//
//  DurationPicker.swift
//  WorkoutsPlus
//
//  Created by Felix Förtsch on 06.10.24.
//

import SwiftUI

struct NumbersOnlyTextField: View {
		@Binding var value: Double
		@FocusState private var isFocused: Bool
		
		var placeholder = "00:00"
		var formatString = "%.0f"
		
		var body: some View {
				VStack {
						HStack {
								ZStack {
										Rectangle()
												.fill(.quaternary)
												.cornerRadius(8)
												.frame(width: placeholderWidth())
										
										TextField(placeholder, text: Binding(
												get: { String(format: formatString, value) },
												set: { newValue in
														if let doubleValue = Double(newValue.filter { "0123456789.".contains($0) }) {
																value = doubleValue
														}
												}
										))
										.keyboardType(.decimalPad)
										.frame(width: placeholderWidth())
										.multilineTextAlignment(.center)
										.focused($isFocused)
								}
						}
						.onTapGesture {
								isFocused = false
						}
				}
		}
		
		private func placeholderWidth() -> CGFloat {
				let font = UIFont.systemFont(ofSize: UIFont.systemFontSize)
				let attributes = [NSAttributedString.Key.font: font]
				let size = (placeholder as NSString).size(withAttributes: attributes)
				return size.width + 20
		}
}

#Preview {
		@Previewable @State var value: Double = 0
		List {
				NumbersOnlyTextField(value: $value)
		}
}