import SwiftUI
import UIKit

struct GiftContactTextField: UIViewRepresentable {
    @Binding var text: String
    let rule: GiftContactInputRule

    func makeCoordinator() -> Coordinator {
        Coordinator(parent: self)
    }

    func makeUIView(context: Context) -> UITextField {
        let textField = UITextField(frame: .zero)
        textField.delegate = context.coordinator
        textField.text = text
        textField.backgroundColor = .clear
        textField.textColor = .white
        textField.font = SodaTypography.body3.localizedFontName()
            .flatMap { UIFont(name: $0, size: SodaTypography.body3.size) }
            ?? UIFont.systemFont(ofSize: SodaTypography.body3.size, weight: .regular)
        textField.autocorrectionType = .no
        textField.autocapitalizationType = .none
        let placeholder: String
        switch rule {
        case .name:
            placeholder = "이름을 입력해 주세요"
            textField.textContentType = .name
        case .phoneNumber:
            placeholder = "휴대폰 번호를 입력해 주세요"
            textField.keyboardType = .numberPad
            textField.textContentType = .telephoneNumber
        }
        textField.attributedPlaceholder = NSAttributedString(
            string: placeholder,
            attributes: [.foregroundColor: UIColor(Color.gray600)]
        )
        textField.setContentHuggingPriority(.defaultLow, for: .horizontal)
        textField.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        textField.addTarget(context.coordinator, action: #selector(Coordinator.textDidChange(_:)), for: .editingChanged)
        return textField
    }

    func updateUIView(_ uiView: UITextField, context: Context) {
        context.coordinator.parent = self
        guard uiView.markedTextRange == nil,
              text != context.coordinator.lastAcceptedText,
              rule.acceptsEditing(text) else { return }
        context.coordinator.lastAcceptedText = text
        if uiView.text != text {
            uiView.text = text
        }
    }

    final class Coordinator: NSObject, UITextFieldDelegate {
        var parent: GiftContactTextField
        var lastAcceptedText: String

        init(parent: GiftContactTextField) {
            self.parent = parent
            lastAcceptedText = parent.rule.acceptsEditing(parent.text) ? parent.text : ""
        }

        func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString replacement: String) -> Bool {
            guard textField.markedTextRange == nil else { return true }
            let current = textField.text ?? ""
            let prospective = (current as NSString).replacingCharacters(in: range, with: replacement)
            return parent.rule.acceptsEditing(prospective)
        }

        @objc func textDidChange(_ textField: UITextField) {
            guard textField.markedTextRange == nil else { return }
            let committed = textField.text ?? ""
            guard parent.rule.acceptsEditing(committed) else {
                textField.text = lastAcceptedText
                return
            }
            lastAcceptedText = committed
            if parent.text != committed {
                parent.text = committed
            }
        }

        func textFieldDidChangeSelection(_ textField: UITextField) {
            textDidChange(textField)
        }

        func textFieldDidEndEditing(_ textField: UITextField) {
            textDidChange(textField)
        }
    }
}