/*

File: LSMClassifier.h

Abstract: LSMClassifier encapsulates common Latent Semantic Mapping (LSM) 

          framework functionalities. By studying this class, you will see

          how to use LSM framework in common text classification tasks.

Version: 1.0

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*/ 

#ifndef __LSMClassifier__

#define __LSMClassifier__

#import "LSMClassifierResult.h"

/*! @enum Error  codes

 *  @discussion Errors returned by LSMClassifier methods.

 *  @constant kLSMCErr                 Generic error code.

 *  @constant kLSMCDuplicatedCategory  The category to add is already in the map.

 *  @constant kLSMCNoSuchCategory      Invalid category specified.

 *  @constant kLSMCWriteError          An error occurred writing the map

 *  @constant kLSMCBadPath             The URL specified doesn't not exist.

 *  @constant kLSMCNotValidMode        The mode specified is not valid.

 *  @constant kLSMSetModeFailed        Failed to set mode.

 */

enum {

    kLSMCErr                   = 1000,

    kLSMCDuplicatedCategory    = 1001,

    kLSMCNoSuchCategory        = 1002,

    kLSMCWriteError            = 1003,

    kLSMCBadPath               = 1004,

    kLSMCNotValidMode          = 1005,

    kLSMSetModeFailed          = 1006

};

/*!

 * @abstract Indicate the mode the classifier is currently in, traning mode or

 *           evaluation mode.

 */

enum {

    kLSMCTraining = 0,

    kLSMCEvaluation

};

/*!

 * @abstract Encapsulate some common routines of LSM framework.

 */

@interface LSMClassifier : NSObject {

    LSMMapRef map;

    /*!

     * Switching between training and evaluation mode is expensive. We use this to

     * store the current mode, and only switch when necessary. You can also explicitly

     * set the classifier into a particular mode.

     */

    unsigned  currentMode;

    /*!

     * @abstract Category Id to category name map.

     */

    NSMutableDictionary* catIdToNameMap;

    /*!

     * @abstract Category name to category Id map.

     * 

     * So that user can refer to a particular category by a meaningful name.

     */

    NSMutableDictionary* catNameToIdMap;

}

- (id)init;

- (void)dealloc;

/*!

 * @abstract Removed all existing categories, and switch to training mode.

 */

- (void)reset;

/*!

 * @abstract Set classifier mode.

 */

- (OSStatus)setModeTo:(SInt32)mode;

/*!

 * @abstract Add new cateogry.

 * 

 * @return noErr The category was successfully added into the map.

 * @return kLSMCDuplicatedCategory The category name has already existed.

 *

 * If current mode is kLSMCEvaluation, on successful return, this method will set

 * mode to kLSMCTraining.

 */

- (OSStatus)addCategory:(NSString*)name;

/*!

 * @abstract Add training text to category specified by name.

 * @return noErr On success.

 * @return kLSMCNoSuchCategory Specified category doesn't exisit.

 * @return kLSMCErr Other errors.

 *

 * If current mode is kLSMCEvaluation, on successful return, this method will set

 * mode to kLSMCTraining.

 *

 * option can be kLSMTextPreserveCase, kLSMTextPreserveAcronyms 

 * and/or kLSMTextApplySpamHeuristics.

 */

- (OSStatus)addTrainingText:(NSString*)text toCategory:(NSString*)name with:(UInt32)option;

/**!

 * @abstract Evaluate input text and return the results.

 *

 * @param text          Text to be evaluated.

 * @param numOfResults  Maximum number of results to be returned.

 * @param textOption    Option for pre-process of text. It can be kLSMTextPreserveCase,

 *                      kLSMTextPreserveAcronyms and/or kLSMTextApplySpamHeuristics.

 *

 * If current mode is kLSMCTraining, this method will set mode to kLSMCEvaluation.

 */

- (LSMClassifierResult*)createResultFor:(NSString*)text upTo:(SInt32)numOfResults with:(UInt32)textOption;

/**!

 * @abstract Return number of categories in the map.

 */

- (unsigned)numberOfCategories;

/**!

 * @abstract Return category enumerator.

 * 

 * Use [NSEnumerator nextObject] to get the category name string.

 */

- (NSEnumerator*)categoryEnumerator;

/**!

 * @abstract Save the internal data to file, including LSM map and the category

 *           Id-name maps.

 */

- (OSStatus)writeToFile:(NSString*) path;

/**!

 * @abstract Load from specified file, and switch to mode.

 */

- (OSStatus)readFromFile:(NSString*)path with:(unsigned)mode;

@end

#endif //__LSMClassifier__