.
    //The Problem: hasMoreResults woult also return YES if there is only one result (no matter if existing or not).
    NSRange hrefStartRange = [tag rangeOfString:@"href=\"" options:NSCaseInsensitiveSearch range:[self restRangeFromString:tag subtractingRange:songLinkStartRange]];
    NSRange hrefEndRange = [tag rangeOfString:@"\"" options:NSCaseInsensitiveSearch range:[self restRangeFromString:tag subtractingRange:hrefStartRange]];
    int hrefStart = NSMaxRange(hrefStartRange);
    NSString *linkHref = [tag substringWithRange:NSMakeRange(hrefStart, hrefEndRange.location-hrefStart)];
    NSRange nameStartRange = [tag rangeOfString:@"<span>" options:NSCaseInsensitiveSearch range:[self restRangeFromString:tag subtractingRange:hrefEndRange]];
    NSRange nameEndRange = [tag rangeOfString:@"</span>" options:NSCaseInsensitiveSearch range:[self restRangeFromString:tag subtractingRange:nameStartRange]];
    int nameStart = NSMaxRange(nameStartRange);
    NSString *name = [[tag substringWithRange:NSMakeRange(nameStart, nameEndRange.location-nameStart)] stringByRemovingHTMLTags];
    return [[SearchResult alloc] initWithName:name fromArtist:artist preview:nil link:[self urlFromHref:linkHref] loadedByHoster:self];
}

-(NSURL*) urlFromHref: (NSString *) link {
    if (![link hasPrefix:@"http://www.songtexte.com"]) {
        return [NSURL URLWithString:[NSString stringWithFormat:@"http://www.songtexte.com/%@", link]];
    } else {
        return [NSURL URLWithString:link];
    }
}

-(NSRange) restRangeFromString: (NSString *) page subtractingRange: (NSRange) aRange {
    int loc = NSMaxRange(aRange);
    return NSMakeRange(loc, [page length]-loc);
}

-(void)resetLoadedResults {
    hasMoreResults = hadMoreResults;
}

-(Lyrics *)lyricsBySearchResult:(id)result {
    NSError *error;
    NSString *page = [NSString stringWithContentsOfURL:[result link] encoding:NSUTF8StringEncoding error:&error];
    if (error || page == nil) {
        return nil;
    }
    NSRange lyricsStartRange = [page rangeOfString:@"<div id=\"lyrics\">"];
    NSRange lyricsEndRange = [page rangeOfString:@"</div>" options:NSCaseInsensitiveSearch range:[self restRangeFromString:page subtractingRange:lyricsStartRange]];
    int lyricsStart = NSMaxRange(lyricsStartRange);
    NSString *lyrics = [[page substringWithRange:NSMakeRange(lyricsStart, lyricsEndRange.location-lyricsStart)] stringByRemovingHTMLTags];
    return [[Lyrics alloc] initWithName:[result name] byArtist:[result artist] withLyrics:lyrics];
}

-(BOOL)canShowInBrowser:(id)result {
    return YES;
}

-(void)showInBrowser:(id)result {
    [[NSWorkspace sharedWorkspace] openURL:[result link]];
}

@end