RxSwift/RxCocoa/iOS/UITableView+Rx.swift

//
//  UITableView+Rx.swift
//  RxCocoa
//
//  Created by Krunoslav Zaher on 4/2/15.
//  Copyright (c) 2015 Krunoslav Zaher. All rights reserved.
//

#if os(iOS) || os(tvOS)

import Foundation
#if !RX_NO_MODULE
import RxSwift
#endif
import UIKit

// Items

extension UITableView {
    
    /**
    Binds sequences of elements to table view rows.
    
    - parameter source: Observable sequence of items.
    - parameter cellFactory: Transform between sequence elements and view cells.
    - returns: Disposable object that can be used to unbind.
    */
    public func rx_itemsWithCellFactory<S: SequenceType, O: ObservableType where O.E == S>
        (source: O)
        (cellFactory: (UITableView, Int, S.Generator.Element) -> UITableViewCell)
        -> Disposable {
        let dataSource = RxTableViewReactiveArrayDataSourceSequenceWrapper<S>(cellFactory: cellFactory)
    
        return self.rx_itemsWithDataSource(dataSource)(source: source)
    }

    /**
    Binds sequences of elements to table view rows.
    
    - parameter cellIdentifier: Identifier used to dequeue cells.
    - parameter source: Observable sequence of items.
    - parameter configureCell: Transform between sequence elements and view cells.
    - returns: Disposable object that can be used to unbind.
    */
    public func rx_itemsWithCellIdentifier<S: SequenceType, Cell: UITableViewCell, O : ObservableType where O.E == S>
        (cellIdentifier: String)
        (source: O)
        (configureCell: (Int, S.Generator.Element, Cell) -> Void)
        -> Disposable {
        let dataSource = RxTableViewReactiveArrayDataSourceSequenceWrapper<S> { (tv, i, item) in
            let indexPath = NSIndexPath(forItem: i, inSection: 0)
            let cell = tv.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! Cell
            configureCell(i, item, cell)
            return cell
        }
        
        return self.rx_itemsWithDataSource(dataSource)(source: source)
    }
    
    /**
    Binds sequences of elements to table view rows using a custom reactive data used to perform the transformation.
    
    - parameter dataSource: Data source used to transform elements to view cells.
    - parameter source: Observable sequence of items.
    - returns: Disposable object that can be used to unbind.
    */
    public func rx_itemsWithDataSource<DataSource: protocol<RxTableViewDataSourceType, UITableViewDataSource>, S: SequenceType, O: ObservableType where DataSource.Element == S, O.E == S>
        (dataSource: DataSource)
        (source: O)
        -> Disposable  {
        return source.subscribeProxyDataSourceForObject(self, dataSource: dataSource, retainDataSource: false) { [weak self] (_: RxTableViewDataSourceProxy, event) -> Void in
            guard let tableView = self else {
                return
            }
            dataSource.tableView(tableView, observedEvent: event)
        }
    }
}

extension UITableView {
 
    /**
    Factory method that enables subclasses to implement their own `rx_delegate`.
    
    - returns: Instance of delegate proxy that wraps `delegate`.
    */
    override func rx_createDelegateProxy() -> RxScrollViewDelegateProxy {
        return RxTableViewDelegateProxy(parentObject: self)
    }
    
    /**
    Reactive wrapper for `dataSource`.
    
    For more information take a look at `DelegateProxyType` protocol documentation.
    */
    public var rx_dataSource: DelegateProxy {
        return proxyForObject(self) as RxTableViewDataSourceProxy
    }
   
    /**
    Installs data source as forwarding delegate on `rx_dataSource`.
    
    It enables using normal delegate mechanism with reactive delegate mechanism.
    
    - parameter dataSource: Data source object.
    - returns: Disposable object that can be used to unbind the data source.
    */
    public func rx_setDataSource(dataSource: UITableViewDataSource)
        -> Disposable {
        let proxy: RxTableViewDataSourceProxy = proxyForObject(self)
            
        return installDelegate(proxy, delegate: dataSource, retainDelegate: false, onProxyForObject: self)
    }
    
    // events
    
    /**
    Reactive wrapper for `delegate` message `tableView:didSelectRowAtIndexPath:`.
    */
    public var rx_itemSelected: ControlEvent<NSIndexPath> {
        let source = rx_delegate.observe("tableView:didSelectRowAtIndexPath:")
            .map { a in
                return a[1] as! NSIndexPath
            }

        return ControlEvent(source: source)
    }
 
    /**
    Reactive wrapper for `delegate` message `tableView:commitEditingStyle:forRowAtIndexPath:`.
    */
    public var rx_itemInserted: ControlEvent<NSIndexPath> {
        let source = rx_dataSource.observe("tableView:commitEditingStyle:forRowAtIndexPath:")
            .filter { a in
                return UITableViewCellEditingStyle(rawValue: (a[1] as! NSNumber).integerValue) == .Insert
            }
            .map { a in
                return (a[2] as! NSIndexPath)
        }
        
        return ControlEvent(source: source)
    }
    
    /**
    Reactive wrapper for `delegate` message `tableView:commitEditingStyle:forRowAtIndexPath:`.
    */
    public var rx_itemDeleted: ControlEvent<NSIndexPath> {
        let source = rx_dataSource.observe("tableView:commitEditingStyle:forRowAtIndexPath:")
            .filter { a in
                return UITableViewCellEditingStyle(rawValue: (a[1] as! NSNumber).integerValue) == .Delete
            }
            .map { a in
                return (a[2] as! NSIndexPath)
            }
        
        return ControlEvent(source: source)
    }
    
    /**
    Reactive wrapper for `delegate` message `tableView:moveRowAtIndexPath:toIndexPath:`.
    */
    public var rx_itemMoved: ControlEvent<ItemMovedEvent> {
        let source: Observable<ItemMovedEvent> = rx_dataSource.observe("tableView:moveRowAtIndexPath:toIndexPath:")
            .map { a in
                return ((a[1] as! NSIndexPath), (a[2] as! NSIndexPath))
            }
        
        return ControlEvent(source: source)
    }
    
    /**
    Reactive wrapper for `delegate` message `tableView:didSelectRowAtIndexPath:`.
    
    It can be only used when one of the `rx_itemsWith*` methods is used to bind observable sequence.
    
        tableView.rx_modelSelected(MyModel.self)
            .map { ...

    If custom data source is being bound, new `rx_modelSelected` wrapper needs to be written also.
    
        public func rx_myModelSelected<T>() -> ControlEvent<T> {
            let source: Observable<T> = rx_itemSelected.map { indexPath in
                let dataSource: MyDataSource = self.rx_dataSource.forwardToDelegate() as! MyDataSource
    
                return dataSource.modelAtIndex(indexPath.item)!
            }
            
            return ControlEvent(source: source)
        }
    
    */
    public func rx_modelSelected<T>(modelType: T.Type) -> ControlEvent<T> {
        let source: Observable<T> = rx_itemSelected.flatMap { [weak self] indexPath -> Observable<T> in
            guard let view = self else {
                return empty()
            }

            return just(try view.rx_modelAtIndexPath(indexPath))
        }
        
        return ControlEvent(source: source)
    }
    
    /**
     Synchronous helper method for retrieving a model at indexPath through a reactive data source
     */
    public func rx_modelAtIndexPath<T>(indexPath: NSIndexPath) throws -> T {
        let dataSource: RxTableViewReactiveArrayDataSource<T> = castOrFatalError(self.rx_dataSource.forwardToDelegate(), message: "This method only works in case one of the `rx_items*` methods was used.")
        
        guard let element = dataSource.modelAtIndex(indexPath.item) else {
            throw RxCocoaError.ItemsNotYetBound(object: self)
        }
        
        return element
    }
}

#endif

#if os(tvOS)
    
    extension UITableView {
        
        /**
         Reactive wrapper for `delegate` message `tableView:didUpdateFocusInContext:withAnimationCoordinator:`.
         */
        public var rx_didUpdateFocusInContextWithAnimationCoordinator: ControlEvent<(context: UIFocusUpdateContext, animationCoordinator: UIFocusAnimationCoordinator)> {
            
            let source = rx_delegate.observe("tableView:didUpdateFocusInContext:withAnimationCoordinator:")
                .map { a -> (context: UIFocusUpdateContext, animationCoordinator: UIFocusAnimationCoordinator) in
                    let context = a[1] as! UIFocusUpdateContext
                    let animationCoordinator = a[2] as! UIFocusAnimationCoordinator
                    return (context: context, animationCoordinator: animationCoordinator)
            }
            
            return ControlEvent(source: source)
        }
    }
#endif