import UIKit

extension RDEPUBReaderController {

    func openExternalURLIfAllowed(_ url: URL) {
        guard shouldAllowExternalURL(url) else { return }
        if configuration.requiresExternalLinkConfirmation {
            presentExternalLinkConfirmation(for: url)
        } else {
            UIApplication.shared.open(url, options: [:], completionHandler: nil)
        }
    }

    private func shouldAllowExternalURL(_ url: URL) -> Bool {
        guard let scheme = url.scheme?.lowercased() else { return false }
        if delegate?.epubReader(self, shouldOpenExternalURL: url) == false {
            return false
        }
        return configuration.allowedExternalURLSchemes.contains(scheme)
    }

    private func presentExternalLinkConfirmation(for url: URL) {
        let alert = UIAlertController(
            title: "打开外部链接",
            message: url.absoluteString,
            preferredStyle: .alert
        )
        alert.addAction(UIAlertAction(title: "取消", style: .cancel))
        alert.addAction(UIAlertAction(title: "打开", style: .default) { _ in
            UIApplication.shared.open(url, options: [:], completionHandler: nil)
        })
        present(alert, animated: true)
    }
}