CoreStore/Sources/Convenience/NSFetchedResultsController+Convenience.swift

//
//  NSManagedObject+Convenience.swift
//  CoreStore
//
//  Copyright © 2015 John Rommel Estropia
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.
//

import Foundation
import CoreData


// MARK: - NSFetchedResultsController

public extension NSFetchedResultsController {
    
    /**
     Utility for creating an `NSFetchedResultsController` from a `DataStack`. This is useful when an `NSFetchedResultsController` is preferred over the overhead of `ListMonitor`s abstraction.
     
     - parameter dataStack: the `DataStack` to observe objects from
     - parameter fetchRequest: the `NSFetchRequest` instance to use with the `NSFetchedResultsController`
     - parameter from: an optional `From` clause indicating the entity type. If not specified, the `fetchRequest` argument's `entity` property should already be set.
     - parameter sectionBy: a `SectionBy` clause indicating the keyPath for the attribute to use when sorting the list into sections.
     - parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
     */
    @nonobjc
    public static func createForStack<T: NSManagedObject>(dataStack: DataStack, fetchRequest: NSFetchRequest, from: From<T>? = nil, sectionBy: SectionBy? = nil, fetchClauses: [FetchClause]) -> NSFetchedResultsController {
        
        return CoreStoreFetchedResultsController(
            context: dataStack.mainContext,
            fetchRequest: fetchRequest,
            from: from,
            sectionBy: sectionBy,
            applyFetchClauses: { fetchRequest in
            
                fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
            }
        )
    }
    
    
    // MARK: Internal
    
    @nonobjc
    internal static func createFromContext<T: NSManagedObject>(context: NSManagedObjectContext, fetchRequest: NSFetchRequest, from: From<T>? = nil, sectionBy: SectionBy? = nil, fetchClauses: [FetchClause]) -> NSFetchedResultsController {
        
        return CoreStoreFetchedResultsController(
            context: context,
            fetchRequest: fetchRequest,
            from: from,
            sectionBy: sectionBy,
            applyFetchClauses: { fetchRequest in
                
                fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
            }
        )
    }
}