//
//  RKFetchRequestMappingCache.m
//  RestKit
//
//  Created by Jeff Arena on 1/24/12.
//  Copyright (c) 2009-2012 RestKit. All rights reserved.
//

#import "RKFetchRequestManagedObjectCache.h"
#import "NSManagedObject+ActiveRecord.h"
#import "NSEntityDescription+RKAdditions.h"
#import "RKLog.h"

// Set Logging Component
#undef RKLogComponent
#define RKLogComponent lcl_cRestKitCoreData

@implementation RKFetchRequestManagedObjectCache

- (NSManagedObject *)findInstanceOfEntity:(NSEntityDescription *)entity
                  withPrimaryKeyAttribute:(NSString *)primaryKeyAttribute
                                    value:(id)primaryKeyValue
                   inManagedObjectContext:(NSManagedObjectContext *)managedObjectContext
{
    NSAssert(entity, @"Cannot find existing managed object without a target class");
    NSAssert(primaryKeyAttribute, @"Cannot find existing managed object instance without mapping that defines a primaryKeyAttribute");
    NSAssert(primaryKeyValue, @"Cannot find existing managed object by primary key without a value");
    NSAssert(managedObjectContext, @"Cannot find existing managed object with a context");

    NSFetchRequest* fetchRequest = [[NSFetchRequest alloc] init];
    [fetchRequest setEntity:entity];
    [fetchRequest setFetchLimit:1];
    [fetchRequest setPredicate:[NSPredicate predicateWithFormat:@"%K = %@", primaryKeyAttribute, primaryKeyValue]];
    NSArray *objects = [NSManagedObject executeFetchRequest:fetchRequest];
    RKLogDebug(@"Found objects '%@' using fetchRequest '%@'", objects, fetchRequest);
    [fetchRequest release];

    NSManagedObject *object = nil;
    if ([objects count] > 0) {
        object = [objects objectAtIndex:0];
    }
    return object;
}

@end