macOS Modal NSAlert with completion handlers

osx-messagebox.swift

// As Modal window:
func messageBox(_ title: String!, message: String! = nil,
                firstOption: String? = nil, secondOption: String? = nil, thirdOption: String? = nil,
                firstAction: (() -> ())? = nil, secondAction: (() -> ())? = nil, thirdAction: (() -> ())? = nil )  {
 
    let alert = NSAlert()
 
    alert.messageText = title ?? ""
    alert.informativeText = message ?? ""
 
    [firstOption, secondOption, thirdOption].forEach { if let option = $0 { alert.addButton(withTitle: option) } }
    [firstAction ?? {}, secondAction ?? {}, thirdAction ?? {}][alert.runModal() - 1000]?()
}

// As Sheet:
func sheetBox(_ title: String!, message: String? = nil,
              firstOption: String? = nil, secondOption: String? = nil, thirdOption: String? = nil,
              firstAction: (() -> ())? = nil, secondAction: (() -> ())? = nil, thirdAction: (() -> ())? = nil )  {
 
    let alert = NSAlert()
 
    alert.messageText = title ?? ""
    alert.informativeText = message ?? ""
 
    [firstOption, secondOption, thirdOption].forEach { if let option = $0 { alert.addButton(withTitle: option) } }
 
    alert.beginSheetModal(for: NSApp.keyWindow!) {
        [firstAction ?? {}, secondAction ?? {}, thirdAction ?? {}][($0 == 0 ? 1000 : $0) - 1000]?()
    }
}

// Usage:
messageBox("You are removing recurring event. What should be done?", message: nil,
 
           firstOption: "Remove this event only",
           secondOption: "Remove all related events",
           thirdOption: "Cancel",
 
   /* UPDATE ONE EVENT */
    firstAction:
    {
 
    },
 
    /* UPDATE ALL EVENTS */
    secondAction:
    {
 
    },
 
    /* CANCELLING - DO NOTHING */
    thirdAction: nil
)

// Both closures and bottons are optional, hence can be omitted:
messageBox("Hello world")