//
//  UITextView+Publisher.swift
//  VDS
//
//  Created by Matt Bruce on 5/1/24.
//

import Foundation
import UIKit
import Combine

extension UITextView {

    public enum Event {
        case editingChanged
        case editingDidBegin
        case editingDidEnd
    }

    public func publisher(for event: Event) -> AnyPublisher<UITextView, Never> {
        TextViewPublisher(textView: self).publisher(for: event)
    }
}

class TextViewPublisher: NSObject, UITextViewDelegate {
    var textDidChangePublisher: AnyPublisher<UITextView, Never>
    var didBeginEditingPublisher: AnyPublisher<UITextView, Never>
    var didEndEditingPublisher: AnyPublisher<UITextView, Never>
    
    private var cancellables = Set<AnyCancellable>()

    init(textView: UITextView) {
        textDidChangePublisher = NotificationCenter.default.publisher(for: UITextView.textDidChangeNotification, object: textView)
            .compactMap { notification in
                (notification.object as? UITextView)
            }
            .eraseToAnyPublisher()

        didBeginEditingPublisher = NotificationCenter.default.publisher(for: UITextView.textDidBeginEditingNotification, object: textView)
            .compactMap { notification in
                (notification.object as? UITextView)
            }
            .eraseToAnyPublisher()

        didEndEditingPublisher = NotificationCenter.default.publisher(for: UITextView.textDidEndEditingNotification, object: textView)
            .compactMap { notification in
                (notification.object as? UITextView)
            }
            .eraseToAnyPublisher()
    }

    func publisher(for event: UITextView.Event) -> AnyPublisher<UITextView, Never> {
        switch event {
        case .editingChanged:
            return textDidChangePublisher
                .map { $0 }
                .eraseToAnyPublisher()
        case .editingDidBegin:
            return didBeginEditingPublisher
                .map { $0 }
                .eraseToAnyPublisher()
        case .editingDidEnd:
            return didEndEditingPublisher
                .map { $0 }
                .eraseToAnyPublisher()
        }
    }
}