/*

 File: EntityModel.m

 Abstract: Provides a simple entity-relationship model for describing 

 records, their attributes and relationships.

 Version: 1.0

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 */ 

// EntitModel maintains an entity-relationship model representation used by a data source

// to define its schema. Uses an Entity object to represent each application entity--defines 

// the entity's properties, including to-one and to-many relationships. This class can be

// used independent of Sync Services.

#import "EntityModel.h"

#import "Entity.h"

static NSString *INDEX_FILE_NAME = @"index.plist";

@implementation EntityModel

// Initializes the entity model representation

- (id)init

{

    self = [super init];

    if (self) {

        _representation = [NSMutableDictionary dictionary];

        [_representation setValue:[NSMutableArray array] forKey:@"entities"];

    }

    return self;

}

- (id)initWithFileWrapper:(id)fileWrapper

{

    self = [super init];

    if (self && [fileWrapper isDirectory]) {

        NSDictionary *wrappers = [fileWrapper fileWrappers];

        NSArray *allKeys = [wrappers allKeys];

        // First set the entity model attributes and initial entities array

        id indexWrapper = [wrappers valueForKey:INDEX_FILE_NAME];

        if (indexWrapper != nil){

            NSData *data = [indexWrapper regularFileContents];

            NSString *error;

            // Convert the raw data to a dictionary

            id dict = (NSDictionary *)CFPropertyListCreateFromXMLData(kCFAllocatorDefault, (CFDataRef)data, 

                                                                      kCFPropertyListMutableContainersAndLeaves, 

                                                                      (CFStringRef *)&error);

            if (error != nil)

                NSLog(@"ERROR in CFPropertyListCreateFromXMLData() decoding entity data: %@", error);

            // Set the properties of the entity model

            _representation = dict;

            [_representation setValue:[NSMutableArray array] forKey:@"entities"];           

        }

        // Now load all the entities, if they exist

        if ([allKeys count] > 1){

            NSEnumerator *enumerator = [[wrappers allKeys] objectEnumerator];

            id key;

            while (key = [enumerator nextObject]) {

                if (![key isEqual:INDEX_FILE_NAME] && [key hasSuffix:@".plist"]){

                    NSData *data = [[wrappers valueForKey:key] regularFileContents];

                    NSString *error;

                    // Convert the raw data to a dictionary

                    id dict = (NSDictionary *)CFPropertyListCreateFromXMLData(kCFAllocatorDefault, (CFDataRef)data, 

                                                                              kCFPropertyListMutableContainersAndLeaves, 

                                                                              (CFStringRef *)&error);

                    if (error !=nil)

                        NSLog(@"error decoding entity: %@", error);

                    // Create and add the entity

                    id entity = [Entity entityWithDictionary:dict];

                    [[self allEntities] addObject:entity];

                }

            }

        }

    }

    return self;

}

// Returns a file wrapper representation of the receiver, where the receiver and

// each entity has its own plist file in the directory.

- (NSFileWrapper *)fileWrapperRepresentation

{

    NSFileWrapper *directoryWrapper = [[NSFileWrapper alloc] initDirectoryWithFileWrappers:nil];

    NSEnumerator *enumerator;

    id entity;

    // Add a file wrapper per entity to the returned directory wrapper

    enumerator = [[self allEntities] objectEnumerator];

    while (entity = [enumerator nextObject]) {

        NSData *data = [entity fileRepresentation];

        [directoryWrapper addRegularFileWithContents:data preferredFilename:

            [[entity valueForKey:@"name"] stringByAppendingPathExtension:@"plist"]];

    }

    // Store the entity model attributes

    // This is sorta klunky

    NSDictionary *attrDict = [NSDictionary dictionaryWithObjectsAndKeys:[self name], @"name", nil];

    NSData *emdata = (NSData *)CFPropertyListCreateXMLData(kCFAllocatorDefault, (CFPropertyListRef)attrDict);

    [directoryWrapper addRegularFileWithContents:emdata preferredFilename:INDEX_FILE_NAME];

    return directoryWrapper;    

}

// Initializes the entity model with the contents of content.

- (id)initWithContentsOfFile:(NSString *)filePath

{

    NSLog(@"filePath=%@", filePath);

    return [self initWithFileWrapper:[[NSFileWrapper alloc] initWithPath:filePath]];

}

- (NSString *)description

{

    NSString *myDescription = [NSString stringWithFormat:@"[\n%@ = %@\n]", 

        @"_representation", [_representation description]];

    return myDescription;

}

- (NSMutableArray *)allEntities

{

    return [_representation mutableArrayValueForKey:@"entities"];

}

// Returns an array of the entity names defined in the entity model

- (NSArray *)entityNames

{

    id values = [[self allEntities] valueForKey:@"entityName"];

    return values;

}

- (NSString *)name

{

    return [_representation valueForKey:@"name"];

}

// Returns the propertyKeys for the specified entity

- (NSArray *)propertyKeysForEntityName:(id)entityName

{

    return [[self entityWithEntityName:entityName] valueForKey:@"propertyKeys"];

}

- (NSArray *)attributeKeysForEntityName:(id)entityName

{

    return [[self entityWithEntityName:entityName] valueForKey:@"attributeKeys"];

}

- (NSArray *)relationshipKeysForEntityName:(id)entityName

{

    id relationshipKeys = [[self entityWithEntityName:entityName] valueForKey:@"relationshipKeys"];

    //NSLog (@"relationshipKeys for entity name=%@ is %@", entityName, [relationshipKeys description]);

    return relationshipKeys;

}

- (void)setName:(NSString *)name

{

    [_representation setValue:name forKey:@"name"];

    return;

}

- (Entity *)entityWithEntityName:(NSString *)entityName

{

    if (entityName == nil) return nil;

    NSEnumerator *enumerator = [[self allEntities] objectEnumerator];

    id entity = [enumerator nextObject];

    while ((entity != nil) && ![[entity valueForKey:@"entityName"] isEqual:entityName]) {

        entity = [enumerator nextObject];

    }

    return entity;  

}

- (Entity *)entityWithName:(NSString *)name

{

    if (name == nil) return nil;

    NSEnumerator *enumerator = [[self allEntities] objectEnumerator];

    id entity = [enumerator nextObject];

    while ((entity != nil) && ![[entity valueForKey:@"name"] isEqual:name]) {

        entity = [enumerator nextObject];

    }

    return entity;  

}

// Archiving support

- (NSData *)xmlValue {

    return (NSData *)CFPropertyListCreateXMLData(kCFAllocatorDefault, (CFPropertyListRef)[self allEntities]);

}

// KVC Compliant Methods

- (id)valueForUndefinedKey:(NSString *)key

{

    NSLog(@"value for undefined key=%@", key);

    return nil;

}

- (void)setValue:(id)value forUndefinedKey:(NSString *)key

{

    NSLog(@"set value for undefined key=%@", key);

    return;

}

- (void)insertObject:(id)anObject inEntitiesAtIndex:(NSUInteger)index 

{

    [[self allEntities] insertObject:anObject atIndex:index];

    return; 

}

- (void)removeObjectFromEntitiesAtIndex:(NSUInteger)index 

{

    [[self allEntities] removeObjectAtIndex:index];

    return; 

}

@end