import Cocoa


extension AXError: Error {

}

func copyAttributeValue(_ element: AXUIElement, attribute: String) throws -> AnyObject? {
    var value: AnyObject?
    let error = AXUIElementCopyAttributeValue(element, attribute as CFString, &value)

    if error != .noValue && error != .success {
        print("copyAttributeValue error: \(error.rawValue), attribute: \(attribute), ")
        throw error
    }

    return value
}

func copyParameterizedAttributeValue(_ element: AXUIElement, attribute: String, params: Any) throws -> AnyObject? {
    var value: AnyObject?
    let error = AXUIElementCopyParameterizedAttributeValue(element, attribute as CFString, params as AnyObject, &value)

    if error != .noValue && error != .success {
        print("copyParameterizedAttributeValue error: \(error.rawValue), attribute: \(attribute), ")
        throw error
    }

    return value
}

func findWebArea(app: AXUIElement) -> AXUIElement? {
    var stack: [AXUIElement] = [app]
    while let element = stack.popLast() {
        let roleResult = try! copyAttributeValue(element, attribute: "AXRole")
        let role = roleResult as? String
        if role == "AXWebArea" {
            return element
        }

        let childrenResult = try! copyAttributeValue(element, attribute: "AXChildren")
        if let children = childrenResult as? [AXUIElement] {
            stack.append(contentsOf: children)
        }
    }

    return nil
}


guard let _app = NSWorkspace.shared.runningApplications.first(where: { $0.bundleIdentifier == "com.google.Chrome" }) else {
    fatalError()
}

let pid = _app.processIdentifier
let app = AXUIElementCreateApplication(pid)

let windowResult = try! copyAttributeValue(app, attribute: "AXFocusedWindow")

// investigate: Conditional downcast to CoreFoundation type 'AXUIElement' will always succeed
guard let window = windowResult as! AXUIElement? else {
    fatalError()
}

guard let webArea = findWebArea(app: window) else {
    fatalError()
}

var webAreaElementsResults: AnyObject?
let query: [String: Any] = [
    "AXDirection": "AXDirectionNext",
    "AXImmediateDescendantsOnly": false,
    "AXResultsLimit": -1,
    "AXVisibleOnly": true,
    "AXSearchKey": [
        "AXButtonSearchKey",
        "AXCheckBoxSearchKey",
        "AXControlSearchKey",
        "AXGraphicSearchKey",
        "AXLinkSearchKey",
        "AXRadioGroupSearchKey",
        "AXTextFieldSearchKey",
        "AXStaticTextSearchKey"
    ]
]
AXUIElementCopyParameterizedAttributeValue(webArea, "AXUIElementsForSearchPredicate" as CFString, query as AnyObject, &webAreaElementsResults)
guard let webAreaElements = webAreaElementsResults as! [AXUIElement]? else {
    fatalError()
}

print(webAreaElements.count)