// Usage: WordCount file
// Counts the frequency of case insensitive words in the given input file and prints them
// in descending order of frequency, sorted ascending alphabetically as a second key
//
// David Hutchens
// March 20, 2007

#import <Foundation/Foundation.h>

@interface CountedWord : NSObject {
   NSString *str;
   int cnt;
}
- (id)initWithString:(NSString *)str;
- (NSString *)string;
- (void)incrementCount;
- (int)count;
- (int)compare:(CountedWord *)other;
@end

@implementation CountedWord
- (id)initWithString:(NSString *)theStr {
   [super init];
   str = theStr;
   cnt = 0;
   return self;
}

- (NSString *)string {
   return str;
}

- (void)incrementCount {
   cnt++;
}

- (int)count {
   return cnt;
}

- (int)compare:(CountedWord *)other {
   int oc = [other count];
   if (cnt > oc) {
      return NSOrderedAscending;
   } else if (cnt < oc) {
      return NSOrderedDescending;
   } else {
      return [str compare:[other string]];
   }
}
@end

void printArray (NSArray *countedWordArray) {
   int i, c = [countedWordArray count];
   for (i=0; i < c; i++) {
      CountedWord *cw = [countedWordArray objectAtIndex:i];
      printf("%i\t%s\n", [cw count], [[cw string] cString]);
   }
}

NSArray *sortedArrayFromString(NSString *str) {
   NSArray *theWords = [[str lowercaseString] componentsSeparatedByString:@" "];
   NSMutableDictionary *dict = [NSMutableDictionary dictionary];
   int i, c = [theWords count];
   for (i=0; i < c; i++) {
      NSString *word = [theWords objectAtIndex:i];
      if ( ! [word isEqualToString:@""]) {
         CountedWord *cw = [dict objectForKey:word];
         if (cw == nil) {
            cw = [[CountedWord alloc] initWithString:word];
            [dict setObject:cw forKey:word];
         }
         [cw incrementCount];
      }
   }
   return [[dict allValues] sortedArrayUsingSelector:@selector(compare:)];
}

int main (int argc, const char * argv[]) {
   NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
   NSError *theError = nil;
   NSMutableString *input = [NSMutableString stringWithContentsOfFile:[NSString stringWithCString:argv[1]] encoding:NSNEXTSTEPStringEncoding error:&theError];
   [input replaceOccurrencesOfString:@"\t" withString:@" " options:NSLiteralSearch range:NSMakeRange(0,[input length])];
   [input replaceOccurrencesOfString:@"\r" withString:@" " options:NSLiteralSearch range:NSMakeRange(0,[input length])];
   [input replaceOccurrencesOfString:@"\n" withString:@" " options:NSLiteralSearch range:NSMakeRange(0,[input length])];
   printArray(sortedArrayFromString(input));
   [pool release];
   return 0;
}