ARK-OS/arkos/arkrt/ark.ui.basic/Sources/Views/TextField.swift

/// A control that displays an editable text interface.
public struct TextField: ElementaryView, View {
    /// The ideal width of a `TextField`.
    private static let idealWidth: Double = 100

    /// The label to show when the field is empty.
    private var placeholder: String
    /// The field's content.
    @Binding private var text: String

    /// Creates an editable text field with a given placeholder.
    ///
    /// - Parameters:
    ///   - placeholder: The label to show when the field is empty.
    ///   - text: The field's content.
    public init(_ placeholder: String = "", text: Binding<String>) {
        self.placeholder = placeholder
        self._text = text
    }

    /// Creates an editable text field with a given placeholder.
    @available(*, deprecated, renamed: "init(_:text:)")
    public init(_ placeholder: String = "", _ value: Binding<String>? = nil) {
        self.placeholder = placeholder
        var dummy = ""
        self._text = value ?? Binding(get: { dummy }, set: { dummy = $0 })
    }

    /// Creates an editable text field bound to a binary integer value.
    ///
    /// The field's content is kept in sync with `value` via simple string
    /// conversion. When the user enters text that cannot be parsed as the
    /// target integer type, the binding is not updated (the previous value
    /// is preserved), mirroring the behaviour of SwiftUI's
    /// `TextField(_:value:formatter:)` when the formatter fails.
    ///
    /// - Parameters:
    ///   - placeholder: The label to show when the field is empty.
    ///   - value: A binding to the integer value to edit.
    public init<V: BinaryInteger & LosslessStringConvertible>(
        _ placeholder: String = "",
        value: Binding<V>
    ) {
        self.placeholder = placeholder
        self._text = Binding(
            get: { String(value.wrappedValue) },
            set: { newString in
                if let parsed = V(newString), parsed != value.wrappedValue {
                    value.wrappedValue = parsed
                }
            }
        )
    }

    /// Creates an editable text field bound to a binary floating-point value.
    ///
    /// The field's content is kept in sync with `value` via simple string
    /// conversion. When the user enters text that cannot be parsed as the
    /// target floating-point type, the binding is not updated (the previous
    /// value is preserved), mirroring the behaviour of SwiftUI's
    /// `TextField(_:value:formatter:)` when the formatter fails.
    ///
    /// - Parameters:
    ///   - placeholder: The label to show when the field is empty.
    ///   - value: A binding to the floating-point value to edit.
    public init<V: BinaryFloatingPoint & LosslessStringConvertible>(
        _ placeholder: String = "",
        value: Binding<V>
    ) {
        self.placeholder = placeholder
        self._text = Binding(
            get: { String(value.wrappedValue) },
            set: { newString in
                if let parsed = V(newString), parsed != value.wrappedValue {
                    value.wrappedValue = parsed
                }
            }
        )
    }

    func asWidget<Backend: BaseAppBackend>(backend: Backend) -> Backend.Widget {
        return backend.createTextField()
    }

    func computeLayout<Backend: BaseAppBackend>(
        _ widget: Backend.Widget,
        proposedSize: ProposedViewSize,
        environment: EnvironmentValues,
        backend: Backend
    ) -> ViewLayoutResult {
        let naturalHeight = backend.naturalSize(of: widget).y
        let size = ViewSize(
            proposedSize.width ?? Self.idealWidth,
            Double(naturalHeight)
        )

        // TODO: Allow backends to set their own ideal text field width
        return ViewLayoutResult.leafView(size: size)
    }

    func commit<Backend: BaseAppBackend>(
        _ widget: Backend.Widget,
        layout: ViewLayoutResult,
        environment: EnvironmentValues,
        backend: Backend
    ) {
        backend.updateTextField(
            widget,
            placeholder: placeholder,
            environment: environment,
            onChange: { newValue in
                #if DEBUG
                    // We perform this check in debug mode to catch backends that cause
                    // unnecessary binding writes, but avoid doing so in release mode
                    // because comparing text may often be more expensive than just
                    // avoiding the additional write at the backend level. These
                    // additional writes are often the result of the handler being
                    // triggered when we call backend.setContent(ofTextField:to:)
                    if self.text == newValue {
                        logger.warning(
                            """
                            Unnecessary write to text Binding of TextField detected, \
                            please open an issue at \(Meta.issueReportingURL) \
                            so we can fix it for \(type(of: backend)).
                            """
                        )
                    }
                #endif

                self.text = newValue
            },
            onSubmit: environment.onSubmit ?? {}
        )

        let text = text
        if text != backend.getContent(ofTextField: widget) {
            backend.setContent(ofTextField: widget, to: text)
        }

        backend.setSize(of: widget, to: layout.size.vector)
    }
}